Home Forums Reloading Big Game Rifles IMR4350 vs H4350

The last time I hunted Elk in CO, it was close to Grandby, West side of the mountains just out of Rocky Mtn National Park. It was 45 below when I left camp opening morning.
That's 115 degrees below sighting in temperature. If it's that cold on this trip, I'm not going hiking to get where I want two hours before sunup.

I think that a lot of people over-think this temp thing. It might make a difference if you are shooting extreme range and small targets, but for normal ranges on large animals, it will be insignificant for the most part.

Sight in for 200 yards and hold in the upper third of the lungs out to 325 or so, and it won't matter if it drops a bit more.

I have killed a number of elk with loads that were supposedly temp sensitive and the elk rode home in the truck anyway.

The big problem isn't reduced velocity at 300 yards. Instead it's assuming the rifle will retain the same point of impact at ONE HUNDRED YARDS in really cold weather.

I have tested a bunch of rifles and loads at zero after sighting-in at "normal" temperatures, and they will shift POI significantly at 100--and there's no way to predict how it will change unless you try it.

One .30-06 shifted POI two inches UPWARD at zero after being sighted-in at 70 degrees--and by a not-so-odd coincidence was a load using a 165-grain bullet and IMR4350.

But if Bugger checks and, if necessary, checks the point of impact at 100 yards in what should be much cooler weather after he arrives, then he will indeed be easily good to go to 300.

"But if Bugger checks and, if necessary, checks the point of impact at 100 yards in what should be much cooler weather after he arrives, then he will indeed be easily good to go to 300."

Yes, it is the point of impact that I'm concerned about. Not the drop in velocity. The more variables a shooter can control the better, IMO.

I'll be checking POI the day or maybe two before opening day at location. I suspect/hope that no one including the elk won't care. However, I really hope the temperature behaves.

If I remember right my favorite load for my 338 is with IMR4350 too. That was my go-to elk rifle/load. As it turns out, even though I have had good opportunities to drop the hammer at 300 yards or so, I have not yet shot an elk at over 150 yards.

Having a less temperature sensitive powder makes sense in all hunting/shooting I think, even prairie dogs, because the temperature on the prairie may climb quite high and shooting a hot rifle on a hot day with the wrong powder is not a good thing.

Now if we (I) could get a famous writer to test loads at tree line with the temperatures on the south side of negative 20 degrees, then we'd (I'd) have it made...

Too late this year though.

Took the three 06's and shot H4350 57 grains and some factory second bullets to get the rifles close. As it turns out they were not to far off. These rifles have cheaper Leupolds -friction adjustments. 2 are 2x7 and one is 4x.

After adjusting two just a little bit I shot the following target. 2 shots from one and three from the other two. I'll load up some good bullets next.
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This reminds me of the angst that is sometimes expended on the virtues, even the "virtual need", for controlled round feed rifles and then negating whatever reliability you gain from that by making ammo which may not chamber easily 100% of the time, or throwing some other problem at it.

I know various fillers, strengtheners, and stabilizers are added to synthetic stocks in the form of glass, carbon, and/or kevlar fibers, but synthetics... plastics, are notorious for expansion variances, often much greater than wood, with temperature changes.

Stocks have evolved. The very worst artificial stock that I know of was Reminfton nylon 66's stock. That would/could change poi by a foot in an hour if one side got wet.

Next was Remington's attempt with their center fire stocks which reminded me of sponge rubber. Not even good for a fire. I think they have come a long way.

The artificial material used for stock that I believe in is Kevlar. I believe, but I could be wrong there's little movement with that material.

As far as wood goes, not all different woods are created equal either. Though I prefer it to all artificial materials except I think Kevlar is near equal.

JB, is the change in POI due to the load itself, or as much in the stock as others are discussing? I was wondering this before reading the comments.

Very good point, and Great insurance on a hunt where you spend alot of time and money to get there, shoot the rifle on location before opening day....could prevent a lot of bad memories.

I suppose if the test is performed with the two powders in the same rifle the stock may be eliminated since it doesn't know which powder is burning.

I count myself fortunate or lucky. To the best of my memory, I've had Wby Fiberguard, Rem Syn, Win Syn, Ruger Syn, & Tikka Syn stocks. I can swear that NONE of them have shifted POI in temperatures from 80* down to 0* or even -4 & -8*.

Klik, I'm not trying to dispute/argue with you but this has been my real life experience. I'm not sure synthetic = plastic.


Jerry

Yeah, I don't believe it's the stock. Or at least I've never seen any evidence pointing in that direction in my rifles, whether the stocks are synthetic or wood.

