IMR4350 and British 303???

Ontariooutdoorsman

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Years ago I loaded some British 303 with IMR4350 as it was listed in the Hornady 4 edition book as a British 303 load. Loved IMR4350 as I could also use it for .30 caliber rifles and one powder did my big guns.
Getting back into reloading I've noticed no new loading manuals show British 303 loaded with IMR4350. What gives......anyone have any reasons why?
 
Years ago I loaded some British 303 with IMR4350 as it was listed in the Hornady 4 edition book as a British 303 load. Loved IMR4350 as I could also use it for .30 caliber rifles and one powder did my big guns.
Getting back into reloading I've noticed no new loading manuals show British 303 loaded with IMR4350. What gives......anyone have any reasons why?

That's a really good question. I looked it up in my manuals - old vs new - and you're right! The Hodgdon load data website does list H4350 for heavier bullets, but not the IMR. Most loads listed for .303 are a bit faster powders. Nevertheless, I have a No. 1 Mk. 3 that only shoots well with 45 grains of H4350 in a 150 grain Hornady...2500 + fps. Go figure. It's also the best accuracy in my: 375 H&H, SVT-40, and .243 (3,700 fps, 60 grain v-max varmint load).

Thanks for bringing that up!
 
It has been my experience that IMR4350 is slightly faster than H4350. Reduce the loads shown for H4350 by 5% and you should be OK.
 
That's a really good question. I looked it up in my manuals - old vs new - and you're right! The Hodgdon load data website does list H4350 for heavier bullets, but not the IMR. Most loads listed for .303 are a bit faster powders. Nevertheless, I have a No. 1 Mk. 3 that only shoots well with 45 grains of H4350 in a 150 grain Hornady...2500 + fps. Go figure. It's also the best accuracy in my: 375 H&H, SVT-40, and .243 (3,700 fps, 60 grain v-max varmint load).

Thanks for bringing that up!

What is the main difference between IMR4350 and H4350
 
I think that what has happened is that there are a lot more powders available now, and more powders better suited to 303, so 4350 got pushed off the page. It is still on the list, but too far down.

I think it is a good powder choice for the 180 and 215 gr bullets.
 
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