Reloading question

[am44mag]

I'm looking into some loads for a 9.3x57 and I'm wanting to be able to use IMR 4320 as that is my favorite rifle powder and works in almost every rifle I own with excellent results. I FINALLY found some data for that round and that powder. It was originally posted on an Italian gun forum and then reposted on Gunboards. Not an ideal source for reload data, but it's all I got.

232 grs IMR-4320 44,0 (min.) - 49,5 (MAX)
258 grs IMR-4320 39,0 (min.) - 44,5 (MAX)

The bullets I'm wanting to use are 270gr. Given that there is only a 12gr difference, would I be safe to assume that a starting load of 39.0gr is safe to use?

[sharps4590]

I assume the 270 gr. bullet is cast and probably gas checked? If so, that's the same approximate weight I shoot in my 9.3 X 57.

I looked up the 358 Win. in Lyman's 47th. They show a starting load of 39 grs. of IMR-4320 with a 275 gr. jacketed bullet. Velocity is listed at 1858 fps but they show no pressure. The max they show is 43 grs. of the same powder with a velocity of 2074 fps and again no pressure. It almost looks as if the Italian site just took the Lyman 358 WCF data and perhaps pressure tested it in a 9.3 X 57....maybe.

The way I would approach that is the 9.3 X 57 is both longer, by 6mm and, the bore/groove diameter is bigger as well. The Lyman data uses a jacketed bullet and, assuming again that yours is cast, all those factors are going to decrease pressure. If it were me, in a good bolt rifle, I'd consider that a safe starting load in a 9.3 X 57 and I would expect lower velocities than listed for the 358, for obvious reasons. However, that is one man's opinion and not a recommendation. You're on your own and you have to make that decision....

'Course, there's always known and proven IMR and H 4895 data and IMR-4064. It's been a while since I worked up the loads for mine and unfortunately I've forgotten where I got my data. Ahhh...wait a minute. Lemme go check my bench. I still have it!!! Evidently in Handloader #125 there was a pile of data for the 9.3 X 57 and somehow I ended up with it. It's all jacketed data and I just looked through it, no 4320 data. It might be worth looking it up just for the sake of having it, unless you already have it.

[am44mag]

The 270gr bullet is a jacketed Speer, but I will be casting 270-285gr boolits for it shortly. Sounds like the 39 gr starting load was pretty much right on the money. I found a copy of that magazine (along with #126-#130) for $11 shipped, so I ordered it. Isn't ebay a wonderful thing?

Thanks for the info!

[Texas by God]

Growing up with a 22-250, I share your fondness for IMR 4320. I'm also loving it with cast in the 30-30 Win. I would use the .358 data without hesitation.

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[sharps4590]

Glad ya found those issues!! Yes sir, sometimes e-bay is a great place to find things. Evidently I got my 9.3 data sheets off line somewhere as they're ran off on my printer. Probably a link someone provided. Win 748 and IMR-3031 were other powders frequently tried in the data and appeared to provide good results. I've not tried either.

[am44mag]

Growing up with a 22-250, I share your fondness for IMR 4320. I'm also loving it with cast in the 30-30 Win. I would use the .358 data without hesitation.

Sent from my SAMSUNG-SM-G930A using Tapatalk

It was the first powder I ever used, and it's my go to powder for most rifle calibers. I load everything from .223 to 30-06 with it.

Glad ya found those issues!! Yes sir, sometimes e-bay is a great place to find things. Evidently I got my 9.3 data sheets off line somewhere as they're ran off on my printer. Probably a link someone provided. Win 748 and IMR-3031 were other powders frequently tried in the data and appeared to provide good results. I've not tried either.

H4895 and RE 15 seem to be some of the most popular ones I could find online.