Have you ever heard of bending an Upper receiver?

[waveslayer]

I recently had to remove my barrel off an AR build I did for the 6.5 Grendel because of the Satern Barrels that had the improper throat cut into them... they scraped it for free and we're great to deal with. It was a pain in the butt to remove the barrel, it took some muscle that is for sure. I had to get my old man with his old man strength to help.

Well I reinstalled the barrel and when I mount any optic it looks like it's facing to the right as if you were aiming the gun... like it's bent. I mounted the same optics on another AR and it looks perfectly straight.

Have you guys ever heard of bending an AR upper receiver?

I know it's bent because I zeroed it before I had the throat scraped and it shot well. I then reassembled it and when I shot it, after torquing down the screws to mount a scope at the same torque as before, it was shooting about 12' to the left. I was able to adjust the scope but I have 2 more clicks of windage available. ..

[Slappy]

Yes, that is why gunsmiths and others have a jig so bending an upper does not happen. Sorry for your loss. BANG BANG!!

[waveslayer]

I even used a upper vise with it....I used the one where the upper sits on it and you pin it to the vise clamp. Any recommendations for a better vise clamp?

[stanprophet]

I even used a upper vise with it....I used the one where the upper sits on it and you pin it to the vise clamp. Any recommendations for a better vise clamp?

Those are not designed to take barrels off. You need a clam shell type or a reaction rod type.

[Tedward]

When you installed the barrel the first time, did you use lock-tite or something? It shouldn't have been that tight but that's a mute issue now.
I use these, no twisting energy at all on the upper, just the barrel extension and barrel nut.
http://www.brownells.com/gunsmith-tools-...27452.aspx
http://www.brownells.com/gunsmith-tools-...od468.aspx
Place the wrench with prongs up, set the barrel nut in it and then the torque tool down thru the upper and into the extension. That works great. Do not over torque it and don't use lock-tite. I also use this barrel assembly paste.
http://www.brownells.com/gunsmith-tools-...=083050100
Might make it easier for future work and less expensive.

[LRRPF52]

Those receiver inserts with the pins will often crack upper receivers as well. I avoid them like the plague, because I've seen literally scores of uppers broken with them.

People offer them to me for free, and I rarely accept them. The costs and energy to attempt to repair a broken aluminum part are better spent on a new upper, in my opinion.

[Sojorboy]

Will billet receivers fit in a clam shell type vise clamp ?

[dmsims21]

There may be some crud between the upper and barrel extension, or the receiver face may be dinged up. 0.004" could throw POI off 12"
It is worth taking it back apart. I would get the reaction rod for the barrel removal.

That brings up another question. How much shift in POI should you expect when removing/reinstalling a barrel.

[LRRPF52]

Will billet receivers fit in a clam shell type vise clamp ?

Some will, many won't. Use cutting board as vice insulators, and do it sideways, so the rail is against one flat, and the bottom of the upper is against the other.

[Sojorboy]

Some will, many won't. Use cutting board as vice insulators, and do it sideways, so the rail is against one flat, and the bottom of the upper is against the other.

Thanks !

[waveslayer]

The interesting thing is the the lower part doesn't have cracks anywhere, it's just when you mount anything to the rail... then you notice that things are not aligned.

[LRRPF52]

What make of receiver is it?

[Slappy]

I have heard of uppers bending doing something as simple as adding and taking off muzzle devices. BANG BANG!!

[LRRPF52]

I have heard of uppers bending doing something as simple as adding and taking off muzzle devices. BANG BANG!!

There should be zero torque applied to an upper when doing muzzle device work. The barrel should be clamped, and nothing else. I've seen a lot of people clamp the upper in a vice, then start torquing on their muzzle devices. We even had a forum member years ago torque their barrel out of the barrel extension.

[stevegun 1]

LRRPF52, your picture made me want to show the ones I made on my Bridgeport. Although I always use the clamshell type your idea is great for those who may not have one yet.

My vise jaws were made from a bit of High Density Poly...... and if you can see the two faint dimples under the 320 SP they are where I put two rare earth magnets in each jaw.

+100 on, clamp on the barrel when working on muzzle devices.

[montana]

http://www.armalite.com/ItemForm.aspx?it...886dae666c

There are different methods and tools for barrel work, here are some if you do not want to make your own . LRRP52 is correct, you should always clamp your barrel when working on the muzzle.

[Klem]

There are different methods and tools for barrel work... LRRP52 is correct, you should always clamp your barrel when working on the muzzle.

+1. Always use the barrel to absorb torque when working on the barrel nut and the muzzle device.

In this case Waveslayer's also talking about removing a stiff barrel so it's not just about rotational torque.

For removing stiff barrels I clamp the barrel with a Davidson barrel vise and remove the barrel nut and muzzle device that way. Then clamshell the upper with the barrel and Davidson still attached in a bench vise. Then gently tap the floating 'wings' of the vise with a small mallet, alternating either side as it slowly comes out. May take a while depending on how stuck it is but they all eventually start to move. Just don't get impatient and start pounding it, or lever the barrel to get it out.

[cory]

+1. Always use the barrel to absorb torque when working on the barrel nut and the muzzle device.

In this case Waveslayer's also talking about removing a stiff barrel so it's not just about rotational torque.

For removing stiff barrels I clamp the barrel with a Davidson barrel vise and remove the barrel nut and muzzle device that way. Then clamshell the upper with the barrel and Davidson still attached in a bench vise. Then gently tap the floating 'wings' of the vise with a small mallet, alternating either side as it slowly comes out. May take a while depending on how stuck it is but they all eventually start to move. Just don't get impatient and start pounding it, or lever the barrel to get it out.

Klem do you know what material that clamp is? FWIW I'd never use steel to clamp the steel barrel. I'd want a softer metal than the barrel. That way if the barrel (where it's clamped) or the clamp is to be inadvertently damaged in any way, I'd prefer it be the clamp.

[LRRPF52]

Davidson barrel vise is of course aluminum for the reasons you state. Spray some rubber on them, and they will grip even better.

[Butterbean]

Davidson barrel vise is of course aluminum for the reasons you state. Spray some rubber on them, and they will grip even better.

^^^^ Yup ^^^^^