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AR-10 Barrel

IMO... order the BCG you want and headspace gage it later it if you have a problem. You can't change the headspace, checking it is purely diagnostic. I would be more concerned about HS if you were discussing a low end barrel.
Thanks. I believe I’ve got everything figured out now. Will post pics when I have it together
 
Krieger and Bartlein are going to be your best of the best. I have 10-12 in the safe in 308 and 6.5cm on multiple MEGA uppers

Headspace bolt for sure, only way I role.

In regards to BCG, I'm a JP or RCA only guy.
The RCA HM coated High Pressure bcg are top of the line.

Little secret, you can buy their 350 398 HP+ BCG for $180 here. They call it their blem, not mechanically but laser engraving, cosmetic they say. Guess what, I've bought tons of these, I've never had one arrive that looked anything different than my non-blems. Same box, nothing wrong with it.

Also, they say backorder. I place an order many times on these blems that say backorder and they all shipped in a few days

You were 100% right about the Blem RCA. I “backordered” it at noon and it’s already shipped!
 
So...I was just reading RCA website description on this blem BCG. Says you can now specify regular gas key or adjustable gas key in the notes. Will come with whatever gas key you choose installed!

That's new. I always paid the extra $40 or so and bought the AGK. Makes this blem deal even more of a smoking deal!


I see the 5.56 blem BCG also is your choice of regular or adjustable billet gas key.

I guess I'm ordering another handul of these.
 
So...I was just reading RCA website description on this blem BCG. Says you can now specify regular gas key or adjustable gas key in the notes. Will come with whatever gas key you choose installed!

That's new. I always paid the extra $40 or so and bought the AGK. Makes this blem deal even more of a smoking deal!


I see the 5.56 blem BCG also is your choice of regular or adjustable billet gas key.

I guess I'm ordering another handul of these.
I thought the ease of adjustment might outweigh the other advantages of the gas key. If I thought I could have got the adjustable gas key free I would have gone for it, but whatever
 
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Gotta ask a couple more questions. Why is y’all’s opinion of having 1. black receivers and FDE furniture and handguard vs 2. all FDE except for a black lower vs 3. total FDE? Also I can get a complete Aero lower for less than it would cost to get a stripped ambi one and build it out. Is it really worth it?
 
Most everything I have is black...goes handsomely with the trem, "black rifle".
I did order "Urban Decay" color on sale that was heavily discounted.
Other than that, "I'll be the man in black."
The AR is a tool...who cares about its color. Rattle can it.
 
Adjustable gas key could be an advantage
With a pin & welded muzzle device, where the gas block will not slip over the welded muzzle device if it need changing....maybe. I'd just machine it off.
Other than that, no thanks, especially on a working tool, something else to cause problems...a solution looking for a nonexistent program.
 
A bolt closing on the round, only tells ya, the bolt closed on a round.
Is the round inside specifications? Is the chamber inside specifications?...some are not, even from the factory.
Ammo recalls come to mind.
You need a go gauge, and a no go gauge, to be sure, your chamber is correct.
Then adjust the ammo if ya handload, to the chamber you know is correct.
 
Are y'all not getting early pressure signs or aggressive ejection with the Toolcraft double ejector bolts?

Every double ejector large frame bolt has given me early pressure signs.

I switched to the JP BCG for the 6.5 Creedmoor and haven't had that issue, but damn they are expensive.
 
Are y'all not getting early pressure signs or aggressive ejection with the Toolcraft double ejector bolts?

Every double ejector large frame bolt has given me early pressure signs.

I switched to the JP BCG for the 6.5 Creedmoor and haven't had that issue, but damn they are expensive.
Interesting, when you say you changed to the JP BCG, which one ? , the HP version with the JP proprietary firing pin ?
Like this...
https://jprifles.com/buy.php?item=JPFP-308HP
IMG_8183.jpg


Or the more commonly style used firing pin like this...
https://jprifles.com/buy.php?item=JPFP-308
IMG_8182.jpg
 
A bolt closing on the round, only tells ya, the bolt closed on a round.
Is the round inside specifications? Is the chamber inside specifications?...some are not, even from the factory.
Ammo recalls come to mind.
You need a go gauge, and a no go gauge, to be sure, your chamber is correct.
Then adjust the ammo if ya handload, to the chamber you know is correct.

All technically true. However, long head space won't cause a catastrophic failure all on it's own. I've seen all kinds of strange combinations over the years that functioned fine enough for test firing. Sure, there's some risk in there but a locked breach AR10 won't explode in your face with .020" of brass growth.

