Home Forums Reloading Big Game Rifles IMR 4350 vs H4350

Any real diff between IMR 4350 and H4350? You can answer the question now, or read on, your choice.

Here�s the deal, I�m about to go on my initial shopping trip for powder and primers. You guys speak highly of H4350 so that�s what I was gonna grab. Loading for 30�06 and .300 wizzum shooting 150�s and 165�s.


My fishing buddy has an uncle(Jack) who has been reloading for like 30 years, I�m new at this so I called Jack up and asked if he could show me the ropes, We have all been fishing together before so there�s no strangers here. Jack said come on over and bring your �06 and some once fired brass.

We spent most of that day going through all aspects of reloading, including getting the 40 once fired cases ready for action, all steps from setting dies to decapping to cleaning, trimming etc�.

Jack has equipment that might be 40 years old, example a Redding balance beam that is still spot on. He also has modern stuff all the way to RCBS charge master and case prep center. A cool blend of old and new.

We found the lands and backed off .005, he says grab some IMR4350 from the cabinet and those 150 grain Sierra Game Kings.

We loaded 10 rounds just for the heck of it, with 56(low end charge) grains of the IMR4350,

Now the sweet part, Jack has access to his neighbors property which has a range all set for 100 and 200 yards, Benches and all. Sweet set up.

Well, I really wasn�t expecting big results with this deal, 150 grain Game Kings? Sounds like a hunting bullet to me.

Well 10 shots at 200 surprised the heck out of me, this was just a starter load .I could post a pic if your curious. A lot of shots touching and cloverleaf�s, impressive to me for a basic starter load at 200 yards.

Back on topic, I�m gonna grab a 8lb keg this weekend of one of these powders($18.75 Lb), why dick with 1lb at 23-25 bucks? Which one, IMR4350 that we used or the H4350 you guys like so much? Is there actually even any real diff?

Jack mentioned he liked the IMR, but thought it was a �dirty � powder, your thoughts?

Also, why am I going to shoot Barnes TSX(the �06 likes these) at .70 cents a pop, when Sierra Game Kings can produce such accuracy at 200 yards? GK�s are like 26 cents a pop.

Any thoughts on the Sierra Match Kings, strictly for target? This stuff is addicting, but so many choices. Talk to me....

Which would work best in your gun(s) is a mystery until you try either. The data for each is usually within a grain of each other, and very close in velocity and pressure at max loads.

If you get to working with a powder measure you'll like H4350 a lot better.

As in like a RCBS uniflow powder measure? which is what I'll be using...

Yes, that's a fine example.

I'll agree on the metering of the H.

That said, it's a coin toss. H is a touch faster, but they are really close. I have had some rifles like H over IMR and the other way around. Both great powders.

It will cost you a little more per lb. But I suggest you buy a pound of each and let your rifle decide. You can then go buy 8 lbs. of whichever. Example; a previous .243 loved IMR 4350 but not so much the H4350. My 7mm-08 is just the opposite. Me? I like loading H4350 better and it is not temperature sensitive.

I have gotten slightly better accuracy with IMR, but I have a ton of H, so that's what gets used.

If I miss, it's gonna be more than by a couple tenths.

******************************************************

Kenneth...

I agree with Lastround 100% on trying BOTH powders before buying 8 lbs of either one, but you haven't tried BOTH powders yet and you don't know if your rifle will "like" IMR4350 or H4350 better. The accuracy of your most accurate load which has the highest velocity will tell you which powder to buy.

One thing, tho'... H4350 made by Hodgon is one of their "EXTREME" powders meaning it is NOT temperature sensitive. Temperature sensitive powders will lower their chamber pressure and thus their muzzle velocity which, in turn, CHANGES the bullet's point-of-impact more and more as the outside temperature goes down & as the range increases.

Whereas if a powder is NOT temperature sensitive (like H4350), a change in temperature won't effect it's velocity much (if any at all) which means if you work up a good hunting load in the heat of summer and go deer hunting in the frigid winter weather, your bullet's point of impact won't change if the powder you're using is "temperature insensitive".

IMR4350 use to be temperature sensitive, but that may have changed now that Hodgdon owns and makes all IMR powders now. However, that fact doesn't mean they're making the IMR powders temperature INsensitive.

So before you buy 8 lbs of any powder, you need to work up the most accurate loads in BOTH powders to determine WHICH powder is the most accurate and gives the best muzzle velocity.

Of course, to check your rifle's muzzle velocity, you need a chronograph. That use to be a huge stumbling block due to the high cost of chronographs. However, now you can buy a new basic (which is really all you need) chronograph for less than $100... so put a chronograph on your list of "needs" since they are a great aid in working up loads.

I used IMR4350 in my .338 Winchester Magnum's pre-'64 Model 70 with good results, but I "retired" that rifle due to it's heavy recoil. Now that I hunt only deer, I've switched to a different couple of rifles and use H4350 in my Ruger #1 International (aka "RSI") in 7x57mm and I use H4895 in my Model 99 Savage in .300 Savage caliber since I prefer to use a powder that is temperature insensitive so I don't have to be concerned with a possible change in my bullet's impact due to temperature.

Good luck on your quest...


Strength & Honor...

Ron T.

Ron,

Just a quick comment: Hodgdon doesn't make any powders.

They buy them from various sources, and IMR4350 is still being made in the same factory (in Canada) where it was made before they bought the brand.

H4350 is made in Australia, by a company that pretty much has a lock on making temp-resistant extruded powders.

Ahhhhhhhhhhhhh soooooo...

Thanks John... good to know.

Ron T.

Long time IMR 4350 user here. I made the switch to H a while back and use it extensively in the 30-06 and 300 wizzum with excellent results. I have noticed a difference in poi and velocities when using the IMR as compared to the H. The H4350 doesn't waiver. However the IMR4350 isn't really that bad but nonetheless it is noticable. I'd go H4350 since it meters better and is less temp sensitive. Groups with 300 wizzum:

10 shot group:


5 shot group:


Groups shot with ol 30-06 using H4350 and different bullet types:



El cheapo winchester power points (180 gr.)


Both are great powders and to be honest IMR4350 has always been my favorite but I honestly think H4350 has it beat......

One comment with respect to Barnes TTSX's and Sierra gamekings. I use both. I shoot a lot of rocks, varmints and steel plates and there's no point in using expensive bullets for that action. I've also used the GK's on game and everything i've shot with them has died appropriately....So, it's personal choice. Work up a load for each bullet and then use whichever is most appropriate for the situation. Rock or deer, probably a GK; Elk or moose, probably a TTSX...but either would work on either.....

Good thread Ken,

I'm moving a couple cartridges over to "H" extreme after years of using IMR 4350. If the published temp stability info is correct, that's all the reason I need. It seems to blow everything else away in that category.

IMR 4350 has been my "old faithful" for years though in many different rounds. I expect H4350 and the other "H varieties" to yield the same if not better results.

For all my range work, sierra's carry the load and I'm yet to be disappointed. I always have some hunting bullets (Partitions) loaded up and found that much of the time, POI doesn't change much if at all.