Help please

[UPSTATERAM]

Hey guys, I’ll give my situation and any help you can give I would appreciate. I’ll give a list of my parts and go from there:

aero lower, vltor a5 buffer tube, Springfield orange buffer spring, h3carbine buffer 5.2oz, Gesielle ssa-e, aero upper receiver, dpms bcg, carbine length gas, 16”dpms barrel. .308

so when I shoot the spent brass stays right in the barrel and doesn’t extract. My bcg try’s to load another round that doesn’t make it into the chamber. I drop, clear the half loaded live round, and charge the bcg and let it go forward, when I manually pull it back it will eject the spent original case at that point.

I’m more of a bolt action guy so any help is appreciated. I don’t think it’s the buffer or spring ? I ordered a toolkraft dual extractor BCG hoping that will solve my problem. Any thoughts or direction? I don’t own a go/ no go gauge. The upper I bought was a complete upper off gun broker and the seller was vague but said it was built buy a reputable place and was on clearance so they were helping to move them.

Thanks for your time helping me troubleshoot this.

Tom

 

[sinister]

Carbine-length gas and a spring that's over-rated for the time-pressure curve. Try a standard or Tubb flat spring.

Is your H3 buffer A5 length?

 

[UPSTATERAM]

Okay. Which color Sprinco would you recommend? Any specific Tubb?

my h3 buffer is carbine length EXPO is the brand. Jus the buffer tube is the a5 which the guy at vltor said works well with a carbine length buffer.

Thanks for your help.

 

[357Max]

Carbine gas on a 16" 308, I bet it's unlocking while the case is stuck to chamber.

The first thing you should check is to confirm your extractor spring has an oring on it (it should)? If it does you'll likely have the same problem with the new Toolcraft. If it doesn't then try the Toolcraft before changing more parts. The Toolcraft extractors are sprung plenty stiff.

My money is on to much gas & trying to unlock to early.

If the Toolcraft doesn't solve it I'd do the following in this order.

1st - Add an adjustable gas block. SLR would be my choice.

2nd - I'd recommend an H4 carbine buffer 6.8 oz.

Home

DetailsThe mission at Primary Weapons Systems is to provide the highest quality sporting/tactical rifles and accessories for sportsmen, military, and law enforcement at a fair, competitive price.The PWS MOD2 Carbine Buffer is perfect for shooters who need to reduce cyclic rate or dampen recoil...

www.primaryarms.com

3rd - For a buffer spring I'd recommend 1st choice - ArmaLite #EA1095 rifle length buffer spring or 2nd choice - JP OSR 308 buffer spring + 7% pressure & OD ground
FWIW - I am running an A5 tube on mine with the rifle length Armalite #EA1095 and a Xheavy 8.5 oz carbine buffer. Mine is rifle gas on a 18" barrel though.

 

[sinister]

In an A5 tube try either the standard carbine spring or the Tubb spring for 30-caliber rifles.

Sprinco recommends the RED spring for 308s using A5 tubes and standard-length carbine buffers. The orange spring is for standard 7" 5.56 buffer tubes with shortened CAR308 buffers. They will slow the bolt carrier group from unlocking a bit, but will also slam the bolt carrier group forward quicker as well (out-running your magazine spring trying to push the weight of 30-caliber rounds into the feed-path , resulting in your described stoppages).

The short carbine and mid-length gas tube distances mean the pressure in the barrel is still rising / powder is still burning - creating expanding gas -- while pressure is trying to unlock the bolt and extract the brass while the case body is still obturated against the chamber wall. Check your case rims -- the extractor might be trying to rip them off the base of the case.

From Sprinco:

"RED Spring": EXTRA Power Buffer Spring, Best option for 16"+ 5.56 barrels with carbine length gas system platforms with standard front sight towers and H buffers, 16" + BBL gas piston guns, *some* suppressed shorties,and later generation Colt LE6920's, 9mm, 6.8 SPC, 6.5 Grendel, .458 SOCOM, 450 Bushmaster, .500 Beowulf, and assorted "Thumpers" using standard 7" depth M4 extension tubes. AR-10 Carbines (E.G. Armalite, Noveske, LMT) using deeper extension tubes and standard length carbine buffers to accommodate the longer .308 BCG also use the "RED" Spring. Please call us to discuss successful historical "recipes" for implementation of the RED spring in .308, 6.8 SPC, etc. RIFLE length extension tube platforms. Color Coded RED. NOTE: NOT for use in .308 Carbines using standard 7" M4 extension tubes and short, stubby buffers. (Use our "ORANGE Spring" below for that specific platform approach application.) NOTE: If you have a seriously overgassed .308 Carbine which has the deeper AR-10 platform receiver extension tube running an H3 buffer firing 175 Gr. Projectiles and / or suppressed, many shooters have experienced success using the "ORANGE" spring, as it is still heavier than a "RED" spring in that application.

