The Firing Line Forums - View Single Post

pathdoc · April 17, 2013, 06:03 PM

Bart B, that sounds like an interesting method.

Coincidentally, I happen to have Hornady's 7th Edition reloading manual to hand and I flicked through it to see if anything had some nice round numbers that I could work this method over with in my head. 150gn bullets in the .303 British fit the bill - IMR3031 gives a 100fps per 2 grains rise between 2200 and 2400fps. The next jump, to 2500fps, demands 2.1 grains and then to 2600 (the maximum load with this powder) is 2.0 grains again.

So there's a possibility that rounding errors could screw with you. Let's assume, however, that the effect is real and look at some others.

Comparing another powder for the same cartridge and bullet, we find that Varget has a two grain jump from 2200 to 2300fps, then 1.9 grains from 2300 to 2400, another 1.9 grain jump from 2400 to 2500fps, and again a 2 grain difference from 2500 to 2600fps, whilst RL-12 has 1.9 grain jumps all the way up, except for the jump from 2500 to 2600fps, which is 1.8 grains (which those who chase velocity might leap upon with eagerness).

There are others, of course, but looking at just these three (so as not to become exhaustive) it would seem I should reach for the ReLoder 12 as my first choice all round. The question I have is that the method you recommend seems to imply I could get as good a result in the middle range between 2300 and 2500fps with Varget as with RL-12. And what are we to make of RL-15, which alternates between 1.7 and 1.8 grain jumps per 100fps all the way up to maximum?

Wogpotter, your method also sounds interesting but there is the issue of finding those multiple manuals. Taking Hornady bullets again as the example, one of those manuals would obviously be the Hornady Handbook. I'm imagining another might be the Lyman and others possibly the powder manufacturers' guides?

April 17, 2013, 06:03 PM	#18
pathdoc Senior Member Join Date: February 12, 2013 Posts: 669	Bart B, that sounds like an interesting method. Coincidentally, I happen to have Hornady's 7th Edition reloading manual to hand and I flicked through it to see if anything had some nice round numbers that I could work this method over with in my head. 150gn bullets in the .303 British fit the bill - IMR3031 gives a 100fps per 2 grains rise between 2200 and 2400fps. The next jump, to 2500fps, demands 2.1 grains and then to 2600 (the maximum load with this powder) is 2.0 grains again. So there's a possibility that rounding errors could screw with you. Let's assume, however, that the effect is real and look at some others. Comparing another powder for the same cartridge and bullet, we find that Varget has a two grain jump from 2200 to 2300fps, then 1.9 grains from 2300 to 2400, another 1.9 grain jump from 2400 to 2500fps, and again a 2 grain difference from 2500 to 2600fps, whilst RL-12 has 1.9 grain jumps all the way up, except for the jump from 2500 to 2600fps, which is 1.8 grains (which those who chase velocity might leap upon with eagerness). There are others, of course, but looking at just these three (so as not to become exhaustive) it would seem I should reach for the ReLoder 12 as my first choice all round. The question I have is that the method you recommend seems to imply I could get as good a result in the middle range between 2300 and 2500fps with Varget as with RL-12. And what are we to make of RL-15, which alternates between 1.7 and 1.8 grain jumps per 100fps all the way up to maximum? Wogpotter, your method also sounds interesting but there is the issue of finding those multiple manuals. Taking Hornady bullets again as the example, one of those manuals would obviously be the Hornady Handbook. I'm imagining another might be the Lyman and others possibly the powder manufacturers' guides?