Best AR-10 Bolt Carrier Group, Barrels and Ammo – A Discussion with John Paul

Best AR-10 Bolt Carrier Group
JP LPR-07 on the range…We talk with John Paul about the small things that make a big difference on these rifles.

What is the best AR-10 bolt carrier group?  What should we be looking for in an AR-10  barrel…and just what ammo should you be stocking up on for your new gas gun?  Bottom line…what are the small, but mission-critical things that need to be at the top of your mind as you work towards the best functioning AR-10 possible?

We recently spoke with one of the great AR innovators, John Paul from JP Enterprises, about a variety of topics, including upgrades he recommends to your AR-15, and what makes an ideal home defense carbine.

We also took time to ask him about the sometimes finicky AR-10.  JP Enterprises offers some very unique and respected takes on the platform.  These include the side-charging LRP-07, and the dual charging PSC-12.

Building a Better AR-10

One thing apparent in JP rifles is that they have some of the best internal components found in any AR-10 rifle.  Chief among these components…perhaps the best AR-10 bolt carrier group you can find.

John Paul details the LPR-07 with Steve from Brownells.  This rifle features JP .308 Low Mass Operating System (LMOS™) with JP High-Pressure EnhancedBolt™

Q:  John, Can you talk briefly about what little things make a big difference on these guns?  We’ve talked to others about the importance of matching manufacturers where we can.  What else needs to be a focus from a builder’s standpoint?  I’m guessing that for starters, it involves finding the best AR-10 bolt carrier group possible…

Best AR-10 Bolt Carrier Group
The JP LRP-07 is currently chambered .308 Win., .260 Rem., 6.5 Creedmoor, and 6mm Creedmoor.

Seeking out the Best Chamber Possible

A:  The first thing to consider is most certainly the barrel and the operating system components. I would most definitely advise anyone to make sure to spend some extra money there.

This is because it’s here you have the whole chamber issue that we talked about earlier.  If you don’t have a really good chamber in these rifles, then they are a malfunction waiting to happen.  That is a problem in a lot of less expensive barrels out there. They have reamer marks and imperfections in the chamber.  Knowing you have a barrel from a really reputable manufacturer is what is going to allow your rifle to operate reliably.

Best AR-10 Bolt Carrier Group
John Paul of JP Industries…one of the world’s leading experts on making reliable and accurate ARs. 

Getting the Best AR-10 Bolt Carrier Group Possible

best AR-10 bolt carrier group
JP .308 Low Mass Operating System (LMOS™) Bolt Carrier

As far as operating system components, if you look at your better manufacturers, they are supplying head spaced bolts. In fact, some of them are actually using ours because we hold our bolts to such a tight tolerance.  By using our bolts, it makes it possible for them to have consistent chambering and head space with bolt after bolt. That said, we’ve done some refining on our bolts to mitigate some of the problems with exotic cartridges.

Best AR-10 Bolt Carrier Group – Beyond .308

With the AR-10, most people are not only looking at .308, but they are looking at .260, 6.5 Creedmoor, and 6mm Creedmoor. With these, it becomes even more important to have the best bolts possible…ones that are really up to the task.

JP High-Pressure EnhancedBolt™ Assembly Completion Group – alleviates issues traceable to over-pressured loads—namely primer flow, ejector smear, extraction issues, and ignition reliability..

To accommodate these cartridges, we have what we call a high-pressure bolt that has a smaller diameter firing pin which mitigates primer flow into the bolt face, and allows the rifle to run at pressures that are maybe not what the .308 would be running at.

Q:  We see many builders leaning more towards 6.5 Creedmoor.  I’d imagine you’re seeing the same?  And, how is 6.5 Creedmoor functioning in gas guns, in your experience?

A:  For us, 6.5 Creedmoor has pretty much eclipsed the .260. We’ve decided to discontinue the .260. Now, I realize that a lot of guys are invested in the .260.  If you are, and you’re already set up to load that cartridge, then the .260 performs pretty much as well as the 6.5 Creedmoor. But, if I were starting out from scratch and I intended to load and I was going to invest, then I would go with the 6.5 Creedmoor. This is because it does have some notable advantages.

