Need advise on AR15 FTE issue

mac67

mac67

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Just finished my AR build. Went to the range for a test fire. PSA lower, Stag (complete factory) M4/2H upper in 5.56. Bench rest w/a full 20 round pre-ban GI alum mag., 55 grain PPU brass/FMJ. First round stripped off no problem. BCG cycled, extractor ripped a piece of the rim off the brass leaving the spent case still in the chamber. (left me w/a double feed) Removed mag and the spent case came out w/a very light tap from a rod. For the second attempt I put only one round in the mag.. Same exact result. (BCG locked back on empty mag) I stopped there for the day. Broke it down, cleaned the BCG, extractor face (claw,rings,gas tube "Look" OK) etc. w/CLP. I don't see any obvious problem's. The one weird thing is I'm not able to hand cycle a spent round. The BCG comes back about 1/4" and then jam's forcing me to break down the gun to remove the brass. Is this "Normal break-in" for an AR ?

(I saw a bunch of stuff posted about the buffer spring,over-gassing,out of spec. chambers etc. but nothing about not being able to hand-cycle an AR)
 
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Not that I have read. I am currently building an AR too but far off from a barrel so I havent looked to hard sorry


Sent from my iPhone while my co-worker is getting electrocuted.
 
Definitely not normal. Was the whole upper purchased complete (already built) with bolt & carrier? If so I would try different ammo then if it continues call stag before doing anything. An upper bought complete shouldn't need tinkering like that.
 
Another_David said:
Definitely not normal. Was the whole upper purchased complete (already built) with bolt & carrier? If so I would try different ammo then if it continues call stag before doing anything. An upper bought complete shouldn't need tinkering like that.
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Yes the upper was purchased complete.
 
mac67 said:
Yes the upper was purchased complete.
Click to expand...

That's disappointing, eh? Is the chamber clean? If it does the same on different ammo I'm thinking it's the extractor or the chamber, which I wouldn't tinker with it--let Stag fix it.

Only concern I would have about the lower is the buffer and spring. What kind of buffer is it? Is the spring new and does it look to be the right length? If you have a really weak spring it can throw off the timing (too fast) and the bolt will try to extract the casing while it is still under pressure. But if you have new parts from a reputable supplier then that shouldn't be the problem. If you bought the buffer & spring from a gun show / flea market, then I would be concerned.

Not sure what you mean by "not able to hand cycle a spent round". Can you hand cycle live rounds? Like load, don't fire, extract?
 
In God We Trust said:
The reason you are having this problem is because you are using .223 brass and not 5.56 brass. 55 grain rounds are always (as far as I know) .223. On 5.56 brass, you will see a discoloration down at the bottom. This is due to the brass being tempered for strength. .223 brass is designed to be fired out of bolt action guns, 5.56 is designed for the violent cycling of a auto / semi auto rifle. Just use different brass and you should be ok.
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Um, no. I shoot .223 and .556 out of my AR and have never had those issues.

My guess is that the chamber is out of spec or head spacing is borked. I wouls see if you can get your hands on a set of go no-go gauges. That would be my first step.
 
In God We Trust said:
The reason you are having this problem is because you are using .223 brass and not 5.56 brass. 55 grain rounds are always (as far as I know) .223. On 5.56 brass, you will see a discoloration down at the bottom. This is due to the brass being tempered for strength. .223 brass is designed to be fired out of bolt action guns, 5.56 is designed for the violent cycling of a auto / semi auto rifle. Just use different brass and you should be ok.
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Wrong. M193 is 55gr. And 223 will work out of a NATO chamber.
 
In God We Trust said:
If the lip is breaking off the casing it is probably .223 brass. .223 is not tempered like 5.56, but it usually works fine in an AR platform. Maybe he got a really crappy batch. Either way, using 5.56 should fix the problem.
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Nope. If it won't run on .223 then going to a strong case will just mask the problem
 
Another_David said:
That's disappointing, eh? Is the chamber clean? If it does the same on different ammo I'm thinking it's the extractor or the chamber, which I wouldn't tinker with it--let Stag fix it.