Instead, I've noticed rifles that change 100-yard POI in cold weather are the same rifles that change POI with powder charges only a grain or two different when working up handloads. Usually they're rifles with relatively lightweight barrels.

However, have never seen 100-yard POI shift noticeably in any rifle when muzzle velocity changed less than 40 fps from 70 to zero. Of course, that doesn't mean it can't happen--but so far it hasn't happened in any of my tests. Which is one reason I'm pretty fond of cold-resistant powders for hunting here in Montana.

H4350 is almost universally preferred to the IMR version by the long range target guys for the reasons Mule Deer stated. I use it in my 6.5x47 Lapua behind a 142 matchking. The accuracy at 1000 yds is pretty incredible.

No one can really say without comparing them in your rifle, but I'd bet on H4350 outperforming IMR4350 any day. The loading manuals publishing "most accurate powder tested" is usually BS. It, like COAL, is rifle dependent & I wish they wouldn't publish it, it's misleading.

In short, use the H4350.

In a couple of .260s, a 6.5 Creed, and a 6.5x47 Lapua... I've seen virtually no difference between IMR4350 and H4350. Identical loads shot essentially identically in terms of accuracy, velocity, POA/POI, and temp sensitivity. I've shot 24 pounds of H4350 and about 10 lbs of IMR4350 in the past 4 years out of the above rifles, mostly with 123s but some 139/140s have been mixed in... and I shoot the exact same charge of each powder and very little changes.

I haven't seen velocity vary between the two powders more than about 30 fps...

I have't seen POI vary by more than about 1/2"...

I haven't seen accuracy degrade/improve by more than about 1/4" or so...

I haven't had any POA/POI issues in temps between 0-90 degrees...

I'm sure some guys can quantify the huge difference between the two powders... but I certainly can't. That's only over the course of about 5000 rounds of mid-size 6.5s though....

Dogshooter,

As I've mentioned a number of times before in various places, temp-resistance is to a certain extent cartridge dependent. Instead of testing IMR4350 and H4350 in several 6.5mm cartridges of similar case capacity, I've tested both in a wide variety of rounds from the .243 Winchester to .375 H&H. Have seen the velocity lost with IMR4350 from 70 to zero degrees range from very little to around 100 fps. (H4350 has remained consistent in all cartridges, usually losing less than 15 fps over the same temperature range.)

IMR4350 turned out to be very cold-resistant in the .375 H&H with 300-grain bullets, but it lost considerable velocity in the .30-06 with 165-grain bullets. In one particular .30-06, impact shifted a couple of inches at 100 yards from 70 to zero degrees--and overall that rifle tended to be very consistent in POI with widely varying loads.

In fact it would shoot full-power handloads with 165 and 200-grain bullets to so close to the same place at 70 degrees that I could use them interchangeably--as long as temperatures weren't too cold. But once the temperature dropped to near zero, the 165/IMR4350 load shifted POI two inches, and the 200-grain load did not. The powder in the 200-grain load was not IMR4350, but H4831.

I agree... different cases/bores will cause different results. I truly believe load density makes a huge difference in temp sensitivity... though I can't quantify that other than with empirical evidence.

I'm just saying in my application (6mm-6.5mm bores and .308ish size cases) they are virtually interchangeable. All of the loads are in the 90+% load density range... probably a coincidence... but I'll take it

That doesn't surprise me.

And my experience also tends to indicate that load density can make a difference. The IMR4350 load I use in my .375 H&H with 300-grain bullets is 80-81 grains, exactly how much depending on the lot, which DEFINITELY fills the case!

As scenarshooter pointed out recently on another thread on the same subject, you never know what any load will do at different temperatures until you test it at different temperatures.

Some 'plastics', like nylon, will absorb moisture which can cause dimensional changes. (Anyone who has used a nylon tent in rainy weather has seen the 'wilting' effect that moisture can cause.) I don't have any idea if the "Nylon" 66 actually used nylon or some other 'plastic' but it's quite possible that moisture affected its stability.

And I wasn't intending to cast aspersions on any and every synthetic stock, but simply pointing out the fact that it can be a factor to be aware of. There are many factors which are affected when temps get cold. 'Correcting' one might be somewhat helpful, but it really isn't a make-or-break factor if there are several others which trump it.

Klik -

Thnx for clarifying about all syn. stocks. Gotcha


Jerry

Klik - I may be wrong, but thought the Nylon 66, used Nylon bearings in the action for smooth lubricity....

I saw evidence of this load density and temp stability business years ago with IMR4831. It did better in the 270 than the 7 RM once temps got into the 0-10 degree range.

This was in the days before there was an internet so no one to really bounce it all off on. I stored it in memory and moved along.