Fire forming brass

[Phil Rizzo]

I think the 270WSM built on a long action with proper throating falls in to this class also. Both the 270ai and 270WSM are under appreciated as are many of the AI and WSM cartridges. I see Bertram is now selling some pretty cool oddball WSM cases again with their new USA distribution partner.

Loading…

deserttechmunitions.com

View attachment 767389

After enough experience and years, I will hands down take a shorter/girthy case, even if I give up a little capacity, versus a long and skinny one. No question about that.
I've parted out, propped up and forgotten about the guns/cartridges I grew up with for the most part. I don't know a disadvantage to that choice, so far.

 

[FEENIX]

I think the 270WSM built on a long action with proper throating falls in to this class also.

Yes! Any of the WSMs thrives in >3.2" COAL.

 

[jseandsje]

I think the 270WSM built on a long action with proper throating falls in to this class also. Both the 270ai and 270WSM are under appreciated as are many of the AI and WSM cartridges. I see Bertram is now selling some pretty cool oddball WSM cases again with their new USA distribution partner.

Loading…

deserttechmunitions.com

View attachment 767389

We have a Savage 16FSS 270 wsm. one of the first ones, with a 1:11 twist. At .0012 off rifling my coal for

 

[FEENIX]

We have a Savage 16FSS 270 wsm. one of the first ones, with a 1:11 twist. At .0012 off rifling my coal for

I have two (24" and 6" barrels) Savage 11Fs in .300 WSMs, both are 1:10" twist. The 24" is loaded with 215 Berger .080" off the lands to keep it a repeater. Not ideal to take full advantage of the 215, but not too shabby at 2850 FPS.

 

[jseandsje]

I think the 270WSM built on a long action with proper throating falls in to this class also. Both the 270ai and 270WSM are under appreciated as are many of the AI and WSM cartridges. I see Bertram is now selling some pretty cool oddball WSM cases again with their new USA distribution partner.

Loading…

deserttechmunitions.com

View attachment 767389

I have two (24" and 6" barrels) Savage 11Fs in .300 WSMs, both are 1:10" twist. The 24" is loaded with 215 Berger .080" off the lands to keep it a repeater. Not ideal to take full advantage of the 215, but not too shabby at 2850 FPS.

We have a Savage 16FSS 270 wsm. one of the first ones, with a 1:11 twist. At .0012 off rifling my coal for

I didn't finish ……..

.012 off rifling. And a Coal of 2.980 for a Nosler 150 BT. (bc = 0.496) Don't know if the extra eighth inch powder space, and less restriction of twist did it, but this runs 3250 fps with Magpro. Stability at 600 ft, to 600 yds, is perfect.

The factory 270 wsm rifle is dying, just because it isn't stamped 1:8 twist.

You do the numbers and let me know if this 1:11 twist is long range worthy.

 

[lancetkenyon]

Since I mostly shoot wildcats, fire forming is a must.

For rifles in SAAMI chambers, I start load development right off the bat. Not many recipes change after 1x or 2x firings. Some of the belted mags change a bit due to shoulders growing .014-.021" depending on brass and chamber.

I can't see fire forming 100-200pcs of brass 3x times before starting load development on standard cartridges.

 

[FEENIX]

I didn't finish ……..

.012 off rifling. And a Coal of 2.980 for a Nosler 150 BT. (bc = 0.496) Don't know if the extra eighth inch powder space, and less restriction of twist did it, but this runs 3250 fps with Magpro. Stability at 600 ft, to 600 yds, is perfect.

The factory 270 wsm rifle is dying, just because it isn't stamped 1:8 twist.

You do the numbers and let me know if this 1:11 twist is long range worthy.

By your numbers, your SG is marginal at 1.2. You need a minimum of 1:975" to use the 150 NBT unless you are at 7000' elevation (SG=1.52). Or use the bullet weight/type designed for 1:11" barrel twist.

That's what re-barreling is for. This is one of the reasons I built my .270 AI with 1:8" in 2012 specifically to propel the 165/175 Matrix VLDs.

 

[dogz]

If I'm working with a wildcat, yes I do. With a Saami round, not a chance

 

[Phil Rizzo]

Who in the hell is a Saami?

 

[dogz]

Who in the hell is a Saami?

Think I saw it on the Jimmy Johns menu...grins

 

[jseandsje]

By your numbers, your SG is marginal at 1.2. You need a minimum of 1:975" to use the 150 NBT unless you are at 7000' elevation (SG=1.52). Or use the bullet weight/type designed for 1:11" barrel twist.

That's what re-barreling is for. This is one of the reasons I built my .270 AI with 1:8" in 2012 specifically to propel the 165/175 Matrix VLDs.

Correcting for plastic tip, I got a 1.34

By your numbers, your SG is marginal at 1.2. You need a minimum of 1:975" to use the 150 NBT unless you are at 7000' elevation (SG=1.52). Or use the bullet weight/type designed for 1:11" barrel twist.

That's what re-barreling is for. This is one of the reasons I built my .270 AI with 1:8" in 2012 specifically to propel the 165/175 Matrix VLDs.

i never checked any stability numbers before I shot, just know I got perfect bullet holes at 600 yards. At 600 ft elevation.

I have checked jbm ballistics, which accounts for plastic tip length. It calculates a 1.421. So I guess that's good enough to 600 yards

 

[FEENIX]

Correcting for plastic tip, I got a 1.34

i never checked any stability numbers before I shot, just know I got perfect bullet holes at 600 yards. At 600 ft elevation.

I have checked jbm ballistics, which accounts for plastic tip length. It calculates a 1.421. So I guess that's good enough to 600 yards

I no longer have 150 NBTs to measure, so I went with what it is on Nosler's website. No matter how you calculate it, it is still marginal at under 1.5 of SG, but if you think you are fine with it, then go with that. In my last four builds (.257 WBY/264 WM = 1:7", .30 LARA = 1:9", and .338 Thor = 1:8"), I went with the or faster twist option for the bullet I am going to use, but that's me. For instance, with my .257 WBY propelling the 163 Chinchaga at 2915 FPS, the SG is 1.83. I am not here to argue or convince you or anyone to do the same, but you asked me, so I responded accordingly. Good luck!

 

[Phil Rizzo]

Correcting for plastic tip, I got a 1.34

i never checked any stability numbers before I shot, just know I got perfect bullet holes at 600 yards. At 600 ft elevation.

I have checked jbm ballistics, which accounts for plastic tip length. It calculates a 1.421. So I guess that's good enough to 600 yards

Tight enough groups and clean round holes means you have the twist needed, at that temperature for sure.

 

[jseandsje]

I no longer have 150 NBTs to measure, so I went with what it is on Nosler's website. No matter how you calculate it, it is still marginal at under 1.5 of SG, but if you think you are fine with it, then go with that. In my last four builds (.257 WBY/264 WM = 1:7", .30 LARA = 1:9", and .338 Thor = 1:8"), I went with the or faster twist option for the bullet I am going to use, but that's me. For instance, with my .257 WBY propelling the 163 Chinchaga at 2915 FPS, the SG is 1.83. I am not here to argue or convince you or anyone to do the same, but you asked me, so I responded accordingly. Good luck!

Not arguing either, just wanted to emphasize that a standard twist, albeit with less than maximum weight, is better than the 8 twisters will admit. And the crossover point for from long to extra long bullets