Only concern I would have about the lower is the buffer and spring. What kind of buffer is it? Is the spring new and does it look to be the right length? If you have a really weak spring it can throw off the timing (too fast) and the bolt will try to extract the casing while it is still under pressure. But if you have new parts from a reputable supplier then that shouldn't be the problem. If you bought the buffer & spring from a gun show / flea market, then I would be concerned.

Not sure what you mean by "not able to hand cycle a spent round". Can you hand cycle live rounds? Like load, don't fire, extract?
Click to expand...

PSA lower kit w/PSA carbine buffer and spring. When I say I can't hand cycle it, what I mean is I'll place an empty round ("Like load") in the chamber then drop the Bolt. (as if ready to fire)
Using the charging handle I'm only able to open the action about a 1/4" before it stops. And I mean stops ! I had the muzzle against the ground and was pulling on the charging handle w/two hands. It just wont budge...

Don't want to try it with live ammo..... Definitely going to be calling Stag in Monday.
 
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I'll place an empty round ("Like load") in the chamber then drop the Bolt. (as if ready to fire)
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Firing a cartridge will distort and expand the exterior dimensions of the case to the chamber of the gun from which it was fired (with a small amount of contraction on cooling). This could well bind it in a different chamber.

Use a new, fresh round and if you're worried about a discharge take the firing pin out of the BCG before testing it.
 
mac67 said:
PSA lower kit w/PSA carbine buffer and spring. When I say I can't hand cycle it, what I mean is I'll place an empty round ("Like load") in the chamber then drop the Bolt. (as if ready to fire)
Using the charging handle I'm only able to open the action about a 1/4" before it stops. And I means stops ! I had the muzzle against the ground and was pulling on the charging handle w/two hands. It just wont budge...

Don't want to try it with live ammo..... Definitely going to be calling Stag in Monday.
Click to expand...

Okay, I understand not wanting to load it with live rounds at home if it's not functioning right. Not sure about loading spent rounds though--never tried that. I would still try some different ammo like a box of Winchester White box 5.56 from Walmart or Dicks. That will probably be the first question Stag asks, "did you try different ammo?"

If you want, post your location or where you shoot and maybe by chance someone here can meet you and help. Aside from trying different ammo I will swap the lower for a different "known good" lower--although it sounds like your lower should work fine. But it would be one more thing to tell Stag when you call them.
 
mac67 said:
Is this "Normal break-in" for an AR ?
Click to expand...

No.


In God We Trust said:
If the lip is breaking off the casing it is probably .223 brass. .223 is not tempered like 5.56, but it usually works fine in an AR platform. Maybe he got a really crappy batch. Either way, using 5.56 should fix the problem.
Click to expand...

You mean annealed, and yes it is. It's probably an overly tight chamber. Check the headspace (if you're near me you can borrow my gauges.)
 
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im going out on a limb here: 223 remington should function flawlessly in a 5.56 Nato chamber PERIOD so should WOLF or simular steel cased stuff.
Im only a few years into ARs so I am no expert......
1. Did you clean this upper? Get all the anti rust compond shit off it? Clean it 1st. Dont smother the thing in oil when your done. Your chamber and bore should be dry patched before you shoot anyway.
2. Dont do anything other than clean it and try a different ammo. Problem persist CALL STAG they will take care of it.
3. As far as I know STAG only offers 5.56 Nato Chambered barrels, this might have changed in the past few years though.
4. Most of the AR malfunctions I have seen 1st hand are from opperator error
Big one is seeing barrels clearly marked .223 remington and they are trying to blast xm193 or LC 5.56 nato ammo.
http://www.northeastshooters.com/vbulletin/threads/30450-223-vs-5-56-explained
5. I see people soaking their firearms in everything from wd40 to 3in1 household oil, see to many actually spraying wd40,clp ect ect into the chamber?

