bullet weight for 1/10 twist 308 in 16in barrel?

[hcalli48]

Im sure this has been asked 400 times, but i'm going to make it 401.

I've looked through countless forums to see what bullet weight would be stable (to prevent baffle strikes) out of a 16in 1/10 upper.

I have a 20in proof research barrel in an upper now on my ar10 with a mark 5 hd 5-25x56 and want something a little shorter for pigs on our property and do not feel like taking off my Leupold everytime I want to throw my night vision or thermal on. I have a Bergara b-14 HMR that im using now as a dedicated pig gun so that im not using bench guns or my deer rifles, but would like to go back to semi-auto 308 and figured a 16in upper would be the sweet spot (no further than 120 yards for pigs and would only be used for this).

I have a couple hundred rounds of 178 ELD-x precision hunters that im using out of my Bergara and current 20in upper and 165 GMX that I shoot out of my Kimber and other hunting rifles.

Would these bullet weights suffice out of a 16in upper and not baffle strike? I know 1/10 20in barrels like 165 and up but not sure about the shorter barrels.

 

[PinesAndProjectiles]

Google the “Berger Twist Rate Calculator.”

You can select any of Berger’s bullets from a pre loaded menu or enter in the data for other bullets manually.

 

[TonyBen]

Try 130 grain hollow points. 1:10" twist is necessary for shorter barrels. I would also try a faster burning powder like IMR-3031.

Tony.

 

[Bobby Ball]

I personally have never had any success with anything lighter than 168. I've had really good luck with 185 juggernauts. And I've just started playing with 200 and 200.20 to test out

 

[hafejd30]

For a 1/10 I’d stay in the 150-178 grain area

 

[45-90]

Just finished a new 16" light weight AR 10 6 lb 3 oz 308 AR10 I have been shooting the new 169 SMK and the new 177 SMK. It has a 1-10 twist the 177 SMK and 44 gr imr 4895 run 2584 fps ave 10.8 S/D in Lake City brass shooting 3 shot groups in .2" and .3" & 5 shots 3/4". Bad weather, hunting season, and an adjustable gas block that failed have dampend further testing...but 130 gr Speer Varmint is usually accurate in any 308. The 169 SMK were showing promise too and running a little faster.
Set it up for 1200 yds, to dial the elevation...confirm that later. This AR 10 has a WC Recon fluted barrel, titanium bolt carrier, 1 oz JG carbon fiber handguard, (3 oz with mounting hardware) titanium muzzle brake, magnesium upper...lighter than many AR 15s, at 6lbs 3 oz.

 

[Shoots 700's]

Maybe try some 155 scenars

 

[hcalli48]

I noticed this with my Kimber mountain ascent, 150 shoots a pattern, went to the 178 eldx and it shot 1-1.2in groups, tried a 165 gmx and its sub moa all day. Saved the 150s for my browning x bolts and mess around bullets for buddies to use. Anything over 150 in those x bolts is 2-3 in groups at 100

I was trying to quote you Bobby and I really dropped the ball on that one

 

[sinister]

Maybe try some 155 scenars

I tried a few hundred at 5,500 feet in Utah out of a 20-inch Armalite and they were just OK out to maybe 700 or 800 yards. Just can't push them fast enough from a shorter barrel.

Maybe a 1-9 twist might help squeezing some further range out of a shorter 16-incher.

 

[chevy_man]

Too much twist is fine until you spin the bullet apart.

Test your loads. That will tell you the truth. (for 125 yard pig gun I would shoot anything that hits 2-3moa, it's not a 1000 yard gun nor are you winning trophies. Just putting a pig down.)

 

[45-90]

I took the 155 Lapua's to 1400 yds ...alot. 17,000 rds many yrs ago in 26" and 27" barrels 12 twist all, on bolt guns it was my LR bullet to that range. Today there are alot of 308 bullets better suited for past 1000yds. But the 308 Palma, with a variety 155 gr have been used for many yrs in 1000yd competitions.

 

[45-90]

Are you going subsonic? Baffle strikes? Or supers? ... I shot, 155, 168,175 gr SMK in barrels from 12, 10, 9,& 8 twist in 308 from 18" to 30" to see the results. With around 10.0 gr of Trail Boss, Did not cycle AR but fairly accurate to 100 yds. And shoot the eye out of a pig at 50 yds...the 200 gr SMK went sideways at 50 yds in the lesser twist barrels.

 

[Bobby Ball]

I probably should have done a little more clarifying in my last post. I'm shooting out of an Armalite ar-10t with a 24" Krieger 1-10. I had the upper done by Geoff Corn, and then over time all the other items, muzzle brake, tunable gas block and buffer, etc. I originally built it to be a 1k yard gun. It's been ok, but I'm still trying to refine it. I started load development about a year ago and have run a bunch of different powder, brass, primers, and bullets. All with magnetospeed measurements plugged into GRT to refine it. I have a strain gauge as well that I use for my wildcat long range precision rifle but haven't used it on the AR mostly due to difficult installation of the gauge on the chamber in the proper location.
When I first got the gun I went through every factory precision round I could find and the only success that I started having with any of them was fggm 168-175 Sierra's. Eventually I moved over to the 185 juggernauts due to my ballistic calculator showing it staying supersonic past 1k where it showed the others wouldn't. More recently I have tried the 175 OTM, 169 sierra, 200 hybrid, and I just ordered a box of 200.20. I was really hopeful for the 169's and just didn't get what I was hoping for. I just finally received a lot of lapua brass and I'm really hoping that's the missing piece of the puzzle. I have a ton of load info if it is of any use to anyone else. And again these are just my experiences. Also, I'm at 6000 ft altitude.

 

[db2000]

Varget is temp stable and great with Berger 185 Juggernauts. 175 SMK also but I had better luck with H4895. I’d vote heavy and big energy it’ll stabilize 150’s if you want.

 

[softcock]

For the Varmint Load. Shorter barrel .308 win,
110 grn. .30 Vmax . . ( 43.7 ) grn. Reloader 10X
.

 

[308pirate]

Try 130 grain hollow points. 1:10" twist is necessary for shorter barrels. I would also try a faster burning powder like IMR-3031.

Tony.

Lol

Where do people come up with this nonsense?

@hcalli48 I have a 17" 1:12 308 Howa that slings 178 ELD-Ms at 2550 fps all the way to 750 - 800 yds without an issue. Beyond that they've list enough speed that the wind slaps them around. But that's not the same as lacking gyroscopic stability.

 

[308pirate]

I tried a few hundred at 5,500 feet in Utah out of a 20-inch Armalite and they were just OK out to maybe 700 or 800 yards. Just can't push them fast enough from a shorter barrel.

Maybe a 1-9 twist might help squeezing some further range out of a shorter 16-incher.

A faster twist isn't going to gain you much (if anything) when the bullet's bc is going to shit due to velocity loss.

 

[308pirate]

I have a couple hundred rounds of 178 ELD-x precision hunters that im using out of my Bergara and current 20in upper and 165 GMX that I shoot out of my Kimber and other hunting rifles.

Would these bullet weights suffice out of a 16in upper and not baffle strikes

As long as they're leaving at 2500 fps or above you will be fine.

I know 1/10 20in barrels like 165 and up but not sure about the shorter barrels.

They like lighter bullets too, at sane velocities.