What twist for my 300 wsm?

[dcali]

I've stabilized 215s out out of a 10" in a .308. It's plenty for a WSM. And if you're talking accuracy, slower twists are better.

What happens way down range with dynamic stability and transonic weirdness is another matter, and not something anyone I know would be comfortable predicting, at least not with commerical bullets. I'm going to go out on a limb that you're going to need to test the specific bullet you want to use at the range you want to shoot, and find out how much a few extra inches of twist will help, if at all. What *will* almost certainly happen is that your groups will open up a bit at sane ranges with a faster twist.

I know, not much help. A inch too fast isn't going to make your rifle suck, so sometimes its wise to be conservative, especially with ELR, where sheer accuracy isn't as important as ballistics. For my money, shooting Berger 215s where I live, I'd go with a 10". Mileage may vary.

At shorter ranges (supersonic, basically), it's hard to go wrong aiming for Sg of roughly 1.5. It's a good practical rule of thumb.

 

[dmoran]

... especially with ELR, where sheer accuracy isn't as important as ballistics.

My own experience is in much opposition, that accuracy trumps ballistics in ELR also. Enough so, that I 'd give up a fair amount of ballistics for raw accuracy. Vertical dispersion plagues extended distance no matter what the wind is, which is why raw accuracy trumps ballistics - IME.
A good example of this was at the EliteLRC 2000yd match last summer in Townsend, MT. It was obvious how less vertical (more accuracy) trumped ballistics to the 5-shot groups and scores. Ballistic supremacy is over rated at all distances, in my opinion.

My 2-Cents

 

[dcali]

My own experience is in much opposition, that accuracy trumps ballistics in ELR also. Enough so, that I 'd give up a fair amount ballistics for raw accuracy. Vertical dispersion plagues extended distance no matter what the wind is, which is why raw accuracy trumps ballistics - IME.
A good example of this was at the EliteLRC 2000yd match last summer in Townsend, MT. It was obvious how less vertical (more accuracy) trumped ballistics to the 5-shot groups and scores. Ballistic supremacy is over rated at all distances, in my opinion.

My 2-Cents

I think that depends on how and what you're shooting. I was thinking more in terms of some of the cold-bore/King of 2 mile ELR matches, and less of the 2000 yard bench-style matches. In those matches, where a hit is a hit, I can see why they like to turn BC up to 11. For the Montana match, I can see why you might not want to emphasize BC quite as much. And I do think that people in all disciplines (except maybe short range benchrest) tend to over emphasize BC at the expense of precision. I blame Bryan Litz for this, although it's not his fault that people haven't quite interpreted his writing correctly. Since he is such an influential writer/engineer, I'd love to see him do some work on precision and group dispersion, as opposed to the drag topics he has so thoroughly addressed.

In either case, I think we agree on the larger point that there is an optimal twist beyond which you are just shedding accuracy for no good reason.

 

[dogdude]

I ran a Lilja 1-10 with Sierra 240's and Berger 230 Hybrid's..1800 rnds worth..never a problem.

 

[dmoran]

@damoncali
Myself blame it on assumption and/or lack of experience. No mater what the shot count or the distance: "to hit the heart, you have to aim for the heart, with probability". The probability is not increased by even say a 25-MOA ballistic advantage, if the percentage of probability starts out less (accuracy). It doesn't matter if it is 1-shot or a string of shots, hit probability is a product of accuracy/precision first and foremost, that compounds over distance -IME.

 

[WAMBO]

So...NW Minnesota ~ 1500' above sea level
I shoot in 0 to -20*F temps...
A 9 twist vs a 10 twist?
Thanks

If it was me I would go with the 1-9" twist if I would be shooting anything heavier than a 210 grain bullet at ranges longer than 1000yds.

 

[Earnhardt]

If it was me I would go with the 1-9" twist if I would be shooting anything heavier than a 210 grain bullet at ranges longer than 1000yds.

I'm leaning towards the 215 Bergers, in a 30" Bartlien barrel.

 

[WAMBO]

Checking the Berger Twist Calculator you would be marginally stable at those temps and altitude with a 10 twist.
I have a Bartlein 30" HV 1-9" twist waiting to be put on a Stiller TAC338, going to have it chambered in 300 NM and use either the 215 or 230 Berger's whichever shoots the best.

 

[theallcineyes]

browning should be a 1-10 twist in 300wm, not 1-8. most everything other than tikka is 1-10 for the .30 cal's.

tikka's twist rate seems to be a little less in all their calibers, not sure why, but haven't heard many complaints.

