Greetings,
I'm looking for some input on rifle twist for a 300 wsm with a 24 or 26 in barrel using mostly 180 gr bullets. What twist would give the best accuracy for shooting out to 600 to 1000 yds?
thanks

The standard 1-10 will handle all weights except something long in the 200 plus grain weight and 1.500 plus length where 1-11 or 1-12 might work better.

There are several free online twist calculating programs...check them out.

1 in 10 will be fine for bullets up to 200-220g depending on design. Longer heavier bullets need a faster twist, like a 1 in 8 or 9, not a slower twist as previously suggested. Some bullet makers mark their boxes (of bullets) with the required twist. Also, most barrel makers have a recommendation on their web sites.

LONGER BULLETS require faster twists...weight per se has nothing to do with it...everyone seems to get that wrong...twist programs ask for bullet weight, bullet diameter and velocity, not weight.

Bullet weight is a function of nose profile for the most part...a round/flat nosed bullet can be heavier for a specific length than a spritzer, and to get the same weight in a spritzer the bullet needs to be much longer than the round/flat nose.

VLD bullets are extremely long when getting into the higher bullet weights no matter what diameter(caliber) and they require faster twists due to the LENGTH.

Did the op say anything about VLDs? He did not! Did I not suggest the OP check with the bullet maker and barrel makers? I did! 1 in 10 will handle most any .30 cal bullet up to and including 230g, period. Many are going to 9 twist with very good results for LR. Screw the "twist programs", practical experience will trump, every time!

quote:

Originally posted by NONAGONAGIN:

VLD bullets are extremely long when getting into the higher bullet weights no matter what diameter(caliber) and they require faster twists due to the LENGTH.

So,, why would you recommend the slower 11 or 12 twist?

quote:

Originally posted by NONAGONAGIN:
LONGER BULLETS require faster twists...weight per se has nothing to do with it...everyone seems to get that wrong...twist programs ask for bullet weight, bullet diameter and velocity, not weight.

Bullet weight is a function of nose profile for the most part...a round/flat nosed bullet

can be heavier for a specific length than a spritzer, and to get the same weight in a spritzer the bullet needs to be much longer than the round/flat

VLD bullets are extremely long when getting into the higher bullet weights no matter what diameter(caliber) and they require faster twists due to the LENGTH.

Dude your going to confuse yourself...a 1-11 is almost made for 168 grain match ammo...heavier longer in 30 cal go with a 1-9 (fast twist) 1-10 does good for everything to about 180 grains super and sub-sonic, you need a faster twist for over 180 and it will stabilize sub-sonic just in case you want to shoot it suppressed and subsonic.

Whoops...stirred up the hornets nest trying to get some teaching in.

Not to put too much of a point on it but Ya'll might just run a few 180 gr bullets lengths through an online twist program...they're free and probably would have saved you some time in response's.

A few examples for OPTIMUM twists at 3000 fs for the 180's. This doesn't mean they won't shoot well in a slightly faster twist bbl, OR, a slightly slower twist. The trier of fact is the rifle's targets and if you want a specific answer you have to have a very specific set of parameters to work from and do the target work.

Hornady 180 gr RN...1.070" - 1-15 T
Hornady 180 gr SP...1.220" - 1-13 T
Hornady 180 gr SST...1.35" - 1-11 T

Hornady 208 gr A-Max...1.408" - 1-10 at <2800 fs, 1-11 T >2800 fs
Sierra 200 gr Matchking...1.39" - 1-10 at <2800 fs, 1-11 T > 2800 fs
(just for edification and comparison...the LONGER the bullet...the FASTER the twist and nose profile has a lot to do with the bullets length/weight ratio.)


I DIDN'T recommend ANY twist...just added what I've found over many years of shooting to be true. I thought it might be useful to the OP...guess I was wrong...does the old saw about bringing a horse to the trough ring a bell????


I WASN'T pissing on your boot, slivers, and I DID make the statement that 1-10 would suffice for most bullets in the 180 gr range at 300 SWM velocities at the beginning of this pissaround. What was it about my post that set you off????

No 505ED I'm not confused...the longest 165 gr bullet I could find in my data is a Barnes 165 gr TTSXBT at 1.46" and the optimum twist for that is 1-10...for the bullets in the 1.25" plus range, even the Hornady A-Max at 1.275" the optimum twist is 1-12 AT 3000fs...but a 1-11 will work just fine with the right bullet length.

I have several 30 cals from 30-30 to 300WM and several 308's with twists from 1-10 to 1-12. Each rifle will shoot a narrow range of bullet lengths and weights depending on the twist at velos from ~2000 to ~3700 fs depending on the bullet weight. The 1-12 twist rifles shoots 170-190 gr RN bullets in the 0.990 - 1.28" range regardless of brand into nice 4's or less when I do my part, but anything over those lengths starts opening groups. The 1-10 twist barrels handle anything I stuff up the spout, but each rifle likes a specific bullet and powder combo for the accuracy level I require, but they all do pretty good with many other weight/lengths/brands.

You don't have to believe a word I say, in fact, I would rather you said BULLSH** and did the math yourselves...you might just put aside some old wives tales and learn something new, like there are MANY DIFERENT 30 cal bullets/brands, each having a different length/weight and the OPTIMUM twist is just a mathematically generated number that is useful ONLY if you understand that it has a RANGE and it ISN'T an ABSOLUTE.

