375 AM/SnipeTac/CheyTec Reloading

[royinidaho]

What are you that are shooting these cartridges using for a press?

I'm using a RockChucker Supreme and it doesn't have enough umph to fill length resize.

Either the handle is too short or the chamber is a bit big on the head end as compared to the dies, or there is something I don't know.

I size the brass as much as I feel comfortable without tearing up the bench and sticking the case in the die...

My spot of bother is that the resized cases chamber with bolt closing pressure. Enough to require increased bolt force to close.

With these cases I also get the "bolt click" on lifting the bolt but no extraction resistance.

On cases that chamber "properly" there is no bolt click. Which I like.

I'm not loading hot. Though I seem to have. :roll eyes:

Cases were originally fired with 142.5 gr Retumbo, 350 SMKs @ 3250 FPS MV. All shots left an extractor mark whose significance varied with the case. But they all had it and primer pocket expansion was quite noticeable.

I'm shooting 377 CEBs ahead of 149.2 gr H-50-BMG and Fec 215s and Jamison cases. MV is only 3100.
The leading edged of the "ring" is right at the case mouth.

Primers are flat but not muffin rimmed (which is unusual for me..:roll eyes

She shoots exceptionally well with this load

Any hints:

I'm thinking:

More sturdy Press mount
Longer press handle
Polish head end of sizing die
Get a 50 BMG press

or

Get some decent advice from you guys.

 

[slewfoot]

Here's my 10 cents of wisdom.... lol Try to find a Redding UltraMag press, they have plenty of leverage. They are a little spendy but the right tool for the job.

Get away from your Jamison brass and move up too Bertrum it's way tougher, you can thank me later...

PM sent...

Slewfoot

 

[royinidaho]

Slewfoot,

I have 100 of the Jamison cases, head stamped. I was informed by the builder that they were a bit iffy but at the time that's what was available.

Your points are well taken. I'll look into them...

 

[wyomingblizzard]

Roy, I am shooting the 338A.M. I am useing the dies provided by Kirby in a RCBS 50 press, they size no harder than any other case that I load. How ever I am only loading 145 grains of HBMG50 under a 300 grain Berger at 3380fps with no pressure signs.

 

[slewfoot]

Good luck Roy... I bet once you get some Bertrum brass the old Rockckucker will be more better...lol... you just might find 100 more fps with zero case head issues...

Slewfoot

 

[Frank7mm]

I'm using a RCBS Ammo master for my 375 design and it seems to work well. I'm on my second firing with Bertrum brass and have not needed to fully size them yet.

 

[bruce_ventura]

Roy, I use a normal press up to 340 Wby, and a Dillon for 50BMG. In my experience, case lube makes a big difference when resizing these big cases. I like RCBS and Dillon brands (in the pump bottles). One Shot has not worked for me. What are you using?

I find it's important to apply a thin coat on the entire case surface, then periodically remove the build up in the resizing die.

 

[royinidaho]

Well, fellas my dumbness has creeped up and bit me once again.

I've been using the RockChucker for years with lesser cartridges. That let me get away with a not quite proper set up.....until now.

Set the dies up properly with ram full up just a schosh over TDC. Works great - now!:roll eyes:

Thanks for the input.