.22 Caliber Conversion Kits

[shawnr1]

I have seen two difference between the older (foam layout) and the newer (plastic mold layout) kit, mainly the bolt assembly.

Does one work better than the other?

Host gun: AC556F

[sswikinger]

Mine came in the molded plastic case. Didn't work too good at first. I bought two mags from a friend and the kit worked great with these mags. If I hadn't got the other mags, I probably would have blamed the kit. CCI Mini-Mags and Rem Thunderbolts worked best.

[toolbox82]

I just recently purchased a spare ciener kit for parts for my ac556. The spare kit I purchased was the older style with the foam packaging. The first thing I noticed different was that the chamber insert on the old foam kit does not have a feed-ramp and the newer style in the molded plastic case I am using has the feed-ramp on the chamber insert. The firing pin on the old kit is round and the new kit is rectangle in shape on the business end. Both bolts worked fine with no noticeable difference in functioning. Another thing to keep in mind is the feed lips on the mags need to be of equal spacing of .170" between them for proper feeding, if the gap is more than .210 you will start getting jams. in the ammo department, the cci mini-mags work great, although I have noticed that the cci mini-mags I am using has a waxy type of coating on the bullet and after a few hundred rounds, the coating starts to build inside of the chamber insert and will give you some issues in extraction. The best ammo I have found so far is Federal auto-match ammo. I performed some powder burn rate testing and found that the federal ammo powder has the fastest burn rate compared to cci mini-mags and Remington thunderbolts. The federal powder burned the cleanest of three. Just wanted to pass along a few things I have learned.
CR

[happycamper]

the fed auto-match.......is that standard velocity ammo?

[sswikinger]

Federal AutoMatch Target
Technical Information

Muzzle Velocity: 1200 fps
Muzzle Energy: 128 ft lbs