Yes this is resurrecting an old thread, but.......
I finally have gotten around to some serious load development for my AHR Pre-64 Win M70 that Wayne Jacobson (American Hunting Rifles) built for me in the cartridge 9.3x62 (Mauser). I had previously been busy reloading and shooting other rifles for various other hunts, and had just not taken the time to get to know the rifle. I can happily report that it has exceeded my expectations thus far, and I am in love...
In considering various bullets that I could possibly utilize, I settled on the 9.3 mm (286 grain) Nosler Partition because of the application I intended on using it for. I wanted a bullet that would be suitable for both a wide variety of African plains game and leopard. The rifle is topped with a Leica ER5i 2.5 - 10x42 scope with the illuminated 4a reticle. I haven't taken any game with the 9.3 mm Partition, but have plenty of experience with it in other calibers/cartridges, and it has performed exactly as John Nosler intended back in 1947. It will consistently give acceptable to very good accuracy, and solid performance with around 65% weight retention. The big reason I liked the Partition versus other premium bullets, is that I wanted a bullet that would rapidly expand when used on cats. The front portion of the Partition does exactly that, but keeps the rear 2/3 of the shank to allow for acceptable penetration. Not the kind of penetration one would expect form a Barnes TSX, Swift A-frame, North Fork SS, etc., but still very acceptable. Couple that with a lot of history in Africa and positive reports of the Partition's performance there, and I felt like it would be a good candidate. In summary, just a good all-around premium bullet.
My goal was to get a accurate bullet to travel in the 2400 - 2500 fps speed range. After researching a lot of different powder options, I came upon an article by a very respectable gun writer named John Barsness. He loves the 9.3x62 cartridge, and writes very fondly of it. His go-to powder for it was Ramshot BigGame. It's a double based, spherical powder (as are all Ramshot rifle powders) that is designed for the 30-06 family of cartridges, and so with his recommendations in hand, I developed a load ladder based on the Optimal Charge Weight method.
A few weeks ago, I took the loaded rounds and my rifle out to our 100 yard range, as I figured this rifle would be used as a 200 yards and in rifle. As I went through the charge progression looking for pressure signs, it became readily apparent that this rifle was going to be a shooter. It wanted to work hard to produce good groups with any charge weight I threw at it. Not once did I have any indication of increased pressure. I finally settled on the following:
Cartridge: 9.3x62 (Mauser)
Case: Norma (fully prepped)
Bullet: 9.3 mm Nosler Partition (286 grain)
Primer: Winchester Large Rifle
Powder: Ramshot BigGame
Charge Weight: 66.0 grains (slight compression)
COAL: 3.37 inches
Crimped: Yes (Lee Factory Crimp Die)
Avg. Velocity: 2510 fps (M.E. 4001 ft/lbs)
Extreme Spread: 17 fps
Standard Deviation: 7.4
The final target at the settled on charge weight of 66.0 grains of Ramshot BigGame is as follows:
The round in the upper left corner (at the extreme edge of the group) was a called "flyer", as I jerked the trigger when another shooter shot his rifle as I was pressing my trigger. From edge to edge, the 3-shot group (minus the flyer) measured around 0.85 inches. Even with the flyer included, it measured at slightly over an inch. Needless to say I am very happy that I could get this rifle to deliver this kind of accuracy and with 4000 ft/lbs of energy at the muzzle to boot. In the OCW method, after a powder charge is settled on, the next variable to play with is seating depth, and often one can get the groups to tighten somewhat. But after thinking about this rifle, and what it's intended purpose is, I didn't think it necessary. If it was a long range sheep rifle, of course, but not for this rifle......
Pretty good for a cartridge designed in 1905.....
As a side note, I took the scope off and shot the rifle with some fouling rounds that were slightly below the charge weight I settled on. At 100 yds, the bullets were consistently impacting a little low and left of my POA, but still way within acceptable limits of what irons should do. With the full house loads, I bet the bullets would strike close to where the scope is printing the bullets at. It would be a dead animal for sure.
After settling on this load for my rifle, I went ahead and loaded up 100 rounds to do some shooting off sticks with.....
Anyway, many months ago, several posters had requested an update once I did some shooting with the rifle. Needless to say, I am very pleased with the results. Furthermore, I think the results are testament to what kind rifle Wayne Jacobson builds at AHR. Not only do they look damn good, but they shoot damn fine as well. I've said that about all the rifles he's built for me however....
*** As a disclaimer, I published my load data to show what worked in MY rifle. This is a "hot" load, but I never once noticed any pressure signs, and feel that I could have pushed it a little more but why risk it.....Incidentally, this was the charge weight Mr. Barsness settled on as well in his article. Use the above data at your own risk.
