Changing Barrels on an AR

[DMW1116]

If I want to swap out barrels and they’re in the same caliber, can I recycle the other parts and put them on the new barrel? Stuff like the gas block, muzzle device (minus the crush washer perhaps), BCG?

I’m contemplating a swap of my 308 Winchester barrel in my AR10.

 

[Ethan Verity]

If I want to swap out barrels and they’re in the same caliber, can I recycle the other parts and put them on the new barrel? Stuff like the gas block, muzzle device (minus the crush washer perhaps), BCG?

I’m contemplating a swap of my 308 Winchester barrel in my AR10.

Most likely (not knowing specifically what you're working with) but I believe most parts in the AR-10 are interchangeable.

 

[DMW1116]

I have a PSA PA10 but might want to upgrade barrels. It's reasonable to see the crush washer as a one-use item. It might not be, but if it were, I wouldn't be surprised. I understand the bolt isn't necessarily going to head space properly with a new barrel, particularly with an AR-10, so a new bolt might be necessary. The rest of the BCG would likely be fine I suspect, unless the bolt or gas rings just don't fit.

My current barrel has an adjustable gas block I really like, so as long as the diameter is the same, I figure it's reusable too. As long as the new barrel's gas system is the same, the gas tube should still work as far as I know. I'm just getting into upper building, so I don't know what sorts of things are of limited use. The other thing is AR-10s are not as universal as 15s. Changing brands could cause some issues, so caution is warranted.

 

[js8588]

I have a PSA PA10 but might want to upgrade barrels. It's reasonable to see the crush washer as a one-use item. It might not be, but if it were, I wouldn't be surprised. I understand the bolt isn't necessarily going to head space properly with a new barrel, particularly with an AR-10, so a new bolt might be necessary. The rest of the BCG would likely be fine I suspect, unless the bolt or gas rings just don't fit.

My current barrel has an adjustable gas block I really like, so as long as the diameter is the same, I figure it's reusable too. As long as the new barrel's gas system is the same, the gas tube should still work as far as I know. I'm just getting into upper building, so I don't know what sorts of things are of limited use. The other thing is AR-10s are not as universal as 15s. Changing brands could cause some issues, so caution is warranted.

Switching to another 308 barrel? Should all work fine.

 

[bfoosh006]

As far as the PSA PA10's , all the barrels parts can be swapped onto another brand DPMS pattern barrel.

Those different brand barrels, include Criterion ( suggested, mine have been outstanding ) , Faxon , AERO, Krieger, DPMS and others.

What brand Adj. GB do you have ? I have had great results with SLR's.

What barrel length do you have, and what barrel length are you considering ?

And if you are looking for more precision oriented sized groups... I True and Glue my barrels in place.

About the 50 sec point. IMHO, It is well worth the effort.

https://www.youtube.com/watch?v=XHxU8VUAHOY&list=PLqwwk7tC6Sdanx0b55g2EL8UV5udC2Gwh&t=54s


My Criterion 18" M118LR chambered can do this, provided I do my part. 168gr FGMM



10rds, 100yds Horn. 155gr AG

 

[DMW1116]

I was looking at a Criterion barrel. 20” is what it has and that or an 18” are what I’m looking at. I think a 16” 308 would be more blast than I’d want to deal with and a 22” or 24” would be too long.

I don’t know the gas block brand. It came on the upper from PSA so it’s their brand I suppose. It works really well with good click adjustments and shuts all the way off so I can run weird Titegroup subsonic loads if I want.

 

[KKJ13]

AR10’s vary in the gas block diameter, verify they will match first or order one so you done have to wait on shipping again.

 

[Shawn Dodson]

Sounds like you have an AR308 instead of an AR10.

The DPMS AR308 design was developed to use as many AR15 parts as possible.

Most gas block journals on the barrel are 0.750" in diameter. (Other diameters are usually on specialty barrels, e.g., pencil and bull barrels.)

I suggest you headspace your bolt with the new barrel, both GO and NO GO. You can't assume the barrel's chamber or your bolt are in spec, which can cause accuracy issues at best and a dangerous condition at worst.

 

[Varminterror]

AR-10/LFAR barrels vary with standard select specifications by gas block journal diameter and gas system length. If your new barrel matches the old gas system length and same journal diameter, then transplanting everything else works just fine.

