AR10 caliber

[RifleBowPistol]

So I have a few AR10 pieces. Got two common AR10 lowers, then picked up a Aero enhanced upper. Then figured out the Aero uppers are DPMS/LR308 style AR10, and not the common AR10 design.

So I am going to wind up with three AR10s. For sure, no question about it, the first AR10 lower, is going to get a 458 WSM barrel. The other AR10 lower very likely will get a 358 WSM barrel. Then there is the Aero upper, it has a common size ejection port, or looks that way, so I don't think that gun will be chambered for a WSM based caliber.

I have been thinking about doing a 358 Win. or a 375 Raptor. But if I do a 358 WSM or 375 WSM, with the other AR10 lower, then why do a 358 Win. or 375 Raptor, other than to have a gun of those bores, minus the recoil. Which I don't think the WSM based calibers would pack much recoil. Not really worried.

I have a 6.5 Creedmoor bolt gun, don't really want a another one. I have zero experience with 244/6mm guns, other than tracking deer somebody else shot with 243s. I got to thinking maybe a 6mm Creedmoor. Then got to thinking maybe a 22 Creedmoor. My thinking with those two calibers, is the case is short enough, and the bullet diameter is small enough. Even with a AR10 mag, I should be able to load the highest BC bullets as long as I choose and not have issues with the internal length of the mag, front to rear.

If I did either of those two calibers, I would probably shoot some of the heavier bullets for those calibers. Anybody have experience with either of these calibers, and how well they fit in AR10 mags? Performance of the calibers?

I know for sure, I don't want to do a 7mm-08, or 308, or 243, 260, because I would not be able to load high BC bullets without having to stuff them way down in the case. The bigger bore rounds like the 358 or 375, I would not use high BC bullets in those calibers, just common old soft points.

[WTJim]

.358 WSM would be my choice!

[STXBOWHUNTER73]

22-250 is on my list

[Mike D]

I was going to suggest 6.5x47 Lapua but you seemed to be leaning toward bigger bore calibers.


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[HogCommander]

FWIW I really like my .338 Federal AR-10. It's in between the bigger bore calibers and the high BC options you mention.

I load Barnes 185 gr TSX bullets and have yet to have a deer take a step after the shot. More frontal surface area on the bullet but same magazine capacity and bolt as a .308.

[RifleBowPistol]

I was going to suggest 6.5x47 Lapua but you seemed to be leaning toward bigger bore calibers.


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It's kind of on my list, along with another caliber. I have a 270 AR AR15, it's a wildcat round based off of 6.5X47 Lapua. That round will duplicate 270 Win. factory ballistics. Really the caliber is not a good choice for a AR15, it would be a much better choice in a AR10. In a AR15, you need to use the shortest .277 bullets you can find, such as Sierra Game Kings, or Sierra Pro Hunters, in 130 gr. With either of those, you can get 2850 fps, with a 20", with a 38 gr. charge of Leverevolution. With a 24" to 26" barrel, it will do around 3150 fps, with the same 38 gr. powder charge. But guys were getting 3100 to 3150 fps, with a 40 gr charge of Leverevolution, with a 40 gr. charge and a 20" barrel. But the bullet has to be seated farther out of the case, to the point it won't fit in a AR15 mag.

I know one of the guys who has a 270 AR ream, I have been talking to him about reaming a barrel for me, for a Remington 700 action. I have been thinking of getting a titanium 700 based action, then a 5R 24" carbon fiber barrel, carbon fiber stock. Then have the barrel reamed out to the 270 AR, then have the throat cut deeper, so I can run something like a Nosler Accubond Long Range or Berge VLD Hunter, in 130 gr., seated out of the case far enough to get 40 gr. in the case. I think that would make a nice light weight deer gun.

A few times, I thought about just doing that rifle build in 6.5X47 Lapua, because it would be easier, that was until, I tracked down the guy with the 270 AR ream. The reason I plan on building another gun in that caliber, is I spent a bit over $400 for the dies for that caliber, so I would like to make use of them, and it's an impressive caliber. Once I get another gun built, I plan on removing the 270 AR barrel from the AR15, and replacing that barrel with either a 224 Valkyrie or 6mm ARC. Because I am not really able to get the most from the 270 AR, when chambered in a AR15.

I still would rather build a 270 AR in a light weight bolt gun, I think that would be the best rifle to build in that caliber. Then I am a little leery of having a 6.5X47 and a 270 AR, that is made from 6.5X47 Lapua brass. The 270 AR case, is very close to 6.5X47 Lapua, in length, and diameter. I would like to have a 6.5X47 Lapua, but just a bit worried about it being so close to the other caliber.

So those are the reasons, I am really thinking of going with a 22 Creedmoor, or 6mm Creedmoor, over a 6.5X47.

[Samson]

I shoot 22cm in a bolt gun and 6.5cm in an Aero M5. The 22cm is shorter, and my load will fit in AR10 mag using the 88gr ELD-Ms. Oal is at 2.74 and that bullet touches the lands at 2.79 in my gun. Its a fun round, not much umph past 600. Its hard to hear it hit steel at 1k. I also have a 270 MSR in an Aero M4 shooting 140 classic hunters and leverrevolution. Its probably my fav right now, but to answer your question though, yes 22cm will fit in an ar10 no problem. We've killed some pigs and Aoudad with the 22cm too.

