PDA

View Full Version : G&g Gr-25



Dirus
09-11-2006, 09:33 PM
After a little delay, my new G&G GR-25 sniper rifle is here. I have to say, it's build quality is the best I've seen in an airsoft gun yet. It almost feels like it was CNC machined. It is pretty weak compared to my MP5, but a simple M120 spring upgrade is in store. Tomorrow I'll get a scope and possibly a bipod and RIS grip from some gun store that's close by.

I will keep y'all posted on any upgrades I do to it.

HammerHead
09-11-2006, 10:46 PM
Based on experiences with another G&G GR25:

1. Loctite the motor set screw in place, with red Loctite. The screw tends to drift.

2. Keep a cleaning rod handy at skirmishes. The stock barrel seems a bit sensitive.

3. Be wary of the stock, it may need some epoxy work to shore it up.

shakman
09-12-2006, 08:02 AM
Other things to watch for:

1. Piston head might be very undersized and not giving adaquate compression. Replacement might be necessary.

2. Stock hopup bucking with undersized nub combined with a weak hopup design make for no backspin on the BB even at full-on. If you replace it with a Guarder clear bucking, that should take care of the problem.

AustinWolv
09-12-2006, 09:42 AM
By the way, I have the replacement size of the pistonhead oring at home that I'll try to post later, found at hardware stores. That should save on replacing the entire pistonhead.

Dirus
09-12-2006, 01:28 PM
Took off the upper receiver, but can't go any further, as the screw to loosen the stock is deep and my long screwdriver doesn't fit good enough for a grip. Took a few pictures of various pieces. It has a nice black painted mechbox and a high torque motor. Motor plate and mechbox use hex screws.

Mad Irishman
09-12-2006, 05:53 PM
Threadlock is the way to go but I would recommend Blue as it's classified as "removable" and Red as "permanent"

Blue - http://www.loctiteproducts.com/products/detail.asp?catid=10&subid=48&plid=153

Red - http://www.loctiteproducts.com/products/detail.asp?catid=10&subid=48&plid=154

Just remember they both are packaged in a red tube! :p

Ronin
09-12-2006, 08:11 PM
Instead of advice, I'm just going to have to say: Damn sexy rifle!

HammerHead
09-12-2006, 08:34 PM
Threadlock is the way to go but I would recommend Blue as it's classified as "removable" and Red as "permanent"
Blue - http://www.loctiteproducts.com/products/detail.asp?catid=10&subid=48&plid=153
Red - http://www.loctiteproducts.com/products/detail.asp?catid=10&subid=48&plid=154
Just remember they both are packaged in a red tube! :p

Sorry, Irish, Red Loctite:


OEM specified as 271
High temperature, high strength for heavy duty applications
Designed for larger fasteners 3/8" to 1" (9.5mm to 25mm)
Locks studs, bushings and large fasteners against vibration loosening
Strengthens slip and light press fits
Removable with heat and hand tools


1. The stock motor set screw on the G&G GR25 is not the small grub screw more commonly used. It's a larger diameter (about 1/2" or so).
2. One of the primary factors that causes set screws to back out of place is vibration from the motor itself.
3. Red Loctite is removeable. It requires very little force to remove a fastener to which it's been applied. I use it all the time.

Dirus
09-12-2006, 08:47 PM
What a chore to open this gun up. Nothing like my MP5, but I guess it wouldn't be. The stock is completely hollow, so one shouldn't have any problems fitting even a large +10V battery. Silencer has foam inside, however I don't believe it does any sound muffling. Two places I had to add a little lube gel was the outside of the inner barrel and slider that opens the hopup door, since they sound like grinding metal when moved. Just a tab of lube on each did the trick. Piston grip is made out of nice heavy plastic.


Upgrades:
Systema M120S spring
Aluminum piston (Swapped from MP5)
Metal spring guide (Swapped from MP5)
The stock piston and spring guide are plastic, and the piston has the o-ring issue, but I decided to pop in the upgraded pieces from my MP5, since it will only be pulling an M90 spring from now on and won't need the better pieces. The GR25 fires a lot better now, but hopup needs a new bucking, just like you said shakman. AustinWolv, if you can dig up the o-ring size, that would be great.

AustinWolv
09-12-2006, 09:05 PM
Look for size AS568A dash number 116 for the oring.

