I want to remove the current muzzle device on my AR and replace it with a different device.

Dumb questions:

1) I don't have a vise nor do I have the recommended action block used to clamp onto the receiver in a vise. Can I have someone hold the upper while I remove the muzzle device? Spec, I believe, is only about 20 ft-lbs which doesn't seem like that much.

2) When I apply torque to remove the muzzle device, why doesn't the barrel also get rotated and loosened? Is it torque to a much higher spec? Is there some other locking mechanism to keep it from rotating?

3) When I install the new muzzle device (timed compensator) using a crush washer, I assume that it will allow a somewhat wide range of torque. If not, what is typical increase in torque for up to one rotation? For example, what if I torque to 20 ft-lbs and the top of the device is at 1:00 instead of 12:00? I need to rotate it almost another full turn. How much torque is allowed -- will it be too much? How much is typical for another rotation like that? Is it better to just back it out to 12:00 from 1:00 instead going forward another rotation?

4) When installing the new muzzle device and applying 20 ft-lbs (for example), does the barrel get tightened more? Or again, is it already at a much higher torque setting and/or is it locked somehow to prevent it from rotating once it's installed and headspace is set?

I really don't want to buy a vise and the action block for 1 time use. I will if I must but would like to do without if possible. But don't want to screw up the barrel either (either loosen or tighten it).

AR barrels have a pin that fits into a slot. The barrel nut is threaded onto the upper receiver. The barrel isn't threaded.

That should help.

Thanks! Okay, so I don't have to worry about torque being applied to the barrel that will cause it to loosen or tighten. Basically, it's fixed in position. Great info, thanks!

Looks like $60 for the action block and then another $60-$100 for a 6" bench vise.

Dang, really don't want to buy that stuff if I can avoid it. But I guess there is no way around it. That's a nice chunk of change for something that I'll use once. It's basically the cost of the ADM mount I'll need for the scope I want to buy. Sigh.

get a Geissele reaction rod instead of the clam shell vise block. It takes away all the pressure from the aluminum receiver and doesn't require you remove your optics to do work on your barrel/muzzle device

quote:

Originally posted by SR025:
get a Geissele reaction rod instead of the clam shell vise block. It takes away all the pressure from the aluminum receiver and doesn't require you remove your optics to do work on your barrel/muzzle device

Here is one Brownells makes that is half the price of a Geissele.

http://www.brownells.com/gunsm...tools-prod27452.aspx

I have an action block that you can borrow. But, you will still need a vise to clamp it in. Honestly though, I think you could do it without using the block and vise. You just need someone to hold the rifle while you turn the muzzle devise off.

You may be able to do it yourself... I've removed a flash hider by holding rifle barrel near the muzzle with one of those rubber jar-top grippers from the kitchen in my weak hand while turning wrench and hider with my right. That was on a factory Stag upper, so YMMV based on body type and grip, etc. 20 ft/ lb isn't much.

quote:

Originally posted by AKSuperDually:
AR barrels have a pin that fits into a slot. The barrel nut is threaded onto the upper receiver. The barrel isn't threaded.

That should help.

Actually barrels are threaded into the barrel extension. But the torque specification for that thread is MUCH higher than that for the muzzle device, so generally there is no problem with ever unscrewing a barrel from the barrel extension.


There was a company selling ARs with improperly torqued barrel extensions. It quickly became apparent.

A v-block that will safely clamp in a vise is probably the safest and best tool for this job, but often a pain in the but because there isn't a lot of real estate on an AR-15 barrel between the FSB or the front of the handguard and the muzzle.


Next would be a reaction rod. Either a Geissele or the Brownells version. I have a Geissele reaction rod and it is simply indispensable in my opinion. I use it all the time. Locks into the steel barrel extension and allows you to do a lot of work without removing optics or handguards.


After that would be the clamshell type receiver blocks.


There are some upper receiver blocks that place all the stress on the upper lugs for the takedown pins. I would not use one of these myself. Too easy to damage your upper receiver.



I suppose you may be able to have someone hold the rifle while you torque off the muzzle device but they will likely wind up putting a lot of force on the grip.

There's a lot to be said for having the right tool for the job.

Do you have a C-clamp and a counter top? Not kidding I have installed barrels on AR uppers in hotel rooms (I did torque them, big fan of following the TM). I laid the upper on the edge of a counter, placed a small block of wood on top and clamped it down with a c-clamp. Then installed the barrel. I also changed the A2 FH out on a friends rifle using the same clamping method but on the coffee table. Just let the end of the barrel hang over the edge.

I own a clam shell and a reaction rod, but hey sometimes you gotta use what you have on hand.

Thanks guys! Fantastic info and tips.

To summarize:
1) barrels are threaded but their torque spec is much higher than the 20 ft-lbs needed for muzzle devices (and also pinned?) so removing/installing muzzle devices is not a concern

2) It may be possible to remove/install the muzzle device with a second person holding upper.

3) It is possible to use a C-clamp and a small piece of wood (I have both).

