Thoughts on a 300WSM barrel ... ?

[Kiwi]

Hi guys, I am interested in your thoughts on a rifle a good friend has just received back from getting re-barreled.

This is a 300WSM with a 26" stainless match barrel ...... with a 1 in 8" twist rate .... (fastest I've heard about is 1 in 9")

So 1 in 8' is an unusually fast rate of twist by my understanding for a .30 cal rifle.

What do you think?

Does anyone have experience with a twist rate this tight in .30 cal?

What projectiles would/does it lend it's self to?

What are it's potential advantages and or disadvantages?

As of today (Saturday) he has not yet put a round through it ..... maybe tomorrow if it stops raining ...

 

[Eddie Harren]

If he specified an 8 twist, he must have had a plan.

 

[ballistic64]

What projectiles would/does it lend it's self to?

Looong ones ;D I dont have experience with that twist rate,but would have to think it would benifit a cartridge that isnt capable of pushing long/heavy bullets with enough velocity to stabilize them in a more common twist rate(Im thinking 308Win).Dont really see an advantage in the 300WSM.I shot 210vlds and MKs with a 300saum that was built with an 11 twist barrel with no stability problems whatsoever.If anything he may see increased pressure signs before he would see them with a slower twist rate.

 

[TonyR]

Bryan Litz recently shared his thoughts on transonic stability on the Long Range Target Shooting Forum. He said that the faster twists help bullets remain stable as they approach or pass through the sound barrier. A 1:8 would probably help the right bullet maintain accuracy out to very long ranges compared to slower twists that would be fine as long as the bullet was super-sonic. Here is the link to the thread.

http://www.usrifleteams.com/lrforum/index.php?showtopic=13415

 

[cmillard]

that is a lot of twist. i shoot 240 smks out of a 30" hart 9"twist .300 win mag. the 240s like a little slower velocity out of that barrel--about 2750 fps. i have pushed it up to 2900+ but groups opened up. i think i ran into over spin on the upper velocity range.

 

[Kiwi]

DocEd = "If he specified an 8 twist, he must have had a plan."

.... he specified a 1 in 10" twist!

... I know! .... send it back and get a 1 in 10" twist ....however, we are booked on a trip to the South Island in 3 weeks for an annual long distance competition and are very dubious about getting it back and being able to work up a load and do the ballistic calcs and confirm them within the time period .... (assuming there is a stainless ultra match 1 in 10 twist now in stock!)

The "gunsmith" said he could not get a 1 in10" twist so he unilaterally decided (and never called) on the 1 in 8" and tried to assure it would work well .... : ... we have no idea whether it will or it won't and are trying to get info from anyone who may know so we can get prepared for the comp ..... it's all a bit nerve wracking!

Thank you guys for the comments so far .... they suggest it's not a total stuff-up as our farthest targets are at 1620 metres.

 

[D-mon]

Hi Kiwi,
I am from Hamilton myself.
I shoot the 300 whisper with a 1 in 8 twist to stabilize the 240gr SMK.
the problem you might encounter is over stability if you use anything below 208-210 gr. And also, if your action is a short action, any heavy bullet (that would suit your twist) would have to be seated quite deep in the case for them to feed in a mag.
Unless you manually chamber your round and that you have the appropriate longer throat for your round.

What is your action? and barrel?
Who is the gunsmith as a matter of curiosity?

NIC

 

[Kiwi]

Hi D-mon .... the action is a Savage and the barrel is a Trueflite Ultra match

Work done:
Supply T/Flight ultra match SS barrel, true the action, thread muzzle and supply muzzle brake, thread protector and suppressor .... because Brownells wouldn't ship an after market recoil lug : the factory lug and action was bedded into my mate's PDC stock.

The work was done by Dan Hardy and is to a very high standard .... we have no beef with the quality of work and in fact the owner has accepted the rifle with the 1 in 8 twist and is working up loads already ..... we will have a better idea of this rifle's pluses and minuses pretty soon I guess.

I was told by Dan that it's a palma chamber ... I think he meant it's a short throat.

 

[canderson]

On the other side. If it will shoot super sonics well, rounds can be down loaded for subsonic use. I have a 1-8 twist on my 300 whisper. Trail boss will fill the case without getting over the sonic boundary.

