Which caliber AR for long range shooting?

[Seancass]

barely related side questions:

Can you chamber an AR in .25 WSSM?

And is .30AR (new, by remington) even a remotely good option?

 

[melensdad]

barely related side questions:

Can you chamber an AR in .25 WSSM?

And is .30AR (new, by remington) even a remotely good option?

Yes, the 25 WSSM is available from Olympic Arms and also from Accurate Technologies in the AR15 platform. However the ballistic coefficient of the 25 is lacking and that is why the 243 WSSM is a much better long range choice.

As for the 30RAR, from Remington, that looks like a failure right off the bat. Info from Remington:

There is a good 30 caliber option, that is the 30 OSSM, which is a factory loaded 30 caliber round based on the Winchester Super Short Magnum case. Rifles are now in production and delivery has started, they come from Olympic Arms. Due to the short magazine, optimal bullet lengths for long range shooting cannot be loaded, but the round shows amazing potential for a hunting round. Its delivering real world velocities with 150 grain bullets that meet/slightly exceed 30-06 velocities!!! However the ballistic coefficient of the 150 grain bullets is not high enough for that to become a serious long range 600+ yard gun.

This information is from Tom Spithauler who worked on the 30 OSSM project:

Three bullets were tested for standardization. A110 grain, 115 grain, and a 150 grain. Here are the results:

110 grain Hornady V-Max
Powder 50 gr. H735
Ave. pressure, 60,300 psi
Ave Muzzle Velocity 3480 fps

115 grain (solid brass with plastic tip: Barnes?, not sure, details not provided)
Powder 48 gr. H735
Ave. PSI 55,700
Ave Muzzle velocity 3358 fps

150 gr. (bullet unkown at this point)
Powder IMR8208XBR (new powder)
Powder charge (varied from 45-51 gr.)
Ave. PSI 56,6000
Ave. Muzzle Velocity 3043 fps

 

[Litlratt]

No argument from me that a 233 will punch paper at those ranges. Don't ask it to knock down a steel ram or set of a reactive target like tannerite at 600 yards. So I'd say we are both in reasonable agreement. However the thread is asking for a great round for long range and the 223 is clearly not that choice. I'm not saying its not possible to use one, I'm saying its not ideal and there are better choices for AR15 rifles. Why would I recommend a round that is perhaps ranked #4 or #5 on the list when there are clearly several better choices? BTW, you mention Palma and does that not require the use of single shot bolt guns while this thread regards an AR15 based build?

Actually the OP asked for paper punching at 400 - 800 yards.
Palma does not require the use of a single shot bolt gun. Service rifles are shot in that match at the Nationals every year. The reason it was mentioned is because it is paper punching at 800, 900 and 1000 yards.

 

[melensdad]

I'd still suggest that it is far from the best option.

But thank you for the clarification on the Palma matches, I've not shot in one of those and was under the impression it was a specialized bolt gun used for Palma matches like the Tubbs 2000 and similar rifles. Its always nice to learn something new!

 

[tenring]

Why so? A wildcat cost no more than any standard round to load unless you go with something so bizarre you have to have the bullets custom made. I load for a 22 Cheetah, a 300 Whisper, a 375/338, and a 450 Alaskan. In most cases the dies were off the shelf, they load on my regular press using standard bullets and powders. The only necessity is that you do reload which is cheaper than buying standard ammo anyways.

I had a .375/.338 built up a few years ago, 10 rounds off a bench with 300 grain Sierras finally made me sell it off. But it did MOA out of 1-10 Douglas that McGowen put on a MarkX action.

 

[Litlratt]

I'd still suggest that it is far from the best option.

But thank you for the clarification on the Palma matches, I've not shot in one of those and was under the impression it was a specialized bolt gun used for Palma matches like the Tubbs 2000 and similar rifles. Its always nice to learn something new!

There are restrictions if you are shooting a Palma rifle. That it be a bolt gun is not one of them. U.S. Palma rules are different than International Palma, which is more restrictive.

 

[sloughfoot]

My Palma gun is a 40X repeater bolt gun in .308 with a 30 inch Kreiger barrel. Not the optimum setup, but it still shoots better than I do. I just need to let the rifle shoot into the center.....

 

[calinb]

I have an Oly upper in 243WSSM that was built for shooting 200 to 600 yards. The barrel was swapped for a Krieger.

Can you please tell me where you got that barrel, Litiratt? I'm interested in a 1:8 twist Oly Mag8 .243 WSSM upgrade too.

Thanks,

-Cal

 

[Litlratt]

Can you please tell me where you got that barrel, Litiratt? I'm interested in a 1:8 twist Oly Mag8 .243 WSSM upgrade too.

Thanks,

-Cal

Bill Wylde barreled it. He had a 6mm blank and chambered it for the WSSM.
I'm considering selling the upper, mags, brass, dies, etc. PM me if interested.

 

[calinb]

Bill Wylde barreled it. He had a 6mm blank and chambered it for the WSSM.
I'm considering selling the upper, mags, brass, dies, etc. PM me if interested.

I'm interested. Unfortunately, I can't PM you until I make 15 posts to this forum. Rather than just spam away with 14 more posts, perhaps you can PM me with an email address and I'll reply via email with a phone number.

Thanks,

-Cal

 

[yotewacker]

I have an AR-10 in 300WSM. It shoots sub=moa. Have shot many 600 yd targets with it.

 

[melensdad]

I have an AR-10 in 300WSM. It shoots sub=moa. Have shot many 600 yd targets with it.

That won't work for the Original Poster. He is building up an AR15 based long range gun. He's going to be limited to the shorter action of the AR15 platform so his choices would likely be a WSSM case like the factory 243 WSSM or a wildcat based on the WSSM, a 6.5 Grendel or one of the 6mm Grendel based wildcats like the 6mmAR Turbo, etc.

 

[jtmarine1911]

I completely agree with melensdad on the 6.5Grendal as the best choice especially for the fact that the OP is using a standard AR lower.
I am currently trying to build my first Grendal upper but am consistantly side tracked from it by other spur of the moment purchases.

I am however hurt melensdad that that you belittle the 308Win. by using 7.62NATO data to compare it to the 6.5Grendal. With such a lower velocity and operating pressure than the 308, it does appear that the 6.5 has the velocity advantage when they are more neck and neck in my opinion.

Here is a calculated performance data of the 308 load I shoot, I did use the elevation, temp, and humidity data from the chart you used. In actuality my personal velocities are a little higher since where I shoot is approx 525ft higher above sea-level but you get the idea. But since this is my handload I guess it is neither here nor there since factory loaded 175gr will range 100-150fps slower and best the 108gr Scenar load by only 2fps.Tough choice since there are so many options to weigh

OK but prove it.

Here is a ballistics table, show me where the 308 is clearly the BEST round for LONG RANGE and, as a follow up, show me how to feed one through an AR15, which is what the OP has for a platform.

Now, using real data, not opinion, please prove it.