Vltor MUR-1A upper cannot use just any armorer's action block.

[ROGOPGEAR]

VLTOR MUR and DPMS panther claw together.

http://www.youtube.com/user/R0GUEKN1...17/ZVwqhYQInvY

[bkb0000]

i've used the panther claw for a couple years now.. it's done a few murs, and everything else i've done in that time. definitely the only upper block i need. i don't have any fears. i've had some barrel nuts that took my biggest torque extension to crack off- no warped nor cracked receivers.

i've done the two blocks in the vise thing- it works, but there are more than a few people who've broken receivers doing it like that. puts too much stress on the ejection port cutout. there was a thread here about a guy who broke his doing exactly that a couple weeks ago.

[Robb Jensen]

I've used the DPMS delrin Panther claw upper block for 60+ installs and have had no problems.
If you're worried about somehow harming the upper you can use a block of wood across the top of the reciever and turn the upper in the vise sideways with the top of the receiver against one jaw of the vise and the bottom of the DPMS block against the other.

I have two of these DPMS blocks and modified one so that it fits with Daniel Defense Lite Rails. You have to remove material from the front edge of the block so that it doesn't bind up the aluminum plate that the 6 screws fasten through to the rail.

[VaniB]

Excellent thread. It's now grown chock full of all kinds of helpfull info on the topic.

I've already purchased the Model1 armorer's bock. I'll just be glad I've got it already and focus it mainly on taking apart some of the factory builds which can be pretty tough. (they don't always put lube on the threads at the factories).

Now I'll also go ahead and buy a DPMS "claw" and focus that mainly for assembling stuff. (while I save the Model1 block primarily for disassembly chores )Being it works on the inside of receivers, (and not the outside) it can be used for that uniquely shaped Veltor, or most other AR15 receivers out there too.

I've concluded that it doesn't hurt to have an assortment of different tools at $35-$45 a pop. There's certainly bigger expenses to worry about in life, and not that.

Thanks again guys for all the help. BTW;That You-Tube video link is neat.

[SHIVAN]

SHIVAN,
What do you think about this upper block set?


http://www.armalite.com/ItemForm.asp...3-50c7880935e0

Never used that, but it looks like a "better 1x2" method that I mentioned...

It would certainly work.

[SHIVAN]

i've done the two blocks in the vise thing- it works, but there are more than a few people who've broken receivers doing it like that. puts too much stress on the ejection port cutout. there was a thread here about a guy who broke his doing exactly that a couple weeks ago.

Sounds like a far too liberal amount of torque on the vise, to be honest.

[bkb0000]

Sounds like a far too liberal amount of torque on the vise, to be honest.

most, if not all, the instances of broken receivers i've seen have been during removal. like i said, i've personally done more than a couple installs with the blocks, and probably some removals.

[Blankwaffe]

Never used that, but it looks like a "better 1x2" method that I mentioned...

It would certainly work.

Im getting ready to do a Aero Precision C.O.P. with a DD CHF barrel,so I think I'll get a set of the blocks and give them a try for this build.
The way the barrel nut goes on/in the COP,having the receiver turned sideways is a must,and I think that block set is the answer....at least it is according to Armalite.

[boltcatch]

I've used something similar to the PRI block up there, but made of delrin, several times on VIS and MUR uppers.

I turn the upper sideways in the vise, so the vise clamps the bottom of the block on one side and the top of a hardwood block on the other (which in turn is up against the top of the flat-top).

I've never had any problems with it, and I'm using a torque wrench so I'm not getting into crazy ft-lbs of torque anyways. It works particularly well when you have a barrel nut that you don't have to line up with the gas tube.