Forgive me if this has been covered but;

[BCIII]

Why is H4350 so heavily favored over IMR 4350 for .260? They appear in consecutive order in burn rate.

Again, I'm sorry if this has been discussed. I did a search before asking, but just keep coming up with H4350.
I have an opportunity to get a decent amount of IMR. Just want to know if it is a good or bad choice.

 

[BobinNC]

IMR-4350 is not a bad choice, when H4350 is unavailable. But IMR 4350, like all IMR powders is more temp sensitive than Hodgdon's line of Extreme Powders, that H4350 is part of.

So the issue is not burn rate nor accuracy, but temperature stability, and this is what makes H4350 more desirable than IMR 4350.

 

[Desert Fox]

I can use either one in my 6.5-47 and both were just as accurate. As a matter of fact I bought an 8 lb IMR since I have a hard time finding the Hodgdon. I'm down to about 4 lbs so once I run out and can't find any, I will start using IMR.

 

[jakelly]

Has anyone got some good data on H4350 vs IMR 4350 temperature sensitivity? A link to some tests would be great.

 

[Skigolfmike]

Hodgdon lists 42.0 gr and 2677 fps for the max load and velocity for H4350 and 43.0 and 2715 for IMR4350 with 140s for the 260. The reality is most of the 260s I know of with 26" barrels shoot about 2850 with the 140s and H4350 and are pushing 43.5gr. Hodgdon says the pressure is slightly lower at the max loads for IMR4350.

What's interesting is the 6.5 CM load data. It shows the max load for H4350 as 40.0 with a velocity of 2660 for 140s, but Hornaday 140 Amax is loaded to 41.5 and, in reality, 42.5 if you pull the bullet and dump the powder. I run 42.6 in my loads. Also interesting is it show 41 gr of IMR4350 being the max load with a velocity of 2607 (slower while the max load for 260 is faster, hmm) and the max load for IMR4350 has higher pressure.

Do a few searches and I think you'll find the IMR4350 probably shoots a little slower than H4350. YMMV, you'll just have to experiment.

 

[BCIII]

Thanks for the feedback.

 

[Asperly Aimless]

Because everybody else is using it!!!

Seriously I have no idea. Yes the H series is less temperature sensitive, but if you keep good notes, any powder is fine.

Just don't sneak up on max, or over max, charge of the "non temp sensitive" powders in the winter time. Sneak up on the max load in the summer. Or make summer/winter loads.

Many ways to skin the cat here, and I won't limit my shooting because my favorite brand of fairy dust isn't available.