7mm WSM

[bjsiillinois]

Was thinking about building a 7mm WSM shooting the 168 Berger VLDs in a hunting rifle. Would be using as a single shot, so magazine length wouldn't be a issue. What would be the optimum barrel length, twist, and freebore for this bullet. What neck diameter would I need for a no turn?

Thanks, Billy

 

[284winner]

25",9 twist, 317/318 neck, .180 freebore. That'd be my choice of numbers

 

[bjsiillinois]

Guess I should have looked for brass availability before I posted this question. May have look at something different.
Thanks, Billy

 

[284winner]

Don't let that run you off. 300 cases properly treated will last a long time. Especially for hunting application.

 

[Kurz]

Guess I should have looked for brass availability before I posted this question. May have look at something different.
Thanks, Billy

Here is some brand new just released brass:

https://www.dowdlesports.com/Winchester-Ammo-Unprimed-Brass-Rifle-7mm-WSM-50_p_41569.html

Regards.

 

[rifleman700]

Was thinking about building a 7mm WSM shooting the 168 Berger VLDs in a hunting rifle. Would be using as a single shot, so magazine length wouldn't be a issue. What would be the optimum barrel length, twist, and freebore for this bullet. What neck diameter would I need for a no turn?

Thanks, Billy

FWIW a 7SAUM has a longer neck and better barrel life and only gives up 50 fps to the WSM and it has better brass. Barrel length depends on where you hunt and what you can get by with. 24-26" is optimum, any longer it becomes a broom handle IMO. No turn neck in hunting rifle. Load a dummy round with the bullet you want to use and have it reamed for those specs. 1-8" twist in case you ever want to shoot the long and heavies.

 

[284winner]

Here is some brand new just released brass:

https://www.dowdlesports.com/Winchester-Ammo-Unprimed-Brass-Rifle-7mm-WSM-50_p_41569.html

Regards.

86.00 per 100. There you go. Good deal. Good brass.

 

[RonAKA]

Step 1 is to figure out where you are going to get all the brass you will need now and in the future. I agree with the comment that the 7mm RSAUM is a bit better choice than the 7WSM. For twist you are 100% safe at 9.5" with that bullet. If you want to sacrifice some BC retention at longer distances for shorter distance accuracy you may get away with a 10.5 or 11" twist. Play around with Berger's twist calculator to decide for yourself. You can fine tune it a bit if you know for sure what altitude and temperature you will be shooting at. I assumed 2950 fps for vel. I would go with a 28" barrel. More "free" velocity for the same powder.

Berger Twist Calculator

 

[bjsiillinois]

I did see that there was 270 WSM available, I could neck up to.284. I wouldn't mind getting the Norma brass, for hunting, it would last a long time.

 

[bjsiillinois]

Here is some brand new just released brass:

https://www.dowdlesports.com/Winchester-Ammo-Unprimed-Brass-Rifle-7mm-WSM-50_p_41569.html

Regards.

Kurz,
Thanks for the heads up on that brass, that's pretty cheap.

 

[bjsiillinois]

25",9 twist, 317/318 neck, .180 freebore. That'd be my choice of numbers

At .180 freebore, would I be able to get the 168s to the lands?

 

[284winner]

At .180 freebore, would I be able to get the 168s to the lands?

Yes.

 

[bjsiillinois]

Yes.

Thanks, I'll have to get a consensus on what twist to use. I want to use the slowest twist I can get away with and still stabilize the bullet with a little more velocity. Berger's usually pretty safe with their twist rates.

 

[RonAKA]

Thanks, I'll have to get a consensus on what twist to use. I want to use the slowest twist I can get away with and still stabilize the bullet with a little more velocity. Berger's usually pretty safe with their twist rates.

I would suggest you read the article at the link below, and then make that decision yourself. You need to start with an assumed twist (try 10), and refine it from there. You also need an expected muzzle velocity, and it helps to input temperature and elevation.

Twist Rate Stability Calculator Update

Essentially you can decide what you want from minimum spin which usually gives maximum accuracy as long as it is stable, SG=1.2 or so. Or you can go with more spin to preserve your BC and long range trajectory, and sacrifice a little accuracy, SG=1.5. Your choice!

 

[bjsiillinois]

I would suggest you read the article at the link below, and then make that decision yourself. You need to start with an assumed twist (try 10), and refine it from there. You also need an expected muzzle velocity, and it helps to input temperature and elevation.

Twist Rate Stability Calculator Update

Essentially you can decide what you want from minimum spin which usually gives maximum accuracy as long as it is stable, SG=1.2 or so. Or you can go with more spin to preserve your BC and long range trajectory, and sacrifice a little accuracy, SG=1.5. Your choice!

Thanks for the link, I'll check it out.

 

[284winner]

Thanks, I'll have to get a consensus on what twist to use. I want to use the slowest twist I can get away with and still stabilize the bullet with a little more velocity. Berger's usually pretty safe with their twist rates.

Berger has another link on there website...making Berger VLDs shoot.

Thanks for the link, I'll check it out.

Google - VLD: Making it shoot. It's Berger's website and gives very good information on how to load the Berger vld for both hunting and target application. RonAKA is correct on the twist calculator link as well. It will give you optimum stability numbers based on twist rate, BCs and velocities. The making it shoot link can be used with all VLD bullets including the Amax and TMKs.

 

[bjsiillinois]

Berger has another link on there website...making Berger VLDs shoot.

Google - VLD: Making it shoot. It's Berger's website and gives very good information on how to load the Berger vld for both hunting and target application. RonAKA is correct on the twist calculator link as well. It will give you optimum stability numbers based on twist rate, BCs and velocities. The making it shoot link can be used with all VLD bullets including the Amax and TMKs.

Thanks, I'll check it out.

 

[CTK]

280 Ackley is giving me 2920 fps. with RL 26 out of a 24" barrel and 168 VLD's. 9 twist. This is a hunting rifle. Took a while to find this load. The VLD's were pretty picky about seating depth and powder load. They did not like to be close to the lands in this rifle. finally got a .3" average @ 100y. Very pleased. I loaded 50 of them and am done for some time. I agonized between the 7 SAUM, 280AI, 7WSM and the 7RM prior to having this gun built. The .284 Win is attractive as well. I wish that there was a 7mm cartridge with 7RM capacity, no belt, and Lapua brass available. Dare to dream....

 

[barefooter56]

Thanks, I'll check it out.

Lots of good advice here on using the tools on our website. If you have any questions or need any help please contact us at techsupport@bergerbullets.com . Optimal twist rate we reccomend for our 7mm 168gr VLD is 1-9". For the 7mm 168gr CLASSIC HUNTER HYBRID bullet its 1-10". Our OPTIMUM TWIST RATES are based on a worst case scenario of 59 degrees at sea level.
Take care,

 

[dkhunt14]

280 Ackley is giving me 2920 fps. with RL 26 out of a 24" barrel and 168 VLD's. 9 twist. This is a hunting rifle. Took a while to find this load. The VLD's were pretty picky about seating depth and powder load. They did not like to be close to the lands in this rifle. finally got a .3" average @ 100y. Very pleased. I loaded 50 of them and am done for some time. I agonized between the 7 SAUM, 280AI, 7WSM and the 7RM prior to having this gun built. The .284 Win is attractive as well. I wish that there was a 7mm cartridge with 7RM capacity, no belt, and Lapua brass available. Dare to dream....

What about 7 Dakota? 7 Ultra Mag? Matt