Example from one source: P/N 9452K28 (http://www.mcmaster.com/itm/find.ASP?tab=find&context=psrchDtlLink&fasttrack=False&searchstring=9452K28) from Mcmaster.com

Size:
Width
3/32"
Actual Width
.103"
Inside Diameter
3/4"
Actual Inside Diameter
.737"
Outside Diameter
15/16"
Actual Outside Diameter
.943"
Material
Buna-N

Mad Irishman
09-12-2006, 09:34 PM
HH, if you say red is the one you would use, I would differ to your judgment as you have infinitely more experience working on AEGs than me. But....having said that, blue is easier unscrew than red. I have a tube of 242 blue that says "removable" and a tube of 271 red that say "high strength" and "permanent". The FAQ on the loctite site gives this info:

How can I remove Loctite Threadlockers?

Blue: Can be removed with hand tools
Red: Apply heat to remove
Green: Apply heat to remove

I'm not trying to break your...er, you know. :p I just want to make sure your saying it's OK to go with red as I've never used it on any of my airsoft equipment.

HammerHead
09-12-2006, 11:05 PM
Well, the information I quoted came directly from the two links you provided in your earlier post ;). Part of it from the link for the blue option, part from red. For my own part - I have been using the thread lock for several years now. Ever since my G3's set screw began slipping on a regular basis.

I've never found it necessary to apply heat to the screw to adjust it. Nor have I had to apply severe force. Some force is required, but that is to be expected, given the purpose of the material.

Red Loctite was recommended to me, simply because blue had not held up well in this application and purple (I believe) was entirely too difficult to remove.

I'm more inclined to recommend red Loctite for the GR25, because of the larger diameter set screw (I have installed similar floor plates on both my HK416D receiver set and my LR300 and used red Loctite on both with great results) and because of the vibration it will have hold up against. Although, vibration in a semi-auto only application will be reduced, the torque required to drive a higher spring could result in increased movement.

Dirus
09-13-2006, 12:31 AM
Well, after spending an hour looking at different online retailers for buckings, I finally fixed it myself. Don't know if it's just my gun, but the hopup knob doesn't turn with even force. Turned it all the way (it gets tough to turn half way), but now hopup is applied nicely. I don't see this bucking working on heavier BBs once I upgrade it, but for now it works good with these .25gs. Guarder buckings aren't all that easy to find. Found some retailers that carry them, but they don't have anything else I need. Will get the Prometheus hard-type bucking from AirsoftAtlanta, along with some other gear I need.

Questions time:
Can anyone suggest a good bipod for under $60?
What are some good +.25g BBs to use once it is over 450FPS?
What's the delivery time on WGC shop orders? They have some nice stuff.

AustinWolv
09-13-2006, 05:52 AM
What are some good +.25g BBs to use once it is over 450FPS?
A number of options:
http://www.lonestarairsoft.com/forums/showthread.php?t=3956
I have quite a few Maruzen SGM .29g that I could sell as well if you want to give those a shot.

HammerHead
09-13-2006, 07:24 AM
Will get the Prometheus hard-type bucking from AirsoftAtlanta, along with some other gear I need.
Questions time:
Can anyone suggest a good bipod for under $60?
What are some good +.25g BBs to use once it is over 450FPS?
What's the delivery time on WGC shop orders? They have some nice stuff.

1. Don't get hung up on the bucking's brand. Odds are the Prometheus bucking will do just as well. Shak recommended the Guarder bucking because that's what he installed in Big Lucky's GR25. Personally, I prefer Prometheus and haven't had a problem with one of their bucking's in my G3 at all.

2. There are plenty of bipods out there for various uses. I recommend visiting Academy, Cabella's and other sporting good stores to examine your options. Though it is likely most of those options will use a sling mount, rather than a rail mount.

3. I use .25 g and .28 g BBs in my MSG90, which currently chronos around 480FPS consistently. I'd suggest taking advantage of Wolv's offer to purchase and try some .29 g BBs from him.

4. WGC shop orders usually arrive in about a week, depending on when you place the order, their holiday schedule and how quickly you complete the transaction with them. We placed a large order last Thursday and expect it to arrive in the next 24 hours or so.