Also while im in the 223/5.56 ammo thinking.....Now that Hornady is pushing STEEL MATCH ammo are guns going to suddenly be OK for steel use? I dont find the steel being any harder than the brass cases. It is soft shit.
CLEAN<SWAP OUT AMMO>CALL STAG
I own STAG products, had to call on CS for a issue with a upper I purchased on a group buy.....they handled it fast and 100%. They should not have to handle it but they did. Since then both my STAG uppers have seen good amounts of shit ammo it eats,chews,and spits everything I jam into it.
 
2012-02-28_23-55-42_342.jpg



thats the "discoloration" that you're calling tempering. you're wrong. you cannot TEMPER brass. its impossible. brass can work harden, but not be tempered. when you heat brass, whether it air cools or is water dropped, the metal is SOFTENED. not hardened. who'd you take a ballistics class from/through? cause i'd LOVE to know what the hell they were talking about.


once again, its probably a headspace issue. did you purchase the bolt with the barrel? 95% of bolts will headspace on a barrel (especially one cut with a mil-spec/nato chamber)

you could also have a burr in the chamber somewhere. if you're local, we can take a look at it through my borescope. that'll let ya know for sure if theres an issue.

did you save the fired case that had the rim ripped off? you can take some measurements of the fired case and see what's getting caught up. my bet is that it won't close on a headspace gauge, and when you chamber a round, you're crushing the shoulder slightly (which is gonna DRASTICALLY raise pressures, and could very easily cause a stuck case / ripped rim.
 
Thanks for all the the help/advise. I've cleaned it (again) I'm going to pull the pin from the group and try to hand cycle it a bit, then grab some new ammo this week and give it another try. I'll keep you posted. Happy Father's Day to you Dad's.
 
mac67 said:
Thanks for all the the help/advise. I've cleaned it (again) I'm going to pull the pin from the group and try to hand cycle it a bit, then grab some new ammo this week and give it another try. I'll keep you posted. Happy Father's Day to you Dad's.
Click to expand...

I'd check the headspace first. It's not safe to fire if it won't close on a go gauge. I'd hate to see you blow the gun up and get hurt.
 
mac67 said:
PSA lower kit w/PSA carbine buffer and spring. When I say I can't hand cycle it, what I mean is I'll place an empty round ("Like load") in the chamber then drop the Bolt. (as if ready to fire)
Using the charging handle I'm only able to open the action about a 1/4" before it stops. And I mean stops ! I had the muzzle against the ground and was pulling on the charging handle w/two hands. It just wont budge...

Don't want to try it with live ammo..... Definitely going to be calling Stag in Monday.
Click to expand...

That almost sounds like you have a rifle length buffer in a carbine buffer tube.... But that shouldn't be the case with the parts kit you have. Have you checked the buffer tube for any obstructions? Can you fully cycle with the firearm empty? If so then I'm inclined to suspect headspacing as well. Try that test again with a snap cap though. As someone previously mentioned spent cases become fire formed to the chamber.
 
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jasons said:
I'd check the headspace first. It's not safe to fire if it won't close on a go gauge. I'd hate to see you blow the gun up and get hurt.
Click to expand...

I'm thinkin the same thing at this point. I pulled the firing pin, put 3 live rounds in the mag, dropped the bolt. The first round ejected w/a firm pull on the charging handle, 2'nd round stripped off and that was it. The bolt stuck shut. Same deal, muzzle down, 2 hands pulling. Didn't budge. I had to break down the gun a tap out the BCG w/ hammer and dowel. WTF.

ps the spring measures 11" and the gun does hand cycle w/out ammo [hmmm]
 
mac67 said:
I'm thinkin the same thing at this point. I pulled the firing pin, put 3 live rounds in the mag, dropped the bolt. The first round ejected w/a firm pull on the charging handle, 2'nd round stripped off and that was it. The bolt stuck shut. Same deal, muzzle down, 2 hands pulling. Didn't budge. I had to break down the gun a tap out the BCG w/ hammer and dowel. WTF.

ps the spring measures 11" and the gun does hand cycle w/out ammo [hmmm]
Click to expand...

Sounds like either the ammo or the chamber is out of spec

If you had access to go/no go gauges that would be the best thing to use

If not, try some different ammo but don't fire it--just load and unload, which if it can't do that I wouldn't fire it
 

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