4) The right tools for the job include:
(a) v-clamp on the barrel (if there is enough space between the FSB / handguard and the muzzle)
(b) reaction rod (Geissele $99 or Brownell $49); receiver block also okay but requires removal of optics
(c) bench vise (4"? 5"? $99?)
(d) armorer's wrench (I have a cheap one from tapco -- good enough?). Is crowfoot wrench (5/8"?) better? http://www.brownells.com/gunsm...nches-prod54565.aspx

Thinking more: maybe the G reaction rod, piece of wood and C-clamp is good enough for this? I just need to buy the reaction rod ($99!)?

Midway has a barrel vice block on sale for about $14. You need to put some leather or inner tube pieces between the block and barrel to ensure it doesn't damage your barrel and of course you'll need a vice. (very cheap at Harbor) This method of clamping does not put any pressure on the barrel nut lock up or the upper receiver.

http://www.midwayusa.com/produ...-jaws-ar-15-aluminum

quote:

Originally posted by NavyGuy:
Midway has a barrel vice block on sale for about $14. You need to put some leather or inner tube pieces between the block and barrel to ensure it doesn't damage your barrel and of course you'll need a vice. (very cheap at Harbor) This method of clamping does not put any pressure on the barrel nut lock up or the upper receiver.

http://www.midwayusa.com/produ...-jaws-ar-15-aluminum

Thanks. Not sure that will fit on my barrel:
1) in front of handguard
2) will it work with lightweight pencil barrels? it says bull or heavy weight barrels? I'm not sure what diameter my lightweight barrels is.

If I went this route and needed to buy a vise anyway, should I just get a vise w/ a built in v-clamp for pipes?

If all you are changing is the muzzle device you don't need an armorers wrench. You can use any 3/4" wrench

quote:

Originally posted by konata88:

quote:

Originally posted by NavyGuy:
Midway has a barrel vice block on sale for about $14. You need to put some leather or inner tube pieces between the block and barrel to ensure it doesn't damage your barrel and of course you'll need a vice. (very cheap at Harbor) This method of clamping does not put any pressure on the barrel nut lock up or the upper receiver.

http://www.midwayusa.com/produ...-jaws-ar-15-aluminum

Thanks. Not sure that will fit on my barrel:
1) in front of handguard
2) will it work with lightweight pencil barrels? it says bull or heavy weight barrels? I'm not sure what diameter my lightweight barrels is.

If I went this route and needed to buy a vise anyway, should I just get a vise w/ a built in v-clamp for pipes?

If you're going to get a vice, ( I'd highly recommend getting one since you own an AR and have begun swapping things out on it - might as well do it right ) get a standard vice then use the job specific blocks, etc, for the task at hand.

This little set of barrel blocks holds large and small diameter barrels:

https://www.amazon.com/gp/aw/d...mSyeU9rQL&ref=plSrch

Thanks. I guess I should buy the tools to do it right.

In terms of a vise, will any of these do? Or should I be looking for something different? I've never had a vise before.

https://www.amazon.com/gp/prod...1&smid=ATVPDKIKX0DER

https://www.amazon.com/gp/prod...1&smid=ATVPDKIKX0DER

https://www.amazon.com/gp/prod...1&smid=ATVPDKIKX0DER

Any of those should be fine, though you could save the shipping costs, ( and wait time ) by simply running down to a local Lowes, Home Depot, SEARS, Harbor Freight, etc and snag up a basic bench vice, ( and don't forget good bolts, washers, nuts and a drill with drill bit to make matching holes ) to use.

I have a 6" Craftsman vice, but a 4" vice or so will work fine.

I think any of those vises are adequate but more importantly is what it will be secured to. You can anchor the biggest vise to a lightweight table and it still won't work. A solid foundation is more important that the width of the jaws.

I have a brand new Yost 34C sitting in the garage on the floor. Don't have a workbench sturdy enough to fit it yet. (Although it's so heavy I can do most things with it sitting on the floor lol).

Also check craigs list. You would be amazed at the amount of good old school vises available. People who don't know what they are or who are moving post them for cheap money. Easier to get 25 bucks than to lug it in the moving van.

Not to go too deep into vises but their are two types, a mechanics vise and a machinists vise. The machinist vise usually has a more accurate mechinism for clamping, not just for brute force like a mechanics vise. Meaning the teeth might be a little finer for accuracy and a little smoother with less "slop".

Thanks guys.

Okay, I'll maybe go with the larger size - figure that will be more versatile in the long run.

Didn't know there where two types; I'm guessing the ones from Amazon are mechanics given the price.

Prime so shipping is free. The local stores have some that are $80 and up. So online is cheaper if they are good.

I have a pretty heavy table in the garage.

What I was thinking was mounting the vise to some wood. Then use c-clamps to fix the wood to the table temporarily.

But good reminder about the bolts, washers and nuts. Once I get the vise, I'll run down to the store and get whatever I need.

Checked CL -- it's generally crap around here. Junk at retail prices.