I have searched the forum and didn’t find answer to this exact question: can I use a DPMS style upper block in conjunction with a regular flash hider wrench to remove/install a flash hider? From the posts I’ve seen, this appears to be ok, but I want to confirm I don’t need a separate barrel vice block for flash hider installation.
Thanks in advance
You can, but I prefer not to.
Clamping the upper in the vise and cranking on the muzzle device means you’re actually torquing the barrel back and forth in the upper. There was a big thread on a couple of the other sites where the “gunsmith” clearly had wrenched the unholly shit out of a permanently attached device and ruined the barrel index pin notch on the upper. This is an extreme example, but it illustrates the point very well.
the correct way is to clamp the barrel itself in the vice. As a general rule, guns or not, you want to clamp immediately adjacent to a joint and not have multiple joints between the vice and the wrench. By clamping the upper you wind up with two joints: the one as the muzzle and the one at the upper.
What you really want is something like this so that you can clamp the barrel, but you can also use wood blocks if you need to.
Humm, that’s what I’m afraid of. With the Brownell barrel vise, do
you clamp it on the barrel or barrel and gas block? If clamped on just the barrel, wouldn’t applying torque to the flash hider turn the barrel in the vise? Also, does the vise handle “pencil” barrels?
Thanks rob!
Product descriptions are nice… especially if you read them 
It clearly states which barrel sizes/diameters it works with.
(Not flaming … just gently slapping you in the head with the field
manual you SHOULD have read first Read more and that way you don’t have to wear that cute pair of asbestos undies as often!)
I have one of these in my shop and I’ve not had any issue with a barrel twisting in the vice block. I’ve not used this particular block for a pencil barrel so I’m not sure.
Is there a pinned FSB on the barrel? That’s your clamping point if so.
No, there’s a LPGB secured via a set screw. Is that gonna be too weak as a clamping point?
I would use the barrel itself as a clamping point assuming you have a barrel of sufficient diameter to clamp into the barrel vise. FWIW,
the Brownells barrel vise “small” jaws measure around .640 ID when clamped in my vise.
yes…