Other than 6.5 Creedmoor and 308, what is the next wildcard cartridge to go big on the AR10 platform?

[Doomer]

Does 8.6 Creedmoor have a chance? What other cartridge stands a chance to challenge the 308 and 6.5 Creedmoor on the AR10 platform as the next hot caliber to blow up on the platform over the next 5 years? Is there room for the AR-10 platform to grow in terms of cartridges or is the Bolt Action rifle just better all around for most large caliber needs?

So, that means not stepping down to the AR-15 platform with the 6.5 Grendal, 6MM Arc, or 6.8 SPC, or stepping up to the big boy calibers with the Falkor/NEMO 300 Win Mag or the Armalite or Ruger 338 Lapua.

If I say something that sounds ignorant, that's because I am. I'm new to guns, and I probably said something in my question that doesn't make sense haha.

 

[Downtown]

Twenty minutes ago you joined a forum that on the gun world internet is notorious for ragging on newcomers until they cry. You started with one of those open ended discussion questions some here just love to tear apart. Granted, it's no "grade my field gear", but it should be entertaining. I hope you have a very thick skin and don't take yourself too seriously. Welcome to the forum.

 

[Doomer]

Twenty minutes ago you joined a forum that on the gun world internet is notorious for ragging on newcomers until they cry. You started with one of those open ended discussion questions some here just love to tear apart. Granted, it's no "grade my field gear", but it should be entertaining. I hope you have a very thick skin and don't take yourself to seriously. Welcome to the forum.

Thanks man, happy to be here. I've got nothing to lose and everything to gain lol. I've spent a lot of time on the /K/ forums over on 4chan, and several gun subreddits.

I'm a literal noob, I live in Portland, I just got a pistol two months ago because my antifa neighbor now has a bunch of guns and I don't think I trust him being armed and whatnot, and I've shot maybe 100 rounds through my pistol? Anyways, I have a bunch of lowers to build out for when I move to Idaho or Montana, and my AR-15 based builds are coming along nicely. But I have a few AR-10 lowers, and I have a few 308 and 6.5 Creedmoor builds I want to do. Those builds aside, I've got one extra AR-10 lower, and I want to do something exotic, I want a wildcard caliber that might pop off over the next 4 years.

 

[Doomer]

I think the calibers that most interest me might be something like the 8.6 Creedmoor, something I can SBR or make into a 12" pistol, and shoot suppressed with subsonics, something like an older brother to the 300 Blackout. My other interest is a cartridge that is hot with the PRS/NRL community that might have a use case outside of the competition world, such as civilian life and military use, and it has to be a cartridge that is meeting a need not fully met by the 308 or the 6.5 Creedmoor, or excelling way past the 308 and 6.5 Creedmoor and other wildcards.

These are the calibers most popular with precision rifle shooters (PRS/NRL), using bolt action rifles, at ELR competitions "... to engage targets from 700-2100 yards … in sustained winds up to 35 mph and wind gusts measured on-site up to 60 mph!" - Cal Zant

Which wildcard cartridge has some crossover potential, not only for civilian use or the precision rifle community but also potential military application? A lot of these calibers seem way too large to fit your average AR-10 / LR 308 receiver set, barrel, chamber, mag, etc. Could any of these large calibers find a home on the AR-10 platform? Is there another cartridge on the horizon that I'm missing or not being used in the PRS/NRL world?

 

[PinesAndProjectiles]

I'd like to know who's the shooter behind the 257 Weatherby and I'd like to ask him if he has to replace his barrel after every match.

 

[Lawrence60]

Does 8.6 Creedmoor have a chance? What other cartridge stands a chance to challenge the 308 and 6.5 Creedmoor on the AR10 platform as the next hot caliber to blow up on the platform over the next 5 years? Is there room for the AR-10 platform to grow in terms of cartridges or is the Bolt Action rifle just better all around for most large caliber needs?

So, that means not stepping down to the AR-15 platform with the 6.5 Grendal, 6MM Arc, or 6.8 SPC, or stepping up to the big boy calibers with the Falkor/NEMO 300 Win Mag or the Armalite or Ruger 338 Lapua.

If I say something that sounds ignorant, that's because I am. I'm new to guns, and I probably said something in my question that doesn't make sense haha.

