Just curious if anyone has had one made and details. How does it perform and was it a good decision to go with a slightly faster twist?
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300 WM 1:8 or 9 twist, has anyone tried this?
- Thread starter shootertom
- Start date
Since the heaviest bullets you're likely to shoot are 220gr and they stabilize fine in the normal 1-10 twist what would be the reason to try a faster twist? Unless you're planning on shooting subsonics in the 220-240gr range its not really a helpful thing to do. . .
Frank
Frank
A good friend of mine is running a 26" 1-9 twist broughton on his surgeon and is running 230's at 2820 and its an absolute hammer
I am running a 9 twist with a 30.5 in broughton. I built a rig to get to a mile and beyond. plan was to shoot 208 and above. with the scarcity of supplies at the time the 240 sierras were the only ones available so I didn't want to rule them out with a 10 twist. I am still working on loads, so far ive got the 230s shooting good at 2800 fps, 215s shot good from 2900 to 3000 fps but will run them around 2950. Ive got the 208s at 2900 fps. Sure you can push them hotter but right now the place I go shooting has steel to 1000 yds. During the breakin i had some FGMM with 190s that shot one hole groups at 100yds. I shot those up for break in so I didn't waste better bullets. I was surprised that they shot so good. I did set them .030 off. chrono had them at 3100 fps. I will get some hot loads worked up when I go to a mile. If your looking for a barrel, call broughton, good people to buy from. I don't know if you can over twist a bullet, but so far this barrel has lived up to all its expectations.
It would be great to be able to shoot some heavier bullets although i know I won't be getting the best muzzle velocity. Im putting together a shorter barrel and thought it would be nice to shoot subs now and then if I would like to load some up. it sounds like a 1:9 would handle somewhere around 215-220 with subs? Just curious mostly though, the barrel is the next purchase and I want to make sure its going to fit what I am looking for.
I think it might also be important to note that the faster twist rate can reduce your accuracy with the lighter bullets.
As Bryan Litz has noted that, based on empirical evidence, faster twist rates result in larger groups as compared to slower twist rates.
As Bryan Litz has noted that, based on empirical evidence, faster twist rates result in larger groups as compared to slower twist rates.
Sub sonics? in a 300 wm? Havent heard of this being done before. Where would I find more info on this?
I wouldn't be to sure about that, the 338LM has a huge following in sub-sonic use, among some very elite anti terrorist teams in Europe. Can't go faster and stay sub-sonic, only way to hit harder is to increase bullet weight (and to some extent shape). I know the German's use AW's/fully suppressed/SB scopes(with a special reticle-set up for sub sonic). But with all things being considered, as a hobbyist, sub-sonic (suppressed) use of a 300WM is less than optimal-so say the very least.
There is little doubt about it, that is why I stated, " as a hobbyist, sub-sonic (suppressed) use of a 300WM is less than optimal-so say the very least. " But as you know, a whole lot, massive amounts, of "stuff" that is in use by various military groups, sells very well... You'd be surprised at how many "tactical shooters" have never spent on day in the military, nor have any intention to do so, but they sure buy a lot of "military gear"!
You would find that in the book of biggest wastes of time and money
Thats what I was thinking. probably why I haven't heard of it.
Subsonic 300wm? Ok so 220gr SMK traveling @ less than 1087fps is 45acp ballistics with a slightly better BC on the bullet. It is my opinion that 300aac accomplishes this just fine with the same bullet. I could see someone having a use for some subsonic loads so they can use the same rifle for multiple uses. Creating a barrel for this use would seem ridiculous to me. I would be worried that there would be so much free space no matter what powder you used that you would be risking detonation/misfires maybe hang fires i don't know.? Maybe some one would end up using some type of packing in the case? Suppressed 300wm is a whole different ball of wax and I believe it to be a fairly common practice.
Just my 2 cents.
Just my 2 cents.
Exactly Holeshot. Subsonic and suppressed 300WM are two different conversations. My 300WM was suppressed but never even thought about shooting subsonics through it. Other cartridges do it safer, cheaper and easier.
The Germans use quite a few AI rifles , from 50BMG , 300WM & 308 , the 308 AW ( G25 ) is used with 16 inche barrel & original BT suppressor , and a 5-25x56mm PMII , in the subsonic role .
The 300WM ( G22 etc ) has a suppressor available , like other sniper rifles , and is used with normal ammo , ie supersonic , the can is to mask the firing signiture , not make it silent .
The 300WM ( G22 etc ) has a suppressor available , like other sniper rifles , and is used with normal ammo , ie supersonic , the can is to mask the firing signiture , not make it silent .
The primary goal is to shoot supers, I just didn't know if a faster twist would take away from the accuracy of supers. If 1:10 is the go to twist for supers than thats what I will use, I just didn't know if i could go a little faster and also be able to add subs.
