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IMR's White Hots are Smokin'!

IMR's White Hots are Smokin'!

The newest in blackpowder substitutes pushes the limits of performance and tradition.

According to the Chinese alchemist Sun-Sy-Miao, blackpowder was invented sometime in the 7th Century AD. Actual use in firearms seems to have occurred in Europe in 1300 AD, and shooters have tried to improve blackpowder ever since.

Chief among the complaints about blackpowder is that it's highly explosive--being sensitive to heat, spark, static and impact. It also produces a considerable amount of white smoke that reveals a shooter's position, clouds battlefields and obscures targets. There's also the matter of heavy fouling that can make follow-up shots tough to load and guns a chore to clean, and if they're not cleaned properly, results in rust. And lest I forget, some folks are put off by the permeating effluvium.


The most well known blackpowder replacement is Pyrodex. This bulk-for-bulk replacement was introduced in 1976. It's less dense than blackpowder, so pound-for-pound you get more shots from a pound of Pyrodex than you do from a pound of blackpowder.

One early attempt at improving blackpowder was du Pont's 1857 patent that substitutes sodium nitrate in place of potassium nitrate. Blackpowder is a mechanical mixture of potassium nitrate, charcoal and sulfur, and sodium nitrate was less expensive and has a lower molecular weight. The resulting "soda powder" is a cheaper and more powerful powder, but unfortunately it's also highly hygroscopic (moisture attracting) and so it's unsuitable for firearms. Soda powder wasn't a waste of effort, however, as it's used in mining where rust isn't the issue it is with delicate firing mechanisms.


The combination of two IMR White Hots and 250-gr. Barnes Expander MZ bullets provided accuracy that rivals many centerfire bolt-action rifles.

Other, more successful improvements, centered on refining the three basic ingredients and how they're processed.

Because blackpowder is a mechanical mixture, the more intimate the mixture the better the powder. Progress in this area includes machine grinding of the ingredients, and mixing them wetted with distilled water. It was also found that blackpowder could be made less porous and better burning if it was heavily compressed to make the surface hard and impermeable.


Controlling grain size was another significant blackpowder improvement. Larger grain powder is more suitable for large-bore guns, while finer grain powder is best used in smaller bore guns.


During the Civil War, Confederates found that refining the potassium nitrate resulted in a higher quality powder. Sulfur lowers the ignition temperature of the blackpowder compound and improves its homogeneousness, so tweaks there are not unknown. Also, the type of wood used to make the charcoal makes a difference in powder quality, and temperature-controlled kilns produce the most consistent charcoal.

In 1882, the Germans came up with "brown" powder that was perhaps the height of blackpowder development. Instead of regular charcoal, brown powder used under burnt rye straw. The result was a powder that rivaled the performance of early smokeless powders.

When smokeless powders came on the scene, there were many choices of blackpowder available to shooters, just as we have many types of smokeless powders available to handloaders today. That situation didn't last, as smokeless powder would eventually take over the small arms propellant world. It wasn't an overnight affair, though, as shooters matured through such things as semi-smokeless powders and "bulk" powders that replaced blackpowder on a direct bulk-for-bulk basis.

White Hots pellets physically weight about 20% less than Triple Se7en Pellets, so mathematically with comparable loads, recoil should be slightly less without sacrificing power.

Today, it's like the 1890's all over again as far as blackpowder choices go, or to be more accurate, blackpowder replicas or replacements. The most well known is, of course, Pyrodex. This bulk-for-bulk replacement was introduced in 1976 with its primary advantage, in my opinion, being that it's safer to handle. An added bonus is that it's less dense than blackpowder, so pound-for-pound you get more shots from a pound of Pyrodex than you do from a pound of blackpowder.

There have been many other blackpowder replacements since. I recall a little flurry of them in the late 1990's including Black Mag, and Black Canyon; and Pyrodex came out with the "Pellet." More recently, the replacement list has grown to include at least Pinnacle, Blackhorn 209, American Pioneer, Shockey's Gold, Clean Shot, Clear Shot and Hodgdon's Triple Se7en, Triple Se7en Pellets and Triple Se7en Magnum Pellets.

And now there's another replacement on the market under the venerable IMR Powder name. And though it may add insult to injury to blackpowder traditionalists, this powder is in "pellet" form, and isn't humble enough to be black, or brown or even grey like other replacements--it's white.

