Babies first AR-10 build (260 Rem)

[nuclear_shooter]

So, my initial plan was to buy an DPMS LR-308 and get the barrel cut to 18"-20". When I asked what people here thought, they said the DPMS SASS might be a better value. Then, when asking if there were any other high value rifles (around $2k), a lot of people just recommended I build my own. After doing some research, and pricing out some parts, I decided to just go for broke and build a 260 Remington (my wallet says 'thanks, Snipers Hide!').

I'll link the full build at the end, but I'll touch on the highlights here. Going to go with the Mega MATEN KeyMod upper/lower set for the receiver, and a JP Ent. 260 Remington barrel. My main question is about the bolt carrier. The JP barrel comes with a pre-headspaced bolt, so I was looking at the JP low mass bolt carrier since I can buy just the carrier (most manufactures just sell the whole BCG, and I would be left with an extra bolt). My only concern is since its a 260, I'm not worried about felt recoil, and the lighter bolt may cause problems with bolt lock time. Does anybody have any recommendations/experience? Buying a full BCG wouldn't be the end of the world.

Rest of the build will be standard DPMS parts, and a Geissele SSA-E trigger and PRS stock. Here's a (mostly complete) list of parts: https://pastee.org/jckez. Any comments and suggestions are welcome!

 

[Fried Chicken Blowout]

Since you're "going for broke" if you've not built many ARs in the past you may just want to order a complete JP rifle from them. But otherwise here's my suggestions based on several years of building many AR15s. I've not built any AR10s so there's my disclaimer. Your miliage may vary but I do have an AR15 that I shoot past 1000 yards.

Get the Geissele High Speed Match for the trigger. Since you're looking at .260 Rem, I assume it's gonna be a long range setup and not for 3-Gun or anything high speed. The High Speed Match is awesome for long range since it's adjustable, super smooth and two-stage.

The PRS is what you want, good choice.

You should also be getting a JP adjustable gas block, especially if you're gonna run a LowMass carrier and buffer. But you should have it regardless of what you use for a buffer and carrier.

Get an ambi safety regardless of what hand you shoot. I shoot left handed and have them on all my guns, BUT when I'm shooting prone I don't wrap my shooting thumb behind the grip. I ride it on the outboard side and operate the "right handed shooter" side of the safety.

Get one of the JP buffer springs for the higher spring rate if they make them for the AR10. I use them in all my AR15 builds.

Based on my research and theory only, I would get it in 6.5 Creedmoor for improved ability to change seating depth to adjust for bullet choice without running into mag length issues. Plus the 6.5 Creedmoor Hornday factory ammo is a smoking deal if you look at the cost of components for .260 Remington and your time loading up the first batch of brass. There is some 120gr 6.5 Creedmoor on the market that will get you going and provide you brass for your own loading later.

And extra bolt is a good thing. You can take a few measurement to make sure it's swappable and then keep it in your shooting bag incase you have an extractor break or other issue. I keep a spare one for my 6mm Fat Rat AR15.

Hope this helps fuel some thought for you.

 

[AMMOWASTER]

I dont know if it matters with the adjustable gas system but I would lean towards a full weight carrier. With the gas turned down you can probably make it work with either setup.

 

[nuclear_shooter]

I dont know if it matters with the adjustable gas system but I would lean towards a full weight carrier. With the gas turned down you can probably make it work with either setup.

Do you have one you would recommend? Preferable one that comes with just a carrier and gas key.

 

[ORD]

Full mass or low mass...either way. But stick to ALL full mass type components or ALL low mass components and do NOT interchange them (i.e. - If you are opting for the JP Low Mass operating system, you need the low mass BCG, low mass/lightweight buffer, AND an adjustable gas system). The theory is that by reducing the total amount of reciprocating mass common with all semi-auto AR platform rifles (heavier/worse with the large frame guns), the you reduce the overall recoil impulse you feel as the shooter, increase the cyclic rate without affecting reliability, increase follow-up shot times, and, at least arguably, improve accuracy.

Personally...you do not NEED the low mass operating system, but its your call. If you don't opt for ALL JP components, then I would suggest just picking up a quality carrier and running the matched/headspaced JP bolt in it, along with the standard LR-308 buffer and an adjustable gas block.

The SSA-E is by far one of the finest triggers on the market, including for a build like what you have on the drawing board. If you want a lighter weight of pull or the adjustability offered by the HS NM, then by all means...go for it, but it isn't absolutely necessary for an excellent, high quality, highly reliable precision rifle trigger group. Lots of people tout the significantly improved lock time of the HS NM trigger group, but practically speaking...and having run both...I have not found any perceptible differences in my own personal accuracy, speed, etc. with rifles equipped with either trigger group. Again...matter of personal preference as what will best suit your particular needs/wants for your build.