[Mike D]

It's kind of on my list, along with another caliber. I have a 270 AR AR15, it's a wildcat round based off of 6.5X47 Lapua. That round will duplicate 270 Win. factory ballistics. Really the caliber is not a good choice for a AR15, it would be a much better choice in a AR10. In a AR15, you need to use the shortest .277 bullets you can find, such as Sierra Game Kings, or Sierra Pro Hunters, in 130 gr. With either of those, you can get 2850 fps, with a 20", with a 38 gr. charge of Leverevolution. With a 24" to 26" barrel, it will do around 3150 fps, with the same 38 gr. powder charge. But guys were getting 3100 to 3150 fps, with a 40 gr charge of Leverevolution, with a 40 gr. charge and a 20" barrel. But the bullet has to be seated farther out of the case, to the point it won't fit in a AR15 mag.

I know one of the guys who has a 270 AR ream, I have been talking to him about reaming a barrel for me, for a Remington 700 action. I have been thinking of getting a titanium 700 based action, then a 5R 24" carbon fiber barrel, carbon fiber stock. Then have the barrel reamed out to the 270 AR, then have the throat cut deeper, so I can run something like a Nosler Accubond Long Range or Berge VLD Hunter, in 130 gr., seated out of the case far enough to get 40 gr. in the case. I think that would make a nice light weight deer gun.

A few times, I thought about just doing that rifle build in 6.5X47 Lapua, because it would be easier, that was until, I tracked down the guy with the 270 AR ream. The reason I plan on building another gun in that caliber, is I spent a bit over $400 for the dies for that caliber, so I would like to make use of them, and it's an impressive caliber. Once I get another gun built, I plan on removing the 270 AR barrel from the AR15, and replacing that barrel with either a 224 Valkyrie or 6mm ARC. Because I am not really able to get the most from the 270 AR, when chambered in a AR15.

I still would rather build a 270 AR in a light weight bolt gun, I think that would be the best rifle to build in that caliber. Then I am a little leery of having a 6.5X47 and a 270 AR, that is made from 6.5X47 Lapua brass. The 270 AR case, is very close to 6.5X47 Lapua, in length, and diameter. I would like to have a 6.5X47 Lapua, but just a bit worried about it being so close to the other caliber.

So those are the reasons, I am really thinking of going with a 22 Creedmoor, or 6mm Creedmoor, over a 6.5X47.

I don’t get the fascination with the .277 caliber anything.

You could also consider a 22x47 Lapua or 6x47. Of course those would be handloading only but the case is a bit shorter than the Creedmoor and is extremely efficient.

I have a 6.5x47 with a 22” barrel and it runs 2920fps with 129 ABLR bullets.


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[WhiplashTX]

Then there is the Aero upper, it has a common size ejection port, or looks that way, so I don't think that gun will be chambered for a WSM based caliber.

It's very easy to open up the ejection port with a dremel tool.

I would have suggested the 300 WSM but your 2.8" limit doesn't work well with the longer bullets.

[WhiplashTX]

I don’t get the fascination with the .277 caliber anything.

I agree with you but Jack O'Connor always get referenced, most haven't read what he actually wrote. He had to use a new caliber to keep manufacturers and handloaders from using old school bullets.

[Samson]

I don’t get the fascination with the .277 caliber anything.

The bullet choice and availabilty during the droughts is about all it has going for it. Wind calls and a low SD matter more than BC with a heavy in any caliber so I guess I dont understand the hate for it.

[Mike D]

The bullet choice and availabilty during the droughts is about all it has going for it. Wind calls and a low SD matter more than BC with a heavy in any caliber so I guess I dont understand the hate for it.

I don’t hate it, I just don’t see the fascination for it. It probably has the least amount of premium high bc bullets of any caliber maybe except for the .257 caliber bullets.


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[Raider4044]

I don’t get the fascination with the .277 caliber anything.


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Me either, especially considering that the amount of bullet choices suck. One of the main reasons the 6.8 Western was DOA when it was introduced.

[Fordnandez]

22-250 is on my list

This

[RifleBowPistol]

I don’t get the fascination with the .277 caliber anything.

You could also consider a 22x47 Lapua or 6x47. Of course those would be handloading only but the case is a bit shorter than the Creedmoor and is extremely efficient.

I have a 6.5x47 with a 22” barrel and it runs 2920fps with 129 ABLR bullets.


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Well years ago, I was going to put a 6.5 Grendel together, a bunch of guys on this one group I was on, acted like that 270 AR was the way to go. It was a lot better than the Grendel, ECT. I saw the numbers those guys were getting they were impressive. So I went that route. At the time I decided to go that rout it turns out the guy who cooked up the caliber was just about done with the caliber. But nobody but him knew that at the time.

The caliber is quite impressive, but very limited in a AR15. So I decided I wanted a 700 chambered for the round. I talked to Harrison, the guy who cooked up the round, he wanted no part of the idea. So after thinking about the whole idea for a while, I realized that it would be a lot easier and likely better to just build that 700 in 6.5X47 Lapua. I see no reason the 6.5X47 should not perform very similar and potentially better than the 270 AR, since the 270 AR is a 6.5X47, that has been shorten 1 mm, then opened up to .277 caliber.

So for a couple years, that was my plan. Then about a year ago, I found one of the other two guys who has a 270 AR ream, he is willing to ream a barrel for me. So I think I am going that route on the 700. Again, mainly because something like $440 for those dang dies, they are some nice dies.

The whole 270 AR mess enlighten me to the potential of the 6.5X47 Lapua. Had I known about it before I paid for that barrel and those dies, I would be building two 6.5X47s. I do want to build a 6.5X47 XP100.

I know if I put the barrel and dies up for sale, it would take forever to get rid of them, and I wouldn’t get crap for them. I with those dies were 6.5X47. I would just toss the barrel in a corner and forget about it. Which is what will most likely happen to it either way.

If I went with a 6.5X47, I would only have to hunt down those non existent 6.5 bullets, and not 6.5 and .277 caliber bullets.