Don't worry we were all new once

 

[2aBaC̶a̶]

A 6.5 PRC would be interesting.

 

[Submarine Sharpshooter]

I own a small frame AR10 and I’d get down with any short magnum small frame upper such that I could retire my bolt 300WM

 

[Submarine Sharpshooter]

A lot of these calibers seem way too large to fit your average AR-10 / LR 308 receiver set, barrel, chamber, mag, etc. Could any of these large calibers find a home on the AR-10 platform? Is there another cartridge on the horizon that I'm missing or not being used in the PRS/NRL world?

If it’s 2.8 inches COAL, it’ll go in an AR10. 2.85ish with KAC mags. Might need new follower depending on round geometry

Any longer and it’s in the territory of what is no longer an AR10 - which truly means nothing in any case, as there are more than two industry standards for what an AR10 is.

By “no longer an AR10”, I mean stuff like the Nemo Omen, Falkor Petra, etc. They MSRP at twice the price of a custom AR10 and perform half as well.

 

[2aBaC̶a̶]

I'm thinking the biggest hindrance is magazine length.

If somone could make a lower that takes AW magazines, it would be a game changer.

 

[LRRPF52]

.260 Rem used to be more popular in gas guns before Hornady did such a great job of promoting and supporting the 6.5 Creedmoor.

Remington just never supported the .260, even though they had the ability to make ammo and Rem 700s in it for TGT use that would have filled the increasing demand for precision rifle and long range shooting.

DPMS and ArmaLite made factory rifles in .260 Rem, as well as complete uppers.

7mm-08 is another good one, but there is practically no TGT ammo that I’m aware of.

.338 Federal was also a flash in the pan it seems.

6.5CM dominates ammo selection with a lot of dual-use loads that do TGT and hunting really well.

I was thinking the suppressed end of things is relatively open ground, depending on how component availability and suppressors fair in the political landscape.

I’ve been finding .260 Rem all over the place, while 6.5CM hasn’t been on shelves in about a year around the plethora of gun stores in my area.

We have Cabellas, Scheels, multiple Sportsman’s Warehouses, and dozens of LGSs within a 30 minute drive. Most LGSs in my area are NFA dealers.

 

[Im2bent]

Thanks man, happy to be here. I've got nothing to lose and everything to gain lol. I've spent a lot of time on the /K/ forums over on 4chan, and several gun subreddits.

I'm a literal noob, I live in Portland, I just got a pistol two months ago because my antifa neighbor now has a bunch of guns and I don't think I trust him being armed and whatnot, and I've shot maybe 100 rounds through my pistol? Anyways, I have a bunch of lowers to build out for when I move to Idaho or Montana, and my AR-15 based builds are coming along nicely. But I have a few AR-10 lowers, and I have a few 308 and 6.5 Creedmoor builds I want to do. Those builds aside, I've got one extra AR-10 lower, and I want to do something exotic, I want a wildcard caliber that might pop off over the next 4 years.

xxx

 

[steve123]

How about a 25 Creedmoor Ackley Improved. .7 BC at 3000 fps or so.

 

[Ghosting]

A 6.5 PRC would be interesting.

It will have to be a custom ar10 frame to fit the 6.5 prc. I have a 308 GA Precision ar10. I called them to see if it was possible to convert it to a 6.5 prc when it first came out and they told me it wont fit in the ar10.

 

[sam4886]

List of AR platform cartridges - Wikipedia

en.m.wikipedia.org

Take your pick.

 

[2aBaC̶a̶]

It will have to be a custom ar10 frame to fit the 6.5 prc. I have a 308 GA Precision ar10. I called them to see if it was possible to convert it to a 6.5 prc when it first came out and they told me it wont fit in the ar10.

You can make it work. The problem is mags. Standard mags fit 2.8 and factory 6.5 PRC is in the 2.9 range. You can get the lighter shorter bullets to fit in a standard mags. All you really need is a magnum bolt.

 

[Long Range 338]

Not to be offensive but what planet are you on? First you start off talking about suppressed cartridges similar to 300BLK and then show a list of ELR cartridges.... You realize these cartridges are on opposite ends of the spectrum?