"ORANGE Spring": The ONLY specifically engineered EXTRA POWER Buffer Spring for .308 Carbine Platforms using standard 7" Depth M4 extension tubes and .308 short 2.5" buffers (Including aftermarket "heavy buffers.") You cannot clip coils from any other commercially available buffer spring to yield the proper spring loads for this application, especially in heavily gassed .308 carbine platforms. We started from scratch on this design to provide Operators with a viable alternative to existing OEM and aftermarket offerings. Platforms known to exist using this approach include DPMS, Bushmaster (Post 2010), Remington, CMMG, Mega, SA Defense, Colt 901, Rock River Arms and many others. Color Coded ORANGE."

 

[UPSTATERAM]

@357Max Okay cool. The oring is pretty clear to see around the extractor spring? Sorry for the noob question.

Hopefully the toolkraft works. Will changing a bcg mess with fitment of the bolt and how it’s supposed to fit?

Thanks for the spring recommendation. I didn’t know a rifle length spring would work with this but that’s good to know when troubleshooting this setup. Also my carbine length gas block is mine is 7.5” if that’s meaningful at all.

 

[UPSTATERAM]

@sinister thank you. I’ll try those springs. I didn’t read the description enough which is my fault. I’ll try the ones you recommended and maybe grab a red Sprinco too.

I’ll check the case rims I saved some of the brass. I’ll mess with the spring and try the order @357Max mentioned and hopefully I’ll be good to go from there. I have two bcm setups I built that are flawless and would love to get this reliability up.

if I switch over to the springs you guys mentioned or the redSprinco should I still increase my buffer weight to that h4 @sinister @357Max?

Thanks guys.

 

[Precision Underground]

Are you saying the case stays in the chamber and the bolt pushes another round on top of it?

 

[UPSTATERAM]

@Precision Underground the case stays in the chamber and the bolt try’s to push another round forward and it makes it approx. 30–40% out of the magazine but gets stuck. I’ve never seen where the brass doesn’t come out of the chamber but that’s exactly what’s happening.

 

[hlee]

What does the head of the spent case that stays in the chamber look like? Pics of that would help.

 

[sinister]

Think about it this way:

308/7.62 uses twice the powder to push a bullet twice as heavy as a 223/5.56 -- yet DPMS chose the short 7" gas tube for 16-inch carbines. Gas port diameter is going to be tricky, and problematic if you add a suppressor and even higher - longer back-pressure.

Armalite considered the problem and went to mid-length. Better, but still not great. Knights went to rifle-length gas in a 16-inch. Even better.

Best might be to extend the gas port out another two inches further -- a la M14 and M1 Garand -- to extend the time-pressure curve for extraction and ejection. The gas pushing the tappet and the comparatively massive M1 and M14 bolts and op rods can be comparable to bolt carrier groups and buffers.

 

[BikePilot]

@357Max Okay cool. The oring is pretty clear to see around the extractor spring? Sorry for the noob question.

Hopefully the toolkraft works. Will changing a bcg mess with fitment of the bolt and how it’s supposed to fit?

Yes, I think it will. The headspace will need to be checked/set between the new bolt and barrel.

 

[UPSTATERAM]

What does the head of the spent case that stays in the chamber look like? Pics of that would help.

I’ll take some shortly. I don’t know if it’ll be a true help since I had to manually charge it and pull the bolt back to extract the Empty shell. I’ll take a few pics shortly.

