.308 or .338?

[ray1970]

While everyone has brought up some good points about the .308, nobody has said anything that would drive me away from the .338 based on my intended use. Still kind of leaning in that direction.

Thanks again for all of your advice and opinions.

[Hoser]

308 hands down.

The 338 Federal cant push any decent 338 bullets fast enough. Past a few hundred yards it would be like lobbing in artillery shells.

[Gunner]

308 hands down.

The 338 Federal cant push any decent 338 bullets fast enough. Past a few hundred yards it would be like lobbing in artillery shells.

See this is whee the debate stops. Hoser chimed in and he knows what he is talking about.

[MarkCO]

See this is whee the debate stops. Hoser chimed in and he knows what he is talking about.

Should have been. .308 over .338 is good advice.

The .260 is a perfectly fine cartridge for the AR-10 platform and factory ammo does a very solid job. The 7mm-08 is also a consideration.

Of the .308 family, .243, .260, 7mm-08, .308 and .338 Federal, I might put the .338 ahead of the .243. Then between .260, 7mm-08 and .308, it is kind of preference if you toss out the prevalence and cost of factory ammo benefitting the .308.

[Delfuego]

I believe you are thinking of the wrong .338.

You know I am! I was thinking 338 Lapua! Not Federal. I thought you were gonna buy and build Glenski's 338 lapua stuff

308 hands down.

The 338 Federal cant push any decent 338 bullets fast enough. Past a few hundred yards it would be like lobbing in artillery shells.

I have had to opportunity to shoot, sight-in and play around with a 338 AR-10. The bullet drop at 600y was considerable; way, way more than 223 or 308.

[cysoto]

When this project is complete it will primarily be used for shooting steel from 200 to 500 meters.

Out to 500 meters? Between those two calibers, .308, hands down.

[Tim K]

If you ever had a desire to shoot in a competition, that 200g bullet will exceed the maximum allowed at some venues.

Personally, I'd go .260 Rem. Significantly better than .308 at long range, low recoil, less expensive (a tiny bit) to load. Since it's .308 based, I assume it should run in the AR-10.

It's on my list of toys to want.

[cysoto]

... I assume it should run in the AR-10.

It does but, in order to make it fit the magazine, you need to load the rounds to a short OAL which will increase the cartridge pressure.

[Tim K]

It does but, in order to make it fit the magazine, you need to load the rounds to a short OAL which will increase the cartridge pressure.

With 123g SMK's, you can easily load to 2.800" without pressure problems. A small compromise from the 142's, but not terrible.

[cysoto]

With 123g SMK's, you can easily load to 2.800" without pressure problems. A small compromise from the 142's, but not terrible.

I have only seen it tested with 142 grainers and it was piercing primers left and right.