If you want to look into suppressed subsonic rounds look into the whisper/jdj cartridges as there is plenty of data out there for them. The downside is nobody likes spends more than $1/ projectile to launch them slowly at close range where they would be most effective.

If you are interested in ELR, these types of cartridges need lots of powder capacity and are seating bullets long. Not only is an AR platform not ideal, but won't allow best performance for these cartridges (not even the 6.5 PRC). ELR is going to require a magnum action even in a bolt gun.

 

[jwramp]

Make sure you notice that the PRB graph was for ELR stuff, not PRS. I don’t see the AR-10 as a great ELR platform at all.

 

[357Max]

Not ideal for ELR as has been said, but this would be spicy in a large frame gasser running PRS speed limit from a 22" at well below pressure limits. 30 degree shoulder should feed pretty well also. Someone build this & LMK how it works!

 

[LRRPF52]

ArmaLite Inc. and DPMS used to make 300 SAUM factory rifles with magazines to support them, then quickly stopped making them. The Gen II steel ArmaLite AR-10B (modified M14 magazine system) seemed to work really well even with larger case diameters.

Once you step away from a .473” case head/.308 or .300 Savage-based parent, there are some challenges for the AR-10, especially with larger diameter cases.

Here’s a guy that bought an ArmaLite Inc. 300 SAUM and shot 190gr and 210gr Berger VLDs with his on antelope 9 years ago. He has since gone to 6.5 SAUM with 143gr ELD-X. He wanted to do 7mm, but the COAL is too long for the AR-10 action with the high BC bullets he wanted to use.

 

[Earnhardt]

How about a 25 Creedmoor Ackley Improved. .7 BC at 3000 fps or so.

OK...let’s hear more about this one!

 

[steve123]

OK...let’s hear more about this one!

I haven't made one, it's just a cartridge and caliber that interests me.
You'd have to call around to reamer Co's to see what designs they have, IMO .004" neck expansion is about right.
Be sure to check the measurement of ribs in the magazine to make sure AI would work before you go forward. Maybe someone else here has built AI in a large frame and they can answer this question.
My 6mmFatRat is an AI and it works well in Grendel magazines so 25CMAI might also work in large frame mags.

A friend had a 7 Saum built in a large frame which he could never get reliable.
Both he and I had 243WSSM's and we could never get them to be reliable.
Just sayin. I'd steer away from magnum bolt face AR's.

 

[Earnhardt]

What gas systems do your Magnum LR308s have?
Rifle or rifle +2”?

 

[LRRPF52]

What gas systems do your Magnum LR308s have?
Rifle or rifle +2”?

ELGS (+2”) at least.

In talking with an engineer/gunsmith buddy of mine who has done a lot of work with 7mm SAUM, he feels there’s just too much case capacity for the bore volume on a gas gun for the 7mm.

There was a team who won the Fort Benning Sniper Competition many years ago using semi auto 7 SAUM, but you haven’t heard anything really since then.

I love shooting 7 SAUM through a bolt gun.

 

[Steelhead]

I've always felt the 6mm Creedmoor was a great match for the AR-10 platform.

 

[Submarine Sharpshooter]

Not only is an AR platform not ideal, but won't allow best performance for these cartridges (not even the 6.5 PRC). ELR is going to require a magnum action even in a bolt gun.

I would be very interested in a magnum chambered long action AR if it could be made in the 7 - 8lb range. Imo very doable with carbon barrel. I have a small frame AR10 right now that has a fairly thick stainless barrel (too lazy to hit it with the calipers) and still comes in right at 7.

That being said, I’d be interested in it to get more energy on game at mid ranges / less than 1000 meters - not for ELR. Like you implied, I think a gas gun is just going to get too hard to drive at longer ranges unless it’s got magnificent dwell time.

 

[Earnhardt]

LRRPF52,
...too much case capacity for the bore volume on a gas gun for the 7mm...
Does this apply to all magnum case LR308 guns?

I think the pressure levels after the dwell time starts really effects the operation of the LR308.

Meaning my 24" 45 Raptor (rifle gas) has less pressure in the barrel during dwell time, and has a less detrimental effect on the BCG, than my WSM does with a rifle +2" with a 26" barrel.

