Need help from LONG RANGE .308 gurus

[shark3-1]

My custom .308 bolt gun is almost complete, I'm just waiting on the A5 which should be here in a month or so. The build is using a Surgeon action and a Broughton barrel.

The problem is that I had ordered a 1-11.25" twist barrel and Broughton sent a 1-10" twist barrel. What problems will I have with this twist? What loads will it work well with and what loads will it work poorly with?

I'm going to run a silencer on it and was thinking that it would be fun to run the subsonic rounds out of the 1-10" barrel, but the purpose of the rifle is to be able to make hits at 1,000yds. So, should I send the blank back and get the 1-11.25", or will I be able to work up a 1,000yd capable load out of the 1-10" barrel?

 

[Zak Smith]

See
http://www.6mmbr.com/308Win.html

A 1:10" twist rate will let you shoot the popular medium and heavy 30-caliber bullets up to the 210-grainers from Berger and Sierra (provided your barrel delivers enough velocity for the heavy bullets). A ten-twist can also work well with the lighter projectiles. John Whidden, who won the recent U.S. Palma Team Trials, has had great success shooting 155gr Bergers with a Broughton 10-twist 5C barrel. A 1:11" twist, found on many factory rifles, is a good compromise. Palma competitors using the Sierra or Lapua 155s have favored 1:12" or 1:13" twist rates, with the theory being that a slower twist rate may offer better velocity since there is less friction in the barrel. A 1:13" twist is fine for deer hunters who prefer a 150gr-class bullet moving 2850-2900 fps.

It sounds like you should be OK for using the 155's up to the 210's.

My LR 308 load is a 155 Lapua Scenar at about 2850.

 

[shark3-1]

Thanks a bunch Zak, you were exactly who I was wanting to hear from.

 

[USSR]

shark3-1,

You will have zero problems out to 1,000 yards with a 1-10" twist in a .308.

Don

 

[Sniper4Life]

If I am trying to kill something at 1k yards, I like the heavier bullets so 1-10 is great.

 

[adobewalls]

The 1-10 will also be better if you want to try subsonic loads. In that case you want to use the heaviest bullet your rifle will stabilize at 1100 to 1200 fps.

 

[db_tanker]

mine is a 1-10 and the 168 and 180 Sierra's are very nice in it.


Bergers are the next thing to be used I think.


of course, I am not shooting out to 1K


D

 

[rockstar.esq]

Please post pictures when you're rifle is complete!

 

[shark3-1]

Thanks guys, I'll be sure to post when complete. Zak, Right now I think that I'm going with the SN-3, but I got to play around with a PMII the other day and I was impressed. With cost not being an issue, which do you prefer? I haven't had the chance to check out both side by side.

 

[rero360]

when did you order your stock? I ordered an A5 back in mid december and should be getting it within the next week or so, but I head back to iraq on thursday, so I probably wont be seeing it for another 6 months. other than that and possibly adding a new trigger, my build is all done. Enjoy your new rifle.

 

[shark3-1]

I ordered it back in the first of January. I have no clue when I will recieve it, I'll bank on another two months at least.

 

[Zak Smith]

Hi,

After shooting both the S&B and the USO scopes for a while, I sold off my USOs and went to PMIIs on all the bolt guns.

* finer reticle lines (at least on illuminated reticles- USO says they can make super-thin non-illum reticles)

* larger exit pupil and more eye relief help tracking target during recoil, also brighter

* for similar scope setup, smaller size and weight

* knobs easier to rezero

 

[Sniper X]

1 in 10 is fine for the scenario you describe, you'll love it. I think 1 in 11 or 11.5 would have been a mistake....but that may be just me.

 

[Ranb]

From what I have read, a 1-10 twist will stabilize 200 grain and down, 1-8 is required for greater than 200 grain. I use 225 cast and 240 sierras in my 300 whisper. Keep in mind that past 200 yards the bullet is trajectory is steep and requires that you have a very good estimate of the range to the target to ensure a hit.

Ranb

 

[Oohrah]

Your kidding, right? Don't recall ever hearing of a 1 in 11.5 barrel.
Humm, 1000 yards and beyond? Go FIFTY !!!! Think you can
still get ammo for $5 to $6 a round, and garanteed mostly a double
tap isn't required

 

[shark3-1]

Dick Tylock:
Your kidding, right? Don't recall ever hearing of a 1 in 11.5 barrel.
Humm, 1000 yards and beyond? Go FIFTY !!!! Think you can
still get ammo for $5 to $6 a round, and garanteed mostly a double
tap isn't required




What?
I just want to be able to go TO 1000yds, as my range doesn't go much further past that. I decided on the .308 because it seemed to be able to do that without breaking the bank.

I don't have much interest in the .50 as there are other calibers that I would rather have if I'm paying $5-6 for every round out the pipe.