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View Full Version : CA M15 400fps upgrade question(s)



shakman
03-15-2005, 11:38 AM
I'm considering upgrading my stock CA M15 to ~400fps.

I know that it's possible to increase the muzzle energy by just replacing the spring, but is that the recommended way to go? What parts do y'all recommend (other than what's already posted in the forums)?

Would the best way to upgrade this AEG be to crack open the mechbox and replace/upgrade internals, or just swap out the spring? Being this is my first time doing an upgrade, is it recommended that I have it done professionally or do it myself?

I want to make sure I do this the right way, so any and all suggestions are appreciated!

Thanx,
Hial

AustinWolv
03-15-2005, 11:49 AM
EEG AEG. ;)


I know that it's possible to increase the muzzle energy by just replacing the spring, but is that the recommended way to go? Yes, for the M15 since it is supposed to have metal bushings already.


What parts do y'all recommend (other than what's already posted in the forums)? How old is your M15? After working on a new one this past weekend, my gut feeling was to replace the piston and pistonhead. However, that was merely based on my impressions of those parts. Thus, you *really* only need to change out the spring, while ensuring your M15 indeed has metal bushings. I would recommend changing out the hopup bucking to a Guarder one if you can. The CA one feels and looks like they chopped up an old tire and stuffed it in there. Their hop packing wasn't even sized well.


Being this is my first time doing an upgrade, is it recommended that I have it done professionally or do it myself? That varies from person to person. Just depends on how mechanically inclined you happen to be. Some people just have trouble working on guns, while others can do it just fine on their first attempt. Following the guide on ASP is all you need. However, if you don't feel you are too good working on things, airsoftworx.com or perhaps a local experienced player can help you out easily.

DarkPaw
03-15-2005, 12:21 PM
First, you do know that to upgrade your spring you will have to open the mechbox right? If you didn't, now you do. And putting a harder spring is really the only way to increase muzzle velocity (significantly).

Things to think about... harder springs cause more wear and tear on your internals... gears and pistons need replacing sooner ect. Your Classic Army should have a version two gearbox, (I'm thinking the gearbox shell may be a little stronger than a stock tokyo marui- someone with more CA experience can correct me) and putting your velocity to 400fps is hitting the upper limits as far as gearbox strain is concerned. (I personally know of 4 cracked gearboxes within the last 4 months- two mp5s, 1 m4 variant, and 1 G3 SG1... all tokyo marui with stock gearboxes, upgraded to m120 spring and metal bushings) I have a TM AUG, I opted to go the middle way and put in a PDI 140% spring... I shoot around 345fps. ( I also have some other internal stuff- deepfire nylon piston, guarder aluminum piston head with bearing, guarder steel bushings, prometheus spring guide, guarder cylinder head, and a guarder air nozzle)

As far as upgrading yourself... you definitely need someone with experience to help you disassemble and reassemble a gearbox the first time, unless you are very good with reading a description online and translating it to real world mechanics. If you're not mechanically gifted, I don't suggest doing it yourself at all... there are some more technical issues like proper shimming and tricky monkey springs. Anyways...

Spring- main controlling factor of velocity
Other internals may add some small change, like a spring guide with a bearing, a piston head with a bearing, a tightbore inner barrel, and proper gear shimming, each of these can contribute a small amount of fps as well.

All you really need for an upgrade is a spring (I like PDIs just remember that their ratings are different than the systema- PDI 170% appox. equal to systema M120), and metal bushings. ( I think your CA should already have metal bushings) I would recommend a spring guide with bearing also.

Hope that helps... DarkPaw

AustinWolv
03-15-2005, 12:32 PM
To clarity, any Ver2 mechbox shell will crack eventually. Yes, even reinforced ones. It doesn't happen overly frequently, but it will happen. The Ver3 mechbox is much more stout and can take a serious beating, even with M150 springs. That is what the AUG has, so DarkPaw is being overly cautious, which is not a bad thing at all as he'll get long life from his internals.

When keeping the stock gears and just changing the spring to a M120 or equivalent, the gears very rarely have to be reshimmed. That only needs to occur if the gears were improperly shimmed to begin with, which might not be all that surprising given CA's history. However, ANY time that gears are changed out, they need to be reshimmed.

shakman
03-17-2005, 09:23 AM
How old is your M15?

It's new. I just got it about 2 weeks before OP:PF.

Based on what has been said, I've decided to go ahead and replace the hopup bucking, install an M120, and possibly replace the piston and head. I figure this will get me where I want to be and will give me some experience inside the mechbox.

Thanks to all who replied!
Hial

Marimba
03-17-2005, 11:48 AM
About a year ago I dropped an M-120 into my CA M15A4. I did not re-shim it. My rifle has the 7mm bearings in it. I used that rifle every weekend for 11 months, and have had only one problem...the hop-up rubber. The CA hop-up rubber is pretty crappy in my opinion. I too switched over to the clear Guarder hop bucking, and my rifle has worked well ever since. I now use Guarder buckings in all of my rifles. Please be careful of the charging handle spring when disassembling/reassembling your gun. It is easy to strech-out.

AustinWolv
03-17-2005, 12:07 PM
Good news, as that means that CA is learning how to shim their guns properly, just like the CA I worked on this past weekend.

cleanshot
03-19-2005, 09:43 AM
Like Marimba I too have replaced my spring and have had no problems out of my CA M15 (well other than a fried motor due to my errors). As for the mechbox and internal from what I have been told, and Wolv correct me if I have some bad info, the mech box is reinforced, it does have metal bushings, metal spring guide, and the piston and piston head are suppose to be poly carbon already. The mechbox looks to be identical to the Systema reinforced mechbox that I purchased from Airsoftworx, but looks can be deceiving.

AustinWolv
03-19-2005, 10:13 AM
Posted above guys:
To clarify, any Ver2 mechbox shell will crack eventually. Yes, even reinforced ones.
Yes, the CA mechbox is supposed to be a reinforced version. Theirs holds out quite well supposedly, but even it is susceptible to cracking near the nozzle.

They do have metal bushings, which I confirmed working on one last weekend. Same with metal spring guide, which looks the same as the Area1000 spring guide. The piston and pistonhead are not impressive however. I would recommend leaving those parts in there and seeing how they hold out.

swampdonkey
03-19-2005, 10:39 AM
I know this is a little off topic on this thread but how would you go about getting the wires through the foregrip when taking the two halfs apart?

shakman
03-19-2005, 12:51 PM
I know this is a little off topic on this thread but how would you go about getting the wires through the foregrip when taking the two halfs apart?

Actually, I found out just last night that there are 2 quick connectors that just slide together (I'm sure that there's a technical name for them, but I can't think of it right now) :rolleyes: . You can disconnect these 2 wires, then the receiver halves will come apart.

After that, the gun disassembles quite easilly.

swampdonkey
03-19-2005, 03:01 PM
where are thes connectors located?

shakman
03-19-2005, 06:16 PM
right here :ding: