IMR4198 vs H4198

[thunder53]

OK, I've searched the forum thread history and read all I can find.

I STILL can't seem to find any consensus answers regarding the differences between IMR4198 and H4198 when it comes to temperature sensitivity/ignite-ability, velocity, overall shoot-ability, etc.

Any updated thoughts or ideas on the issue?

I have normally been shooting IMR4198, usually now duplexed with 4759 (10/48-50).

To keep it simpler, I'd like to just shoot straight 4198 of the variety that will be most temperature stable, give me the best change to ignite and create the best/most consistent velocities/pressures.

It wasn't as much concern previously as I only had 2 break SMLs (ProHunter & Apex), but now I have a new bolt action SML arriving tomorrow (hopefully) and I will be upping the overall charge by 10-16 gr.

Your feedback is appreciated.

Thanks

[edge]

H4198 SEEMS to meter better, ignite easier, builds a bit more velocity and pressure.

I am not sure if most of those are just subjective or not.

edge.

[Deleted]

I use a savage plug in my rifle and I have not had good luck with igniting IMR 4198. I've read that the new arrowhead plug and H4198 has been doing well shooting full form bullets don't remember anyone saying any good luck with straight charges and smooth form.

With the arrowhead plug and making sure your primers seal close to 100% is your best bet. Not so sure on the savage plug still trying to see if I can get mine too.

[thunder53]

Jan 7, 2016 22:49:36 GMT -5 @78riverrat said:

I use a savage plug in my rifle and I have not had good luck with igniting IMR 4198. I've read that the new arrowhead plug and H4198 has been doing well shooting full form bullets don't remember anyone saying any good luck with straight charges and smooth form.

With the arrowhead plug and making sure your primers seal close to 100% is your best bet. Not so sure on the savage plug still trying to see if I can get mine too.

For what it's worth all 3 of my SMLs have Slufoot Savage breechplugs with WIN209 primers (new gun will use CCI Mags), two also have bushing set ups (1 break and 1 bolt). I have both .040 and .030 bushings.

Haven't had ANY issues with the break guns going bang so far, even with a ventliner set up.

So far just shot with sabots or smooth form sabotless. The new gun does have a barrel drop with it and I could consider a full form sizer. (lots to do before I get there)

[subcalshooter]

I've never had an issue igniting straight charges of H4198 with land riders and .060 Veggie wads using a savage style bushing plug and .030 bushing. I use federal primers and my guns are all headspaced very good, my primers come out very clean, no blowby, which is a big help. I keep the pfc drilled to 5/32 after every 20 shots or so.
The problem with H4198 isn't so much the igniting it (for me and many others) it's the temp sensitivity and the loss of speed shooting straight H4198, when the temps drop, so does the speed, which to me is a problem and no good. Hence the duplex.

I shot from 68-74 grains of straight H4198 with 275 Parker BE's and 275 Parker MH's just to test for accuracy, never had an ignition problem and found good accuracy, but I still wouldn't hunt with it because of the velocity lost in cold temps.
Just my $.02

[Dave W]

Similar to Guy's post. Never shot the I version but from the data I have seen, it seems to loose speed as well when the temps plummet. If the 4198's are similar to the 4350's, the H version may be a little cleaner burning.

[cuda]

All I have ever shot was IMR4198 in both of my guns. One is a 10ML-ll 50cal and a Stevens McGowen 45cal the 45 has never failed to fire and the 50 has but the powder got wet hunting in the rain.

[quillen52]

How much velocity difference do we see with colder temps? Looks like if I chrono and sight my gun in the lower fall or early winter temps the differences would not be that great. Probably more difference is noted when shooting in summer temps and then shooting in the colder temps of hunting season. One of the primary rules of hunting is to verify point of impact immediately prior to hunting.

[esshup]

In my Pac-Nor .45 barrel ML-II using the factory vent liner, I've had much better accuracy with straight H than with IMR. (right around 1/2 moa with H, 4 moa with IMR) I am still using sabots, Blue Harvester, and the Barnes 195g bullet. I use the gun for hunting, not paper shooting, and only use paper to verify that the load is good, and the gun is still shooting where it did last year. So, your results may be different than mine. I am told that my load is pushing the limits of the sabot, but I've never had an ignition problem, nor a sabot problem. I use a CCI 209M primer and 70.5g of powder. Most if not all of my hunting is done in temps from 50 down to close to zero.

Once I load the gun after verifying POI at 100 and 300 yds, I put a layer of electric tape on the muzzle and leave it alone until I need to squeeze the trigger. Our hunting season goes from around the middle of November until the first weekend in January. I'll shoot it, dry swab it, load and leave it alone. I have shot it as early as mid October, loaded and left it until first shot in December. IIRC velocity was around 2850 fps. I've never checked it since getting that load a numbers of years ago, but the POI is pretty consistent at 100 and 300 yds from year to year.

At the end of the season I'll shoot the load out of it, clean it and throw it in the safe.

