Am I loading too Hot

Boomer posted some excellent info. To add to what he has said; Those craters are the result of the new Bolt face design Remington is using. It is not caused by too big a hole or too small a pin, it is that the face of the bolt, around the firing pin hole is slighlty counter sunk. This serves no useful purpose and can result in easier pierced primers. Most accurizing gunsmiths can ifx that problem by "Bushing" the hole.

As to primers, with the RUM series, and any cartridge using more than 75 grains of powder, I would highly recommend the Federal 215M or the Winchester Large rifle magnum primers. Both are quite a bit hotter primers. I have seen a lot of click booms, delayed firings and failures to fire (the primer goes off, some of the powder is burned and the powder is clumpy but the round does not fire) with many different batches of CCI 250 in cartridges that burn 75 to 120 grains of powder.
 
Dean2 said:
Boomer posted some excellent info. To add to what he has said; Those craters are the result of the new Bolt face design Remington is using. It is not caused by too big a hole or too small a pin, it is that the face of the bolt, around the firing pin hole is slighlty counter sunk. This serves no useful purpose and can result in easier pierced primers. Most accurizing gunsmiths can ifx that problem by "Bushing" the hole.

As to primers, with the RUM series, and any cartridge using more than 75 grains of powder, I would highly recommend the Federal 215M or the Winchester Large rifle magnum primers. Both are quite a bit hotter primers. I have seen a lot of click booms, delayed firings and failures to fire (the primer goes off, some of the powder is burned and the powder is clumpy but the round does not fire) with many different batches of CCI 250 in cartridges that burn 75 to 120 grains of powder.
Click to expand...

The Primers showen in the pictures are Winchester Large Rifle Magnum Primers
 
It's not over pressure.

It's either your rifle or rifle/primer combination.

Personally, I've found that the Berger data that was emailed to my by them (about three years ago) was on the conservative side. This was for 6.5x55, .308, and 30-06. In comparing their data to other's, I found the Berger data was almost always on the very low end compared to other manufacturers of bullets in the same weight class.

BTW - I was having all sorts of ignition problems with my .375 RUM, until I switched to Remington 9 1/2M magnum primers, which is (who would have guessed...) what the reloading manuals list for this cartridge. I reload for other magnums (300, 338, 375 H&H), and CCI 250's or Win LRM primers work for them, but NOT in the RUM. The darn RUM just needs more juice than those other primers provide...
 
So went back to the range yesterday All the Primers are still making the same Indents on the Primer so I'm not concerend starting to get my load where I want it. THis target was 3 shot at 200Yrds.

300RUMTarget.jpg
 
You must log in or register to reply here.
Back
Top Bottom