This is about the load I worked up for my rifle (see "One a little different from Germany" in the Single Shot Rifles thread) and the effect of changing powder lots. Way back when I first got this rifle there was very limited choice of bullets and also not much loading data available. Norma made ammo with 232 and 286 grain bullets and had loading data for their powders. Of course this is way before Al Gore invented the internet so there was no easy way of finding out who might have some. Fortunately there was a guy in my local club who had a basement full of all kinds of brass and he was able to come up with some and he also had a few factory loads I could use to compare. I found out that Colorado Custom Bullets (now Barnes) offered some 9.3s in 250 grains but at about that time Speer came out with a 250 grainer also (the latest ones are 270 grains.)  My trusty Powley Computer (anyone remember those charts?) when fed all the data on barrel length, case capacity, bullet diameter and sectional density came up with duPont 4320 as the best powder for it. I shot the factory loads so I could compare and immediately decided that Norma 286 grain ones were too hot for my taste (and rough on the shoulder.) So I backed off some on the load suggested by the Powley and loaded single rounds at 1 grain increments and for a comparison loaded some with 3031 and 4064. From these I was able to determine what I felt were loads that would be a little below factory level. Then I tried some 3 shot groups with several loads with each of these powders. The 3031 was quickly eliminated but one of the loads, 56 grains of 4320, put the 3 shots into 15/16 inch at 100. The 4064 was just under 2 inches. Further testing with half grain increments confirmed the 56 grains of 4320. All was good, almost. I had finished off that can of 4320. No sweat, new can. Whoa! What happened? I had to start all over again with the new can and ended up with 54.5 grains and had to change the seating depth to get back to the accuracy level of the old 56 grains. I wrote duPont expressing my displeasure with the situation (snail mail!) and received a reply that unless they were from the exact same lot there were no guarantees. Having arrived at a load that satisfied me at that point and having most of the new can of 4320 available along with a good supply of the 250 grain Speers I haven't tried to better it. With the powders that are available now, the 270 grain Speers, and new data maybe I'll try again.

Thanks, Arnie, I'll get some when I see it and give it a try.

Dales, thanks for the info. I see that Nosler says 57.5 grains of Varget is max for their 250 and as my rifle is over 100 years old I don't think I want to push it as far as I would with a Ruger;-) The 270 Speer load looks doable however.

Sorry, Larry, sure don't.

Well, here we are only a couple of weeks shy of 2 years since I started this thread and I finally got out to the range with the rifle. There were nice conditions and I had 36 rounds to fire with new Hornady brass, 250 grain Speer bullets, and Vihtavuori 135, Varget, and H380 powders to test plus 4 rounds loaded with my long ago derived load of 4320 for foulers and sighters. Why bother since I had a good load? It was a long time ago and with what would now probably be considered a "legacy" powder - big stick 4320. So off with 2 new and one older powder. I like to shoot 10 round strings but the 9.3x74R will never be considered a benchrest cartridge and I figured 40 rounds from the bench with the relatively light rifle would do my shoulder in so 4 rounds with each load - one to get on the target and 3 for group. That's probably enough for a hunting rifle as the barrel gets hot fast and one shot is enough anyway, right? Using data from the Nosler Manual (there was no data available back when I worked up the 4320 load) I had for the Vihtavuori 135 50.5, 51.5, and 52.5 grains; for the Varget 53.5, 54.5, and 55.5 grains; and for the H380 58.5, 59.5. and 60.5 grains. The book velocity on these varied from 2280 to 2366 fps for the V135, 2312 to 2396 fps for the Varget, and 2405 to 2474 fps for the H380. My shoulder seemed to indicate that all of these might be a tad umper than my 4320 load. I put targets out at 200 yards for maximum effect but when I fired the first 4320 there was no hole. Then I remembered that sometime in the last 25 years of so I had switched scopes and hadn't resighted so I fired the second one at 100 and found the correction I needed to make and fired the last 2 4320s at 200. Results later. V135 was next and the first shot was not on the target so the targets came in to 100 and I shot the rest there so I wouldn't be wasting them. I shot 4 from the 9.3 and then racked it and shot 10 from my 44-40 to give the 9.3 barrel a chance to cool, then 4, then 10, then it was cease fire time to mark and change targets. Results: V135 groups were 1.7, 1.08, and 1.22 inches respectively; Varget .95, .70, and 1.35 respectively; H380 1.5, 1.18, and 1.05 respectively. Not bad for a 100 year old rifle. Oh, and the 2 I fired at 200 yards with the 4320 load? They were 1.04 inches apart! Looks like I have 4 loads to give a more definitive trial next time.