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psriley
07-20-2007, 11:44 AM
I need to torque a FH about another 1/8 of a turn, which is going to require clamping the upper in a vise. Question is, can I clamp on the flats of the upper receiver (its a flat-top), or do I need to clamp on the barrel itself? Seems like clamping on the receiver and torquing the FH might rotate the barrel extension interface with the receiver, and possibly bend or break the index pin. Is this something to be concerned about, or am I over-thinking it?

Cheers!

Technical Ted
07-20-2007, 11:47 AM
Barrel vise jaw blocks (bought or home improvised)
http://www.bushmaster.com/shopping/gunsmith/Images/amer-001.jpg

Scratched the upper receiver block. You could wind up torquing the barrel in the receiver.

psriley
07-20-2007, 11:55 AM
Barrel vise jaw blocks (bought or home improvised) or an upper receiver vise block required.
http://www.bushmaster.com/shopping/gunsmith/Images/amer-001.jpg
http://www.bushmaster.com/shopping/gunsmith/Images/om-003.jpg

Wow, that must be the fastest reply in the history of the Internet. Thanks! So, it's okay to clamp the receiver in the vise and turn the FH? I have a reliable way of clamping the on the receiver flats.

Technical Ted
07-20-2007, 12:05 PM
Wow, that must be the fastest reply in the history of the Internet. Thanks! So, it's okay to clamp the receiver in the vise and turn the FH? I have a reliable way of clamping the on the receiver flats.
Best bet is to remove the handguards and clamp the barrel using barrel vise jaw blocks or wood blocks with a groove and the barrel wrapped in thin leather.

Clamping the receiver without a receiver block is not recommended. Not certain what you're referring to when you say "receiver flats" but if it's what I'm thinking, you stand an excellent chance of deforming or damaging the receiver.

psriley
07-20-2007, 12:43 PM
Best bet is to remove the handguards and clamp the barrel using barrel vise jaw blocks or wood blocks with a groove and the barrel wrapped in thin leather.

Clamping the receiver without a receiver block is not recommended. Not certain what you're referring to when you say "receiver flats" but if it's what I'm thinking, you stand an excellent chance of deforming or damaging the receiver.

I see what you're saying...the barrel vise immobilizes the both the barrel and receiver. I've been clamping the receiver top and bottom between a couple of pieces of wood in the vise jaws, per the build-it-yourself thread on arf. That works fine for actually installing the barrel. I'll try it by clamping the barrel in leather and see how I do. Thanks...

ar15barrels
07-20-2007, 2:15 PM
Wrap a thick piece of leather around the front sight base.
Flip the upper over so it's upside-down in the vise.
Clamp on the leather.
Index your muzzle device perfectly upside down.

Remove the upper, flip it over and all should be well.

mltrading
07-20-2007, 3:35 PM
Randall's solution is good and working.

I would suggest the use of barrel vise. IMHO, it's not good to use receiver claw/action block in this case. You still have chances to screw up the barrel/receiver alignment.

Just remember to place some padding material between barrel and BBL vise. Then you are good to go.

-hanko
07-20-2007, 7:43 PM
I need to torque a FH about another 1/8 of a turn, which is going to require clamping the upper in a vise. Question is, can I clamp on the flats of the upper receiver (its a flat-top), or do I need to clamp on the barrel itself? Seems like clamping on the receiver and torquing the FH might rotate the barrel extension interface with the receiver, and possibly bend or break the index pin. Is this something to be concerned about, or am I over-thinking it?

Cheers!
You only need/want to clamp the upper when you're installing the barrel...

Torque in this case acts between the fh and barrel...clamp the barrel with either a dedicated barrel vise or vise jaws like those earlier in this thread. If marring the barrel finish bothers you, tape the barrel where it contacts the vise or vise jaws. Taping with the sticky side out eliminates adhesive residue.

hth

-hanko

SemiAutoSam
07-20-2007, 7:50 PM
Before I had the $$$ to purchase barrel jaws I used a big chunk of leather and it worked fine.



You only need/want to clamp the upper when you're installing the barrel...

Torque in this case acts between the fh and barrel...clamp the barrel with either a dedicated barrel vise or vise jaws like those earlier in this thread. If marring the barrel finish bothers you, tape the barrel where it contacts the vise or vise jaws. Taping with the sticky side out eliminates adhesive residue.

hth

-hanko

gn3hz3ku1*
07-20-2007, 8:31 PM
why not just get another crush washer?