I would like to load a 375 H&H. It calls for AA4064. I have IMR 4064. How close is the burn rate and are they interchangeable.

just work up a hair, but I have never seen any real differences in the 2 to be concerned about..

just don't start at max, and you should be fine...why not waste a bullet or two just to be on the safe side..

i have loaded both in my 7MM-08 with the same load. very accurate with both. like seafire said, work up. I also loaded both in the 30-06 with 150s same load.

Most if not all reloading manuals have a burn rate chart; have you checked it?

Kevin Rohrer
one of us

Posted 17 January 2012 14:38 Hide Post
Most if not all reloading manuals have a burn rate chart;

none of my reloading manuals have one

Quite a few years back, when I converted from IMR to AA powders, I called Accurate Arms and asked about the comparability of the two powders... I was told that AA powders were one grain slower than the IMR equivalent, and that if I was using IMR 4831, AA 3100 was the same powder, but nitrocotton based as opposed to nitrocelluloas based. I subsequently found that 60 grains of AA 3100 shot to exactly the same point of aim as IMR 4831. I have shot AA 3100 in my .270 ever since.

i know that you can't load from a burn rate chart from grain to grain. but, it can be used as a reference point. on all my burn charts XMR 4064 is usually a tad slower than the IMR

Burn rate is a special test. They don't make up the chart by burning the powder in cartridges. There are some very important things that change the burn rate of powder and that is the size and shape of the cartridge, the caliber and bore size, the weight of the bullet, temperature, and other things. The chart is only to give the powders a reference on the charts compared to others that were burned in a special test.

The couple times I compared I found AA4064 to be just a touch slower. Maybe a grain or two.

Hornady has IMR4064 in their 8th Edition.

I loaded up some 300 grain bullets two nights ago using the minimum load for barrel break-in on a new rifle.

For a 300 gr bullet, they list 52.3 gr min and 68.7 gr as max.

For a 270 gr bullet, they list 61.2 gr min and 73.4 gr as max.

For a 220-225 gr bullet, they list 64.4 gr min and 72.8 gr as max.

I am currently using AA 4064 in a couple of cartridges. Although I have not had occasion to compare it directly to IMR 4064, the loads I am using are just a tad heavier than most sources would indicate for the IMR version.

I like the "short cut" nature of the AA 4064 grains. It meters much better than the IMR 4064 I used many years ago (although the current version of IMR 4064 may have a different kernal -- I'm not certain.)

From what data I have and from the manuals it seems "SAFE" to say that you can load A-XMR 4064 with 3 to 4% more powder than you can with IMR 4064. From all indications this seems conservative. roger