We’ve had excellent results with it.  As far as function, if you don’t want to load, there is good factory ammunition out there that will perform in a gas gun…and that’s a critical thing.

Tremendous video review via Sniper’s Hide.  Also check the online version of the review which has a great list at the end.

Best AR-10 Ammo – A Word of Caution

Q:  To get these guns working reliably, in addition to having a quality barrel and the best AR-10 bolt carrier group possible, you mention the ammo.  I’ve had issues where I stock up on ammo, only to discover what I’ve purchased just isn’t cycling.  Are these rifles inherently finicky?  Is it the ammo?  

A: A lot of people don’t realize it, but most of your ammunition manufacturers don’t pay any attention to gas guns. The fact is, they only develop their ammunition in manually operated bolt-gun type fixtures. They don’t consider anything about what the internal ballistics or the pressure curve of that ammunition has to be to reliably operate a gas gun. They are only concerned with maximum velocity out of a manual rifle. And a lot of that ammunition is not compatible, and will not function in gas guns.

AR-10 Ammo – Try Before You Buy

The uninitiated will buy a gas gun and think that any factory ammunition will run in that thing, and that is absolutely not the case (laughs) so, get over it! Don’t buy a bunch of something until you have tried it and know:  A. – that it is functional, and B. – that it shoots accurately.  Hornady has done a pretty good job because they realize a lot of their ammo finds its way into gas guns…with the proliferation of precision gas guns over bolt guns.  That’s a migration we’ve seen over the last five years.

John Paul and Brian Whalen invite you to come learn the fine art of long range precision shooting at Blue Steel Ranch in New Mexico.

Bolt vs. Gas Guns for Long Range Precision Shooting

Q:  In regards to bolt guns vs. ARs, I’ve got some friends who do long range shooting, and it’s hard to convince some of them to give the AR platform a look once they’ve invested so much in their bolt gun.  I’ve seen you shoot both quite happily at Blue Steel Ranch.  Any advice for the die-hard bolt gunners out there? 

GA Precision – Crusader – One of the author’s most beloved bolt guns from one of the best bolt gun companies on the planet…who now also makes an amazing gas gun.


A:  There’s been a migration and people have started to realize a gas gun can do everything a bolt gun can do, just faster. There are some dyed-in-the-wool people that just absolutely don’t believe gas guns can shoot as accurately as bolt guns. To that, I would say: no that’s not the case.

To me, I think these shooters are more technique-sensitive. In other words, the techniques some people have developed to run their bolt guns do not transmit over to a gas gun.

I look at it like two different pieces of software. If I am shooting a bolt gun, I have one manual rifle technique. When I shoot a gas gun, I have a differing way of getting into the rifle…controlling the trigger and all that stuff. This enhances my ability to shoot the rifle accurately.

Best AR-10 Bolt Carrier Group

Q: Final advice for the AR-10 builder, or any AR builder?

A:  Overall, when it comes to internal components on something like an AR-10, the mistake you don’t want to make is saving a few dollars on the front end and regretting it on the back end.  We’ve all done it.  I’ve done it myself. (laughs). 

I’m trying to provide the best performance at the best value with no regrets.  If people spend that extra few dollars on internal components, they are going to be happy.

That said, whatever you buy, you don’t want to go to the low end of it.  You want to go with parts suppliers that really have a good reputation.  You can’t a hide a bad reputation with the internet now.  It’s obvious and you can see what people have to say about components.  Do the research.  You can get real information that is not colored by advertising dollars that someone spent.  

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Thanks to John Paul for talking to us about the importance of having the best AR-10 bolt carrier group possible.  And also for helping me convince a few of my buddies to put the bolt guns down for a second.  To learn more about John Paul and JP Enterprises, please visit them at their website.

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  1. John Paul is one of the top gas gun builders in the country. His hardware isn’t cheap but the guy knows his stuff. The action on his rifles feels like it on roller bearings.

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