 

[Kiwi]

Yeah, we thought of that and he has a very nice new suppressor too .... but, the primary want is a 1600 metre shooter.

 

[TonyR]

Please let us know how it shoots at those long distances. I think you will be better off with the 1:8 than the 1:10 given the muzzle velocities and BCs you will be working with at that distance. You should also look for the promised 230 gr 30 cal Hybrids from Berger later this year. They need at least a 1:10 but are expected to have a BC of around .750.

 

[D-mon]

Hi kiwi,
I m quite surprised with what Dan Hardy has put on your action.did you try to have a word with him about the out comes if the gun don't shoot straight?
By the way I ran the balistics of your 300wsm through the iPod,and there no way that a bullet will remain supersonic at 1600m.Yes the bullet will reach 1600m if you have enough slope on your rails and adjustments in your scope,but your bullet will have to cross the transonic zone with out losing accuracy,and that is going to be hard to do against the big boys playing with 338 lapuas and 50 bmgs.
By the way, who got the idea of chosing this caliber for shooting that distance?
Good luck anyway .
Nic

 

[Kiwi]

Hi Nic .... I too was quite surprised (to put it mildly) .... I have had a word with him, but he was occupied at a Napier show so it was not conducive to a protracted discussion ... I'll call him tomorrow.

I know his work has been in great demand the last year or so and I suspect the pressure of success is inducing a bit of a speed wobble, anyway, I love the guy's work and hope he can keep the balls in the air for his growing customer base.

My mate has about 30 rounds down the tube as of this afternoon, shoot-and-clean stuff, he is using 155 Scenars for this and they are doing .8" at 100 metres and there is virtually no fouling (a good sign) ... this is encouraging as the common wisdom is that it should shoot heavier pills not little 155s ....

He is a farm manager and has the owner there tomorrow but hopes to get into the 208 Amax loads by the week end .... I'll keep you guys posted as this seems to be territory that is not well charted!

The idea of 300WSM was his and he's quite happy with that ... if he can push them at 2700 fps they will go trans sonic at around 1450 metres at sea level (where we test on his farm in the Northern Kaipara) ... the comp is at 2700 ft above sea level so we should see some advantage gains there but not to 1600 I suspect ....

JBM says they need to be launched at 2950 fps to be on the edge of super sonic at 1600 metres .... bolt lift could be a bit stiff by then eh! ....

 

[D-mon]

Hi,
I see your mate is from Kumara country

We are having the F-class nationals comp this week end at Whatawhata near Hamilton. That would have been a good test ground for your new rifle...
Let us know if you think you could make it.
NIC

 

[Kiwi]

Just saw your post re: Whatawhata ..... went surfing instead after that tropical cyclone slid past the East coast .... even Orewa was 4 o 5 foot!!!

Who won the comp?

I'm off to Tekapo in two weeks .... YAY! ... ;D

 

[Kiwi]

An up-date on the 300WSM ......

Pushing a 208 Amax it is shooting 8 inch groups at 1125 meters (1230 yards) and the speeds are at around 2800fps ..... JBM says at that speed it's super sonic to 1500 meters (1640 yards)

If the super fast twist helps with trans-sonic stability, he just might be OK to the 1620 meter target (1771 yards, or a whisker past one mile ... )

 

[D-mon]

Hi,
I finished 3rd in open class with a 6mmbr. There was really a poor attendance that weekend despite the nice weather.
I managed to nail 7 spearwing plovers with my 22-250 as well on that range the same weekend.
Good luck for the shoot in south island. I would be keen to go there sometime. I am building a 6.5 creddmoor soon to shoot thes kind of comp. (not at 1500m though).
NIc

 

[Kiwi]

3rd's pretty cool Nic! .... 8)

There are 36 shooters registered for the comp this year, 10 up on last year so it's getting more popular for sure.

I doubt they would want more than 40 or 45 in future as the comp runs ... practice Friday, comp Saturday and a re-shoot for anyone keen on Sunday.

Here is the link to the comp's web-site ..... http://www.gunslinger.net.nz/ .... might see you next year eh? ...

 

[D-mon]

Hi Kiwi,
Well good luck for this shoot this weekend.
Let us know how it went. We are expecting a full report ;-)
By the way you should stop in Hamilton the way back up if you can.

Nic