How much reduction in charge is okay?

[huntsman]

I am wanting to try some 8mm mauser reloads that are quite reduced from maximum. My data says that what I am wanting to do is okay, but I wanted to get some practical advice from you veterans before I try it.

I want to create a more handgun-load type of velocity just to see how it works. I am using IMR 4064 and 150 grain bullets. According to my data, I can go down to 23 grains safely, but I only need to go down to about 26 grains for the velocity I seek. This is going to leave a lot of empty space in the cartridge, as that is about half of compressed load territory in the 8mm.

I'm wondering if I ought to use a faster powder, or if I might need some type of filler to get consistent performance. Any input will be appreciated.

[ricciardelli]

IMR-4064 From 36.0 grains to 53.0 grains
 Remington 9-1/2 Primer

[Nobade]

Try something faster like IMR 4759 or 4198, or AA5744 for reduced loads around 1500-1700 fps. The 4064 won't burn properly at such low levels. Use cast bullets for even better performance at those speeds.

[Reed1911]

If you want to continue using the 4064, use a cotton ball, tear off enough fluff to take up the space, run it into the case using a small screwdriver (on top of the powder), and load as normal. The cotton will keep the powder close to the primer and take up the excess space. When the shot is fired most of the cotton will burn up, and any that doesn't will get pushed out of the bore.

[Val]

The Speer manual calls for 22 to 26 grains of  IMR4198 for 150 grain 8mm Mauser reduced loads. This results in a muzzle velocity of from 1663 to 1966 fps.

I've used 4198 for reduced loads in my 7.62X54R Mosin Nagants with good results.

I'll be trying some of the 4198 reduced loads with my Milsurp Mausers when I get the time.