EDIT: Well guys I've had some success many hours into today fiddling with this project. I've tried around 10 different high caps at random in this gun, all sorts of brands I've got allot of them from TM, CA, to newer stuff. Either way on a whim I tried an old Star 30 round low cap, and the dang thing fed consistently and fps was +-2. It was a smidge low around 403 where I was seeing some 430's but it's 100% consistent. So I dug around tried some other mid caps and found another original generation G&P midcap that feeds and is 100% as well. So I have some sort of mag related issue that doesn't make a bit of sense to me. These same mags just for reference feed in every other M4 gun I've got around without any issues and they run the gamut brand wise as well.
So rather than my long question below which I'll leave there in case it might help someone seeing my issue in full and having any ideas. So now I'm curious to guys that have dug into mag compatibility problems and their solutions. What is actually causing the issues, is the hopup not pressing the release on the mag fully, too much pressure too little? Just curious what you guys have found, this is honestly the first time I've had mag issues with any of my m4's over the years. I used to only run TM mags so that could be part of it, but I'm wondering if anyone else has dug into it. I'm curious at this point but I'd also like to be able to correct this issue so I can use any of my mags as well.
-------------------------------------------------------------------------------------------
Well guys I've been working on a project for a while now basically a DMR M16 built from bits and pieces. I got a bunch of random parts and threw it together but I've been having problems and honestly I'm out of ideas of what could be causing this issue at this point.
So first I'll describe what it's doing. Random feeds probably feeds BB's 9 out of 10 shots maybe a bit higher but FPS is down in the 100-200 range most of the time with an occasional full speed BB at around 420fps with .25's. Hopup of course is all over the place because the velocity is all over.
Parts, metal body upper and lower don't know the brand but the fit together is fine, same goes for stock, and outer barrel. I've got a G&G plastic hopup chamber I was trying to get to work but once these problems started I suspected the hopup unit was the cause so I went ahead and bought a ZCI unit, but the issue still is there. I've tried several different buckings, several hopup chambers and same basic results. A few buckings gave me more misfeeds but I think it was how tight the lips were for feeding. I wasn't sure what nozzle came with the gearbox I picked up used so I thought despite the specs being on length wise I'd replace it also with a ZCI nozzle since it would match the hopup unit hoping for good results. Same thing. I did put an M140 spring in here along with an upgraded motor, cycle rate is good but I don't think it's fast enough to cause any issues, especially with that heavy of a spring. I replaced the tappet plate with a new SHS tappet plate. The other one I had was slightly too thick causing some issues or I thought. After thinning and fighting with the old one I decided it might not have been putting enough forward pressure on the nozzle to feed properly and seal but the same issue was still there. Spring on the tappet seems to be strong doesn't seem any different than any other version 2 boxes I've had apart over the years. Tried several barrels with the same results. I forgot to mention above the hopup unit is shimmed with orings to the geabox and it's got a fair amount of pressure against the box and should have a good seal.
So I'm looking for suggestions, I've been reading and racking my brain trying to come up with possible causes and honestly thought I had it on the run today with the new nozzle and hopup unit, but alas same issues again. So ideas would be more than appreciated, particularly if you've seen this issue or something like it and other things I can try.
Take care!
Luke