And really those 2 barrels have the exact same dwell time, but the dwell pressure in much higher in the WSM
(Dwell time being the amount of time the bullet is in the barrel AFTER it passes the gas port)
I have a much broader range of powder loads with the 45 Raptor, than with the WSM.
When I'm pushing the WSM from 50-55kpsi, the WSM, with 3 different bullet weights, and a myriad of powders...wants to work with a few combos
I believe that with a heavier than 9/10 oz. buffer this would be achievable.
I'd like to try a 12-15 oz buffer in the WSM.

the PRC/WSM/Sherman are all FAIRLY SIMILAR in case capacity...

At what point does the case capacity/bore volume level out, to where a guy can start pushing the Magnum cases to there full potential in a LR308?

With the current BCG and buffer weights that are available, is the .308 case variant the best option out there right now for max performance?

 

[308pirate]

Thanks man, happy to be here. I've got nothing to lose and everything to gain lol. I've spent a lot of time on the /K/ forums over on 4chan, and several gun subreddits.

I'm a literal noob, I live in Portland, I just got a pistol two months ago because my antifa neighbor now has a bunch of guns and I don't think I trust him being armed and whatnot, and I've shot maybe 100 rounds through my pistol? Anyways, I have a bunch of lowers to build out for when I move to Idaho or Montana, and my AR-15 based builds are coming along nicely. But I have a few AR-10 lowers, and I have a few 308 and 6.5 Creedmoor builds I want to do. Those builds aside, I've got one extra AR-10 lower, and I want to do something exotic, I want a wildcard caliber that might pop off over the next 4 years.

My suggestion is to stop wasting time and money on rifles and instead spend both getting to be competent with a handgun, which is what you most likely will use to defend yourself.

100 rounds through a pistol that you got two months ago is about 1000 miles away from being competent.

 

[Carole Baskins]

I think the calibers that most interest me might be something like the 8.6 Creedmoor, something I can SBR or make into a 12" pistol, and shoot suppressed with subsonics, something like an older brother to the 300 Blackout. My other interest is a cartridge that is hot with the PRS/NRL community that might have a use case outside of the competition world, such as civilian life and military use, and it has to be a cartridge that is meeting a need not fully met by the 308 or the 6.5 Creedmoor, or excelling way past the 308 and 6.5 Creedmoor and other wildcards.

These are the calibers most popular with precision rifle shooters (PRS/NRL), using bolt action rifles, at ELR competitions "... to engage targets from 700-2100 yards … in sustained winds up to 35 mph and wind gusts measured on-site up to 60 mph!" - Cal Zant

View attachment 7615958


Which wildcard cartridge has some crossover potential, not only for civilian use or the precision rifle community but also potential military application? A lot of these calibers seem way too large to fit your average AR-10 / LR 308 receiver set, barrel, chamber, mag, etc. Could any of these large calibers find a home on the AR-10 platform? Is there another cartridge on the horizon that I'm missing or not being used in the PRS/NRL world?

417 Black Mamba? LOL.

 

[Raufoss]

25-47 Lapua.

 

[357Max]

My suggestion is to stop wasting time and money on rifles and instead spend both getting to be competent with a handgun, which is what you most likely will use to defend yourself.

100 rounds through a pistol that you got two months ago is about 1000 miles away from being competent.

Good advice for sure. I recently got a Staccato P with RMR (my first optic hand gun) & at 500 rounds I'm nowhere near competent with it. Going to bring it every time I take the rifles out for the foreseeable future. I need an optic hand gun mentor.

When I'm pushing the WSM from 50-55kpsi, the WSM, with 3 different bullet weights, and a myriad of powders...wants to work with a few combos
I believe that with a heavier than 9/10 oz. buffer this would be achievable.
I'd like to try a 12-15 oz buffer in the WSM.

the PRC/WSM/Sherman are all FAIRLY SIMILAR in case capacity...

At what point does the case capacity/bore volume level out, to where a guy can start pushing the Magnum cases to there full potential in a LR308?

With the current BCG and buffer weights that are available, is the .308 case variant the best option out there right now for max performance?

In my opinion if you need north of 9 oz buffer in an AR your gas system is FUBAR.

