H4350 and IMR4350?

[stinnett1981]

So I accidentally bought 6 pounds of IMR4350. I meant to buy H4350. I currently have a 260AI being built and have a unchanged of 123g Lapua Scenars. I planned on using H4350 since I already 2 pounds of it. Are these 2 powders the same? Hodgens load data website shows a big difference on max velocity between the 2. The IMR4350 is 100fps slower with 120 and 125 grain bullets. Need some help please!

 

[ShootDots]

They are NOT the same powders. IMR 4350 is slightly faster burning. It has larger kernels which make the load density less than the H-version.. You CAN NOT interchange load data.. They are as different has IMR 4831 and H4831..

 

[Romulus]

Not interchangeable. IMR 4350 is a bit faster than H4350. I considered shooting it during the depths of the powder shortage in my 260 AI but i found an 8 of H4350

 

[2506]

As has been said they are not the same but don't sale the IMR short. You will not know what velocity YOU will get with it out of YOUR rifle. Work up loads with both powders to see what you can get. You may be surprised.

 

[mikegaiz]

I think you will find that IMR-4064 will give you better groups in that case.

 

[Elwood]

Would IMR-4831 be a close match to H4350? and is IMR-4350 significantly faster than H4350? I'm looking for a replacement powder for a 284W when my H4350 runs out, and as H4831SC is unobtainable I will be looking towards IMR.

Usual rules of work up will apply.

 

[Brians356]

Would IMR-4831 be a close match to H4350?

No.

And is IMR-4350 significantly faster than H4350?

Um, how much is "significantly"? They are intended to be very close, so I'd have to say "no", however they are not interchangeable (as has been pointed out) and there may be a powder or two that falls between them in certain burn rate charts, but Hodgdon lists them at positions 114 and 115, i.e. two peas in the same pod:

http://www.hodgdon.com/burn-rate.html

Oddly, Vihtavouri show IMR 4350 a step slower than H4350 in their two-dimensional presentation. That should tell you how imprecise this science is:

http://www.lapua.com/upload/reloading/reloadingburningratechart2011.pdf


Brian

 

[racesnake]

In my 6XC I get better accuracy and more velocity with IMR4350 as compared with H4350.

 

[Raythemanroe]

I like IMR4350, has worked good for me...

 

[stinnett1981]

I guess I will give it a try. Now I have a excuse to buy a chronograph. I normally get my velocity from JBM ballistic calculator from writing down my bullet drop in 50 yard increments from 100 yards to 1200 yards. It takes a while, but it's fun. Anyone else do it that way too?

 

[SDDasher]

In my 6XC I get better accuracy and more velocity with IMR4350 as compared with H4350.

++1 In my 6x47 I am consistently getting lower SD's & ES's using the IMR 4350 than the H 4350. I chrono all practice/load testing rounds.

 

[Brians356]

I guess I will give it a try. Now I have a excuse to buy a chronograph. I normally get my velocity from JBM ballistic calculator from writing down my bullet drop in 50 yard increments from 100 yards to 1200 yards. It takes a while, but it's fun. Anyone else do it that way too?

That assumes you can measure bullet drop accurately, ditto atmospheric variable. Throw in dispersion (unless you are shooting one hole groups out to 200, and tight regular groups at distance, with the group centers obvious) any such calculations will be pretty inaccurate. But if you have the time and plenty of ammo, it seems like a fun exercise.

Ever checked your calculated velocities against a chronograph?

Brian

 

[ShootDots]

Would IMR-4831 be a close match to H4350? and is IMR-4350 significantly faster than H4350? I'm looking for a replacement powder for a 284W when my H4350 runs out, and as H4831SC is unobtainable I will be looking towards IMR.

Usual rules of work up will apply.

Go to IMR 7828, you may very well like it better than ANY OTHER powder you have tried... If you choose the SSC "version" over the "regular" version, you may have to back off 1-1.5grs.. Somewhere betwixt 54.0 and 56.0grs with a 180 will make you wonder why you did not try it first.. If you are shooting 140class hunting bullets, the IMR 4831 will work GREAT!...

 

[Grimstod]

What about 30-06. Would it be better for that cal with a 28in barrel?

 

[p-man]

Lord knows that is the most recommended powder for 30-06, 280, & 270 - would be surprised if you can't move that for what you paid for it

 

[mikecr]

I would try the IMR.
My lot of it is SLOWER than H4350, and my load workup favored the IMR in 26wssm Imp/28" barrel/139Laps.

 

[Elwood]

Would IMR-4831 be a close match to H4350? and is IMR-4350 significantly faster than H4350? I'm looking for a replacement powder for a 284W when my H4350 runs out, and as H4831SC is unobtainable I will be looking towards IMR.

Usual rules of work up will apply.

Go to IMR 7828, you may very well like it better than ANY OTHER powder you have tried... If you choose the SSC "version" over the "regular" version, you may have to back off 1-1.5grs.. Somewhere betwixt 54.0 and 56.0grs with a 180 will make you wonder why you did not try it first.. If you are shooting 140class hunting bullets, the IMR 4831 will work GREAT!...

Benjamin, many thanks for the heads up. I have a horrible feeling that is one of the IMR powders out of stock in the UK!! I will inquire.

 

[Brians356]

I would try the IMR.
My lot of it is SLOWER than H4350, and my load workup favored the IMR in 26wssm Imp/28" barrel/139Laps.

How the heck do you improve a WSSM case? I suppose steepen the shoulder. Body already has only ~0.01" taper which is typical for Ackleys.

Brian

 

[mikecr]

I took it up to 35deg shoulders. It currently has the same capacity as a 260AI, which I feel is perfect in 26cal.
My next chamber will take it further to 45deg only for experiment.

 

[Brians356]

I took it up to 35deg shoulders. It currently has the same capacity as a 260AI, which I feel is perfect in 26cal.
My next chamber will take it further to 45deg only for experiment.

My feeling is there's a reason Ackley stopped at 40 deg. - probably well past the point of diminishing returns. But there's little joy in pure plagiarism, what?

Brian