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CMMG Conversion Bolt Update
4/1/2012 6:02:38 PM
About a month ago I bought a CMMG conversion bolt from CDNN. I also purchased a forward assist adapter, BHOA, and anti jam charging handle. Unknown to me at the time, this was a "new" pre-evolution model, so my magazines were incompatible with the BHOA. I purchased some CMMG mag followers that were supposed to work with the BHOA, once fitted I was disappointed to learn they didn't work. An email to CMMG explaining my issues resulted in Chris at CMMG offering to exchange my old mags for the evolution mags, he also recommended I chop the bolt catch spring a couple of coils to boot. This I did, and I now have a operable BHOA. I modified the back plate of my bolt to cut in the notch that allows me to now use my forward assist adapter. So my bolt now works just like an evolution kit.
Off to the range this morning verified the full functioning of the bolt and BHOA. The only issues I had was with the Remington ammo I had on hand. I has so many misfires, I ended up throwing about 75-100 rounds in the trash. When the rifle went bang, the function was great, along with the accuracy. I was easily able to group 3/4" - 1" at 25yds, and group 1.5" at 50yds with the appalling Remington ammo. I did have 50 rounds of federal ammo on hand that was much better in regard to misfiring. Moral of story: Knowing what I know now, if I was to do this again, I would have just purchased an evolution kit. If you have an older kit, which can still be bought new, using them with the old mags are fine. The BHOA can be made to work with the older kits, but you will need evolution mags for the BHOA to work. At the time I bought my kit, I was not aware that there were pre-evolution kits out there - a case of ignorance is not bliss.
I would like to thank Chris at CMMG for his generosity for allowing me to exchange my three old version mags for the evolution type, and his assistance in helping me overcome my BHOA issues.
Off to the range this morning verified the full functioning of the bolt and BHOA. The only issues I had was with the Remington ammo I had on hand. I has so many misfires, I ended up throwing about 75-100 rounds in the trash. When the rifle went bang, the function was great, along with the accuracy. I was easily able to group 3/4" - 1" at 25yds, and group 1.5" at 50yds with the appalling Remington ammo. I did have 50 rounds of federal ammo on hand that was much better in regard to misfiring. Moral of story: Knowing what I know now, if I was to do this again, I would have just purchased an evolution kit. If you have an older kit, which can still be bought new, using them with the old mags are fine. The BHOA can be made to work with the older kits, but you will need evolution mags for the BHOA to work. At the time I bought my kit, I was not aware that there were pre-evolution kits out there - a case of ignorance is not bliss.
I would like to thank Chris at CMMG for his generosity for allowing me to exchange my three old version mags for the evolution type, and his assistance in helping me overcome my BHOA issues.
4/1/2012 8:36:10 PM
I try to warn guys that the cheap kits you find are old, discontinued kits bought out cheap.
Same with some of the "complete CMMG uppers" you find unusually cheap.
Bought as incomplete, old bolt added, then sold as complete Evolution uppers.
Buyer beware.
Dave N
Same with some of the "complete CMMG uppers" you find unusually cheap.
Bought as incomplete, old bolt added, then sold as complete Evolution uppers.
Buyer beware.
Dave N
4/2/2012 12:38:22 PM
are you sure the rounds were duds? I had a CMC tactical trigger group that made it seem like I had A LOT of duds. once I swapped that out for a mil-spec with full size hammer it fired 100% on the same ammo. something to think about.
4/3/2012 11:59:09 AM
Originally Posted By autotech6506:
are you sure the rounds were duds? I had a CMC tactical trigger group that made it seem like I had A LOT of duds. once I swapped that out for a mil-spec with full size hammer it fired 100% on the same ammo. something to think about.
are you sure the rounds were duds? I had a CMC tactical trigger group that made it seem like I had A LOT of duds. once I swapped that out for a mil-spec with full size hammer it fired 100% on the same ammo. something to think about.
I hope not. My rifle has a Geissele SSA trigger group, which has full power springs. When I took the rifle out the first time with the conversion, shooting the same ammo, I encountered fewer misfires than I did last Sunday.
