IMR 4350 or H 4350 for a swift A frame out of a 375 H&H

[Rburns28]

Anybody got any advice on which powder would be a better choice? Will be working up a load for cape buffalo and plains game. From what i've found looks like the H4350 has a little faster velocity over all. Not really concerned with speed more concerned with better groups and being accurate. I will be using 300 gr bullets. Thanks for any input, Randy

 

[Green Chile]

H4350 gets faster velocities. As to grouping, there is no way to know without running some groups through your rifle. Every gun is a little unique. Most likely result is you will find groups that are better than can be held in field positions.

 

[Yukontom]

Anybody got any advice on which powder would be a better choice? Will be working up a load for cape buffalo and plains game. From what i've found looks like the H4350 has a little faster velocity over all. Not really concerned with speed more concerned with better groups and being accurate. I will be using 300 gr bullets. Thanks for any input, Randy

They are very much alike so you will probably get similar results. The H4350 is supposed to have a slightly slower burn rate so maybe a bit more powder but you don't know until you try. I do use way more Hodgden powders over IMR including H4350. Recently it also depends on what you can get. Lots of H4350 out there right now.

 

[Ontario Hunter]

I believe Hodgon owns IMR now?

For my 404J I use Accurate 4350 (A4350) which also I believe is now under the Hodgon umbrella. It gives very good groups with 80 gr pushing 400 gr Barnes bullets. I need to chronograph that load but I suspect it's around 2200 fps. At fifty yards bullets are landing on top of each other (very fat bullets). At 100 yards it shoots about MOA, maybe a bit more. But I'm 72 and shooting on sticks.

Accurate powder was all that was available when I finished building the gun in June 2023. Kinda hard to find load data but from what I've seen, it seems all three powders perform very similar. One does a bit better in extreme temperature environments (IMR?).

 

[Wyatt Smith]

Either one is fine.

 

[Fryeguy]

One thing to look at as well is the temp stability. I think H has it, IMR doesn’t. It probably doesn’t matter at all unless you are running upper end pressures and then change to a much hotter atmosphere, but it’s something to look into. Having said that, I found better accuracy with IMR in my last 375 and 270 aframes. I also go for accuracy not necessarily speed. I try to find the balance between both, I don’t want to be shooting too slow.

 

[uplander01]

Agree with the previous post, I think H4350 will have more temp stability, at least that's what they preach about extreme powders.

 

[WyoBull]

Either one will be fine, I just have never used it for the 375 H&H. A friend of mine who used to be one of my college professors back in the day turned me onto his 375 H&H load. He uses RL15. I used it when I worked up a load for my rifle and it shot so well I never even looked at anything else.
Good luck with your load work up and post some target pics when you get it dialed in.

 

[uplander01]

If you have access to good old' IMR 4320, I've had fantastic luck with that powder in 375's. Lowest standard deviation of any powder I've handloaded for the 375.

 

[C.W. Richter]

RL15 is best in 375. CCI 250s best SD. LOVE many IMRs, but this one works (several RLs work best in larger for caliber cases.) Consider the 350s if DG is involved. Swift SP/Barnes Banded S or TSX for all

 

[PHOENIX PHIL]

I don't know how H4350 does in my M70 375HH with 300gr projectiles. I started with IMR4350 and never found a reason to try another since the accuracy was outstanding with whatever 300gr bullet I topped the round with.

Your rifle may prefer H4350 or even RL15 (if you can find it) as suggested above. Only one way to find out. If you want to try a faster powder, Varget is usually considered the twin brother of RL15.

 

[F. Vaccaro]

I read an article that suggested try a powder & if it didn’t group well with a load that’s not maximum, try a different powder with a similar burn rating. He said that rifles often show a marked preference for one powder. Try one with a safe load & if it doesn’t group well try the other powder. He said that often gets quicker results than trying many charges with the same powder & often saves components.
Wish I could recall where I read that.

 

[sgt_zim]

To-may-toe/to-mah-to.

Whichever gives you ~1 MOA at 2500 fps. No harm in trying them both of you have them. You can get 300 gr TSX for ~$1 apiece from several places. Do a 10 or 15 shot ladder with each, see what you get.

In the Big Game Hunting podcast, Kevin Robertson says 2400 fps is about ideal for 375 and 9.3x62. Do with that what you will.

If you have any Varget, BLC(2), 2000MR, Big Game, or RL15, those are worth a try as well.

 

[ftrovato]

I've always been a believer of reading the manual associated with the specific bullets when possible.

In this case Swift has a comprehensive manual.

 

[Luvthunt]

IMR 4350 is a compressed load in my 375 loadings and even tho I crimp I found the 300 gr bullets creep a bit. Be sure to check OAL and your mag box length.

 

[Berettaco]

I use 77Gr of H4350 in my sako 375 and it averages 2,475FPS and sub MOA. I would not start with that load, maybe 74-75 and work up

 

[457121]

RL15 is best in 375.

My .375 shoots 4"-5" groups using RL15 or IMR 4064 no matter what jacketed bullet I use. IMR 4350 or H4350 will clover leaf to the point of holes touching at 100 yards with any bullet brand I've tried. Also IMR 4350 has proven very temp stable in the .375 varying less than 20 fps from 20* to 90* F. The now retired Rob Reiber from Hodgdon says that powder compression and primer type in certain cartridges can make some combinations temp stable. John Barsness wrote an article about powder temp stability for Handloader magazine and found that the .375/IMR 4350 load worked as well as any temp stable powder.

 

[WyoBull]

My .375 shoots 4"-5" groups using RL15 or IMR 4064 no matter what jacketed bullet I use. IMR 4350 or H4350 will clover leaf to the point of holes touching at 100 yards with any bullet brand I've tried. Also IMR 4350 has proven very temp stable in the .375 varying less than 20 fps from 20* to 90* F. The now retired Rob Reiber from Hodgdon says that powder compression and primer type in certain cartridges can make some combinations temp stable. John Barsness wrote an article about powder temp stability for Handloader magazine and found that the .375/IMR 4350 load worked as well as any temp stable powder.

This just goes to show how every rifle is not the same in what it likes.
My Winchester model 70 375 H&H loves RL15 and will cloverleaf 3 shots at 100 yards as evidenced by the photo below. I have never shot anything else out of it because this load shot so well for me. The second photo is off sticks at 50 yards.