I had worked up a beautiful hunting load for my "99" in .300 Savage, 41.5 grains of IMR4895 that shot tiny 3-shot groups, considerably less than a minute of angle.
Then Hodgdon bought out IMR and the next pound of IMR4895 came in a Hodgdon "bottle" rather than the familiar IMR rectangle metal can. When I loaded that powder... suddenly, the M.V. dropped 80 fps compared to the muzzle velocities I had been getting. To insure it wasn't just the conditions (temperature), I checked a "test" round from the former IMR made powder can. And sure enough, my chronongraph gave me 2627 fps on a cool (35�) day for the "old" IMR4895 and on the SAME day, it gave me 2547 fps using the "new" Hodgdon-made IMR4895...
80 fps LESS!!!On a hot (85�) day, the "old" IMR4895 yielded 2685 fps... an average of 20 shots. So temperature really made a differnce in muzzle velocty with IMR4895, but the "new" IMR4895 obviously yielded a MUCH lower muzzle velocity, so I went looking for a new powder to launch my hunting bullets (150 grain Nosler Ballistic Tip, boat-tailed bullet).
And so, two years ago, I worked up my current "hunting load" which is now 40.8 grains of Hodgdon H4895 powder which is one of Hodgdon's "EXTREME" powders and is claimed by Hodgon NOT to be effected by outside air temperature... and so, it should yield 2635 fps whether it's 85� or -10�.
On a coolish day (34�), 40.8 grains of H4895 (one tenth of a grain less than the listed MAXIMUM LOAD of 40.9 grains) behind the same 150 grain Nosler Ballistic Tip bullet sparked by the same standard Winchester primers in the same "accurized" Winchester cases yielded an average M.V. of 2635 fps with an amazing velocity deviation of just � 3 fps (+1 fps/-2 fps) and gave less than a minute of angle accuracy out of the 24-inch barrel of my 1953 Model 99 EG.
The above are the readings I got from actual shooting. I don't know if Hodgdon changed the IMR4895 or not (they claimed "not" in their email answer to my email inquiry) and IMR4895 is supposedly still made in the same Canadian factory it has been made in for many years when the former IMR owners controlled IMR powder manufacturing.
Why the "difference"? I dunno... but it IS "different" than it use to be. Loaded with IMR powder purchased in 1995, the chronographed muzzle velocity of 41.5 grains of IMR4895 using the same components as above yielded an average muzzle velocity of 2708 fps. The next can (2002) of IMR4895 was slower (2695 fps) and the next can (2004) even slower by a slight margin.
The next can (2006) was down to 2685 fps on an 85� day and, finally, the Hodgdon BOTTLE of IMR4895 dropped all the way down to 2547 fps!!! You
TELL me "
wot happened" 'cause I sure the heck don't know !~!~!
And so, in 2006, I went looking for another powder for my hunting loads in my "99". I tried 40.0 grains of IMR3031 which yielded 2665 fps, but always with one "flier" outta 3 shots. Then I tried H4895 and found my "new" hunting load.
A well-known gun writer who posts on this site (24-Hour Campfire) claims it was "just a difference in the production lot of IMR4895", but I purchased a 2nd. "bottle" of IMR4895 and it yielded just about the
SAME MISERABLE muzzle velocity (2551 fps). And so, I concluded it WASN'T "the lot", but rather a change in the formulation of IMR4895.
You might try my "hunting load" (40.8 grains of H4895)... it works for me!
Jus' my 2�...
Strength & Honor...
Ron T.