AR No-No

[Kp321]

Had to pull the barrel on a DPMS today, one of the uppers with no dust cover. Anyway, my Brownells upper vise does not fit these receivers properly. Some smiths have reported that they use a barrel vise rather than a receiver vise so I tried it. Bad idea! Instead of loosening the barrel nut, it sheared the barrel locating pin. Finally got things fixed up by minor modifications to the Brownells vise. Lessons learned, 1. Don't use barrel vise, 2. Buy DPMS receiver block.

 

[ApacheCoTodd]

Using proper barrel vice blocks is the original military method. When barrel, block and vice are compatible it's still a way I use 30+% of the time.

The problems arise with varying block and barrel exterior dimensions.

I'd say shearing that pin is indicative of a DPMS cobb-up in the assembly/manufacturing tolerances rather then a failure of the concept of un-barrelling using barrel blocks.