338 SHERMAN

[elkaholic]

Guys. Here is some very impressive info on the 338 Sherman. Jace ran some Superformance through his 25" Bartlein 5r this week with both the 285 ELDM and the 250 Berger. Past data from 4 different rifles have all been close with RL17 and H100v so I have no reason to doubt these numbers. All done over magneto speed.
Yesterday he ran the 285's over 2700 and the 250's up to 2957'! Today he backed off a bit, 1.5 grs. On the 250, and ran them
again. 2700+ with the 285 and around
2920 with the 250. I also asked Jace to test temp stability while he was at it. Here is what he found:
67.5 grs. of Superformance at ambient of 46 degrees behind a 285 yielded 22' slower than rounds from pants pocket
next to skin. 69.5 superformance behind a
250 Berger was only 8' different.
Not a total scientifically controlled test, but pretty revealing.
He is going to start working on an accuracy node now, but feels pretty good about running the 250 around 2900 and the 285 near 2700. This cartridge continues to amaze us! It is so under bore
for a 338 that the barrel should last indefinitely. And 4800+ ft/lbs. from an '06
case size!!

 

[Pdvdh]

Nice.
What's the best Brand & Cartridge for the parent case? I forgot... Too many S and SSs to keep track of.

 

[ruby76]

Unnnnreal. Has anyone tried Superformance in any of the shorts?

 

[elkaholic]

Nice.
What's the best Brand & Cartridge for the parent case? I forgot... Too many S and SSs to keep track of.

270 RWS Baby!!!!

 

[elkaholic]

Unnnnreal. Has anyone tried Superformance in any of the shorts?

Not to my knowledge, but i think you had better try a case full in your 338 SS when you get it together! Based on the load density in the Sherman, I think it just might work.

 

[elkaholic]

See Jaces post on the " 338 Sherman boomstick" thread.

 

[Idaho Trecker]

Unnnnreal. Has anyone tried Superformance in any of the shorts?

I ran it in my 300ss and I did not have the same results as you did with temp. For me 100v was better. Almost seems like we had exact opposite results. I think in page 5 or 6 I have my my superformance results. https://www.longrangehunting.com/threads/300-sherman-shortmag-ss.172174/page-6

 

[CjC73]

I know an older thread. But could someone with a 338 Sherman measure the outside of a loaded round at the neck? Needing to order bushings for my whidden dies.

Currently I have 270 brass sized up to 35 Cal.

What's a good fire forming load? Powder and oal. I'm on the hunt for some cheap bullets as well.

Thanks

 

[elkaholic]

I know an older thread. But could someone with a 338 Sherman measure the outside of a loaded round at the neck? Needing to order bushings for my whidden dies.

Currently I have 270 brass sized up to 35 Cal.

What's a good fire forming load? Powder and oal. I'm on the hunt for some cheap bullets as well.

Thanks

.362 with 270 Norma brass
Fire forming
225 grain. 59 grains RL17
60 grains H100v
58 grains RL 16
56 grains 414

 

[CjC73]

362 bushing? Or 362 outside measurement?

 

[elkaholic]

.362 loaded. I used a .360 bushing

 

[slingshot_68]

Has anyone tested for accuracy with reduced loads, perhaps around 338-06 speeds? I want to build this for elk but I don't think I would need all the horsepower for deer.
Thanks

 

[elkaholic]

Has anyone tested for accuracy with reduced loads, perhaps around 338-06 speeds? I want to build this for elk but I don't think I would need all the horsepower for deer.
Thanks

Yes, mine shot bugholes when I loaded it light. You could do that with several powders too!

 

[CjC73]

Do you have any loads to start with Rich? Or powders... I'll use mine for deer as well.