Brass remains in chamber, bolt locks back. Am I over gassed?

I am not judging any particular brand. I prefer things that work without proprietary constraints.

Possibly the chamber is so tight that it needs a (looser bolt) ?

And on the other hand tool craft bcg being Daniel Defense (complient) ?

Proprietary non interchangeable parts on an ar suck, like being held hostage.

I like the term mil spec, it implies parts will match / swap to a reasonable degree.
My best understanding is that mil spec doesn't exist on the AR10 platform. I'm just trying to do my best here, working through my mistakes. I simply want a working gun at this point, so whatever the simplest, most reasonably priced option is, will be the one I go with.
 
Kind of my point, no agreed spec a mess.

Cheapest way would be to send the barrel back and get a nice mid tier barrel from someone else.

Several mid grade companies out there with moa or less guarantees for less money.

I'm not getting into a brand pissing war but my last barrel is 1/2 moa for 250$
 
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I am not judging any particular brand. I prefer things that work without proprietary constraints.

Possibly the chamber is so tight that it needs a (looser bolt) ?

And on the other hand tool craft bcg being Daniel Defense (complient) ?

Proprietary non interchangeable parts on an ar suck, like being held hostage.

I like the term mil spec, it implies parts will match / swap to a reasonable degree.
There is no "mil spec" for a large frame AR unless you are talking about SR-25 and KAC everything.

There is no standard. Parts have tolerances and fitment all over the place, which is why you stick with same same for the build to increase likelihood it will not only work, but wear together.

AR's are not legos, despite being able to smash the pieces together.

Think about it. Take a bunch of random parts, from random companies that do not adhere to the same Spec/TDP and expect them to work together when they have never even been tested.

This is why you buy a whole rifle/stick to same manufacutre for large frame AR builds (Such as LMT).
 
There are a number of ways to determine the maximum COAL of a particular bullet weight/profile for your chamber. You can then compare that measurement to the COAL of the factory ammo that has the same bullet to confirm if it is jamming in the lands.
 
What is the BTO measurement on your ammo?
Have you done a measurement, on your chamber, with a dummy gauge to find what the BTO measurement is, where the bullet is "touching the lands"?
Is the chamber a standard 6.5 CM SAAMI chamber where the freebore is .199"?
Or is it a non-SAAMI chamber where the freebore is less than .199"?

With the bullet jamming into the lands it's causing a pressure spike, that is noticable is ARs, but not so noticable in bolt action guns
Hence the brass shavings, and extraction problems.
Do you reload?
Have you tried Hornady 6.5 CM ammo?

And yes, you absolutely need an AGB on a 6.5 CM
 
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There is NOTHING wrong with the bolt carrier..
PER POST 38.... drop round in chamber, it stuck... pulled apart....
THAT is a too short throat !

Shoot a hot round in this chamber, welcome to the stuck case, because it's way over pressure.

SO....
try this.
Pull a bullet. Dump the powder.

Drop the empty new case in the chamber and ease the bolt closed. Hear the extractor snap over the rim. Pull the charging handle to extract the round.

If it extracts fine, you know the function is correct.

THEN. Same round, no bullet, drop empty case in chamber, let bolt slam closed from lock back. Pull charging handle to extract the round.

If it extracts fine, you know the function is correct.

It would be nice to hear back from the OP that he tried this and IF it worked as I described, we KNOW the bolt carrier is NOT the problem, it's the barrel "as chambered".
And, an EASY fix for any half competent gunsmith.

ANY ammunition sold by a recognized manufacturer should chamber and extract MANUALLY from the system. If it does not, it's 95% a bad barrel chamber job, not to SAAMI spec, and a liability issue in the wrong hands.

Best to yall.

Too many companies out there selling parts are into it for the profit, let the buyer beware. And an AR10 can be finicky, new from the factory, put together by a reputable company. And it goes downhill from there.
It's not rocket science though, and, they can all be fixed, and all can be tuned to specific ammo.
Adjustable gas blocks, different buffer weights, and patience.
 