Dirus
09-13-2006, 11:00 AM
I took the stock G&G piston, spring and spring guide and put them into my MP5. After about 10 shots, it locked up. Reminded me of when I cracked my sector gear, so I was getting very worried. Fuse was still OK, so I decided to open the mechbox again. Guess G&G internals are complete crap. The spring somehow get its end off the side of the guide and wedged itself between the guide and the piston, locking it in place. When I opened the box, it didn't even pop out. Piston, spring and guide came out as one piece... I took the piston head off (in anticipation of putting on a new o-ring), and found it to be fractured in many places. The cracks are radiating outwards from the center, leading me to believe they came from the factory like that (when center metal piece was inserted into plastic head, it was slightly too large and fractured all the plastic pieces). Guess I will order an aluminum head too.

AustinWolv
09-13-2006, 11:13 AM
Guess G&G internals are complete crap.
http://www.austinairsoft.com/forums/showpost.php?p=47304&postcount=5

miguel
09-13-2006, 07:49 PM
What are some good +.25g BBs to use once it is over 450FPS?

G&P .28
Thats all I use in my rifle so I have nothing to compare them to. Someone else might have a better sugestion.

AustinWolv
09-13-2006, 08:35 PM
G&P .28g are one of the brands measured in that link above. :)

Dirus
10-05-2006, 05:49 PM
Ok, received my order of upgrades, and just got the rifle put back together.

The results from the coke can chrono were encouraging. Judging from RedwolfAirsoft article, I'm shooting over 500 FPS.

Had some issues with the 10.8V battery I ordered. It was in a long stick arrangement, but that was 1 inch too long for my stock. Rewired it into a 3x3 design so it fits perfectly, with room to spare. However, one of the batteries just lost contact, so it's not working. I will look into that later. After putting in the upgrades, I tried my 8.4V, which managed to pull the spring without a problem. Fired about 20 rounds (doing the chrono), then the fuse blew (15A). Is it because I'm using a lower voltage battery, tougher spring, or is it something different? I shimmed the gears perfectly, so I doubt thatís the problem.

Couldn't use the bushings that came with the gear set, as the G&G box uses 7mm bearings. Should I upgrade the bearings? What is a good brand/type for DMRs?

Upgrades just installed:
Prometheus M150 spring
Prometheus triple torque gear set (includes piston, piston head, spring guide, anti-reversal latch, shims, 6mm bushings)
G&P M140 torque motor (Couldn't find a store with Systema Super Torques in stock, and this was suggested to me on another forum)
Guarder tappet plate

shakman
10-05-2006, 07:01 PM
The results from the coke can chrono were encouraging. Judging from RedwolfAirsoft article, I'm shooting over 500 FPS.
Before you field it, please make sure you properly chrono it to make sure you're under TASO limits.


Had some issues with the 10.8V battery I ordered
I'm not sure a 10.8v will have enough voltage to push back that spring. It certainly won't on mine. I had to go to a 12v.


then the fuse blew (15A). Is it because I'm using a lower voltage battery, tougher spring, or is it something different?
It's probably because you drained your battery trying to use a 8.4v to drive that spring. What I suspect happened is that the battery lost it's power while the spring was mostly compressed. It couldn't develop the force to drive the spring back anymore, but it was still drawing amps causing the fuse to blow.


Should I upgrade the bearings?
No, but I would recommend swapping out the bearings for straight bushings. Bearings can be problematic.

AustinWolv
10-05-2006, 07:45 PM
images/styles/graydeluxe/misc/quotestr70/06.png Quote: images/styles/graydeluxe/misc/quotestr70/08a.png

images/styles/graydeluxe/misc/quotestr70/12.png



Had some issues with the 10.8V battery I ordered

images/styles/graydeluxe/misc/quotestr70/01.png
images/styles/graydeluxe/misc/quotestr70/03.png I'm not sure a 10.8v will have enough voltage to push back that spring. It certainly won't on mine. I had to go to a 12v.
With the right gear and motor combo, the 10.8v will power it just fine, especially if the pack has decent capacity and discharge rate.

You are dead-on with the 8.4v pack explanation.

Does the GR25 have bearings or bushing in it currently? 7mm bearings, of good quality which is an unknown in a G&G gun as far as I'm concerned, would be acceptable. Howver, since they are an unknown, metal bushings would be a more reliable route.

Dirus
10-05-2006, 11:52 PM
They are 7mm bearings. The ones that came with the gearset are bearing also, I noticed.

I will fix my 10.8V battery tomorrow (one connection needs re-soldering). It's 3000mAh with high power output, so it should be sufficient. If not, I can always buy another cell and link it up for 12V. But seeing a 8.4V pull the spring, I don't think I'll to. I've stuck in a 20A fuse now (only spares I had), so it should be more tolerant.

