338 SHERMAN

[slingshot_68]

This Wilson expanding mandrel works really well for expanding the cases. I go straight to 33 cal from 270 with zero problems. I just jam the bullet into the throat and fireform

 

[benchracer]

This Wilson expanding mandrel works really well for expanding the cases. I go straight to 33 cal from 270 with zero problems. I just jam the bullet into the throat and fireform

This is a really solid suggestion. I just ordered the die in .338 and an additional mandrel in .30 cal.

 

[Shane Lindsey]

FWIW, if you can get Peterson 280AI brass, it forms up and is 2.495" ish. After fire forming it was just long enough to trim back.

270 brass, still has never made it to 2.495" and some are on their fifth firing.

Barrel is slow and pressures fast.

 

[benchracer]

FWIW, if you can get Peterson 280AI brass, it forms up and is 2.495" ish. After fire forming it was just long enough to trim back.

270 brass, still has never made it to 2.495" and some are on their fifth firing.

Barrel is slow and pressures fast.

Yup! I am running Peterson 280 AI brass in my 338 Sherman. It is, by far, the best match to the Sherman specs. Forms at the right length, no need to anneal, no need to neck turn.

I am given to understand that some of the smaller diameter Shermans require neck turning when using Peterson 280 AI brass. I am not sure where the dividing line for that is.

 

[Shane Lindsey]

FWIW. Accuracy with the FF loads and 280ai were a little more accurate than the 270 brass.

Hoping this gives me some more confidence inn this.

 

[benchracer]

FWIW. Accuracy with the FF loads and 280ai were a little more accurate than the 270 brass.

Hoping this gives me some more confidence inn this.

I went back over our earlier correspondence. Made me wonder if your barrel has a tight bore? If so, I was wondering if lapping the bore might help?

Anyway, food for thought...

 

[Shane Lindsey]

I spoke to someone about that and he mentioned lapping, but made it sound like that is required prior to chambering???

Maybe someone that has lapped one after chmabering can chime in. I did run some JB through it, but I do that every couple hundred rounds for throat maintenance anyway.

Literally cannot get anywhere close to the velocities that are posted here. Pressure at 59gr Rl17 with 250 Berger, Peterson 270 Win cases at about 2599 FPS. No accuracy here, indicating it needed to be much slower.
59.5gr Rl17 with a Speer 225gr BTSP at about 2662 FPS.

Fireforming with the 250 Berger and 250 Hornday and SWP at 2200 FPS showed promise. I was about to give up on this weight bullet until I saw those. But...that is almost as slow as my muzzleloader, and it is accurate...

 

[CjC73]

@elkaholic - What Hornaday headspace comparator should I use for the 338 Sherman?

 

[elkaholic]

@elkaholic - What Hornaday headspace comparator should I use for the 338 Sherman?

.375

 

[GeoHog]

Don't know if anyone still checks this, but thought I'd through it out there -

I'm looking to either rebarrel a rifle in 338 Sherman, or build a switch lug rifle, and have the 338 Sherman as an option.
I've talked with people that said they could do a barrel for 338 Federal, but didn't know enough about 338 Sherman to do it.

What are the differences between the two? Or if a short action is chambered for 338 Federal, could it shoot the Sherman?

Apologies for having such basic questions. Up until now, all I've worried about my gun is - point it at where you want the bullet to go.

 

[Shane Lindsey]

You would want a long action for the 338 Sherman. Optimal mag length would be about 3.6" to give you some wiggle room. 3.5" + OAL for the 250 Bergers to the lands. I tried it in an older Savage 110 and couldn't get that long to load in the mag.

 

[BigDon]

Don't know if anyone still checks this, but thought I'd through it out there -

I'm looking to either rebarrel a rifle in 338 Sherman, or build a switch lug rifle, and have the 338 Sherman as an option.
I've talked with people that said they could do a barrel for 338 Federal, but didn't know enough about 338 Sherman to do it.

What are the differences between the two? Or if a short action is chambered for 338 Federal, could it shoot the Sherman?

Apologies for having such basic questions. Up until now, all I've worried about my gun is - point it at where you want the bullet to go.

Call Eric at LRI if you have a Long Action. I don't think it will work in a short action.

 

[elkaholic]

You do need a long action for the Sherman. It will run 250 Bergers north of 2800 though.

 

[Shane Lindsey]

@GeoHog

When you are able to, PM me.