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Follow up:

So I dropped a round in the barrel and couldn't manually eject it. Kept at it and eventually the bcg pulled the brass apart from the round, which remained lodged in the barrel... gun powder everywhere. At that point I called Wilson Combat to discuss solutions and they had a couple interesting things to say:


1) The round staying lodged in the barrel upon manual ejection is common and normal, if not outright predictable. They said the barrel has very tight tolerances, and this came as no surprise.

2) They headspace barrels only to their BCG, and buying their BCG (.308) will likely resolve the issue. Any other BCG will be a crap shoot.

So it appears I'm neither under or over gassed, not anything else at the moment other than mismatched.

Anyone want to buy a barely used toolcraft 6.5 CM BCG?
You dropped this round in "by hand"? Did you then let the BCG fly into battery? Could this have dislodged the projectile enough to enter the lands, causing the stuck bullet?
 
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What am I supposed to do, baby it?
In the grand scheme of things; no. It is, however, a 6.5cm 🤷‍♂️ so there is that....

If the thought didn't cross your mind, then you had not thought of everything. And is that not what this thread is for? Collective thoughts and discussion on whats wrong with your rifle....

The inertia of large frame carriers has been known to do a multitude of strange things. Acting as an inertia bullet puller is not out of the realm of possibility.

But, by all means; beat the fuck right out of 'er to find those weak points. Lord knows I would.
 
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Short throat and tight chamber. I’ve seen that only on some of our 6PPC and 6 Dasher chamberings. Pulling bullets with a bolt gun is one thing….but an AR10? That’s insane
 
Absolutely. Sending the entire upper. Maybe they'll be good sports and tune the gas block as well.
Uhhh…. That gets tuned to your buffer weight, bcg, load, gas system. If they can’t shoot your gun, how can they tune the gas block?
Is this the first AR that you have built?
 
Uhhh…. That gets tuned to your buffer weight, big, load, gas system. If they can’t shoot your gun, how can they tune the gas block?
Is this the first AR that you have built?

Obviously they'll have to fix the barrel/bcg relationship first. If they get it working then the gas system will at least be in the ballpark, and I'll be able to make whatever simple adjustments are necessary at that point.

I've built plenty of AR15s, this is my first ar10
 
Building you do the actual work on the receiver and barrel. Ever chamber a barrel? I have. I have even made my own stocks. Not for a AR but several bolt actions. If you just buy parts and put it together you are assembling it.
My sincerest apologies for having so grossly misrepresented my workmanship, and stealing your gun building valor. I am but a mere assembler of rifles,. You sir, are a mighty builder.
 
OP. take the new empty unfired case that left the bullet in the bore and chamber it, then pull the charge handle back to see if you can extract the case easily. If you can you know it's not a headspace problem and the idiot at Wilson that told you all that crap is just trying to cover up the issue. I expect this to be the case since the bullet was left in the bore and that was what was sticking.

I know who makes Wilson Combat barrels(not Wilson) and they try to do it right but if they get a bad reamer from PTG then all bets are off.

If you want to correct the issue on that barrel, buy a reamer from JGS, Manson or Clymer. Pull the barrel out of the receiver to ream the chamber.
 
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Their barrels are crude. The work done to them is pretty good. But the blank itself seems like it was made by Bear Creek.
All the work done to those barrels is done by the same company. They drill the deep hole, pull the button, stress relieve, profile, chamber, thread and crown. It is not like little home gunsmiths that buy blanks and then finish them.
Compare the crown on a BCA barrel to a Wilson, the 11 degree crown on a Wilson(not Wilson Arms) is sharp enough to cut you. A BCA like most is flat with a chamfer.
 
OEM barrel manufactures make barrels for all of these big names you see, Rem, TC, Ruger, Model 1 sales, LWRC etc( just examples). The same company may make the barrels for all of those companies. The difference between the barrels made by the same OEM is the specs. If you have a company that doesn't really know anything about barrels(those that may have been selling bicycle parts last year) they write a PO to the OEM manufacturer with crappy specs and you get crappy barrels. The next company may be owned or ran by someone that knows what he is doing, he writes a PO with good specs and extra steps you end up with good barrels.
Then again some OEM companies just turn out crap, regardless of the specs. If the OEM uses HSS reamers and the chambers are so rough they must be sanded and polished, walk away. Same goes with the bore and button pulling, some experiment with pulling speeds and lubricants to make sure they get a smooth bore, others yank or push the button through and then the HAVE to lap the bore to make it smooth. Some couldn't cut a good crown to save their life.
 