 

[AMMOWASTER]

ORD covered it pretty well. JP makes great stuff so their carrier is good to go

 

[sawman556]

Stick with a full mass carrier. Tune it with a heavybuffers.com rifle buffer. Use a Armalite AR-10 action spring.

 

[nuclear_shooter]

The full mass carrier I was looking at was 762 Industries, but I see some complains about them having lots of tooling marks. Any other recommendations? I really don't need a lightweight buffer system, .260 has less recoil than .308 which I don't really find to have much recoil at all.

 

[ORD]

The full mass carrier I was looking at was 762 Industries, but I see some complains about them having lots of tooling marks. Any other recommendations? I really don't need a lightweight buffer system, .260 has less recoil than .308 which I don't really find to have much recoil at all.

There are several companies now making all variants of "improved" bolt carriers for the DPMS-pattern rifles, including but not limited to: JP (as previously discussed), 762 (as you mentioned), Rainier Arms NiB, Young Mfg, etc., etc. The only one I have handled that I had reservations about was the 762 as they aren't as nicely finished/polished as other mfgs. Now, mind you...it isn't likely to effect the fit/function of the rifle one bit...but if I'm paying good money for a product...I expect it to not only get the job done, but to also look like it wasn't machined without a care in the world.

 

[nuclear_shooter]

Stick with a full mass carrier. Tune it with a heavybuffers.com rifle buffer. Use a Armalite AR-10 action spring.

$125 seems a high price to pay for a buffer...

 

[ORD]

$125 seems a high price to pay for a buffer...

WRONG! Worth every penny and then some...BUT, not entirely necessary in a build with an adjustable gas system, especially if you'll not be shooting the rifle suppressed. If you WILL be shooting your rifle suppressed, then I personally like the addt'l weight that Clint's buffer afford you and the benefits derived therefrom. I've been using them for many years now and swear by them.

 

[nuclear_shooter]

WRONG! Worth every penny and then some...BUT, not entirely necessary in a build with an adjustable gas system, especially if you'll not be shooting the rifle suppressed. If you WILL be shooting your rifle suppressed, then I personally like the addt'l weight that Clint's buffer afford you and the benefits derived therefrom. I've been using them for many years now and swear by them.

Interesting, I will have to keep that in mind. That's exactly why I started this thread. Whats another 100 bucks when paying 2400 for a rifle anyway?

Incidentally (and I feel like this is a really stupid question) but I was looking at Rainier's BCG's and this was the only one I could find: Rainier Arms™ | Browse | Bolt Carrier Assemblies | Rainier Arms BCG - Nickel Boron... but it doesn't specify if its for 308 type systems or 223 type systems (I assume/a quick google indicates there is a difference). Is this the one you were referring to?

Maybe its time to change my handle to noobular_shooter .

 

[FCS]

260 has higher port pressure as running slower burning powder then 308. I wouldn't go lightweight on carrier and you'll probably want to heavy up buffer some over standard weight.
Properly sized port makes all the difference in the world.
YMMV.

 

[nuclear_shooter]

260 has higher port pressure as running slower burning powder then 308. I wouldn't go lightweight on carrier and you'll probably want to heavy up buffer some over standard weight.
Properly sized port makes all the difference in the world.
YMMV.

Would this still apply if I went 6.5 Creedmore?

Edit: Looked at the reloading data and it appears they use many of the same powders.

 

[ORD]

Incidentally (and I feel like this is a really stupid question) but I was looking at Rainier's BCG's and this was the only one I could find: Rainier Arms™ | Browse | Bolt Carrier Assemblies | Rainier Arms BCG - Nickel Boron... but it doesn't specify if its for 308 type systems or 223 type systems (I assume/a quick google indicates there is a difference). Is this the one you were referring to?

No...that's an AR-15 BCG that you linked to above and there IS MOST DEFINITELY A BIG DIFFERENCE between .308 and 5.56 carriers. I looked on Rainier's site and didn't see the 7.62, DPMS-pattern carriers so I'm not sure where they have gone, but they did/do make one that is NiB coated.

Here's another site that sells Rainier stuff and the .308 BCG: Rainier Arms NiB Match Grade.308/7.62x51 BCG

 

[997/2man]

The full mass carrier I was looking at was 762 Industries, but I see some complains about them having lots of tooling marks. Any other recommendations? I really don't need a lightweight buffer system, .260 has less recoil than .308 which I don't really find to have much recoil at all.

The JP bolts/bolt carriers are as slick as glass. There are very few rough spots on a JP rifle. Buy with confidence, JP is super to deal with, their staff is very knowledgable. I've called in the past with a question, John Paul answered the phone.

Not a lot of hoopla or B.S., just great rifles.

 

[Fjr86]

I run a Fulton Armory chrome BCG in my LR308 build which did not include a bolt. I run with a JP bolt.

Just checked their website and they don't have any completed bcg available, only stripped. Mine was complete when I bought it couple years ago.