 

[UPSTATERAM]

@sinister yea that makes sense. adjustable gas block being an option too? I’ll try this toolkraft dual extractor and and see where that leads me. I thought it was odd to have a 7.5” gas carbine but I got the complete upper for $699 which I thought was solid. I tried asking what port diameter they drilled but the guy who sold it said the builder doesn’t give that for some reason. I don’t have the tools to measure properly either. I won’t run suppressed since I’m in the communist state of NY. “Upstate” at least.

 

[Bolo]

Heya bud,
All good advice up above, but one additional q.
If you load up a single round in the mag, what happens when you fire? Do you get extraction and does the BCG lock back?

 

[bfoosh006]

Make sure your barrels chamber is clean. If you could...Post a pic of a fired case , looking for any scuff marks.

IMHO, a carbine length gas system in a .308 barrel is probably going to benefit from a Adj. GB greatly. Limited gas flow allows the chamber pressure to drop, just enough to allow extraction at a more moderate chamber pressure.
The fired case is still being pressed against the chamber walls at high pressure with the carbine gas system while it is trying to extract.

I will second the Tubbs 308 Flatwire choice, I use them in all my Large Frame AR's.... 308 and 6.5CM, All gas system lengths and stock patterns. ( LaRue sells them cheap )

You can get a decent idea of gas port size with a good drill bit set or order a few at specific sizes ( see link ) ... use the shank end. At least then you can know if the GP is "kinda" ok. IMHO, it is important to know. ( I have seen some wildly out of spec sizes on unknown barrels. Friend had a .105 GP on a AR15 Carbine length Gas... he brought it to me because it kept breaking hammer pins ! )
https://www.custompartnet.com/drill-size-chart

 

[357Max]

@357Max Okay cool. The oring is pretty clear to see around the extractor spring? Sorry for the noob question.

Hopefully the toolkraft works. Will changing a bcg mess with fitment of the bolt and how it’s supposed to fit?

Thanks for the spring recommendation. I didn’t know a rifle length spring would work with this but that’s good to know when troubleshooting this setup. Also my carbine length gas block is mine is 7.5” if that’s meaningful at all.

Yes the oring will be obvious. Pictured below is a Nitride Toolcraft extractor. As always you should check headspace with a Go gauge (with ejector removed). That said changing BCG/bolt should not affect fitment. Unless you've ordered the Boron/Nickel/trick coating flavor of the week. Those coatings can cause problems with head space. Nitride coating does not add much to the surface & is one of the better BCG coatings. DLC is best adding only .0001

I stand by the order I recommended.
Adj gas block
Heavy buffer H4 Carbine
Armalite, JP, or Tubb's flatwire (rifle length spring)

 

[UPSTATERAM]

Heya bud,
All good advice up above, but one additional q.
If you load up a single round in the mag, what happens when you fire? Do you get extraction and does the BCG lock back?

that’s a great question. I took it to the range real quick before work. That’ll be the first thing I try. I should be able to try again sometime
This week.

 

[UPSTATERAM]

@bfoosh006 thanks a lot for that advice. I should order some pins. Just pop the Handguard off and easy to measure from there? What would be an in spec or reasonable hole for a 7.5” GB and 16” barrel?

 

[UPSTATERAM]

@357Max thank you. I’ll try in that order once I get this toolkraft dual extractor that shipped already. It’s the black nitrate one so that should be good to go.

is my DMPS BCG worth keeping? I put it for sale in the PX. Thanks a lot for that pic that’s definitely clear as day. Going bear hunting shortly but I’ll try to check that out later tonight or this week.

Thank you all very much.

 

[Precision Underground]

If you charge twice does it chamber then extract the round? Def need an adjustable gas block on it, extraction issues or not. That’s going to be a lot of gas really fast on a carbine system.

 

[sinister]

so when I shoot the spent brass stays right in the barrel and doesn’t extract. My bcg try’s to load another round that doesn’t make it into the chamber. I drop, clear the half loaded live round, and charge the bcg and let it go forward, when I manually pull it back it will eject the spent original case at that point.

Tom, it sounds as if your chamber is properly dimensioned and the extractor and ejector work as designed. I don't think there's anything wrong with your bolt carrier group.

This points to the gas system and your pressures. I'm interested to hear what your gas port size is, knowing it's already carbine-length.

If it was my rifle I'd swap barrels for one using a rifle-length gas tube, and an XH buffer for the H3. There's probably a reason it was on clearance.

