Possible dumb question on bullet choice (.308)

[Gundoc]

I have an AIAX308 with an 18" 1/12 twist barrel (yes I know it's a bit short, did it on a whim- going to get a 6.5 barrel for 'proper' shooting)
My main interest for the 308 barrel is hitting steel out as far as I can get it (and hogs out to about 200yds)

what thoughts on bullet weight selection? I'll be reloading mostly so I can shoot more for the same money..

 

[diverdon]

SMK 175 with 4064 should get you 900 to 1000 yards.

 

[Gundoc]

SMK 175 with 4064 should get you 900 to 1000 yards.

From an 18" barrel?? Wow. I thought I'd limited myself by chopping that far

 

[...]

Yeah .308s dont need a ton of barrel length.....18-22" seems to be pretty standard......because you only lose something on the order of 18fps per inch of barrel.

Now with the 1/12 twist barrel you might have issues stabilizong the heavier 175gr bullets....so you might be better off with 168gr.......but a lot of people report getting just fine accuract with the 175s our of 1/12s, just something to watch out for.

 

[bogeybrown]

FWIW I have a 18" 1/12 on one of mine and it handled 175SMK just fine. I plugged a nominal MV of 2450fps (for Black Hills 175) into my solver which trued out perfectly at 875yds.
Depending on DA mine was right in the heart of transonic range at 1k so not optimum, but I could get 2nd/3rd round hits on a 66% IPSC at 1100. My misses were close enough that I don't think stabilization was the primary issue.
Chrono yours and see what it's telling you for MV at distance, but I don't think you'll have an issue with 175, especially if you're handloading and can nudge MV a bit

 

[Centuriator]

SMK ... 175 grain ... if you have the skills it is more than capable. Enough said. You can thank me later. I've shot it in several bolt guns and in each instance it has been sub-MOA, when I did my job behind the trigger with a high-power scope, precision trigger, and great rifle.

Good luck.

Cheers!

 

[MarkLeupold]

185 Berger Juggs or VLD's run pretty good with minimal velocity. Try 2000MR powder for a little more speed. Frank (Lowlight) has tried it out of a 22" and seen some good things.

Sent from my SAMSUNG-SM-G920A using Tapatalk

 

[bogeybrown]

185 Berger Juggs or VLD's run pretty good with minimal velocity. Try 2000MR powder for a little more speed. Frank (Lowlight) has tried it out of a 22" and seen some good things.

Sent from my SAMSUNG-SM-G920A using Tapatalk

I think the OP's (justified) concern isn't so much velocity as the relatively slower 1/12 twist rate on his barrel. At a certain point a barrel won't properly stabilize a bullet beyond a certain weight. "Conventional" thought would put a 185 on the far side of ideal for a 1/12, but who the hell knows, he may be able to develop a great load for it.

 

[MarkLeupold]

I think the OP's (justified) concern isn't so much velocity as the relatively slower 1/12 twist rate on his barrel. At a certain point a barrel won't properly stabilize a bullet beyond a certain weight. "Conventional" thought would put a 185 on the far side of ideal for a 1/12, but who the hell knows, he may be able to develop a great load for it.

Ah, I missed that part of the post. Agreed, 185's may be a tad much.

Sent from my SAMSUNG-SM-G920A using Tapatalk

 

[Gundoc]

Thanks for the info guys, I was concerned that the combo of short barrel combined with the 1/12 would cause issues. I'll see how I go with some factory 175 vs 168 and see which one works out best, then work into a recipe from there.
thanks for being gentle!

 

[Timo Turl]

Nosler 175gr RDF.

 

[SubOptimal]

What about a 155 Scenar, 1:12 twist shouldn't be a problem and the BC is pretty good. A bit more V shouldn't hurt.

 

[diverdon]

What about a 155 Scenar, 1:12 twist shouldn't be a problem and the BC is pretty good. A bit more V shouldn't hurt.

That's probably a good option. I picked the SMK 175 first because it is $.09 per bullet cheaper, but if he has any trouble getting the SMK to work then the Lapua is the way to go.

 

[Triggered]

Both of my .308 Sakos were the 1:11 twist with 26" barrels, so I assume I'm in the relative ballpark of a 1:12 minus the 8" inches extra.

On my A7, it did remarkably well with 150gr Hornady interlock soft points for whatever reason out to 500yds or so and then they loss their juice. Granted, it's a deer killer round, it did very well for whatever reason. Past 500yd I went over to the 175 SMK that everyone has mentioned. Shot a 2.5" group of 3 at 630yd using those FGMM 175s on a near windless day.

When I moved over to the TRG 22, it ate just about anything I threw at it for shelf ammo (of decent quality). Does well with 168 Hornady HPBT I load up by hand, not so much with 150 FMJ BT, but is a complete face melter with 178 Hornady ELDs. Shot a 2" group of 5 at 500yds yesterday with 25mph wind gusts.

If you're smashing pigs, maybe try those Interlocks, otherwise SMK and the ELDs are my personal preference in handloads. Those Interlocks would group as tight as I could shoot them at 300yd with my A7 (zero range) and they're only $20 a box.

 

[308pirate]

I shoot a Howa 1500 with a 1/12 barrel (it's a few years old, they are now 1/10) and it has zero problems stabilizing 175 RDFs as far as that bullet will reach.

People ovethink this shit way too much.......

 

[mtwarych]

I would suggest 165gn Nosler Acubonds for the piggies and Nosler 165gn Ballistic tips for everything else.

I shoot both with the same load and the same POI.

 

[scharfschutze762]

Did a test on a 308 1/12 twist barrel remmy. at 24 inch barrel it was fine out to 1k at 90deg almost sea level. cut it to 20 inch it still shot 1 hole and great out to 600. when it tested at sea level at 1K it went to shit. wasnt enough spin on the bullet at transonic coupled with the wind it was all over the place. ammo tested was 168 and 175 grain federal match. Same gun has 1/9 twist 18" barrel now and shoots great at 1K. our AR10s with 16 inch barrels have 1/8 and 1/9 twist and shoot well to 1K..if your gonna shorten the barrel extra spin is your friend.

 

[308pirate]

..if your gonna shorten the barrel extra spin is your friend.

Correct. Seems in that certain things get forgotten in the shorthand of twist and bullet weight.

Speaking of stabilization........bullet length, not bullet weight; and bullet rotational velocity, not barrel rifling rate of twist are the things that actually matter. Obviously we can use the short hand when we deal with common barrel lengths and bullet construction (lead core/copper jacket). Once you step out of those norms, gotta think a little more about it.