7mm mag reduced loads

[orsogato]

Hi,

I had this post in "The Art of the Rifle" and realized it should be here.

I recently read that if one tries to make a "Reduced" load for a 7mm Rem Mag that it creates dangerously high chamber pressures.


My Nosler reloading manual says that a good starting load for a 150 grain ballistic tip bullet is 48 grains of IMR 4895 this gives a mv of 2780 fps according to the book.

If I wanted to say only put 46 or 45 grains of 4895 probably dropping velocity 100 fps or so would this create a dangerous c.u.p. pressure situation.

 

[Art Eatman]

Hmmm. Dunno about the 4895. What I do know is that some of the slow-burning pistol powders are quite usable in large rifle cartridges for reduced loads.

As a for instance, around 20 grains of 2400 in an '06 will push a 169-grain lead gas check at around 1,900 ft/sec, +/-. Per the book I used, a gas-check bullet can be pushed to around 2,400.

So, going by guesswork and extrapolation, you could probably use, say, 25 grains of 2400 behind that 150-grain bullet and get maybe 2,300-2,400; maybe more. I'd gues that the use of oatmeal or some such filler would give more uniform ignition.

It's one of those deals where you're just gonna have to start somewhere and tinker. Then you can write a book, "Reduced Loads for the 7mm Maggie" and get rich.

, Art