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I had a similar problem with a mainstream brand AR-10 chambered in 6.5 CM. It was headspaced at the factory, so I assumed I over-gassed and put an adj gas system in. Problem persisted. Upgraded to a Ruber City Armory BCG, the problem persisted. The chamber was cut wrong.
I replaced it with a proof CF BBL and had a professional gunsmith install the BBL and it's an amazing rifle now. Granted I did change from 6.5 creed to .308 for... reasons. And with an AR-15 stock and LPVO it makes for one hell of a light-weight battle rifle.

This is one BAMF now.
20190504_115221.jpg
 
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6.5cm AR10, Aero upper/lower/lpk. Toolcraft 6.5cm double ejector bcg. Odin Works AGB. Tubbs flat wire buffer spring, MP PRS Gen 3. Wilson combat 22" stainless fluted
Get rid of your double ejector bolt, use JP enterprises high pressure bolt also superlative Arms Adjustable gas block. The oden works loosen up. Plus the JP bolts have a 1 piece gas ring & make sure your bolt is lubed heavy lucas synthetic oil.
 
Get rid of your double ejector bolt, use JP enterprises high pressure bolt also superlative Arms Adjustable gas block. The oden works loosen up. Plus the JP bolts have a 1 piece gas ring & make sure your bolt is lubed heavy lucas synthetic oil.
What’s wrong with the x2 ejector bolts? Seekins Uses them in their SP10 rifles and I believe LMT does as well
 
Get rid of your double ejector bolt, use JP enterprises high pressure bolt also superlative Arms Adjustable gas block. The oden works loosen up. Plus the JP bolts have a 1 piece gas ring & make sure your bolt is lubed heavy lucas synthetic oil.
Hmmmm yeah, the only valid suggestion is heavy lubing....
 
Looking at the picture of your pulled bullet, it seems like where the bullet touched the lands is way too deep on the bullet. For a SAAMI chamber the bullet should have jump to the lands but in your picture the bullet seems jammed into the lands well past the tangency of the ogive. Jamming a bullet that much would create significant pressure issues that would expand the case excessively and cause extraction issues. It seems like your barrel is defective. I agree to buy a go and no-go gauge and check your headspace. I would also check the OAL of your S&B cartridges to make sure they aren’t overly long.
 
A lot to read here, so I only read some of it.

Does the fired case have black soot on its forward end? Is the gas system length less than rifle length?

A 140gr projectile, practically by definition, employs a slower propellant; which means that peak pressure occurs further down the barrel. Combined with a shorter Length gas system (if that's what you have), this forces the bolt to unlock and the carrier to attempt extraction while there is still significant pressure in the case. Usually the case resists this and sticks in the chamber, often with some evidence of excessive extraction energy being exerted on the the case rim. Some signs of ejector drag can also be present.

This can be as easy to fix as replacing the ammo with another load, preferably with a lighter weight bullet.

The cause is that power peak and its lateness. The case is binding to the chamber with far too much force for the extraction process to succeed. It causes something called dwell, which means that the pressure hangs in there far longer than is useful. This can cause extractors and other pricey parts to come apart. It's often found in extra long barrels (over 20") , where the bullet remains in the barrel during the longer distance before emergence. In the process, the pressure dwells in the barrel long enough to inflict wear and damage that exceeds typical design limits.

I know that folks are often looking for that semi that reaches far enough to amaze the crowd. But the techniques that can bring this about with the bolt guns usually don't work so well with the AR's. I my situation, I accept the limitations, and try to build and operate AR's which cling as closely as possible to the original AR-10/308, AR-15/.223 as is reasonable. Getting the dreamed-for performance can often actually be achieved, but it's by those who are not lesser men such as myself. I stay away because it gets expensive replacing those parts I wreck when I work beyond my own lesser skills.

