09-09-2004, 08:53 PM
I need information about the swapability of the Classic Army metal hop-up for the Systema hop-up. I began to have some problems with my hop-up after having my Classic Army M15A4 for about a month.(bbs dropping to the ground after traveling only 40-50 feet) A simple hop adjustment corrected this problem. But after a week or so the problem returned. This happened more and more frequently. I thought the screw that presses against the main hop adjustment gear had loosened up but after checking, I found it to be very snug. At this point I removed and inspected the metal hop-up assembly and found that the little rubber "nub" that presses against the hop bucking had become very hard, brittle, and partially collapsed on one side. I then replaced the hop bucking and the little nub. "Voila" I said. Wrong! Now the hop works perfectly, but backs its self off after firing a few rounds. The small plastic gears seem to have loosened up due to me disassembling the hop-up mechanism, and will no longer stay "set". So, I did some research and discovered that others have experienced the same trouble. It seems to me that the Classic Army hop-up is almost an exact copy of the Systema hop-up. I was wondering if this is truly the case. The consensus seems to be that the Systema part is superior to the Classic Army. I need to know if this is truly a drop-in replacement, as I do not wish to cut away metal portions of my rifle to get it to work.