Shoot it, check the brass. If you absolutely need to know, buy HS gages.
 
The .020" brass growth could lead to case head separation where you'd get some high pressure gas coming your way.
I have seen cartridges not fire, from over sizing.
The .020" excess could cause such a problem, using enough firing pin energy pushing the cartridge forward, when it finally stops there is not enough energy to fire the cartridge.
 
Interesting, when you say you changed to the JP BCG, which one ? , the HP version with the JP proprietary firing pin ?
Like this...
https://jprifles.com/buy.php?item=JPFP-308HP
View attachment 8461498

Or the more commonly style used firing pin like this...
https://jprifles.com/buy.php?item=JPFP-308
View attachment 8461497

The Fulton Armory with the JP bolt and small diameter pin. I couldn't find the complete JP BCG and I needed the bolt to have it headspaced to the barrel. I have since bought one of the complete JP BCGs for the next build.


FA/JP HP BCG

New build BCG

JP Rifles HP 308 BCG
 
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The .020" brass growth could lead to case head separation where you'd get some high pressure gas coming your way.
I have seen cartridges not fire, from over sizing.
The .020" excess could cause such a problem, using enough firing pin energy pushing the cartridge forward, when it finally stops there is not enough energy to fire the cartridge.

Case head separation doesn't happen with a single firing and .020" of shoulder movement. The loaded cartridge can't move that far forward with the rim under the extractor, the shoulder just blows forward. Going from memory, new brass in my 6.5G grows .017" with an in spec chamber.

You're not wrong about measuring the chamber or that it needs to be within spec though. I just don't find AR headspace to be such a concern with high quality parts. For a single gun I'd skip the gages and check the brass. If OP is going to build more guns, or set HS on bolt guns with barrel nuts, owning gages is a must. I totally understand why you might not see it the same as me and my opinion was more strict at one point too.
 
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Case head separation doesn't happen with a single firing and .020" of shoulder movement. The loaded cartridge can't move that far forward with the rim under the extractor, the shoulder just blows forward. Going from memory, new brass in my 6.5G grows .017" with an in spec chamber.

You're not wrong about measuring the chamber or that it needs to be within spec though. I just don't find AR headspace to be such a concern with high quality parts. For a single gun I'd skip the gages and check the brass. If OP is going to build more guns, or set HS on bolt guns with barrel nuts, owning gages is a must. I totally understand why you might not see it the same as me and my opinion was more strict at one point too.
We tend to agree in general...just not on how much one can, or should get away with...I'm being a bit more cautious, but not by much.
CNC manufacturing has made AR parts and even some bolt guns with barrel interchangeability possible.
Quality parts, inspection, and good personal help all of that to happen.
But every so often a few crap parts get through.
One should have gauges to check the accuracy of what others have made in your build.
Being into precision, I check everything. And that helps get small groups.
In this picture I use a chamber "go gauge" to check the accuracy of the Wilson case gauge, which is .002" off.
The aluminum gauge is made with the Wildcat chamber reamer, and brass case sized to fit. Then used to chamber the rifle.
So I like precision, and knowing where to size the brass case precisely for multiple rifles of the same caliber, and of course less case stretch and reworking the brass, after each firing.
 

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I’m looking at buying an AR-10 barrel in .308 and have more or less narrowed my options down to a 20” Krieger 1:11 M110 profile ($650, no bolt) and a 20” Shilen 1:10 full length tactical profile ($550, bolt included). I want the rifle to be a multi-purpose long range rig, not to bulky to carry around and not so light that it can’t shoot long strings accurately. I’d like to hear thoughts on these brands in general and on these two profiles. Thanks
really ? I have a 308 barrel that I never chambered a round .I did not want a 308 .I wanted a 708 but it was not offered . bought a 708 barrel and did the R&R .barrel been in the safe 4 years . then I wanted a 6.5 creedmore .ordered the 6.5 CM barrel and did the R&R .
now I have a DPMS 708 barrel and a BCA 308 barrel that would like to have a new home. come to think about it there's a 223 barrel in the safe to .happy trails
 
Fellas, you could have told me that you have to be 21 to buy a lower, just went to pick mine up and found out the hard way. Somebody needs to get a hold of the freakin ATF. That is the definition of infringing on a man’s rights to keep and bear arms!
 
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Fellas, you could have told me that you have to be 21 to buy a lower, just went to pick mine up and found out the hard way. Somebody needs to get a hold of the freakin ATF. That is the definition of infringing on a man’s rights to keep and bear arms!

