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308 Winchester rifling twist

 
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  #15  
Old 12-20-2010, 09:21 AM
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Re: 308 Winchester rifling twist

Quote:
Originally Posted by gei View Post
Going to have have another 308 built, will shoot 168 and 175 weights exclusively, what twist barrel would be best?
gei - the twist is not as important as the "make". 1 in 11 to 1-13 will do it . the 1-in 12 on the remington or the 1-11 on the 5-r are great. J.e.custom- i have shot competiton also. German Salazar has a blog 'Rifleman's Journal" several articles and all kinds info there on both the .308 and 30-06 loads and twist rates. he has shot 185's out of a 13 twist.
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  #16  
Old 12-20-2010, 09:24 AM
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Re: 308 Winchester rifling twist

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Originally Posted by J E Custom View Post
OK .

I'm not going to argue with you about it because you can use anything you want to. "BUT" I
competed for 12 years in the match game. and Loaded only two bullets for my 308 and they were
the 165 GKHP and the 168 SMK and I even managed to win the 1000 yard matches several times
and lots of 6,8and 900yard matches.

I had a 40x Range master with a 27+inch barrel and It was very competitive as long as I loaded it
hard. It had a 1 in 12 twist and would not shoot the heavy bullets at all.

Other competitors recommended the 1 in 10 and when I built my custom that is what I built it in.

I don't Like to boast but for the sake of this post I will mention that I have many match and class
wins with this combination and even a few state wins in the NRA palma and National matches.
So Maybe I am just lucky.

I know there are new Bullets that could be better but I know what worked and have not changed
my mind.

You also said that some use a 155 gr ? why would a 155 work and not a 168?

I still have my match rifle and it will still shoot sub 1/2 moa with Iron sights.

As you know all rifles are different but as this post was about twist rates all of my 30 cal rifles are
1 in 10 and will perform with the best of them.

So that is still my recommendation especially for the 308.

Nuff Said: you may have the last word.

Sorry we don't agree, but isn't that what makes the world go round.

J E CUSTOM
One would think w/ the 168 A-max, Berger, and JLK that 1000yd would be very doable. I'm w/ ya on this one J E. I wish I would have contacted you for barrel twist recommendation before ordering my barrel. Oh well, I should be able to do what I want w/ my 1:12! I've settled on Hornady's new 178 BTHP. Has a big BC for a 178 grain bullet. I would like to get a hold of some JLK's and see what they do too.

Tank
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  #17  
Old 12-20-2010, 09:26 AM
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Re: 308 Winchester rifling twist

JE

The 155s are longer and more dynamically stable. That is why they work and the 168 normally does not after you cross that 900 yard mark.

The 155s have been the "go to" bullet for years in the Palma arena, no major competitor uses the 168 at 1k. That is why there have been three new 155s in the last few years just for the 1k Palma game. In fact, the 155 was the only allowed bullet in the international palma game.

Quote:
Palma: The NRA defines the Palma rifle as one that is chambered for .308 Winchester (7.62 mm NATO), and has metallic sights. The NRA does not define any explicit weight for the rifle and sights or the trigger. However, the Palma rifle is regulated by an international standard (set by the Palma Council). This organization requires that the rifle weight no more than 6.5 Kg (about 14.3 lbs.), and the trigger must lift a weight of at least 1.5 Kg (about 3.2 lbs). Moreover, this group limits the available bullets to one: the 155 gr Sierra Match King Palma bullet. The U.S. NRA does not make any restriction.
It helps that they are using 13 and 14 twist tight bore barrels that are 30-32" and they push the bullets to over 3000 fps.

FTR guys are using the 10, 11 or 12 with heavy standard bore barrels and tend to use the heavier 185 or 190s for wind bucking capabilities although many are using similar palma type barrels and 155s also.

BH

Last edited by BountyHunter; 12-20-2010 at 09:30 AM.
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  #18  
Old 12-20-2010, 09:27 AM
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Re: 308 Winchester rifling twist

Quote:
Originally Posted by gei View Post
Going to have have another 308 built, will shoot 168 and 175 weights exclusively, what twist barrel would be best?

Pac-Nor 27" Match(not Super Match) 3-groove 1:10.25"twist on my Savage action shoots everything from 155gr(palma projectiles) to the 190vld exceptionally well. Only tried a few 208grAMAX's so far, but no keyholing so far.....then again, I haven't found the 'load' yet.


Not sure if you could actually over stabilize a projectile with a 1:9"tw barrel? I could see the projectile being ripped apart from excessive velocity in a fast twist barrel........ Then again, big high BC projectiles retain more velocity and don't need to be pushed as hard as those little projectiles to stay supersonic at range.