Dirus
10-17-2006, 11:50 PM
A new problem has come to light. After a few shots, it stops firing completely. I don't think it is due to the voltage being lower than 12V. When I pull the trigger, the motor doesn't even budge, even though it is getting power. If I take out the motor plate, lower and raise the motor back into the gearbox, it works again. Even my semi-drained 8.4V can pull a few more shots, until the same happens. Could the helical gears be the culprit? Or the bearings? Hoping to have my rifle up and running for OP:DV.

beensniped
10-19-2006, 11:19 AM
Welcome to the world of G&G GR-25. I've had one for a year now that has only been fielded once because of the prob. after prob. and prob. If you figure out how to get it all working let us know and good luck.. I just gave up.

Dirus
10-19-2006, 12:45 PM
Well, I took apart the mechbox, looked around, reshimmed and relubed the gears. Readjusted the motor height (probably the problem). Fired about 100 rounds without a problem. I will take it out to OP: DV, and give it a field test.

I was expecting to run into many problems with this GR-25, but I think I've ironned them out now.

shakman
10-19-2006, 12:54 PM
I just gave up.

Looking to unload one on the cheap? :D

Seriously, it can be done to make it work properly. I worked on BigLucky's for a while and it's working quite nicely now. Best bet it to replace all the G&G internals with something decent, like Prometheus.

beensniped
10-20-2006, 10:23 PM
Yeah that is what I've figured out. Right now I'm looking for a new trigger/internal wiring harness and I figured out a standard M-16 one wont fit. So I'm on the prowl again.

HackerZC
01-24-2007, 12:07 PM
From what I understand, the GR25 uses a longer nozzle and cylinder head right? Well how much longer?
I'm seriosuly thinking of getting a G&G SR25 this weekend and wanted to stick a systema complete mecha-box in the thing. So before I spend like $800, where can I get a longer nozzle and cylinder head to stick in the systema box... or can you at all?

Would getting a G&P SR-25 just be a better option?
I'm trying to setup a DMR at 500fps per TASO rules.

shakman
01-24-2007, 12:28 PM
From what I understand, the GR25 uses a longer nozzle and cylinder head right? Well how much longer?
*This much*

The only thing different between that cylinder head and nozzle and the standard v2 cylinder head and nozzle is length. Your best bet is to order the parts you need from http://www.wgcshop.com or http://www.redwolfairsoft.com. You will need these parts if you purchase a standard v2 gearbox in order to work in the GR25.


Would getting a G&P SR-25 just be a better option?
If you find one, let me know. They haven't been available for some time. I would suspect the G&P would be a better AEG, but I don't have any firsthand knowledge of that one in particular.

AustinWolv
01-24-2007, 12:36 PM
Another option is to wait for CA's version.

HackerZC
01-24-2007, 03:47 PM
Well I have access to a G&P SR-25, and the CA25 (they are both available from over seas). The reason I was so set on the G&G was because of the body (knowing I'd have to rip out the internals).
I know the G&P has an extended mechbox which makes it different from any other box out there, and the CA I know almost nothing about except that it's more expensive than the G&G lol.

Dark Paladin
01-24-2007, 03:54 PM
The CA's internals tend to be of higher quality than G&G's. The only thing you'd really have to be concerned about is the hopup bucking that CA uses. And even then there's a fair chance you'd get a decent hopup instead of having to replace it.

HackerZC
01-24-2007, 05:00 PM
Well the question is does the the CA still use the V2 mechbox, and is the air nozzle and cylinder head any longer than the standard ones used in a v2 mechbox?

Dirus
01-24-2007, 09:55 PM
You do not want to keep the GR-25 internals, the pistonhead was cracked in mine, and the gears stripped only after 100 rounds (teeth snapped off the sector gear). If those new Systema complete gearboxes had been out when I got mine, I would have gotten one in a heartbeat.

The GR-25 uses a standard V2 mechbox, but the nozzle and cylinder head are slightly longer. If you get a replacement box, just swap in those two pieces and you are set to go. You can order replacement pieces directly from G&G, if you ever feel inclined. Don't think I've ever seen aftermarket GR-25 nozzles and cylinderheads.

A GR-25 with a Systema M170 Magnum drop-in mechbox, using the stock nozzle/cylinderhead, and a M150 spring should work perfectly. Other than that, only other things you might upgrade is the barrel and hopup bucking. The GR-25 body is amazing compared to other (CA/ICS etc) metal bodies. Haven't handled any G&P products, so I can't compare.