A good gunsmith can salvage it by welding or capping the present gas port and locating and drilling one further out for a rifle-length tube.

 

[UPSTATERAM]

If you charge twice does it chamber then extract the round? Def need an adjustable gas block on it, extraction issues or not. That’s going to be a lot of gas really fast on a carbine system.

I’ll try that tonight in the basement. Maybe I didn’t need the toolkraft but o well it’s ordered.

 

[UPSTATERAM]

@sinister you’re probably right about clearance. I usually have the buy once cry once mentality but after building two BCM recently I was trying To keep costs down as this is for drives and hunting thick woods upstate NY.

I wonder what the port size is too. Was trying to keep it short at 16” so it could be maneuverable in the woods.

Any chance the toolkraft will help or sounds just more gas related? I have one pretty good smith but I’m not opposed to mailing it out to a really good one. Maybe with the new BCG, if i buy an adjustable GB and have it changed to rifle length I’ll be in business.

 

[sinister]

This is my short Armalite AR-10. It's got a 16-inch 1-10 twist Criterion, rifle-length gas. Might be handy for hunting upstate. A LOT more accurate than the Winchester 100 I started with:

 

[UPSTATERAM]

@sinister that looks great. Hopefully the tweaks I make will have it good to go. I’ll post brass pics and rigor now.

 

[UPSTATERAM]

:

 

[Precision Underground]

Pull the bolt and see if the case rim is seating under the extractor easily and being held well. I would think there would be more of a mark on the brass if the gas was blowing a fully seated ejector off the rim

 

[UPSTATERAM]

That makes total sense. I inspected all 6 pieces of brass and none has many marks at all.

I’ll try a a new buffer spring and see if this toolkraft helps the situation at all.

 

[bfoosh006]

After seeing your pics, and I don't see anything bad, I'd still clean-up that chamber a little.

Doing that will "aid" easier extraction.... and allow your tuning to be more effective.

In for any gas port size readings... this will help decide the best solution.

 

[UPSTATERAM]

Absolutely. I’ll try to get that measurement this week and I’ll keep the thread updated. Appreciate the help.

 

[Bolo]

Looks like a pretty rough chamber, and timing might be off just a bit and unlocking early.
For comparison purposes, a few pics..

Top to bottom: unfired, overgassed, correctly adjusted. Note pressure signs on the primer- it's extreme and yours isn't that far out of whack. Hard to see, but the 8 to 10 o'clock position has a bit of smear and the rim is warped. Not a big obvious gash.

L to R: unfired, overgassed, adjusted. Rim damage is a bit clearer, with lots of carbon blowback. This was one of the ones that barely extracted, and the damage to the rim is similar to one of your pics.

My suggestion is to polish up the chamber and go with a stronger buffer spring for starters.

 

[JbBooks]

You do know you’re getting a dual “ejector” bolt not a dual “extractor” bolt.

 

[RyanScott]

I have a Criterion rifle gas barrel like Sinister uses for sale in the PX.

 

[UPSTATERAM]

I have a Criterion rifle gas barrel like Sinister uses for sale in the PX.

could you send me the link please?

 

[UPSTATERAM]

You do know you’re getting a dual “ejector” bolt not a dual “extractor” bolt.

Yes, poor wording on my end. Hopefully it’s a better option than my dpms and I didn’t waste my money.

 

[UPSTATERAM]

@Bolo thanks for the pics, I can see what you’re saying. Your brass that barely extracted is pretty similar.
I’m going to test fire a few this am and see what happens and post the results.

 

[RyanScott]

could you send me the link please?

Accessories - 16” Criterion 308 AR-10 barrel, JP bolt

LNIB, JP bolt carrier completion kit, gas tube. $500 shipped. Zelle, Venmo, PayPal, fees at your expense. PRICE REDUCED 10/17: $425

www.snipershide.com

 

[sinister]

Right there's a turn-key solution. Criterions are solid, the JP bolt is the cherry and whipped cream.

 

[UPSTATERAM]

@sinister @357Max @Bolo

I shot 3 this am I’ll attach pics. First was a single round. It didn’t stayij the barrel it ended up almost over the empty magazine but slightly before it The 2nd round didn’t come out and was in the barrel I took pics as it sat. I shot the 3rd round and it wouldn’t come. I recharged the BCG a handful of times and it wouldn’t come out... ? I have to
Wait until I get home to put a cleaning rod down the barrel to pop it out.