Scott
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  #19  
Old 12-20-2010, 09:33 AM
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Re: 308 Winchester rifling twist

liltank - i don't know what kind of barrel you have. if you go to 6mmbr and riflemans journal you will see the 1-12 twist you have is great for that weight bullet
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  #20  
Old 12-20-2010, 09:44 AM
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Re: 308 Winchester rifling twist

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Originally Posted by roninflag View Post
liltank - i don't know what kind of barrel you have. if you go to 6mmbr and riflemans journal you will see the 1-12 twist you have is great for that weight bullet
I know, the twist game is a gamble as to what is going to happen. After owning a 1:10 I decided that I wanted less pressure and more velocity from the .308. I figured going to the 1:12 would justify this idea and still allow me to shoot up to 200grn bullets. I could never do the loads suggested w/ my factory Savage tube. The only two factors that come to mind is that it may have had a tight bore, and that the 1:10 restricted the speed of the bullet. So I went w/ a 1:12 Lothar Walther. Looking forward to putting it through its paces.

Tank
__________________
Matthew 7:13-14
"Enter through the narrow gate. For wide is the gate and broad is the road that leads to destruction, and many enter through it. [14] But small is the gate and narrow the road that leads to life, and only a few find it.

If you find your self in a fair fight, your tactics suck!- Marine 1st Sergeant Jim Ryfinger

Friends don't let friends develop canonitis!-chucknbach

arguing over the internet is like the special Olympics....even if you win, you are still...special!
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  #21  
Old 12-20-2010, 11:57 AM
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Re: 308 Winchester rifling twist

Not to dive into the hornet's nest here, but yes, a 1x12" would worked just fine for what he's looking for here; the 168s and 175s will work in the 1x12", or even 1x14s for that matter. I've shot quite literally millions of both of these bullets in both twists.

The 168s, at least the SMKs are not, and never have been 1,000 yard bullets. They were designed specifically for 300 meter competition, and have been used (by some) for the 600 yard line as well. The vast majority of us shooting bolt guns, however, shot the 168s at 200 and 300, and switched to the 190s or even 200s for the 600 and 1,000 yard lines. In the M14/M1As, the 168 was often used at 600, but for the 1,000 yard line, the 180 was the go-to bullet (can't use anything heavier than this out of consideration for the gas system in the M1 and M14), as the 168 would go subsonic at around the 900 yard mark. Asa is off just a bit in his comments about the 180s; the redesign was done in the mid 1990s. It was a stupid thing to do, and there were one or two of us (their only competitive shooters) who railed against this switch, which involved changing the boat tail angle and length. The intent here was to allow the use of the same BT punches and form dies as the 168, thereby simplifying things for the machine shop. It also dropped the BC significantly, and made the bullet completely useless for what had been its main reason for its existance. We were over ridden, and the change was made. They had to continue to make the old style, long boat tail design for AMU on special orders after that, because they (AMU) wouldn't use the new design. The M16s came on the scene a few years after that, and made the whole issue moot anyway. Don't see many .30 cals on the line anymore, in almost any flavor. A foot note to this is the development of the 175 currently used in the M118LR load. This bullet was developed when Lake City needed an accurate bullet for long range sniper ammo, and to replace the M852 168 grain Match loading. The reason they just didn't use the M852 for this application, was that it just didn't perform at 1,000 yards. The 175 was designed with some of the same features as the old 180, and will stay supersonic out to the 1,000 yard line, no problem. Again, the 175 was the upper weight limit allowed as the ammunition could have seen use in the M24s or M40s (bolt guns) or the gas operated M21s.

There was a question as to why the 155s would work (stay supersonic at 1,000) and the 168s wouldn't. The 155 is a bit of a special case, and worth some explanation. To begin, none of us use the 155s beacuse they're the "best" bullet for 1,000 yard shooting. They aren't, not by a long shot. We use them because they're the max weight allowed by international Palma rules, period. My own Palma gun is typical, in that it uses a 1x13" twist and a tight bore (.2980" bore, .3065" groove, if I recall), being set up specifically for the 155s. In this application, there were several "violations" to bullet design that were incorporated to result in a bullet that would stay supersonic when fired from a 308 Win case. It has a very short bearing surface (less that the normal one caliber required for most designs), a fairly long boat tail and a sharper ogive (the combination that results in reduced bearing surface), and an extra small meplat. Even with all this, the bullet still needs at least 2,950 fps to be comfortably supersonic at the 1,000 yard line, which is why virtually all Palma guns run 29"-30" barrels. Take the same gun and load, but substitute the normal 150 grain SMK, and you've got a tumbling, subsonic bullet long before it reaches the target. Given our 'druthers, most of us would go for a 190-210 grain bullet in a heartbeat. In fact, most US Palma competitors who don't have any intention of competing in International matches, or those within the US that require the use of the 155s (such as the US Palma tryouts, and some other matches), set their guns up for, and use these heavier bullets. It's a matter of match requirements, not superior ballistics, that brought the 155s to the fore today.

As I said, not trying to stir the hornet's nest any more, but there seemed to be a few things that could stand some clarification. Hope this helps.
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