IMR4320 temperature sensitive and loads for 22-250?

27 March 2002, 10:59

<Mudruck>

Im thinking about working up some loads for the 22-250 using IMR 4320 and 55grn VMax or Berger 55grn MEF bullets. Is IMR4320 known to be temperature sensitive? Has anyone had any luck using 4320 in 22-250? Im not looking for an extremely fast load, somewhere around 3300fps or so. I use 4320 in other cals I load for and if I can get away with using it in the 22-250 thats one less jug I have to keep up with.

Thanks
Mudruck

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"Our Country won't go on forever, if we stay soft as we are now. There won't be any America - because some foreign soldiery will invade us and take our women and breed a hardier race!" - CHESTY PULLER, USMC
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Utah Varminters Association http://www.armscenter.com/uva

27 March 2002, 11:22

R-WEST

mud -

IMR lists a max of 36 Grains 4320 with 55 grain bullet, for 3540 FPS. I'd imagine you'll find a good load in the 34 or 35 grain range, much as you would for 4064 or 4895. 4320 is no more or less temp sensitive than other IMR powders, so, you should be able to find a good load. I've only used 4320 in the 22-250 with some 70 grain Speers a long time ago. If memory serves, it worked pretty well.

You're doing the right thing by simplifying your powder inventory. I wish I could do that.

R-WEST

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"the spotlight of truth will cause the cockroaches of deceit to run for cover every time"
Rush Limbaugh

28 March 2002, 01:59

R Flowers

Mudruck: Back more years ago than I want to admit, my dad and I shot LOTS of IMR 4320 in our 22-250 rifles. It was considered to be THE powder to use back when the cartridge was a wildcat, and even when it first became a standard cartridge.

Believe me, with limited data available and everyone wanting to make a 220 Swift out of their new go getter, we used some pretty hot loads.

We never saw any unexpected temperature sensitivity with that powder. Like I said, we shot some hot loads and found we might need to back of when we tried them in the summer, it was all a learning experince, it seems.

I used IMR 4320 all the time till it was hard to get for a time. (IMR was apparently having trouble with production then.) I tried a bunch of other stuff and settled on H 4895. I have tried most every thing available and keep coming back to H 4895.

One phenomenon that I noticed with IMR 4320 when I finally got a chronograph was that even if a rifle shot really good groups with it, the shot to shot variation on the chronograph was often pretty huge. It was sort of strange, IMR 4320 would have an extreme spread that was MUCH worse than other powders, but would still shoot tiny little groups in some rifles. Go figure.

Hope this helps, R Flowers

28 March 2002, 05:18

<Mudruck>

Great, Thanks for the info...

Ill work up some loads and see how it goes. I just didnt want to have to change loads when the season warms up or cools down. Im not super concerned about speed or spreads in velocity as much as about MOA accuracy or less, which I know the 12FV will do from the rounds I fired while breaking in the barrel. I donï¿½t think the coyote is going to really mind if the round I hit him with was going 100fps slower then the last one to come out of the barrel.

Mudruck