Need help from LONG RANGE .308 gurus


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shark3-1
May 4, 2007, 03:29 PM
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?

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Zak Smith
May 4, 2007, 04:01 PM
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
May 4, 2007, 05:10 PM
Thanks a bunch Zak, you were exactly who I was wanting to hear from.

USSR
May 4, 2007, 05:11 PM
shark3-1,

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

Don

Sniper4Life
May 4, 2007, 06:09 PM
If I am trying to kill something at 1k yards, I like the heavier bullets so 1-10 is great.

adobewalls
May 4, 2007, 06:13 PM
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
May 4, 2007, 06:41 PM
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
May 4, 2007, 08:40 PM
Please post pictures when you're rifle is complete!

shark3-1
May 7, 2007, 10:05 AM
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
May 7, 2007, 10:28 AM
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
May 7, 2007, 11:04 AM
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
May 7, 2007, 12:49 PM
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
May 7, 2007, 12:53 PM
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
May 7, 2007, 01:03 PM
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
May 7, 2007, 05:28 PM
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:D

shark3-1
May 7, 2007, 06:39 PM
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.

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