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towtruck

Crap builds...

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Guy at work bought a used carbine and it has never shot right for him. It always stove pipes. I have not witnessed it but he says it tries to load another round and fails to get the spent case out of the way. He shows me the gun yesterday and right away I find the barrel is loose in the upper....it twists back and forth. I now have his upper and I am going to work it over for him. Right away I think it's under gassed. I pulled the gas block and it was lined up correctly but that hole in the barrel looks tiny. I'm going to size it and possible open it up a little for him. I will check the chamber for smoothness and look at the gas system for any problems before I reassemble it. Someone looks like they took a hatchet to the barrel under the hand guards as there is a big slice and burr in the barrel mid way between the gas block and receiver. 

 

He used different magazines, different lowers, and I believe different BCG's all to no avail. I should be able to get it running for him...I just hope the barrel nut comes off for me....the nut seemed pretty tight but the barrel still moves. When it cools off tonight I will take it to the shop and get that barrel nut off and check it all out...fun fun. 

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Well, I pulled it apart and gave it a once over. Everything looked good. The gas port is actually .093. This barrel is 16.5" and that size port is big for this barrel length so I left it alone. I lined everything back up and re-torqued the barrel nut. I have good air flow through the gas tube and block. I am going to take one of my lowers and my magazines and hit the public range in the morning. I'll bring a spare BCG with me to try if the original still fails in my gun. 

 

If it works on my lower I will have to check his lower and see where the carrier stops and if the bolt head goes too far back past the ejection port. If that is the case he can try shimming the back of the buffer tube to stop the BGC a little shorter. 

 

One step at a time should get us there. 

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Well, my observation of the large gas port was spot on. I took the upper to the range this morning and while it functioned on my lower just fine it was pitching brass forward to 1:00. 

 

He will have to make a choice to put an adjustable gas block on it or swap out for a heavier spring or buffer. I'll have him check to see if his bcg is extending to the rear too far and maybe shim it out a little first before swapping out parts if it is. 

 

....on to the next project. 

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16 hours ago, towtruck said:

but that hole in the barrel looks tiny. I'm going to size it and possible open it up a little for him.

:tongue:

 

Have fun.

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TT, 

You are a good man. 

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Good job TT.  I've offered to run and tune a gun for a guy I used to work with but he never got around to bringing it in.  Truth be told, he's never shot it and paid way too much for it during the big scare.

I told him he'd better make sure it works before he needs it!

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He bought a new PSA upper and is going to see how it shoots on his lower before he messes with the other one. 

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My buddy had a gun built for him.  Saw something similar.  Nut was tight but the barrel would move slightly forward and aft.

 

Up until then, I'd never seen that before.  He took it back to the shop and they fixed it up for him.

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On 7/14/2019 at 1:34 AM, newbe said:

My buddy had a gun built for him.  Saw something similar.  Nut was tight but the barrel would move slightly forward and aft.

 

Up until then, I'd never seen that before.  He took it back to the shop and they fixed it up for him.

You woulda thunk they would have noticed that little detail before they let it out the door.  I would check it all out to mak`e `su`re` there wouldnt be any more surprises.

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7 hours ago, hlhneast said:

You woulda thunk they would have noticed that little detail before they let it out the door.  I would check it all out to mak`e `su`re` there wouldnt be any more surprises.

You had to tug on the barrel to really see it, but it definitely moved back and forth.

 

All the shop did was install the barrel for him.  Thinking the but was out of spec.  Not sure as this was a few years ago.

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On 7/14/2019 at 12:34 AM, newbe said:

My buddy had a gun built for him.  Saw something similar.  Nut was tight but the barrel would move slightly forward and aft.

 

Up until then, I'd never seen that before.  He took it back to the shop and they fixed it up for him.

 

I had a shotgun like that.

Then I noticed it was a Browning Auto Five :D:

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47 minutes ago, srjdsmith said:

 

I had a shotgun like that.

Then I noticed it was a Browning Auto Five :D:

 

You are showing your age.

 

Greg

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50 minutes ago, srjdsmith said:

 

I had a shotgun like that.

Then I noticed it was a Browning Auto Five :D:

I hope that it moved more than just a little.

2 minutes ago, GLShooter said:

 

You are showing your age.

 

Greg

I still have two of 'em. What does that show? :ohmy:

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57 minutes ago, Longhair said:

I hope that it moved more than just a little.

I still have two of 'em. What does that show? :ohmy:

 

I means you have good taste that started early on.

 

Greg

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4 minutes ago, GLShooter said:

 

I means you have good taste that started early on.

 

Greg

I was half expecting you to say that I was a glutton for punishment, wanting to haul those heavy buggers around, but the fact is.......muscu.gif 

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