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AR help - please :)

daveyburt

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Upper build rifle length lower carbine buffered in rifle length tube?

That can cause some weird gaslock on good bcgs.

Not really following you but; a 20" stock Colt rifle from day one. Flattop short barrel upper on the original lower now.
 

Mtn_Guy

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Factory brass ammo - LC headstamp


I didn't want to get caught up in the parts decisions that go into it. I told the 'smith' "build it as you would build your own".
ETA - will inspect the tube interface - thx!

It was totally dry when I got it so

The Smith said he test fired it. Would one clean it DRY afterwards before giving to the customer?
I would think not but, possibly?

it is likely that he did not lube it when he test fired it. For a few rounds to check function, it’s not going to be detail stripped and ultrasonic cleaned before being returned to you...

My $0.02...

get to know your carbine. Take it down as far as your comfortable — field strip it and remove the buffer and spring, breakdown the bolt/carrier, etc. clean it all really well. inspect for areas of heavy carbon buildup. There shouldn’t be any heavy carbon as a new build, but you don’t know if it was put together using used/spare parts ( just because they say it had XYZ parts doesn’t make it so, unless you can see the badging).

Inspect the parts for wear patterns with a flashlight. It is a new build, so they should be barely worn. Look in the buffer tube to make sure if they pinned your stock they didn’t impinge the spring travel.

lubricate properly and re-assemble paying attention to how the parts interact with each other. Manually manipulate to make sure all runs smooth. If it’s binding the way you’re suggesting, something is either misaligned or impinging free movement someplace. Better to figure it out before damage occurs
 

enbloc

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Any Gunsmith worth his salt should have test-fired it for function/tuning before placing it back in your hands... Just Saying.

And I don't mean 1 lousy round...


Ammo ain't cheap... but He is!

You should have come home from the Range with a smile and an erection... nothing else.
 

daveyburt

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Any Gunsmith worth his salt should have test-fired it for function/tuning before placing it back in your hands... Just Saying.

And I don't mean 1 lousy round...


Ammo ain't cheap... but He is!

Yep - he said he did. He said is shoots very nice.
I didn't have the same experience.
:(
 

Mtn_Guy

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Also, are the bolt and the barrel from the same manufacturer? It’s always good to try to match the brand of bolt and barrel to make sure they interface. While it really shouldn’t matter, not all MIL-spec is mil-Spec and some Gucci brands that hold tighter QA tolerances than standard MIL-spec may get hung up with mis-matched parts.

In theory, as the gun wears in with normal use, the parts will break in and should run more reliably. BUT you obviously want to make sure you don’t have any alignment issues or foreign objects, etc which will cause premature wear
 

daveyburt

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-I put the new BCG in the old upper. Feels the same as the new upper.
-Old BCG in new upper - feels fine (slightly easier to get out of lockup but, not much at all) - assuming due to it being 'new'. Old BCG in old upper feels the same as old BCG in new upper.

Also, are the bolt and the barrel from the same manufacturer?
Not sure. - will be sure to ask. - thx!
I see absolutely no wear or rub spots.

I've been into it (as the old rifle) for a detail clean strip. BCG disassembled kinda stuff. -bout it.
 
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jayhitek

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That, I did not try. But, i guess i could try that mag in there here at home to see if it makes it feels different. thx!
Actually, this is the first time that mag has been used.
I have a couple of different uppers that don't like certain mags of mine. I have painters tape on the side of some of them with sharpie "300 only. or Not for 300" etc.
 

enbloc

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Rest easy Davey. You'll get this all sorted out, and learn a lot along the way. Good Times!
 

daveyburt

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Rest easy Davey. You'll get this all sorted out, and learn a lot along the way. Good Times!
Yep. Was really hoping it just worked as he noted.
I guess he could have burned thru a full mag just fine, and thought it to be fine, without trying to using the charging handle to unload.

Just tried a few different mags in it - all feel/act the same.

I would contact the gunsmith I’m sure you paid good money for a completely built upper.
yes - already left him a message.
-just curious to what you guys thought first. IE: Educate myself before I roll back in there.

and, as usual, you all rock!
 

enbloc

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Report back if anything changes...

Also, ask the Gunsmith to let you watch a little and discuss diag process.

If he says "No", take a picture of his face and post it here...
 

fshalor

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Not really following you but; a 20" stock Colt rifle from day one. Flattop short barrel upper on the original lower now.
I. Thought you paid someone to build the upper. How would it then be stock? Confused.

I just know if you fiddle with gas system lengths and lower buffer tube systems, you can lock up a bolt.

Was only trying to help. I guess I'd this is stock, than its never been touched or modified by someone. K.
 

cathouse01

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Yep - he said he did. He said is shoots very nice.
I didn't have the same experience.
:(
Did he try it with your lower or one of his? If it was one of his, it probably was a standard AR lower with the small front pivot pin. You said your lower was the old Colt A2 with the large take down pivot pin hole and a cam pin for the front pivot. I would check the interface between the upper and the buffer tube. I have one of those old A2 lowers and using the cam pin to get them to work with a new small pin uppers can take a bit of fiddling.
 
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