I'm building an 8" 300 blk upper.  The tools I have include a polymer clamshell vice block and aluminum barrel blocks.  I typically use the barrel blocks to install/remove muzzle devices to avoid putting torque on the index pin hole.  I can't use these blocks on this barrel cause there is simply no room for it.  Should I just use the polymer receiver block?  I don't really want to shell out the coin for a reaction rod.  Perhaps the bev block I could swing if that would be an appropriate tool for this job.  The device I'll be installing is a silencerco ASR mount with shims.

Thanks guys

Just use a couple of wooden scraps.  If you want you can saw out a "channel" for the barrel, but for MD installation wood blocks will work fine.

I installed a AAC 51T brake on my 8 inch cmmg 300 blk barrel with the bev block. Worked like a charm.

Actually I had a brain fart.  I won't be able to use any type of barrel clamp.  The rail I'm using won't fit over the muzzle device so must be installed first, and it goes right to the threads, leaving no room for even some small wood scraps.  I'll just get a bev block.

Wouldn't a reaction rod be the tool for this situation?

I could have kicked myself for not jumping on the BF geissele deals when I found out they were throwing one in for free

Twofer

Threefer

Wtf