Hope this helps.

HackerZC
01-25-2007, 08:47 AM
It actually does quite a bit Dirus. All the searching I've done over the past two weeks have brought up a lot of your posts on the subject, and that's really what I've been going by.
I was planning on doing pretty much exactly what you recommend (getting the systema complete mech box) and totally replacing the internals. I was planning on the m150, but I guess that getting the m170 box saves you money on the motor (something I had not thought about till now). I was looking for some sort of confirmation that the long nozzle would work fine with the systema box and you've pretty much given me that much.
I was looking at the G&P, but honestly I have to say the G&G interests me more. I can get the G&G stateside for $200 less than the G&P from china (that's before shipping).
Do you know how to get in contact with G&G about getting those parts? www.guay2.com does not seem to work. I'd honestly like to get two sets (one to put in the systema box, and one for replacement). But word is G&G is hard to get a hold of.
Thanks again!

AustinWolv
01-25-2007, 09:19 AM
If you are making this into a high-powered rifle, Prometheus parts are a better route than Systema, in terms of gears and pistons.

HackerZC
01-25-2007, 09:43 AM
I'm going for 500fps with .20's (though I'll be using .36 or so)
If I were to go that route what would you recommend as a good reinforced gearbox?
The advantage of the systema is that it's a complete box, and overall is less expensive than piecing something together (that's my main reason for wanting to go with the systema box). But considering it will be very powerful (previously the highest I've gone in an AEG is 400fps) I might as well do whatever will make it more reliable.

I find myself asking if maybe it wouldn't just be better to get an all metal saw (I have a star MKII, but it's not metal) considering how much this is all going to cost lol. I really want a DMR though, it's the only thing I don't have.

Village
01-25-2007, 09:47 AM
HackerZC: try accessing G&G through their business site, http://b2b.guay2.com. They have a contact form there that might help a little more.

AustinWolv
01-25-2007, 11:11 AM
I'm going for 500fps with .20's (though I'll be using .36 or so)
If I were to go that route what would you recommend as a good reinforced gearbox?
The advantage of the systema is that it's a complete box, and overall is less expensive than piecing something together (that's my main reason for wanting to go with the systema box). But considering it will be very powerful (previously the highest I've gone in an AEG is 400fps) I might as well do whatever will make it more reliable.

I find myself asking if maybe it wouldn't just be better to get an all metal saw (I have a star MKII, but it's not metal) considering how much this is all going to cost lol. I really want a DMR though, it's the only thing I don't have.
First, Ver2 mechbox shells will break. It does not matter what parts are in them or who made the shell out of the various airsoft manufacturers. There is one however mentioned below that was created to fill that void.

Second, after you nail down the shell issue or just learn to live with it, the parts you put into that shell are what you want to be the most reliable, well-made that your budget can afford so you aren't having to consistently replace parts. In my experience, Prometheus are the best of the bunch out there, and Systema is overpriced for what you get compared to the life versus cost ratio.

If you end up wanting an Armalite-style DMR, you should consider looking into this shell: http://www.andairsoft.com/preoraaexv2b.html
Conversely, consider guns of the Ver3 mechbox variety, as thestock Ver3 shell is much more robust than stock Ver2 shells.

Lastly, no matter how much money you pour into the project, remember that these are high-impact mechanical parts with a finite life. They will break eventually.

Typically, creating a reliable 500fps/.2g DMR semi-auto AEG is relatively expensive, any route you go. There is no getting around that. About the cheapest route you can go for a sniper rifle is upgrading a VSR-10 but obviously that is bolt-action.

HackerZC
01-25-2007, 02:33 PM
Wolv:
Honestly I'm sick of armalites, but I like the look of the SR25, it's beefy. This is pretty much a gift for myself, and if I wanted it bad enough I'd get the Barret (I can afford it) but I'm not crazy enough to spend that much on a single gun... not yet anyway.
So the Version 3... what uses that? The G36 if I remember correctly but that's the only one I know about.
I've had people recommend the M14 but it's not really my cup of tea (the EBR is hot, but again, the price is way up there).
I already have a VSR-10 G-Spec that's fully upgraded so I'm trying to stay away from the pure sniper rifles (was looking at a pre-ban Tanaka m700 AICS, but after upgrades and mags, it would cost the same as a semi-auto AEG).
So really my mind is open to other possibilities... I'm just being picky is all.