The PRC/WSM/Sherman SST are different in ways that matter a lot!

PRC = COAL to long.
WSM = Case head not designed well for AR system & COAL to long
Sherman SST = SAUM case head + shortened COAL + 30 degree shoulder.

From a practical standpoint I'd rate best AR10/DPMS options in the following order (this doesn't account for component availability):

• 6 or 6.5 x 47
• 6GT
• 6XC
• 6 or 6.5 Creedmoor
• For Mag bolt the Sherman SST's 6/25/6.5 would be the only I'd be interested in.
• Edit insert 25 cal in front of any of the above. I'm a 25 fan, but bullets are unobtainable right now.

My current DPMS is a meat and Potatoes 308. It's dialed, runs anything reliably & shoots factory match 168/175 @ .5 moa if I do my part.

The very debatable topic would be weather or not there is enough advantage to running a magnum head 6 vs a 6 Creedmoor? There is a school of thought that barrel life could possibly be improved running a magnum 6 on cruse control vs 6 Creed at max pressure?
I don't know the answer. I'd think pressure + heat equals velocity, but then again if your 300fps under max load in a mag bolt head maybe some of the heat gets absorbed by the case itself vs the throat.

To me the juice isn't worth the squeeze unless I inherit a fortune from an unknown relative.

 

[Earnhardt]

I stated they a SIMILAR in case capacity, NOT case dimension

 

[Odysseus1911]

I've been wondering if cases with steel heads (ala Sig's .277 Fury) are going to catch on and be applied to existing cartridges. If so, we could potentially see small-frame AR cartridges approach the performance of large-frame AR cartridges (6.5 Grendel approaching 6.5x47L performance), and large frame AR cartridges approaching magnum action performance (.308 performing somewhere between 30-06 and 300 WM).

I'd be pretty happy with a 300 blk that could approximate .308 performance.

 

[RTV]

Thanks man, happy to be here. I've got nothing to lose and everything to gain lol. I've spent a lot of time on the /K/ forums over on 4chan, and several gun subreddits.

I'm a literal noob, I live in Portland, I just got a pistol two months ago because my antifa neighbor now has a bunch of guns and I don't think I trust him being armed and whatnot, and I've shot maybe 100 rounds through my pistol? Anyways, I have a bunch of lowers to build out for when I move to Idaho or Montana, and my AR-15 based builds are coming along nicely. But I have a few AR-10 lowers, and I have a few 308 and 6.5 Creedmoor builds I want to do. Those builds aside, I've got one extra AR-10 lower, and I want to do something exotic, I want a wildcard caliber that might pop off over the next 4 years.

if you are buying these rifles for defensive purposes (which it sounds like you are)
and you are this new to everything i would STRONGLY recommend you buy a high quality factory AR15
as your self defence rifle.

 

[2aBaC̶a̶]

But he wants to go down the rabbit hole of obscure large frame AR issues and unreliabilty coupled with unobtanium ammo and begginer reloading issues.

 

[JoshPutman]

How about that new 6.8 Western cartridge, that's supposed to be pretty hot shit.

Specs show a length of 2.755" to 2.955", so it should fit I believe.

 

[LRRPF52]

LRRPF52,
...too much case capacity for the bore volume on a gas gun for the 7mm...
Does this apply to all magnum case LR308 guns?

I think the pressure levels after the dwell time starts really effects the operation of the LR308.

Meaning my 24" 45 Raptor (rifle gas) has less pressure in the barrel during dwell time, and has a less detrimental effect on the BCG, than my WSM does with a rifle +2" with a 26" barrel.

And really those 2 barrels have the exact same dwell time, but the dwell pressure in much higher in the WSM
(Dwell time being the amount of time the bullet is in the barrel AFTER it passes the gas port)
I have a much broader range of powder loads with the 45 Raptor, than with the WSM.
When I'm pushing the WSM from 50-55kpsi, the WSM, with 3 different bullet weights, and a myriad of powders...wants to work with a few combos
I believe that with a heavier than 9/10 oz. buffer this would be achievable.
I'd like to try a 12-15 oz buffer in the WSM.

the PRC/WSM/Sherman are all FAIRLY SIMILAR in case capacity...