 

[nuclear_shooter]

I run a Fulton Armory chrome BCG in my LR308 build which did not include a bolt. I run with a JP bolt.

Just checked their website and they don't have any completed bcg available, only stripped. Mine was complete when I bought it couple years ago.

I noticed a lot of places sell full bolts or fully stripped bolts. Looks like you need a jig to properly stake the gas key...

 

[ORD]

I noticed a lot of places sell full bolts or fully stripped bolts. Looks like you need a jig to properly stake the gas key...

That is very true with respect to either getting a stripped carrier that you'll need to finish assembling with the proper parts, or getting a complete BCG which will include a bolt you don't need (but can likely sell as a separate part after the fact to offset the cost somewhat).

You do not absolutely HAVE to stake your carrier key screws in place. All that the staking does is give you some added insurance against a carrier key screw backing out. There are plenty of highly reputable mfgs, including Young for one, that make high quality BCGs and carriers and they absolutely REFUSE to stake the carrier key screws and otherwise REFUSE to warranty any of their carriers that have been staked.

I have used the Young recommended key installation method numerous times over the years and never had an ounce of problem with a key working loose or with any key screw backing out. Here is what they recommend and I'll just second their methodology for use on any rifle that won't be used on the two-way range, etc.:

1) clean the oil from the gas key and the mating surface on the carrier and from the screw threads (they use brake cleaner, but anything in that class will work);

2) Apply a very light coating of Permatex high temp/strength thread locker gel on the bottom of the key (Its Permatex #27005...the 5oz, squeeze gel container, or if you want a LOT of it, they make a larger, 10oz tube). You can also used Permatex gasket sealer, but it can be messy as all hell and cause issues in comparison with the gel. Make sure you don’t use so much that it squishes into the gas port hole which will REALLY @#$% things up royally (if it sets up anyway).

3) Coat the screw threads with the same gel and then install the key and torque the screws to 55-56 in/lbs.

4) Allow the Permatex to set up over 24hrs (although its generally GTG after an hour or so).

If you do decide you MUST HAVE IT STAKED, then you'll need to either pay to have it done properly, or get a specific .308 AR carrier key staking tool as the Brownells tool (the most common one) will NOT work on the large-frame carriers...only the AR-15 based carriers. Don't go off half-cocked and try to DIY it by hand with a hammer/punch/chisel/etc. as you'll likely just @#$% it up and then have a mess on your hands.

 

[nuclear_shooter]

That is very true with respect to either getting a stripped carrier that you'll need to finish assembling with the proper parts, or getting a complete BCG which will include a bolt you don't need (but can likely sell as a separate part after the fact to offset the cost somewhat).

You do not absolutely HAVE to stake your carrier key screws in place. All that the staking does is give you some added insurance against a carrier key screw backing out. There are plenty of highly reputable mfgs, including Young for one, that make high quality BCGs and carriers and they absolutely REFUSE to stake the carrier key screws and otherwise REFUSE to warranty any of their carriers that have been staked.

I have used the Young recommended key installation method numerous times over the years and never had an ounce of problem with a key working loose or with any key screw backing out. Here is what they recommend and I'll just second their methodology for use on any rifle that won't be used on the two-way range, etc.:

1) clean the oil from the gas key and the mating surface on the carrier and from the screw threads (they use brake cleaner, but anything in that class will work);

2) Apply a very light coating of Permatex high temp/strength thread locker gel on the bottom of the key (Its Permatex #27005...the 5oz, squeeze gel container, or if you want a LOT of it, they make a larger, 10oz tube). You can also used Permatex gasket sealer, but it can be messy as all hell and cause issues in comparison with the gel. Make sure you don’t use so much that it squishes into the gas port hole which will REALLY @#$% things up royally (if it sets up anyway).

3) Coat the screw threads with the same gel and then install the key and torque the screws to 55-56 in/lbs.

4) Allow the Permatex to set up over 24hrs (although its generally GTG after an hour or so).

If you do decide you MUST HAVE IT STAKED, then you'll need to either pay to have it done properly, or get a specific .308 AR carrier key staking tool as the Brownells tool (the most common one) will NOT work on the large-frame carriers...only the AR-15 based carriers. Don't go off half-cocked and try to DIY it by hand with a hammer/punch/chisel/etc. as you'll likely just @#$% it up and then have a mess on your hands.

This is great info have, thanks. I'm probably going to let whats available at the time. If I cannot get the Young (seems they're always out of stock) I'll probably just go 762 Industries. It doesn't look like there is a 'bad' choice here.

Anybody have thoughts on .260 rem vs 6.5 Creedmore? It seems like .260 is the safer bet... if 6.5 Creedmore ends up 'winning' the popularity contest, I can still make .260 brass from .308 brass. Everything else seems fairly well matched (MV, trajectory).