Village:
Thanks for the link!

AustinWolv
01-25-2007, 02:37 PM
Ver3 - G36 series; AK series; AUG

Dirus
01-25-2007, 09:57 PM
After working on a V3 mechbox, it does appear a lot more durable. Unfortunately there aren't too many options that include it. Might want to take a look at the SL8/9, look pretty decent for a DMR.

Despite Prometheus internals being of better quality, I still suggest the Systema Magnum kit. It will save you a lot of time piecing together all the parts you'd need to upgrade in the mechbox.

Suggested upgrade parts for the GR-25 if not getting a complete drop-in kit:
Tappet plate, gears, bushings (7mm), motor, piston, piston head, spring guide, spring, shims, and the mechbox wires (heat up a lot after a few shots, it's only 22awg).

I am currently rewiring it myself, so I might even install a MOSFET if I can fit the proper wiring. Installed some 14awg copper strand wiring from Home Depot, but it is too thick to fit in the handgrip next to the motor. Can either rewire with 16/18awg or use 18awg just for the grip section.

HackerZC
01-26-2007, 07:10 PM
BTW, where typically does the V2 gearbox break?

HammerHead
01-26-2007, 07:30 PM
I've had two break on me, this is the worst case scenario:

http://www.lonestarairsoft.com/forums/photopost/showphoto.php/photo/1950/si/bad%20gearbox/what/allfields

HackerZC
01-26-2007, 07:47 PM
Ouch. So basicly the impact from the spring just snaps the front off?
And here I was expecting the mech box to rip itself apart with shredded metal all over the place.

Have you been using a reinforced mechbox or just regular ones? What were you running and how long did they last?
With all the talk of the v2 failing I'm giving serious consideration so a G36 sniper (not SL8/9, but actual G36 with super long barrel and such).

AustinWolv
01-27-2007, 09:53 AM
Have you been using a reinforced mechbox or just regular ones? It doesn't matter. Any commonly available Ver2 out there has exhibited that failure at some point.
The only one I have not heard of breaking is the billet CNC one linked to earlier.


What were you running and how long did they last? It will vary some. I've had a stock one break at just over 30,000 rounds with a M120 and metal bushings upgrade, had another stock one break in the lower 20,000 round range with same upgrade, and have seen several others break in that same 20,000-30,000 round range at the same upgrade level. With a stock spring or something like a M100-level, they'll last for multiples past that mark.
With a heavier spring than M120, I don't have raw data to share at each spring level.

HackerZC
01-27-2007, 01:41 PM
Looks like I'm gonna have to get a bunch of new mechbox's then. I have a couple guns running m120's.
Mind you one is my P90 (not sure how the v6 hold up, I've had no problems so far though) and an ICS M4 with it's v7 split gear box (that one you just replace the top, so it's very simple).

I'm going through and pricing my options now. In the end I want the longest gun (for accuracy) with the highest duribility possible. Know anything about the PSG-1 mechbox?

AustinWolv
01-27-2007, 02:03 PM
You need to note we are talking specifically about Ver2 mechbox shells above, not Ver6 or Ver7 or Ver1 or Ver-whatever. ;)

I have not owned the PSG-1, although some members on this forum have, so they can speak better to it. Doing some research here and other forums will help with that.

HackerZC
01-27-2007, 02:12 PM
Yeah I know, but if the failure is in the front of the mechbox, I'm fairly sure the v6 is even weaker in that area (as the metal is not as heavy as in the V2 if I remember correctly), and the v7 is basicly a split V2 with a slightly different motor angle.
Hope that makes sense.

But yeah I'm searching PSG-1 stuff right now. Again not really my thing but it would fit the "long" roll, and I hear it's tough... but we'll see what more have to say.
I've also contacted MTHaynes about that CNC mechbox and the possibility of using it in the GR25. With any luck he'll get back to me fairly quickly.

Dirus
04-04-2007, 12:20 AM
My Guarder SP160 spring (530FPS) just came in the mail today, and I promptly installed it, along with my new KA 7mm bushings. This spring is a LOT harder to get into the mechbox than the 400FPS ones, took a good 20 mins before I could figure out a way to prevent it from flying out when closing the shell. I reshimmed and relubed the gearbox in the process. After getting everything back together, I pulled the trigger and... It compressed the spring, but then stopped before it could even cycle once.