 

[shooter74]

If one goes and reads what Mr. Litz actually has written about twist rate you will find that what he says is that you can achieve precision with twists that result in an SG less than 1.5 but that you lose a percentage of your intrinsic BC due to wobble or the bullet not presenting it's minimum profile forward, and that higher twist rates can lower the precision.

Shooting to 1000ish a 1:10 will certainly stabilize up to a 215H. I believe that when Bryan Litz won the F-TR FCNC shooting 215s from a 308Win he used a 1:10.

edit: and @shooter74 doesn't comment on his intended use.

Sorry I’ve been very busy at work. The intended use will be to take it out as far as possible. I have several dedicated small group paper punchers. Stability at extreme distance is what I’m inquiring about

 

[shooter74]

The OP never said extended longrange. I wouldn't even consider a 300 WSM for ELR. It just doesn't have enough speed or bullet weight.

The solids are a totally different animal and needs much faster twists and even different throats. Matt

Only reason for the wsm, is I’m a small guy 135 lbs. I’ve shot all the rum’s and big stuff just tired of the recoil for a while. I just wanted a mild recoiling accurate case design, I could shoot some distance with and for the most part see my own impacts. That’s because where I moved I know absolutely no one that shoots near me. So most of it will be just me alone.

 

[shooter74]

I'm leaning towards the 215 Bergers, in a 30" Bartlien barrel.

That’s what I ended up ordering that same exact barrel in hv contour.

 

[shooter74]

Checking the Berger Twist Calculator you would be marginally stable at those temps and altitude with a 10 twist.
I have a Bartlein 30" HV 1-9" twist waiting to be put on a Stiller TAC338, going to have it chambered in 300 NM and use either the 215 or 230 Berger's whichever shoots the best.

I have a Stiller tac30 action going with the exact same barrel. I will be using the 215 hybrids.

 

[284winner]

15-16 lb 338 Lapua improved with 300s with a brake is going to be an easy rifle to shoot at 135lbs. Brakes are worth every penny in those big cartridge rifles moving heavy bullets. Not really crazy about them other than for recoil reduction.

 

[DennisH]

Several years ago I ended up with a Remmy 308 sporting a "custom" 12 twist 30" Bartlein Barrel by mistake. I had a bad attitude with this barrel, but ended up keeping it. And "now" I am glad I did.

I never did tell anybody about my 12" twist barrel. My first first 308 barrel was a 10" twist, and still consider it to be one of my best to this day.

Since acquiring my first 12 twist, I have order 2 more over the years. "ALL" "MY" custom built 12 twist 308 rifles are considered my favorite rifles. My Bartlein's (12 twist) love 168 smk's, and Berger 190's in both of my 12 twist. I use Varget Powder exclusively in these barrels.

I know I stated my 10 twist, and 12 twist 308 Barrels are my favorite barrel. I won a few (over-all) matches with both twist barrels.

My 10 twists will shoot anything from 110 grain to 210 grain Berger's with ease, all sub MOA groups @ 100 yards! I love the Hornady 110 Tap's. Super Fast, Super Accurate, and will cause more than enough damage to your target to bring it down.

 

[69mach]

I’ve been shooting a Stiller tac30 with a rock creek 10t 28” tube using 215 Berger’s in a 300 wsm. I can only get to 1400 Yards at my personal “range”. I just had Lee gardener build me a defiance deviant 30” 9t Krieger in 300wsm. I found a place to get to 1700 yards safely and Im looking at trying out the high bc Sierra 230 grainers. I’ve read a 30” 9t should suffice.
Just because a 300 wsm isn’t the best elr cartridge out there means nothing. That’s part of the fun of it. Pushing a cartridge to its max. 22lr isn’t the best 200yd cartridge but we still do it, bc it can be a challenge.

 

[284winner]

Anybody interested in shooting ELR(1500+ yards) and wants fairly consistent groups in environmental conditions unknown, WILL NOT be using 10 twist 30 caliber rifles. If they are, they aren't concerned about score or worrying about the bullets making it on target. Any 6mm or larger (high BC) bullet will make it to well over a mile, just not on target with any regularity. The big heavy 30s with 9 twist or faster barrels seem to be the minimum out on the ELR camps. I hear about alot of big 7s making it as well but them guys are picking there days when zero wind is present. That's the exception rather than the rule. With all the experience I'm reading here from regular ELR shooters, it's best to listen rather than teach. Let the teachers teach and learn from the lesson. I certainly have and being out and using many of the lessons has helped a ton.