Knowing your states gun laws is probably a good start before buying a firearm

It's 21 to buy a handgun and long gun varies by state between 18 and 21
 
Nice! Got the same here M5 with Criterion medium wt 20" bbl. Practice day at 500yds with Nosler 168's & IMR 4064
View attachment 8517894
View attachment 8517895
Nice! Got the same here M5 with Criterion medium wt 20" bbl. Practice day at 500yds with Nosler 168's & IMR 4064
View attachment 8517894
View attachment 8517895
Nice! Got the same here M5 with Criterion medium wt 20" bbl. Practice day at 500yds with Nosler 168's & IMR 4064
View attachment 8517894
View attachment 8517895
I got some imr 4895, hopefully it does well behind some 168 eldms
 
It’s a long story, but I ended up with 2 bolts for my Ar-10: the nice, smooth nitride one from my RCA BCG, and a phosphate Fulton Armory one that got sent free with my barrel. The Fulton Armory bolt is headspaced for the barrel; the RCA is not, but the bolt closes over a round and there are no problem signs on fired cases (to my very limited knowledge). Could I expect better accuracy from the headspaced bolt? Is it worth switching out and shooting a ton of groups to see?
 
It’s a long story, but I ended up with 2 bolts for my Ar-10: the nice, smooth nitride one from my RCA BCG, and a phosphate Fulton Armory one that got sent free with my barrel. The Fulton Armory bolt is headspaced for the barrel; the RCA is not, but the bolt closes over a round and there are no problem signs on fired cases (to my very limited knowledge). Could I expect better accuracy from the headspaced bolt? Is it worth switching out and shooting a ton of groups to see?

Headspace isnt an accuracy thing necessarily.. It has to do with your brass fitting in the chamber in simple terms..

Every custom manufacturer I know headspaces their barrels to RCA and JP bolts. So I am pretty sure your fine but the only way to know is order a go gauge for your rifle and test it out yourself.
 
My "Blem" Rubber City BCG with Fulton Criterion barrel passed "Go" and "No-Go" gauge test. As padom states, it's not necessarily a accuracy enhancement, but function and safety.

The early days of 308 AR's there were a lot of compatibility issues since there was not set "standardized" designs which lead to potential short, or the opposite, excessive headspace between various bolts and barrel manufacturers. In the last decade mfr's got their act together and the well known bolt and barrels are good to go.

Keep the spare bolt as a spare...you never know when you may need one. It's generally a good idea if you switch barrels to put a new bolt with the new barrel.
 
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My "Blem" Rubber City BCG with Fulton Criterion barrel passed "Go" and "No-Go" gauge test. As padom states, it's not necessarily a accuracy enhancement, but function and safety.

The early days of 308 AR's there were a lot of compatibility issues since there was not set "standardized" designs which lead to potential short, or the opposite, excessive headspace between various bolts and barrel manufacturers. In the last decade mfr's got their act together and the well known bolt and barrels are good to go.

Keep the spare bolt as a spare...you never know when you may need one. It's generally a good idea if you switch barrels to put a new bolt with the new barrel.
What groups do you typically get with the Criterion/RCA combo (I know there’s a ton of variables involved in that question)? I’ve been shooting some 175 FGMM and some 168gr Hornady Black with the AMAX bullet and have yet to get a group under 1.5 MOA. What would you recommend?
 
What would you recommend?
Realistically, both those ammo should do well in your rifle. A lot of it is the 308 AR is dependent on fundamentals: Consistent pull into the shoulder, sight focus, managing the bipod, etc. My background was NRA service rifle (sling, glove & coat) and now re-learning with a bipod; F-class T/R, this rifle and a Mk12 Mod 0.

Last year I did the Hide membership here and watched all the videos, real informative and helpful.
 
Realistically, both those ammo should do well in your rifle. A lot of it is the 308 AR is dependent on fundamentals: Consistent pull into the shoulder, sight focus, managing the bipod, etc. My background was NRA service rifle (sling, glove & coat) and now re-learning with a bipod; F-class T/R, this rifle and a Mk12 Mod 0.

Last year I did the Hide membership here and watched all the videos, real informative and helpful.
 
that it’s just me who needs to step it up?

I mean sure, wind and mirage can definitely affect group size. So in theory my rifle could be MOA capable or maybe sub-MOA, and yours could be too. But it's not like distance magically multiplies mistakes. Like I mentioned, the large-frame AR sitting on a Harris bipod is just more difficult to drive straight and true. At first I was shooting about 3 MOA at 5 or 600yds, but after the video training I'm at 1.5 MOA.
 
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