Can Prometheus Triple Torque gears pull such a spring with a 10.8V? I tried to daisy chain two 8.4V batteries together with bare wire, but they were also unsuccessful in pulling the spring (probably a lot of power lost due to bad contacts). I'm wondering if I need to sell these gears and get some max/infinite gear ratios.

With all this trouble, the MGC4AEG conversion kit is looking more and more tempting.

Edit:
The description of the triple torque gears say they can pull MS150 springs. But being Prometheus, their MS150 spring is only rated at 400FPS. Also forgot to note that the fuse blew right after the motor stopped. I will open the mechbox again tomorrow to see if anything is out of place. I know new springs tend to shoot 'hot', is there a way to break in the spring without running it through the mechbox?

shakman
04-04-2007, 07:09 AM
Welcome to the fun that's called DMR's! :D

Gear shimming becomes critical when dealing with higher strength springs like the one you bought. Too much, and the gears won't turn. Not enough, and the gears will destroy themselves by grinding against each other. Sounds to me like you've got too much.


Can Prometheus Triple Torque gears pull such a spring with a 10.8V?
In theory, yes. The Prometheus triple-torque gears should eat anything you feed it. However, the gears will only generate the torque needed as long as the motor itself has the torque to overcome the forces involved. Is it the stock motor or did you upgrade it also?

As far as the battery goes, the V-Match that I worked on for a while will not run with anything but a 12v battery when I dropped the M150 spring in it. However, my M21 is just fine with Prometheus double torque gears and a 9.6v battery. So again, in theory, you should be fine with your 10.8v as long as the discharge rate of the cells is high enough. You really want something that's got at least a 30A discharge rate to ensure you are getting the power needed to drive that spring.

Have fun!

AustinWolv
04-04-2007, 07:16 AM
With all this trouble, the MGC4AEG conversion kit is looking more and more tempting. Trust me, it isn't. I'll update that thread with details in the near future.

Learn how to shim a mechbox, list what motor you have, and you'll be fine.


But being Prometheus, their MS150 spring is only rated at 400FPS Where did you see this? Because you are wrong, especially considering that I've gotten Prometheus MS135s to power guns doing 430-460fps/.2g.

Dirus
04-04-2007, 08:59 AM
Where did you see this? Because you are wrong, especially considering that I've gotten Prometheus MS135s to power guns doing 430-460fps/.2g.
From personal experience and is also listed on a few sites too. For the longest time I thought my rifle had issues.
http://www.redwolfairsoft.com/redwolf/airsoft/ProductDetail?prodID=12952

I've got a G&P M140 motor, supposedly just as good as a Systema STU. I'll reshim the gears again and see how it works.

AustinWolv
04-04-2007, 10:31 AM
That is a shame that info is wrong, as is your experience. You shouldn't believe everything that retailers put on their sites. If you did, Evike would sell the greatest products known in the industry.

Here's the airsoftcanada spring chart: http://arniesairsoft.co.uk/?filnavn=/articles/newbie_guide/faq/spring_guide.htm

It further backs up my point, showing a Promethus MS120 doing 420fps/.2g.

Your rifle does have issues if it is only doing 400fps/.2g with a Prometheus MS150. Most likely, you have air seal problems.

A Prometheus MS150 spring will do well over 400fps/.2g, as it will do more in the 500fps/.2g neighborhood and over if other good parts are chosen and assembled well.


've got a G&P M140 motor, supposedly just as good as a Systema STU
Have you found data to support that "supposedly"? Honest question, as I have not used that motor in any of my guns. Just curious since there are a lot of "supposedlys" in airsoft forum heresay that is often false and just passed around as gospel. If you have exhausted other possibilities, you may want to borrow a motor from someone to give it a shot.

Dirus
04-04-2007, 11:09 AM
The Prometheus MS150 I have seems easy to compress. Didn't notice any difference compare to my Systema M120S. This new Guarder SP160 however, is a lot stiffer than both. If the MS150 is truly 150m/s, then the Guarder might be mislabelled.

If reshimming doesn't work, I might just order a new Systema motor. My MP5 needs a new motor (Turbo2000 finally died), and this G&P works well in it. Not sure if the Magnum motors are worth the extra $30 over the STU. Off I go to find reviews and prices.

AustinWolv
04-04-2007, 11:12 AM
Take a look at the Eagle Force motors; they work well and don't have a "sweet spot" operation period as much as the regular (non-Magnum) Systema motors do.

