My 338 Sherman Shortmag

[David Lindler]

338 usually measure around .364-.365.
If using a bushing die reduce this to a 362-360 bushing.
Several things can cause a sticky case.
1. Check the amount of shoulder bump.
Take a fired case and bump the shoulder farther back a few thousandths at a time until the bolt will close on the case with ease.
Try reducing case neck size with smaller bushing in die.
Check overall case length.
Your chamber may be tight with not much free bore. May have to seat bullet a little deeper.
Load around and keep adjusting bullet depth deeper until the bolt closes easy on a loaded around.
Hope this helps

 

[jsmitt6]

More baseline data with the 250 Bergers.

H4350 powder - 60 gr. - 2663
61 - 2690
62 - 2715
63 - 2759

I started seeing slight extractor marks at 61 grains, at 63 had a slight heavy bolt lift. I think there is some more room in the case beyond 63 grains so worth exploring at a later date with better brass.

N560 powder - 60 gr - 2481
61 - 2562
62 - 2587
63 - 2669
64 - 2699

I got slight extractor mark starting at 62, and the 64 grain was slight heavy bolt lift. I think there's a bit more room left in the case.

I'm sounding like a broken record about my brass but its crap. Period. It's a limiting factor to what this cartridge is capable of. I'm going to circle back to RL17 and reduce the charge a bit to save my brass and see what sort of accuracy I can get. The velocity was good down below 61 grains (just over 2800) so I loaded a few at 60.5, 60.7, and 60.9. I really want to reach my 2800 goal with an accurate load for hunting season. I'm still on the hunt for RL 16 as well so I hope to do some testing with it too.

Ruby - I know that this post is over 2 years old.. Do you remember the COAL you set the 250 Berger with the H4350? I have several pounds of H4350 and just got 100 of the ADG brass. Will start loading soon while I wait for my barrel to be reamed. Thanks in advance.

 

[ruby76]

Ruby - I know that this post is over 2 years old.. Do you remember the COAL you set the 250 Berger with the H4350? I have several pounds of H4350 and just got 100 of the ADG brass. Will start loading soon while I wait for my barrel to be reamed. Thanks in advance.

Which reamer are you using? I originally did mine with the standard throat reamer and have since throated it about another .120. I am now at 3.036 coal with the 250 berger touching the lands. You'd want to back off at least .020. I'm now concentrating on the 230 eldx at a coal of 2.868 which is .030 off. Still messing around with it and have loaded H4350 up to 61.5 grains at 2771 fps with the 230. Varget seems to be more accurate in my rifle.

 

[elkaholic]

Ruby - I know that this post is over 2 years old.. Do you remember the COAL you set the 250 Berger with the H4350? I have several pounds of H4350 and just got 100 of the ADG brass. Will start loading soon while I wait for my barrel to be reamed. Thanks in advance.

Which reamer are you using? I originally did mine with the standard throat reamer and have since throated it about another .120. I am now at 3.036 coal with the 250 berger touching the lands. You'd want to back off at least .020. I'm now concentrating on the 230 eldx at a coal of 2.868 which is .030 off. Still messing around with it and have loaded H4350 up to 61.5 grains at 2771 fps with the 230. Varget seems to be more accurate in my rifle.

Highly recommend trying the new N555 if you can get some. I have a feeling it will be a winner! More energy than 4350

 

[ruby76]

Highly recommend trying the new N555 if you can get some. I have a feeling it will be a winner! More energy than 4350

Varget is for sure getting better velocity than H4350. I'll keep an eye out for N555

 

[elkaholic]

Varget is for sure getting better velocity than H4350. I'll keep an eye out for N555

I had a guy use it in a 300 Sherman which uses about the same powders and it out ran 4350 by 75' with good accuracy. Its supposed to be very stable too!

 

[ramrod79]

What would be a good starting point with 565 and 230s

 

[elkaholic]

What would be a good starting point with 565 and 230s

565 would be too slow to pressure up

 

[Capt RB]

If h4350 to Varget is working Rl16 seems to make more speed with stability and 100V although not as stable has been easy to work with for top velocities and great case fill in the creed 300wsm and 06. I haven't used it enough in others to know how it would work to speak about it.

 

[jsmitt6]

Which reamer are you using? I originally did mine with the standard throat reamer and have since throated it about another .120. I am now at 3.036 coal with the 250 berger touching the lands. You'd want to back off at least .020. I'm now concentrating on the 230 eldx at a coal of 2.868 which is .030 off. Still messing around with it and have loaded H4350 up to 61.5 grains at 2771 fps with the 230. Varget seems to be more accurate in my rifle.

I am using the standard reamer. I have a remington 700 and am constricted by an AICS mag that has an overall case length of 2.950".

 

[ruby76]

I am using the standard reamer. I have a remington 700 and am constricted by an AICS mag that has an overall case length of 2.950".

Standard reamer is supposed to be 2.970 to lands so you should be good. Which mag are you using?

 

[jsmitt6]

Standard reamer is supposed to be 2.970 to lands so you should be good. Which mag are you using?

I will be using the accurate mag 7mm SAUM mag. I have 2-3 rounders and 2-7 rounders. Just sent my bolt to LRI to get the face opened up to a magnum bolt face and fluted. I am having my barrel done at Preferred Barrels, a local shop here in Utah who just got a reamer from Rich directly. Will throw it all together in a MPA Ultra Lite chassis and make this an elk slayer. I haven't ever been this excited about a rifle in a long time.

On another note, just got 100 ADG brass from Rich. I am good to just run them through the dies to neck it up from a 7mm to a 338, correct? Then just check the length and make sure it is still at 1.930? Thanks for all the help, Its really appreciated!

 

[ruby76]

I will be using the accurate mag 7mm SAUM mag. I have 2-3 rounders and 2-7 rounders. Just sent my bolt to LRI to get the face opened up to a magnum bolt face and fluted. I am having my barrel done at Preferred Barrels, a local shop here in Utah who just got a reamer from Rich directly. Will throw it all together in a MPA Ultra Lite chassis and make this an elk slayer. I haven't ever been this excited about a rifle in a long time.

On another note, just got 100 ADG brass from Rich. I am good to just run them through the dies to neck it up from a 7mm to a 338, correct? Then just check the length and make sure it is still at 1.930? Thanks for all the help, Its really appreciated!

I'm using an accurate mag WSM.

I expanded my necks with a .30 cal first, then the 338. Others have just necked straight up. I trimmed the length after fireforming to 1.930

 

[jsmitt6]

I'm using an accurate mag WSM.

I expanded my necks with a .30 cal first, then the 338. Others have just necked straight up. I trimmed the length after fireforming to 1.930

Ruby, I appreciate the help and all the info/knowledge that you have put into this and other threads. It ultimately led to my decision to jump into the 338 SS game.