New 230 smk in a 300wsm

[Mudpro]

Anyone tried the new 230gr seirras in a 300wsm for fclass yet? What twist rate is everyone running/ reamer freebore?

 

[JaoeyP]

Have not tried in anything and I'm not an F-class shooter, but I was curious is these would work in the 10" twist 300 Win Mag I just ordered. I called Sierra and Paul said they are 1.754" in length. Running through the JBM calculator, assuming 2800 fps, the SG value is 1.177. Probably want about a 8.75" twist or faster to stabilize them I'm guessing.

 

[JBT47]

I would imagine not too many people will have a fast enough twist to shoot this bullet.

 

[LA50SHOOTER]

I'll be running a 1-9 twist for these 230's in a couple of cartridge cases that are a little bigger. - I have not seen a lot on 230 gr. bullets and success or failure in the 300 WSM. - The 215 gr. Berger's have shot well in one WSM I own & velocity was very much acceptable. - I'm not sure the trade-off to shoot 230's is something that realized gains can be achieved in the 300 WSM. - By all means if you find success with them I'd be very interested to hear more. - I believe you'll need a 0.280 or greater free-bore to get these out far enough to where your not infringing on valuable case capacity. - The 300 Norma Mag. Improved that I've planned has a 0.280 free bore and that case has a pretty long neck on it.

Good Luck & Good Shooting - Ron -

 

[retired]

i shoot BERGER 230 in a 26" 300 wm 1/10 and the sie 220

 

[LA50SHOOTER]

i shoot BERGER 230 in a 26" 300 wm 1/10 and the sie 220

Understood, but these new 230's from Sierra have a very long ojive and not as much bearing surface as the 230 Berger or 220 SMK.
I went 1-9 twist in hopes that I'll get them to shoot well in the 300 NM Imp. knowing that if the new 230 gr. Sierra doesn't shoot well then I have 230 Berger's to try as well & I know that the 230 Bergers are going to be plenty stable. - I'll be trying them in a 5R and a conventional 4 groove 30" barrel. - also in a 30 Nosler, 30" conventional 4 groove 1-9 twist, again knowing that I'll have Berger 230's as a good contingency.
If these new 230 Sierras don't shoot I'm not going to fiddle with them & waste a bunch of barrel life when Berger's will. I was impressed with the bullet when it was released on the market so I picked up a couple of 50 round boxes of them to check out and to build some dummy-rounds so that I could properly spec the free-bore of the reamers for my chambering jobs. (Because i want neck-turn chambers and optimum seating depth)

- Ron -

 

[JBT47]

i shoot BERGER 230 in a 26" 300 wm 1/10 and the sie 220

I’ve shot 230 Bergers in 4 different 300 Win Mags all with 10 twist...however this new Sierra bullet is a different animal and will require a significantly faster twist.

 

[Ledd Slinger]

I'm running a 1 in 8" twist barrel on the 300 Norma Improved rifle I'm building.
1 in 9" can work according to a stability calculator depending on your geographical elevation. 1 in 10" is gonna be way too slow.

I have a few hundred of the new Sierra 230 MKs on hand and they are very long. Longer than the 250gr 338 cal Berger Elite Hunter VLDs I use in another rifle. No doubt they'll need a tight twist. I would suggest going with the twist recommended by Sierra which is 1 in 8". Won't even notice a difference in velocity over a 1 in 9" (might be 5 fps slower with an 8 twist) but the added stability may show up a little better on long range targets.

 

[Ledd Slinger]

Heres some photos for reference on the new Sierra 308 cal 230s.

Left to right:
Berger 6.5mm 140gr VLD
Sierra 308 cal 230gr MatchKing
Berger 338 cal 250gr Elite Hunter VLD


Sierra 308 cal 230gr MK - OAL


Small tipped meplats

 

[gilmillan1]

I ran them in a 9.5 twist at 2840, but I could not get them to shoot as good as the berger 230s. Maybe I need more twist. It is a very good looking bullet. A 280 freebore works great for it.

 

[Ledd Slinger]

I ran them in a 9.5 twist at 2840, but I could not get them to shoot as good as the berger 230s. Maybe I need more twist. It is a very good looking bullet. A 280 freebore works great for it.

Ran your numbers with the Sierra 230gr on the calculator. At zero elevation, your SG is 1.4 which is "marginally" stable. At 2000 feet elevation your SG is 1.5 which is the minimum number required to consider a bullet stable. Unless you were testing them way up in the rocky mountains, you are right on the ragged edge of good stability. Would probably shoot better for you with a 1 in 9 or faster.

 

[JaoeyP]

I ran them in a 9.5 twist at 2840, but I could not get them to shoot as good as the berger 230s. Maybe I need more twist. It is a very good looking bullet. A 280 freebore works great for it.

I think these new high BC bullets have narrow velocity windows that they like, same with seating depth.

 

[gilmillan1]

I cannot say that the bullet will not shoot, maybe I just needed more testing, but the 230s shot so good that I just let that bullet go. Ill let someone with more patience try them.

 

[JaoeyP]

I cannot say that the bullet will not shoot, maybe I just needed more testing, but the 230s shot so good that I just let that bullet go. Ill let someone with more patience try them.

I can understand that. I built a 243 with 7" twist with the specific intent to shoot Sierra's 110 Matchkings. I tried a little, didn't quite get there with it, then tried the 115gr DTAC and hit a load that grouped immediately. Doesn't mean that 110 won't shoot, it's just hard to want to pursuit it since I have another load that is already working.

 

[284winner]

Understood, but these new 230's from Sierra have a very long ojive and not as much bearing surface as the 230 Berger or 220 SMK.
I went 1-9 twist in hopes that I'll get them to shoot well in the 300 NM Imp. knowing that if the new 230 gr. Sierra doesn't shoot well then I have 230 Berger's to try as well & I know that the 230 Bergers are going to be plenty stable. - I'll be trying them in a 5R and a conventional 4 groove 30" barrel. - also in a 30 Nosler, 30" conventional 4 groove 1-9 twist, again knowing that I'll have Berger 230's as a good contingency.
If these new 230 Sierras don't shoot I'm not going to fiddle with them & waste a bunch of barrel life when Berger's will. I was impressed with the bullet when it was released on the market so I picked up a couple of 50 round boxes of them to check out and to build some dummy-rounds so that I could properly spec the free-bore of the reamers for my chambering jobs. (Because i want neck-turn chambers and optimum seating depth)

- Ron -

How did the 9 twist work for you with your 300 NM build with the 230s ?

 

[LA50SHOOTER]

How did the 9 twist work for you with your 300 NM build with the 230s ?

I'll send you a P.M.

 

[284winner]

I'll send you a P.M.

Sounds good.