Another remedy can be to employ a longer gas system, but this advice comes far too late to help you at this particular time.

Before doing any of these, try this....

Since the gas block is adjustable, load the magazine with one round only, then crank the block all the way closed. Then reopen it in small increments after each shot until the bolt locks back. Then open it up one more small increment, to account for the inconsistent powder charges in most commercial loads. If this works, you should not need to resort to any of the above remedies.

When the time comes where you are making your own ammo; it helps to work with faster propellants and lighter weight bullets in AR's than one would often use with bolt guns.

Hoping this helps.

Greg

PS I learned a lot of this in my experiments on the 6.5 Grendel. I built two, the only difference being barrel lengths, 20" and 24". The 24" eradicated its extractor. Part of it was too much powder (the 6.5G can be quirky and shy when revealing its pressure signs) and the extra 4" of dwell overstressed the extractor for longer time intervals than would be reasonable. I replaced the extractor with a J-P Grendel Special, and that worked 'OK'; but from now on, I'm sticking with 90gr TNT's for that barrel.

So..., small differences can make for insurmountable consequences. Remember that.

The 20" thrives on the 120gr Gold Dots I started it out with. I am confident enough to have bought a spare identical (AR Stoner) barrel. These barrels are built as Bull Barrels and can get heavy to carry around. But they're also not a heavy as my M-14 that I lugged around in 'Nam for 13 months, so I'll cut short the additional whining on that part. I just wish they were available as a lightweight barrel. Meanwhile, that weight pays off in pretty good accuracy at 20".

I can understand why there's an Eastern European nation seriously testing it as a replacement infantry chambering.

FWIW, I am not a signatory of any international conventions.
 
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A lot to read here, so I only read some of it.

Does the fired case have black soot on its forward end? Is the gas system length less than rifle length?

A 140gr projectile, practically by definition, employs a slower propellant; which means that peak pressure occurs further down the barrel. Combined with a shorter Length gas system (if that's what you have), this forces the bolt to unlock and the carrier to attempt extraction while there is still significant pressure in the case. Usually the case resists this and sticks in the chamber, often with some evidence of excessive extraction energy being exerted on the the case rim. Some signs of ejector drag can also be present.

This can be as easy to fix as replacing the ammo with another load, preferably with a lighter weight bullet.

The cause is that power peak and its lateness. The case is binding to the chamber with far too much force for the extraction process to succeed. It causes something called dwell, which means that the pressure hangs in there far longer than is useful. This can cause extractors and other pricey parts to come apart. It's often found in extra long barrels (over 20") , where the bullet remains in the barrel during the longer distance before emergence. In the process, the pressure dwells in the barrel long enough to inflict wear and damage that exceeds typical design limits.

Another remedy can be to employ a longer gas system, but this advice comes far too late to help you at this particular time.

Before doing any of these, try this....

Since the gas block is adjustable, load the magazine with one round only, then crank it all the way closed. Then reopen it in increments after each shot until the bolt locks back. The open it up one more small increment, to account for inconsistent powder charges in most commercial loads. If this works, you should not need to resort to any of the above remedies.

When the time comes where you are making your own ammo; it helps to use faster propellants and lighter weight bullets with AR's than one would often use with bolt guns.

Hoping this helps.

Greg
Thanks for the input.

1) It's a rifle length buffer system. I've tried playing with different buffer weights and springs, to no avail.

2) I've exhausted every possible gas block adjustment I can make, also in conjunction with varying buffer weights and springs.

The bottom line is, by default, in nearly every scenario, the brass fails to extract, and the process to extract it is brutal and wholly unnatural. I cannot manually extract an unfired round, nor a fired round. Something is terribly wrong here, and all evidence points toward the barrel.

I'm sending my full upper to wilson combat today, and we shall see what they have to say about them matter. I'll certainly be reporting back here on their findings, and actions.

My guess is that they either ream or replace the barrel.
 