I wouldn't say 1:10 is the go to. It's the go to for the heavier bullets. IIRC Berger recommends 1:11 for their 210s and 1:13 for 175s
Boots Obermeyer told me he has no problem shooting SMK 190s at 1:14, but 1:13 to be safe.
IMO you need to shoot the heaviest (read longest / highest BC)bullet you can for your twist rate. You just gotta find that one.
Edit: I had a wild comma on the loose.
Brian Litz has posted a teaser from his next book. It talks about the loss of BC with bullets that appear to shoot well but are marginally stabilized (sg of 1.4 or so). That may be worth a read for you. If you are planning to shoot 230+ heavies then I'd say that a 1:9 might be the ticket.
+1 to xtr. if your goal is to stretch the limitations of the cartridge at a mile or beyond, having a little more twist with 230-240s cant hurt, but not having it will. from my research 1 in 9 was what I felt was best for me. Before I rebarreled, my sendaro with a 10 twist shot the 230s just fine out to 1k. Never tried any further. They were also a bit slower with a factory barrel. Never ran thru the chrono but they were around 2650-2700.
Im on the process building 300 norma mag improved 35* shoulder..when i started gathering parts i already made up my mind that i only going to shoot 230hybrids and 240smk building this riffle as my ELR mile to wtever.. i called broughton and berger altho berger recomend 1:10 ORRRRR faster for the 230 broughton said 1:9.5 is perfect 230-240.but the man also said 1:9twist wont hurt anything..i couldve get bartlein in 1:10 right away but i decided to wait couple months for 1:9broughton.heavy palma 30".guys getting away shooting 240 on 1:10 but its better to be safe than...crossing finger hoping that it will work..
The minimum bullet weight I plan to shoot is 190 grain, would a 1:9 yield less accuracy than a 1:10 with something like this?
during my break in I used up some fgmm with the 190 smk. I just set them .030 off. with a shoot and clean regimen I was getting 1/2 group at 100 yds not trying. figured I would use them up and save the good stuff. chrono was 3100fps. I went with a heavy barrel broughton 1 in 9tw, finished at 30.5 in. Sets in a aics 1.5 stock, total weight about 18 lbs.
I did shoot some HSM 190 smk factory loads at 1k and a 3 round group was about 5in. I am no br shooter, just a weekend warrior and I do get lucky quite often with a good group, but its easy to group at 1k with this rifle. If there is a accuracy loss with the faster twist and a lighter bullet im not seeing it.
Ive decided to go with a 1:9 twist on the barrel, could you all give me suggestions on those that have worked well for you. I am leaning towards Barlein as of now, we spoke this afternoon and it looks like I would have a 5-6 month wait on that.
mine is a broughton. was about a 3 month wait ordered sept and got it before xmas. I went with a broughton from several other recommendations on the hide. I thought it was a little odd, but call leave a message. someone will call you back. may take a day or so. very good people to deal with. Broughton Rifle Barrels by North Manufacturing Co., Inc.
last weekend there was no wind on Saturday I was able to stack about 4 rounds ontop one another at 1 k. probably a 2 in group. as I said I am no benchrest shooter but even a blind squirrel finds a nut every once in a while. I was shooting the 230 berger .743 bc with a little h1000 at 2800fps.
last weekend there was no wind on Saturday I was able to stack about 4 rounds ontop one another at 1 k. probably a 2 in group. as I said I am no benchrest shooter but even a blind squirrel finds a nut every once in a while. I was shooting the 230 berger .743 bc with a little h1000 at 2800fps.
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Like everything twist rates are a compromise. I didn't read where litz says that higher twist rates lower accuracy but if you read his post about the new accubond lr bullets in the ballistics section of this forum u will see that higher twist rates can increase the bc performance of bullets shot out of higher Vs lower twist barrels. So if both are true you pick the proper twist for the bullet or bullets you plan to shoot (calculating the stabilization factor nessesary) and the distance or distances you expect optimum performance. The new berger 230 match hybrids is a game changing bullet that can allow a 300 wsm to run with a 338 lapua trajectory wise but you won't get the high bc from that bullet if isn't properly stabilized by a very high twist rate. After reading lutz's work from now on I will be running the highest bc bullets I can with the fastest twist barrels I can find for long range shooting but this is only from my interpretation of some great ballistic research.
I have a 24" 300 WM with a 1/9 twist 3 groove and shoot the 230's out of it at 2800. They shoot very well, well enough that it hits at 2K. I also shoot the 175's at 3150 and they also shoot very well.
So my gunsmith talked me back into a 1:10 twist and said that it should shoot anything i put through it aside from subtonics and will perform better than the 1:9. I checked the berger site and it says it should work well with their 230s so I do believe my decision is made.