It is entirely feasible that the springs were mislabeled, as it has definitely happened before. The difference between a M120-level spring and a M150-level spring is noticeable by feel alone.

Dark Paladin
04-04-2007, 12:09 PM
From personal experience and is also listed on a few sites too. For the longest time I thought my rifle had issues.

And my personal experience says a MS120 will do 380fps with .25g. I'd say your rifle still has issues.

Dirus
05-13-2007, 12:40 PM
Upgraded the wiring to 16AWG tin-coated copper wiring and installed a Systema Magnum motor. I have to say, the Magnum is really powerful. It puts the G&P M140 motor to shame. It pulls the 530-FPS spring with my 8.4V 10A battery without a problem. The M140 couldn't pull this spring even with the 12V 35A battery. The Magnum provides faster trigger response with the 530 spring than the M140 did with the 400 spring.

Now I'm not sure which battery is best to use, seeing how even my lowest battery can power it. 8.4V, 10.8V or 12V? Trigger response is quite fast with the 8.4V (can pull the spring even when it's mostly compressed), and lightning fast with the 10.8V and 12V. Could using the higher voltage battery cause damage?

RoyalGoat
03-12-2008, 06:27 PM
Well, I realize that this is ancient but it has been a great source of information for me thus far. I've had a GR-25 for about a year and a half now and I am looking to upgrade it to around 450. From what it seems, the general agreement is to get the drop in Systema Gear box and then swap out the cylinder head and nozzle into it. This I can do but I am curious as to which Systema box I should get, I am not sure whether or not to get the M16 VN version or the M4/SR15 version, from the descriptions and the pictures I see no difference between the two.

Secondly, would I be better of getting the M120 gearbox and buying an M130 spring or get the M150 box and getting a lighter spring?

And, would a 9.6v3600 Intellect battery pull the necessary setup or would a 10.8 be required?

Thanks

AustinWolv
03-12-2008, 08:34 PM
A 9.6v pack would drive a M130 just fine.

However, you cannot drop in a typical Ver2 mechbox into the GR-25, because the GR-25 uses a longer mechbox shell due to the 7.62mm form factor than the typical Ver2 which is based on the 5.56mm form factor:
http://www.wgcshop.com/pcart/shopper.php?itm=GP-ACC-SR25RGB_cat_Gearboxs

shakman
03-12-2008, 08:43 PM
Actually, that's not entirely correct. The G&G GR25 uses a standard v2 mechbox shell with an elongated nozzle. The G&P SR25, on the other hand, uses the elongated mechbox (that's what CA based their CA25 on.)

So, you can get the standard v2 mechbox if you want, but you still have to crack it open to put in the proper nozzle and cylinder head.

AustinWolv
03-12-2008, 09:01 PM
Doh, I was thinking of the G&P. Apologies.

DarthRobby
03-12-2008, 09:19 PM
If you still need a bipod, I am selling one on ebay.
Here it is, if you want it. (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MESEX:IT&item=290213956065&_trksid=p3984.cSELL.m315.lVI)

RoyalGoat
03-12-2008, 11:18 PM
Alright, so the Systema Gearbox will work (with the replacing of the cylinder and nozzle), but which model of the Box should I get the SR-15 version or the M16A1 version? I see no obvious difference but for a price like that I need to be positive.

Also, would the stock cylinder and nozzle work or would others be necessary?

AustinWolv
03-13-2008, 02:06 AM
Main difference between the two is cutouts in the SR15 shell to support popping open the upper receiver from the lower receiver, like TM AEGs do to mimic how you open up real-steel AR15s. There is a nozzle length difference between the M16VN/XM and the M16A2/M4/SR15 as well due to their hopup chamber styles.

As I understand it, the G&G GR-25 doesn't open up that way anyway, as the upper and lower receiver slide apart. Thus, you can use either of those mechboxes since you'll be replacing the nozzle with the GR-25 version anyway.

RoyalGoat
04-01-2008, 11:35 PM
Well, looks like the planned upgrade is going on hold for a while... I was recently working on my GR25 in my garage and someone... closed the garage door, snapping the reciever in two near the stock. Now I am left with a gun with a broken reciever, a receiver which I cannot find anywhere, even through my contact with G&G, they do not have one available. So, I am wondering if it would be a decent decision (or viable for that matter) to choose a standard M4 reciever (SR15 preferably) and use the existing gearbox, stock, barrel/RIS, silencer, etc from the original GR25. Any thoughts? Any ideas? Will this even work?

Thanks