Does this help at all?

 

[357Max]

Remove your bolt from carrier. Pull the extractor out of your bolt, it’s easy just put pressure In with your thumb tO relieve spring pressure and push the pin out with a small punch.
Take photos of the spring & of the lip portion that grabs the shell.
Regardless if the oring is present, beefing up the extractor is lipstick on a pig.
Needs less gas, delayed opening.

Even if you change barrels you’ll not regret the adj gas block and heavy buffer purchase.

 

[sinister]

Good looking rifle.

Certainly looks like a short carbine gas problem.

The hardware all seems to be doing its job as designed. The extractor claw is trying to pull the case out but rolls off the rim after trying to yank out the case while the brass is still swollen and in friction-contact with the chamber.

Again, a good gunsmith might be able to salvage this particular barrel. Mid-length may work OK since you're not suppressing the gun, while rifle-length gas would give you the most benefit. Besides not functioning, when you shoot it how's the accuracy? Worth keeping?

To get this rifle humming you're going to need to balance some patience and money. You have lots of barrel options (to include trying to salvage this one).

Primary Arms carries this 16-inch rifle gas Criterion for $278.99:

 

[Bolo]

Something I didn't notice on the original pics, and I can't tell if it's camera tricks or the real deal... it looks like the case is wider in the rough area compared to the shiny clean area just forward of the case head.
Can you get a caliper on that and tell me if I'm nuts?
If the middle of the case is ballooning out, I'd think that chamber would be no bueno.

 

[UPSTATERAM]

@sinister thank you for your knowledge, sir. I’m going a different route and going to sell this. Bought an aero mid length complete upper by some miracle they had one in stock when I looked today which it hasn’t in months and months. 16” mid length with all aero equipment. I’ll get an aero bcg and hoping this will be good to go. If anything ill
And an adjustable gas block and should be ready to rock? What are your thoughts on my current h3 buffer at 5.2 oz ? I’ll get that tubbs spring.

thanks in advance!

 

[UPSTATERAM]

@Bolo measured and there all consistent. I think they were 3.454 offhand but not in front of me.

 

[UPSTATERAM]

@357Max i had a coupon and got a good deal on the aero complete upper and will buy aero bcg and return the toolkraft. I will probably get an adjustable gas block put in. If you see my response to sinister above what Weight buffer would you recommend? I’ll get that tubbs buffer spring like you guys said. Then I should be ready to rock!

 

[sinister]

The H3 should work with a carbine spring. I'm a cheap bastid and use an XH buffer to try to get as much life out of cartridge cases as possible. An adjustable gas block can't hurt.

 

[Bolo]

@Bolo measured and there all consistent. I think they were 3.454 offhand but not in front of me.

Ok, so it's my eyes then. Either way, I think you'll be much happier with midlength gas.

 

[Ravenworks]

@sinister thank you for your knowledge, sir. I’m going a different route and going to sell this. Bought an aero mid length complete upper by some miracle they had one in stock when I looked today which it hasn’t in months and months. 16” mid length with all aero equipment. I’ll get an aero bcg and hoping this will be good to go. If anything ill
And an adjustable gas block and should be ready to rock? What are your thoughts on my current h3 buffer at 5.2 oz ? I’ll get that tubbs spring.

thanks in advance!

Dude,you need to STOP WTF you are doing and start reading up.

What makes you feel it's okay to buy shit,use it and then return it?
That is REALLY fucked up.

YOUR biggest problem is buying shit and having no clue as to why.

So you're buying an Areo BCG, did you know Toolcraft makes their bolts?

You should go back and RE-READ this thread,all the answers are given to you.

 

[UPSTATERAM]

Hey @Ravenworks how about you chill the fuck out. I said I’m returning the toolkraft that is en route I haven’t gotten yet— reading comprehension bud. I’m selling the other upper and will be honest about the 20 rounds through it and luckily live in america where capitalism is alive and well.

I have read this thread and appreciated everyone who helped and have learned. If you want to be constructive or helpful great; if not, stop wasting both our time.

Its confirmed that toolkraft makes their bolts? I only knew it to be speculation.