CHRONOGRAPH COMPARISON 250-gr. SABOTED BULLET
CHARGEMUZZLE VELOCITY (fps)STANDARD DEVIATION
3 Triple Se7en Pellets185825
2 Triple Se7en Pellets153922
2 Triple Se7en Magnum Pellets152842
2 White Hots Pellets171213
NOTE: Average of five consecutive shots measured 15 feet from the muzzle with a PACT MKIV Chronograph/Timer.

IMR "White Hots" are preformed charges intended for use "in newly manufactured in-line muzzleloading rifles of .50-caliber using a 209 primer ignition system." The quoted part of that preceding sentence is found on the back of White Hots packaging and I think it's a pretty significant statement.

To me, it says, "This isn't your father's blackpowder replacement. Don't bother trying this in old guns or flintlocks. This powder is designed with and for the latest technology and we're not going to compromise so you can shoot it in your outside hammer caplock or even your Remington Model 700ML with the old No. 11 nipple system."

Kind of a bold interpretation, I know, but that's how it comes across to me. Rather than looking backward, White Hots are a current and forward-looking product. IMR doesn't even try to equate White Hots to equivalent grains of blackpowder in its loading data either; loads are two pellets or three.

Even though there is loading data for three pellets, the packaging warns not to exceed a total load of two pellets. The three pellet load data is shown for use only in firearms whose manufacturer instructions specifically recommend three pellet loads in a particular gun.

To test the new White Hots, I chose Knight's new KP1 muzzleloader. While this is a three-pellet gun, it was a loaner, so I stuck with the recommended two pellet loads.

Fouling from IMR White Hots (l.) is more tan compared to the black fouling from Hodgdon Triple Se7en Pellets (r.). The lighter fouling reduces staining on your hands and cleans up easily with water.

I began my range test by sighting in at 50 yards using an old unmarked package of 250-grain polymer tipped bullets in sabots. At this point, all I wanted to do was get the shots on paper so I could move back to 100 yards and still be on target when I switched over to 250-grain Barnes Expander MZ bullets. I chose those Expander MZ bullets as I've used them so often and for so long that their performance is no longer a variable to me. I also used the unmarked bullets for some chronograph comparison between the new White Hots, standard Triple Se7en pellets, and Triple Se7en Magnum pellets.

As you can see in the nearby table, velocity from two White Hots is noticeably greater than I what I achieved from two Triple Se7en Magnum pellets. It was interesting to note that statistically two standard Triple Se7en Pellets had the same velocity as two Magnum pellets.

From the velocity comparison it was obvious that White Hots produced higher velocity. Even so, I'm not certain they are more "powerful." Instead, my conjecture is that the increase in velocity from White Hots may be attributable to them physically weighing 20% less than the Triple Se7en Magnums. It stands to reason that if there's less ejecta in the form of burned powder, then more of the pellet energy goes into pushing the bullet. It also stands to reason that if the pellets weigh 20% less, then there would be less recoil than from the Magnum pellets. Mathematically, that's true, but perceived recoil was the same as far as my shoulder was concerned.

ACCURACY RESULTS
LOADSMALLEST (in.)LARGEST (in.)AVERAGE (in.)
2White Hots Pellets, 250-gr. Barnes Expander MZ, Winchester 209 Primer0.972.351.82
NOTE: Average of five consecutive five-shot groups at 100 yards fired from an MTM Shoulder Gard Rifle Rest.

Though I wasn't really shooting for accuracy at 50 yards, the results were remarkable. Shot after shot landed one on top of the other and made me wish I still had the packaging for those old bullets, could remember what they were, or at least had enough to finish my work and still have some left over for hunting. But I didn't, so with the KP1 sighted in about four inches high at 50 yards, I moved back to the 100-yard line, switched to the 250-grain Expander MZ bullets, and started shooting for accuracy.

Accuracy was nothing short of exceptional. In fact, this gun, powder, and bullet combination shot accurately enough to rival many centerfire bolt-action rifles.

The White Hots cleaned up easily with plain water, and instead of leaving a black stain on the patches and my fingers, dirty patches came out tan. Velocity from the curious new pellets was excellent, and low standard deviation authoritatively backed up by consistent accuracy on the target paper. In fact, the only thing I found troubling about White Hots was that they're white! It just seemed unnatural to me, but then so did synthetic stocks and stainless steel rifles when they first came out. As with those, it will be consumer preference that determines the future of White Hots, because one thing's for sure, the performance is there.

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