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Posted: 10/11/2004 6:44:43 PM EDT
OK, so I am trying to install a flash suppressor on a 16" barrel. I have the barrel in my aluminum blocks and that in my vise. The problem is that the barrel starts spinning before the crush washer crushes. I am not applying a lot of pressure. I took a little finish off of the barrel and decided to stop. My question is: Can I put the upper receiver in an action block and then torque the FS on or will this strain any part of the upper too much? I know the torque value on the FS is 15 to 20, but what does it take to crush that darned crush washer?

Link Posted: 10/11/2004 7:00:35 PM EDT
You must not have the vise cranked down tight enough. I just did one and I had to use a cheater bar on the vise handle in order to get it so the barrel wouldn't spin. It can be done!
Link Posted: 10/11/2004 7:04:28 PM EDT
Technically, you _shouldn't_ stress the upper receiver by clamping it in a vice block to torque the flash hider. My personal oppinion though is that this has a good chance of streching the upper or very slightly rotating the barrel out of index.

I would recommend that you try your aluminum blocks again, and this time use some rosin (something like this) to prevent the barrel from slipping.

Link Posted: 10/11/2004 7:07:37 PM EDT
The cheater bar idea crossed my mind. I just didn't know how much I can tighten the vise without hurting the barrel, if that is possible. I don't have an action block but will buy one if that would work better than the barrel blocks.

Link Posted: 10/11/2004 7:10:09 PM EDT
Thanks Techie,
I am ordering some right now! I tried duct tape and masking tape but those just seemed to make it slip worse.

Link Posted: 10/11/2004 9:16:17 PM EDT
Use barrel vise jaws for removal, installation of flash hiders, brakes, comps. DO NOT use an action block for this purpose. You will twist the barrel in the upper.

Use action block for removal, installation of barrels into upper receivers. Do not use barrel vise jaws for this, again, you will, in this case, twist the receiver on on the barrel.

Link Posted: 10/11/2004 9:32:14 PM EDT
Use a thin piece of rubber between the barrel and barrel vice and it will hold much better and help protest the finish on the barrel.
Link Posted: 10/12/2004 5:22:34 AM EDT
I used a peice of bike tire inner tube between the blocks and the barrell. It held everything fine while installing the FS.

Link Posted: 10/12/2004 6:29:52 AM EDT
[Last Edit: 10/12/2004 6:46:02 AM EDT by Marksman14]
Where can one get a barrel vise jaw block?

I'd like to avoid bushmaster if possible...

Anyone have a part# for brownells?

Also...do these blocks clamp the portion of the barrel underneath the handguards?

I was going to throw my uppers in my action block for installing the flash supressors, but I guess I won't be doing that anymore...

Thanks guys,

ALSO- do these things work on both A1 pencil barrels and A2 gov't profile barrels?

Did some searching...easier to find than I though...but still have no idea about the bold question up there...I only ask because I refinished both barrels I am installing, and don't know how the vice blocks will react to the alumahyde II finish. I don't want to damage it.
Link Posted: 10/12/2004 10:46:01 AM EDT

I never even bother with the barrel blocks, I've always used nothing more than a piece of leather wrapped around the barrel and put it directly in the vise. The leather prevents the barrel from spinning and protects the finish...

Link Posted: 10/12/2004 11:32:37 AM EDT
[Last Edit: 10/12/2004 11:40:18 AM EDT by SHIPSNIPE1]
I guess everyone has their own recipe for success.
Here's mine:
Sturdy vise (clamp on table type won't cut it)
Barrel blocks
Leather liners for blocks (mine are just scraps of old belt, the tougher the better)
Rosin (apply to the leather contacing the blocks and the barrel.)
Degrease the exterior of the barrel.
Clamp it as tight as tight as you can. Take a break, come back and try torqing the vise some more.
Begin work, if you see any movement at all stop and torque some more.

Easy way to see if your barrel is starting to turn: using a black marker place a witness mark near the top of the location where your barrel is clamped. Make sure you mark both the barrel and the clamp. The marker will come off with some isopropyl when you are done.

Jaybo : Your finish may not be damaged, you might have just smeared the aluminum from the blocks on your barrel.
Link Posted: 10/12/2004 3:21:09 PM EDT
#1 Clamp the barrel on the part in front of the sight.
#2 Use something in between the blocks and the barrel Rubber, Leather, 90 Mph Tape, Whatever
#3 Clamp it tight really tight Really Really tight.
#4 Use a good Wrench.
Link Posted: 10/12/2004 5:13:24 PM EDT
Shipsnipe1, you were right, what I thought was finish off of my barrel was just aluminum off the blocks. I took some oil and a bore brush and gently brushed the mar right off. My barrel is still 100%. You should have seen the smile on my face. Well, I ordered the rosin from brownell's last nite and it shipped today. I have learned a lot from you guys and in a few days when u.p.s. shows up I'm sure I will have no problem getting the Flash Suppressor on.

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