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Building you do the actual work on the receiver and barrel. Ever chamber a barrel? I have. I have even made my own stocks. Not for a AR but several bolt actions. If you just buy parts and put it together you are assembling it.
So unless you tards are machining your own reciever from bar stock or rifling your own barrels your just an assembler as well. These days with prefit / shouldered / barrel nut options attached to a reciever in a drop in chassis there is not any God damn difference anymore.

Most manufacturers brands are just assembled from vendors parts with a proprietary logo.


I once mentioned "building an AR" in front of my gunsmith and I instantly felt ashamed.
Actual gunsmiths are hard to come by. My son went to school for two years and now trying to apprentice with the same smith that has taken care of my stuff since the early 1980's.

Inletting a wood stock is an artisonal thing, craftsman, one piece of gunsmithing skill.
 
I think that's an excellent first step to a successful fix.

Were they I, they would replace the barrel with one including a +2" length gas system.

Personally, I think your rifle, as is, might do better with 120gr factory ammo.

Then, personally, I would look into a second upper (maybe build one?) using a 22" to 24" barrel that has a +2" gas system. I understand that stepping into such a venture can come with some trepidation; but believe me, if such an Old Duffer as I can build these things, damned near anyone can. Meanwhile; I make it clear; I am NOT an expert.

If you have an AR-15 .223/5.56, consider building an Upper with a 24" 1:7" Twist barrel. It will handle loads of up to 77gr, and makes a nice beginner's project as well as a decent Varmint gun for both two and four-legged Varmints. Optics above 24x are often rich men's scopes, and be done without quite nicely for a Varmint gun. Once done, you'll feel a lot better about such ventures. Just understand that AR10's have no Mil spec, and it typically works better to match brands of upper and lower receivers.

The hardest part is building up the courage to start. That's I what I did and I've had a hand in it since then. Seven AR's so far...
 
"So unless you...are machining your own receiver from bar stock or rifling your own barrels your just an assembler as well"

Yep, and I have stressed this point as well in the past; I do consider myself a builder, but not of guns.

I scratch build (and fly) rubber band powered free flight scale model aircraft, staying pretty consistently with those in the 1/24th scale (1/2" = 1ft). This is a holdover activity from the early 20th Century; I began with it in 1949.

I start with plan images on the internet, usually .PDF files, download, then scale them properly, then print them out in tile format and join them as complete plans. The plans are taped to ceiling tiles (2' x 2', they can be pierced with straight pins), covered with wax paper (transparent and glue doesn't stick) and structures are built right on the boards.

My components are Balsa Wood sheets, Tissue Paper, Cellulose Glue, Piano Wire, and long rubber bands.

I occasionally design and draw my own non-scale plans or modify scale plans to create plans for scale models that don't exist in plan form, as I am currently doing with a 1/24 Kawasaki Ki-100 1a "Goshikisen" (Army Fighter Type 5) Interceptor, cobbled together at the end of WWII to bring down the B-29's over Japan itself. It was considered one of the finest interceptors, of any nation, during that war.

Once completed; the structures are covered with fine tissue paper, gently shrunk down by passing the covered structure through an atomized cloud of 90% isopropyl, and fixed to prevent further shrinkage (and warped structures) with one or more coats of Krylon clear brushing lacquer. Usually the color of the tissue is very close to perfect (I have BIG collection of colored tissue paper), so pigment painting becomes optional, but camouflage patterns and aircraft markings must be masked and applied using acrylic paints and an airbrush.

Final step is trimming/adjusting the aircraft to fly under both rubber power and as a glider when the power runs down. Propellers can be bought but are traditionally carved, canopies are drawn using heated clear plastic and vacuum (I use a purpose built dental vac-former), and just about all of the wire parts are bent and cut manually.

FWIW, I've been spending a lot more on model airplanes than on guns this last year; and the way the future is looking, I may be out of guns completely and into model airplanes permanently by the and of this year. The other site I haunt.

FWIW, I don't do frustration well...; and these days guns are just one huge mass of frustration.

...As the rest of you are finding out...

Greg

PS: For Example...
 
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