Have to agree with the above.
I have a 1:13" twist top of the line 155gr Palma barrel, it shoots them well, but anything heavier, forget about it.
1:10" is all I use in my 300WM and I use Nosler 200gr Accubonds on the 1000yrd line, in fact my 338 Edge barrel is also 1:10".
Jusr saying.

Cheers.

Why will you get a suppressor strike with a 208 grain a max at 1000 fps with a 1-11 1/2 but you will not with a 1-9? Just asking this is in a 308 win..I am learning here? I know it has to do with the velocity...that is why I went to a faster twist...now I know a WSM will not be used sub-sonic,but a whole lot of guys are trying to use 1-10 blanks for blackouts,and 308 win sub-sonics,and messing up a few cans in the process. Thanks for the lesson it was informative...over my head but good info!

Ed

Yeah...the 155 Horn Palma is ~1.198" long and many of the bullets designed for Palma type of competition all fall into the same length range...but go to a hunting style 150 gr, especially a boat tail, VDL style, or solid brass CNC turned bullet and the length jumps to ~1.28 plus which still should stabilize in a 1-13 at ~2700 fs or above, but anyone that's played this game for any length of time knows that each rifle decides what bullet/powder combo it likes.

I suspect the suppressor strikes have a lot to do with the bullet length and spin rate at such low velos and twist rates. I've studied cans, built a 50-70 "Whisper"(a cheap 510 Whisper with same ballistics but components cost a ton less) to play with but decided not to build a can due to all the govmnt BS. I had several can designs started, the muzzle threaded, the pieces to start the interior cones and baffles and the paperwork on my desk, talked to a couple of people that would do the paperwork for correctness for a fee but just said...****** it.

Examples for a 208 gr at 1000fs

Hornady A-Max - 1.34" requires a 1-10 to stabilize from 800 to 1200 plus, 1333 RPM at 1000 fs.
Hornady BTHP - 1.48" requires a 1-90 " " " " " " , 1200 RPM at 1000 fs.

I can't understand WHY anyone would go with 1-11.5 T and expect those long bullets to stabilize. It's so simple to check out twist rates online and in many interior/exterior ballistics software programs. It is simply a question on bullet spin and the fact that bullets aren't being stabilized, tipping/yawing in the bore and going into the can at a cone angle that is larger than the bore ID of the can. When that happens, shi* happens to the can and anything close by. With a twist that slow I wouldn't get much longer than 1.25" which covers many 175-185 gr target/hunting bullets with relatively high BC's but still does a good job at whisper velos.

I've had the same thing happen in muzzle brakes on occasion and usually with a bullet that became unstable in the bore due to many reasons...some apparent, some not. You can feel the bump sometimes and sometimes not...you just totally miss your target depending on the distance or get a bullet hitting sideways on a paper target or see the copper coating on the brake hole. All my events didn't seem to bother the brake or cause any damage. If it happens more than once with a particular bullet/weight/brand I just change bullets...seems to work out in the end.

This stuff isn't rocket science and isn't cast in stone, you just have to read the actual signs and forget all the theoretical stuff when it's not working.

I've had a rifle in my hands since I was ~10 years old, 63 years, and been doing this reloading/rifle building stuff for 50 plus years and learned what I know the hard way...today it's a simple matter to go online and learn knowledge that took me years to acquire in just minutes. I keep learning new things every day, or things that I haven't already worked on in the past. I think it is totally cool and awesome.

Many of the hoo-haw dust ups that get going online could be stop simply by the OP's just taking time to actually look up the question online...ALL the answers are found there...or at least most of them. Aggressiveness is hardwired into humans genes and more so in men...we may be in the 21 century but our genetic makeup is still several million years in the past.

Luck

For a shorthand version remember this:

-Bullet weight is usually a good proxy for bullet length. It doesn't work for roundnose, some very short flatbase bullets, and VLD-type bullets, but for most it works well.

-A twist faster than necessary will still work; a twist slower than necessary won't. Too fast a twist usually only matters to bench rest shooters.

-Velocity matters. But only in limited circumstances. More correctly the bullet spin rate matters. But only in limited circumstances. The rifling twist causes the bullet to rotate. It is this rotation that stabilizes it.

The formula is this (MV x 720)/Twist = RPMs

MV is muzzle velocity in feet per second. Twist is the rifle twist rate expressed in inches.

Too slow a rotation caused by a subsonic or low velocity load won't allow the bullet to stabilize. Too fast a rotation with very frangible bullets (e.g., Sierra Blitz or Hornady SPSX) will tear them apart.

LWD

quote:

Originally posted by Svenskar:
Greetings,
I'm looking for some input on rifle twist for a 300 wsm with a 24 or 26 in barrel using mostly 180 gr bullets. What twist would give the best accuracy for shooting out to 600 to 1000 yds?
thanks

I think you may fine that heavier bullets work better in this caliber. I recently built one with a Krieger 10 twist, and it loves 190g and up bullets.

While each barrel has its likes and dislikes (bullet/powder), mine does not care for lighter bullets.

I have 210's grouping in 1/4 (5 shots) at 100 yards. That is sufficient accuracy for me.