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Location: Eatonville, Wa
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IMR4350 VS H4350

So, I have a perfect load worked up for a 7mm wby mag, with a 140 grn nosler partition. I was using the IMR 4350 but, I just got a steal on a bunch of H4350. When I looked in the nosler manual, they dont list the H4350 as an option for that bullet weight. In the 150 grain it is an option with max being 5 grains below the Imr. Anyone know how close these powders are? Im not planning on starting out at max by any means but I have to think they are somewhat close.

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IMR4350 VS H4350

I didn't find it for the 140 gr but I did for the 160 and 175 gr and the starting load and ending load both times had the H4350 at 1 gr more than IMR4350 so if you start at your starting load for IMR 4350 and work up from there, you should be good to go.

exbiologist's picture
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IMR4350 VS H4350

In none of my manuals do they list H4350 and IMR 4350 as using the same charge. The two powders are different, treat them as such.

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IMR4350 VS H4350
exbiologist wrote:
In none of my manuals do they list H4350 and IMR 4350 as using the same charge. The two powders are different, treat them as such.

As you see from my above post, both powders are different. H4350 uses slightly more grains of powder(1 gr.) than IMR4350 using identical bullets and components. As stated, if you start at the lower level and safely work it up from there, it will work just fine.

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IMR4350 VS H4350

I like IMR best but have used H4350. I just started with a min chg and worked up a pressure load first. They are very close to the same burn rate.

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IMR4350 VS H4350
exbiologist wrote:
In none of my manuals do they list H4350 and IMR 4350 as using the same charge. The two powders are different, treat them as such.

I dont think anyone here thought they were the same. They are close but not the same. What I am wondering is if anyone here has seen anything from the manufacturer on using this powder with that bullet. As it is right now I will probably just do like chester suggested.

Don Fischer's picture
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IMR4350 VS H4350

From Hodgdon manual #24

140gr bullets

Start 65.0 @ 2984 ----- max 69.0 @ 3222

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IMR4350 VS H4350

Thanks don. I will give that a shot. I heard somewhere that both powders used to be the same based on a military powder and one company had a surplus of it and sold it to the other. Anyone hear of that?

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IMR4350 VS H4350

Hodgdon got its start selling surplus military powder. I'm thinking it was either 4831 or 4895, can't really remember. We used ti buy that stuff in bulk in paper bags!

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IMR4350 VS H4350

They are similar, but not the same burn rate powers and not interchangeable with the same charge weight.

IMR4350 is a slightly faster burning powder than the Hogdon H4350. Being that the H4350 is slower burning I don't think you would be in any danger using the same grains of H4350 as you did for IMR4350, BUT I would for safety sake start low and work your way back up slowly. You may find that you need a grain more of Hodgdon to get the same velocity as you had with the IMR. Still, it's wise to start low and work up a charge slowly.

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Location: Scottsdale, Arizona
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IMR4350 VS H4350

They are definitely not the same powder. Having said that, when I find a "perfect load" I never change a thing. That means even when I find a good deal on a component. Every component has a specific function and the magic combination is what makes this a perfect load. That is not to say there is no other load that can accomplish the same results. I guess I am too much of a perfectionist. I work hard to find a load that works perfect in a given rifle and then I load a few hundred rounds exactly to spec. I will even insist on the same lot number of the powder. Then at the moment of truth in the field, I have full confidence of where the round will land. Is all of this necessary? Absolutely not. Will I keep doing it? Yes. The over riding consideration is safety. Please do not experiment without proper data. The manufacture will help you if you need it. Even with published data, I have been known to use the bullet puller when I reach the first sign of too much pressure. The word "probably" has no place in hand loading.

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