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pit808
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Posted: 5/12/2012 3:39:40 PM
[Last Edit: 5/16/2012 5:26:55 AM by pit808]

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Hi guys. I'm new to galil's and I noticed the top of the barrel has not been shimmed but welded to the receiver (ORF). Is normal? I'm thinking it's not and was done by the builder to fix poor barrel to receiver fit. Could someone school me on this?
Thanks
mustangduckk
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Posted: 5/12/2012 10:38:23 PM
Originally Posted By pit808:
Hi guys. I'm new to galil's and I noticed the top of the barrel has been welded to the receiver (ORF). Is normal? I'm thinking it's not and was done by the builder to fix poor barrel to receiver fit. Could someone school me on this?
Thanks


Is it normal? Its a normal way of half-assing a Galil build.

The Galil build is supposed to be head spaced by torquing the barrel into the receiver. If the shoulder on the barrel is cut too deep, it won't torque properly. Your builder welded it in place. The proper technique is to shim it till it torques to around 150 ft lb if I remember correctly.

My build required .010" of shimming to get it to torque in.

I'd check yours with a 5.56 head space guage to make sure they got that right. If so, keep it and shoot it. Check it again a few hundred or thousand rounds down the tube.

If its still good, you're probably ok. The major downside to the weld is that you're now suck with that barrel and barrel profile. There's no removing it to change barrels or reprofile for SAR length.

WTS/WTT: 1 kidney or liver chunk for AK parts.
DBrown
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Posted: 5/14/2012 2:27:08 PM
Pit,

This is NOT normal. The barrel is NORMALLY just screwed and torqued into the receiver.

There might be several reasons why this work around was performed. Mustangduckk has pointed out the most likely cause, and the correct solution. With the gas block installed on an old barrel it is unlikely that the barrel timed correctly when fitted into the receiver.

If the welds were deep and penetrating, which they must be if they are to bear any stress, it would impact the heat treatment of the receiver. If they are not, they will eventually fail. Please let me illustrate my reasoning with a different example. When a gas piston is fully screwed into the bolt carrier, then slightly backed out and riveted this allows a little flex at the joint. The stress is placed on the rivet and not on the piston's shoulder and treads. In like manner, the shoulder of the barrel is not equally bearing on the receiver. The treads are not fully tightened by torquing, so are also not fully engaged. The welds will be STRESSED as they are load bearing. Each shot will impact them.

If you are worried about this rifle I suggest that you have good cause.

DB
pit808
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Posted: 5/14/2012 3:17:57 PM
Thanks guys. I guess I'll just shoot it and keep an eye on the headspace as mustang suggested. If it ever fails, I'll get it rebuilt correctly.
mustangduckk
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Posted: 5/14/2012 4:07:15 PM
Originally Posted By pit808:
Thanks guys. I guess I'll just shoot it and keep an eye on the headspace as mustang suggested. If it ever fails, I'll get it rebuilt correctly.


Do you have 5.56 head space gauges? They will be needed if you're going to periodically check the head spacing.

WTS/WTT: 1 kidney or liver chunk for AK parts.
DBrown
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Posted: 5/15/2012 12:02:57 AM
[Last Edit: 5/15/2012 12:57:13 AM by DBrown]
" I guess I'll just shoot it."

Dear Pit808,

While I have not ever seen this rifle I am already concerned about it. I certainly would not trust it to contain a detonation within a few inches of my face. I have not friends enough that I can afford to preemptively lose any.

I would have the rifle examined by a competent smith. The issues which are most troubling are the headspacing, and whether the headspacing can even stay consistent as the rifle currently is. But, the hardness of the receiver is in question as well. This should be examined by testing the receiver in several location, not just were it has been most impacted by the welds. When the bolt is locked into the receiver both lugs on the bolt should be equally engaged. Read about Garand builds and it becomes immediately apparent how this is done.

As it is now, both lugs may equally be engaged, and the headspacing might be correct, but, it is easy to imagine both of these factors changing with the slightest failure of the welds. Welds which will be stressed with each use. A few thousands of an inch is hard to perceive even with proper tools. But, this is all the movement necessary to create a hazardous situation.

Sorry to be so negative and alarmist. Sorry to be posting on the internet where advise is free and of doubtful origin and value. But, I would have you risk neither your rifle nor physical harm. Please let me urge you to spend a few dollars on prevention and to have the rifle properly fixed.

DB

Edit:

Before the Assault Weapons act, it was unusual for a barrel to be welded. I know smiths who affix permanent attachments onto a barrel by means of a weld frequently. This does not mean it is safe or should be done. This really is less than desirable and potentially very unsafe. The laws which encourage this are NOT there for your safety. Never forget this.