[rossman40]

IMR (Improved Military Rifle) powders started out being made by DuPont. Some of the powders date back to the early 1900s. Something about the history of Hodgden and H4198. There was a gap after WWII that you couldn't get reloading powders before DuPont and Hercules (which latter became Alliant) got back to making it for the civilian market. Bruce Hodgden seen a chance and got his start buying surplus powder. It could be a leftover partial lot, "de-milled" or pulled from ammo declared surplus, or a lot that didn't quite make the grade. Bulk powder back then was shipped in wooden or cardboard barrels. A lot of powder nowadays is usually 32,000 or 64,000lbs and from what I have seen, when shipped in bulk, shipped in aluminum containers much like this,



Roughly 44"X44" and about 6' tall. 64,000lbs would be two semi truck loads. Tales are told that when Bruce started out he had rail cars of powder parked on sidings around Kansas and would sometimes blend the powder on a tarp in his garage and package it. Supposedly he got a large lot of IMR4198 and packaged it as H4198 and then everybody wanted more. DuPont wasn't going to sell to a competitor so he took some of what he had left and as the story goes contacted Nobel in Scotland to make it and then a few years later Nobel stopped making powder and he then went to Australian Defense Industries (ADI) to have it made. Since DuPont closed down their powder mills in the US, production of DuPont smokeless powders was moved to Valleyfield, Canada which was a DuPont built plant. Later DuPont pulled out of powder market and the DuPont powder line was picked up by the newly formed IMR Powder Company. Now the Valleyfield plant pretty much follows the DuPont recipe for IMR4198, ADI had to match what Hodgden had as far as burn rate and power for H4198. To make matters worse Hodgden took over IMR in like 2003 and when they couldn't get IMR4198 in a timely manner from Valleyfield a few years ago (after General Dynamics bought the Valleyfield plant in 2001), they had ADI make a lot of it. So you have Australian made H4198, Canadian made IMR4198, and then you could run across some Australian made IMR4198 that is close to the Canadian product but not exact.

The main difference is Canadian made IMR4198 has a flash reducer and different stabilizer/plastizer.

[jims]

:)Now that is a powder keg.

[rambler]

Jan 9, 2016 1:25:13 GMT -5 rossman40 said:

IMR (Improved Military Rifle) powders started out being made by DuPont. Some of the powders date back to the early 1900s. Something about the history of Hodgden and H4198. There was a gap after WWII that you couldn't get reloading powders before DuPont and Hercules (which latter became Alliant) got back to making it for the civilian market. Bruce Hodgden seen a chance and got his start buying surplus powder. It could be a leftover partial lot, "de-milled" or pulled from ammo declared surplus, or a lot that didn't quite make the grade. Bulk powder back then was shipped in wooden or cardboard barrels. A lot of powder nowadays is usually 32,000 or 64,000lbs and from what I have seen, when shipped in bulk, shipped in aluminum containers much like this,



Roughly 44"X44" and about 6' tall. 64,000lbs would be two semi truck loads. Tales are told that when Bruce started out he had rail cars of powder parked on sidings around Kansas and would sometimes blend the powder on a tarp in his garage and package it. Supposedly he got a large lot of IMR4198 and packaged it as H4198 and then everybody wanted more. DuPont wasn't going to sell to a competitor so he took some of what he had left and as the story goes contacted Nobel in Scotland to make it and then a few years later Nobel stopped making powder and he then went to Australian Defense Industries (ADI) to have it made. Since DuPont closed down their powder mills in the US, production of DuPont smokeless powders was moved to Valleyfield, Canada which was a DuPont built plant. Later DuPont pulled out of powder market and the DuPont powder line was picked up by the newly formed IMR Powder Company. Now the Valleyfield plant pretty much follows the DuPont recipe for IMR4198, ADI had to match what Hodgden had as far as burn rate and power for H4198. To make matters worse Hodgden took over IMR in like 2003 and when they couldn't get IMR4198 in a timely manner from Valleyfield a few years ago (after General Dynamics bought the Valleyfield plant in 2001), they had ADI make a lot of it. So you have Australian made H4198, Canadian made IMR4198, and then you could run across some Australian made IMR4198 that is close to the Canadian product but not exact.

The main difference is Canadian made IMR4198 has a flash reducer and different stabilizer/plastizer.

Ken, you could work for Wikipedia...or do you    LOL

[moto357]

Interesting info Ken. I remember when I got my first smokeless 45, I just had to have IMR4198. Drove an hour to my local gun shop up in Plattsburgh, NY. Once home I had noticed on the back of the can it said packaged in Plattsburgh, NY, then in much smaller letter stating where it was made in Canada. Being close to the boarder there is a railroad that goes through all the factories in Plattsburgh and either south to Albany/NYC or north into Canada. Even though I knew the powder wasn't from Plattsburgh, it felt like the closest thing to "buying local" when grabbing some powder.

[Dave W]

Jan 8, 2016 10:08:17 GMT -5 quillen52 said:

How much velocity difference do we see with colder temps? Looks like if I chrono and sight my gun in the lower fall or early winter temps the differences would not be that great. Probably more difference is noted when shooting in summer temps and then shooting in the colder temps of hunting season. One of the primary rules of hunting is to verify point of impact immediately prior to hunting.