 

[Lo-Profile]

If I want to swap out barrels and they’re in the same caliber, can I recycle the other parts and put them on the new barrel? Stuff like the gas block, muzzle device (minus the crush washer perhaps), BCG?

I’m contemplating a swap of my 308 Winchester barrel in my AR10.

You can, but I'd just build a new upper receiver. Costs are about the same either way. That way you can swap them easily if needed

 

[Varminterror]

You can, but I'd just build a new upper receiver. Costs are about the same either way.

This is only true when the upper and barrels are relatively garbage quality.

It’s easy to sink $250+ into a handguard these days, $100 in an LFAR upper receiver, $75-150 in a gas block, $100-200 in a BCG… a GREAT barrel can be hand for $250-450, so I guess I just wouldn’t agree that $250-450 = $1000…

Let alone factoring any of the reasons someone might be swapping barrels - I swap mine when I’m throwing a barrel away, so building a new upper wouldn’t mean I have two which can be easily swapped, it means I’d have one I can use and one with a burned up barrel fit for the garbage stuck in it…

 

[DMW1116]

I’m in for a better barrel but first I need to check this one out. I plan to go over a couple of things. It’s been giving me high pressure on reloads sooner than expected (37 grains on a powder with a max charge of 42) and difficult extraction on unfired rounds when our range goes cold. I have to remove the magazine and extract any live rounds when the range goes cold.

 

[gotboostvr]

I’m in for a better barrel but first I need to check this one out. I plan to go over a couple of things. It’s been giving me high pressure on reloads sooner than expected (37 grains on a powder with a max charge of 42) and difficult extraction on unfired rounds when our range goes cold. I have to remove the magazine and extract any live rounds when the range goes cold.

Might be a snug, or roughly machined chamber.

 

[DMW1116]

Might be a snug, or roughly machined chamber.

I don't think its rough. I don't see signs of that on the brass. However, I've had 2 loads that hit pressure signs way earlier than expected. One was a 308 Service Rifle load that should have been more than fine. The other was a a 150 grain FMJ load that showed some pressure only 3 grains above minimum and 4 grains below the maximum of 42.

 

[gotboostvr]

I don't think its rough. I don't see signs of that on the brass. However, I've had 2 loads that hit pressure signs way earlier than expected. One was a 308 Service Rifle load that should have been more than fine. The other was a a 150 grain FMJ load that showed some pressure only 3 grains above minimum and 4 grains below the maximum of 42.

Yeah, a rough chamber by itself shouldn't cause over pressure, but a tight throat/ chamber might.

Give a cartridge the sharpie treatment and check for rubs

 

[DMW1116]

Thats something I hadn't considered. I'll try that with a couple of cartridges. The main load that gives trouble is my 175-grain SMK load. It is quite difficult to remove a live round from the chamber to clear the gun for going down range. I'll try some others and see what happens.

 

[bfoosh006]

No offense intended... but have you throughly scrubbed the chamber clean ?

It is quite possible you have a short throat in your current chamber.

Please black sharpie a whole round, and gently hand chamber one ( IE not from the mag, and just using the hand on the charging hand ) , then look for obvious marks.

Oops... leave a portion of the case head un marked... so you can tell which way the round was oriented when cambering... something like 12 o'clock.

Please post pics of the chambered sharpie'd round.

 

[DMW1116]

The chamber is clean. However it won’t hurt to clean it again. I haven’t really messed with it since I tried the FMJ load. I may try to start messing with it this weekend but I’d like to clear out some stuff from my 357 loading.

 

[TonyAngel]

If you're having trouble extracting live rounds, it could be your ammo. Have you tried screwing in your sizing die a bit more? Or check the external dimensions of a loaded round and make sure they're in spec.

As for the signs of over pressure, what velocities are you getting? Published data is only for reference. If you're getting the velocity you'd like to get, back off the charge a tad bit.

 

[DMW1116]

I don’t have a chronograph. I’m generally searching for accuracy so if it’s a little slower I’m not too concerned. I’ll have to try some measurements of the ammo.

 

[4v50 Gary]

So long as parts are standardized, sure you can. Just be sure to check headspace.

 

[FL-NC]

Should not be a problem as long as the replacement barrel in in the same "pattern" as the rifle. You see, there are multiple "patterns" of AR10, and they don't all interchange.