At what point does the case capacity/bore volume level out, to where a guy can start pushing the Magnum cases to there full potential in a LR308?

With the current BCG and buffer weights that are available, is the .308 case variant the best option out there right now for max performance?

45 Raptor has all kinds of bore volume and uses much faster burning powders to punt those .452” bullets out quickly. That makes it a totally different rifle from an engineering standpoint due to the pressures, port pressure, and plug dwell as you describe.

7 SAUM or WSM is really asking a lot from a gas gun not engineered around it. We really have to control bolt lock time until residual pressure has subsided. It would be great to have a well-behaved 7mm Magnum gas gun, but the ability to make really fast follow-up shots also challenges the throat and bore life.

I think the .300s do better for those reasons, as there is more bore volume relative to case volume.

It makes you start thinking about machine-gun barrel steel and bore linings with Stellite or hard chrome, but then there needs to be a way to control bore straightness and uniformity for accuracy.

 

[LRRPF52]

How about that new 6.8 Western cartridge, that's supposed to be pretty hot shit.

Specs show a length of 2.755" to 2.955", so it should fit I believe.

It’s basically a shortened .270 WSM meant to shoot longer VLD ogives seated optimally.

The best people to cover down on this would be Accuracy Systems. They’ve been doing custom AR-10 magnums and alternate chamberings for the better part of the last 2 decades.

Accuracy Systems

22-250 Remington 243 Winchester 6MM Creedmoor 257 Roberts 257 Roberts Ackley Improved 260 Remington

6.5 Creedmoor 7MM 08 Remington 7MM SAUM 7MM WSM 284 Winchester

308 Winchester 7.62 x 51 MM NATO 308 Winchester Match 300 Savage 300 SAUM

300 WSM 325 WSM 338 Federal 358 Winchester 450 Marlin

 

[308pirate]

But he wants to go down the rabbit hole of obscure large frame AR issues and unreliabilty coupled with unobtanium ammo and begginer reloading issues.

Yeah, what could possibly go wrong?

 

[Submarine Sharpshooter]

How about that new 6.8 Western cartridge, that's supposed to be pretty hot shit.

Specs show a length of 2.755" to 2.955", so it should fit I believe.

The low end of that range has only .045 in to spare and the high end is a full .155 in too long - that is quite a bit too long.

Even if we assume KAC or Larue mags are used, the high end is still something like .105 in too long.

Time will tell if it’s supported well in the AR10 market. Given that it’s probably not going to feed anything but the lightest weight / shortest / lowest BC bullets I would guess probably not.

 

[2aBaC̶a̶]

Yeah, what could possibly go wrong?

Today's AR builders are tomorrows why isnt my gun cycling correctly threads.

Dont want to deprive the community of a good "what not to do" thread.

 

[Thetraveler1963]

As far as suppressed AR-10's go the 375 Raptor is my absolute favorite. Also goes well as a short to mid range large and dangerous game caliber. Bear, moose, elk.

 

[Earnhardt]

As far as suppressed AR-10's go the 375 Raptor is my absolute favorite. Also goes well as a short to mid range large and dangerous game caliber. Bear, moose, elk.

Loads?
Accuracy?
Velocity?
Thanks

 

[TonyTheTiger]

Still trying to figure out what a wildcard cartridge is.

 

[Cjs58]

I think something like a 270 wsm or a 300 wsm would work in the AR10 format or the 7mm08.

 

[Krupples]

375 or 45 raptor

 

[troysutton3187]

Try the 500 blackout when they are done with it. I dont know much about it except rumors unfortunately. But I'm sure the interwebs will have something

 

[Northman623]

Custom AR10 Rifles Accuracy Systems Gunsmith Gunsmithing AR 10

AR10 Rifles customized by Accuracy Systems Inc. ASI does custom gunsmithing, builds Custom Rifles and rifle Rebarreling on AR10 rifles.

www.ar-10-rifles.com

 

[Thetraveler1963]

Loads?
Accuracy?
Velocity?
Thanks

Load Data | 375RAPTOR

www.375raptor.com

 

[Earnhardt]

Load Data | 375RAPTOR

www.375raptor.com

Do YOU have any load data, velocities, group pics?
Yea’s or nay’s for the 375 Raptor?