TG has a number of traces that deal with temp comparison that shows velocity loss, and gain for that matter with some of the faster boosters.

Here is an example that someone posted:
fwiw- just conducted a short test w/ 327mh tested from 73 deg to 13 deg which resulted in a approx. 100 fps total loss @ 200yds. at that distance with the same rest my poi was largest @ approx. 1.25" now if I were to take a shot 350yds or farther I would have to make an adjustment(dialing) to connect in which I have those figures just in case.

73 deg.....2741,34,20
70 deg.....2700,04,23
31 deg.....2717
27 deg.....2666
13 deg.....2645

the 31 -13 deg test were all fresh loaded in am. with the barrel out for at least an hour to reach ambient temp.

bullets all seem to load consistently for the above results_ notice the fps swing with this particular load from 31 to 27 degrees.

hope this helps!

When I was still shooting straight charges of 4198, one of my hunting loads that was settled on in 30 degree temps, picked up velocity in the summer. The group size had approximately doubled from winter time groups. By dropping the powder charge velocity and accuracy returned to the winter time results. I have never tried adding powder to a load in cold temps to see if you can recoup the lost velocity and see if there is any accuracy difference. Think it was Savageshooter that told me years ago that he changed his booster level in the .50 cal when temps got extremely cold.

At normal hunting distances, probably never going to miss a deer, kill zone on a deer is not exactly small. At longer distances where you might have to dial and wind has more time to work on the bullet it may be an issue. Easier for me to just shoot a good duplex and not worry about the temp extremes.

[rambler]

Nice research Dave! Thanks for digging into this.

[rossman40]

There are only 3 smokeless plants left in North America. The St Marks facility in Florida is the newest, it was built by Winchester and mainly makes ball powder and is now owned by General Dynamics. At least two truck loads of powder a day goes to the Lake City ammo plant, been there and seen it.

Valleyfield Canada plant was built by DuPont in WWII and then DuPont ran it for the Canadian government. The Canadian government sold it to the French firm SNPE and went thru some name changes but was finally sold to General Dynamics in 2001. This plant makes all the powder for the Canadian Forces (GD now also owns the Canadian ammo plants). It makes the IMR powders and is also the home of BH209 which was developed there as a black powder substitute. Lot of devices like expelling charges and initiators in the military still use black powder.

If it says "Made in USA" and is flake or extruded powder it comes from the Alliant/ATK/Federal plant at the Radford Army Ammunition Plant in SW Virginia. The facility goes under the name New River Energetics. The Radford plant is also the only place left in North America that makes nitrocellulose, the main ingredient of smokeless powder and supplies the other plants. ATK has teamed with BAE to totally upgrade the nitrocellulose facility. ATK has also dumped a bunch of money into what they call a Flexible Energetics Facility (FEF) which allows them to make some pretty high tech stuff. Most of the new work has been on propellants for Insensitive munitions (IM) or Low-Vulnerability Ammunition (LOVA). ATK also now has a working relationship with Nitro-Chemi which makes some of the Reloader series.

The only thing Hodgden makes is Pyrodex and Triple 7 at a old B-29 base in Kansas which is also home to their distribution center. They did buy out GOEX which is the only black powder mill left in the US.

Western powders brings most of their stuff in from Europe. Some of the Accurate ball powders do come from the St Marks facility.

Anymore you can tell who actually makes the powder just by what country it was made in.

[Richard]

For what its worth...............back in Dec. I shot both powders side by side. The bullet I used was a 300 gr. XTP which had its base hollowed out with a counter sink to reduce weight to 274 gr. The Temperature was 37* and I used 78 gr. of each powder and shot two three shot groups. (.060" veggie wad) This with a Brux 28" .45 barrel. The IMR version produced an average 2856 fps with a 19 fps ES and the Hodgedon version 2782 fps with a 51 fps ES.

[thunder53]

Jan 9, 2016 11:53:36 GMT -5 Richard said:

For what its worth...............back in Dec. I shot both powders side by side. The bullet I used was a 300 gr. XTP which had its base hollowed out with a counter sink to reduce weight to 274 gr. The Temperature was 37* and I used 78 gr. of each powder and shot two three shot groups. (.060" veggie wad) This with a Brux 28" .45 barrel. The IMR version produced an average 2856 fps with a 19 fps ES and the Hodgedon version 2782 fps with a 51 fps ES.

First, thanks for all the feedback.


Richard, How about any accuracy differences with those two test loads? (also, what primer are you using?)

[Richard]

Accuracy about the same and using a Win. 209 primer. This test was not about accuracy as it was an experimental bullet. The IMR shot 1.3 and the H shot 1.4" Both were triangular.

[rangeball]

Back when Earnhardt was doing work with opening up flash holes and PFCs, I went with a .040 bushing and enlarged PFC in hopes of avoiding the temp fps loss with h4198 as a single. I'd hoped to test it in warm and cold temps but wasn't able to, then my chrony went MIA, and others that made the same decisions haven't been able to test either.

In my mind I'm still unsure if I solved a problem or not. Hope to determine some day soon.