Hottest Isn’t Always Best

To read the full version of this article, see the December 2008 issue of Deer and Deer Hunting. Subscribe today!

Muzzleloading hunters who have made the transition from a No. 11 percussion ignition system to a No. 209 primer-ignited rifle can attest to the superiority of the hotter primer ignition. Even so, because of the hotter flame and higher pressure produced by these primers, many shooters have encountered a few loading and accuracy problems.

Fortunately, there are some simple solutions to these dilemmas.


One common problem is the unexplainable flier — a shot that is three or more inches away from others on the target.

One hunter who first suspected that the pressure produced by No. 209 shotshell primers was causing the problem was Cecil Epps, owner of Precision Rifle Custom. Epps does a lot of test-shooting with his line of saboted soft-lead swaged bullets and would have to be considered a “better than average” rifleman.

To test his theory that No. 209 primer pressure can move the powder charge, sabot and bullet slightly forward before the powder has a chance to ignite, he machined a new breech plug for his .50-caliber Thompson/Center Encore. The new plug allowed him to chamber a shortened .22 Hornet case — primed with a milder, small-rifle primer. And he immediately found that while he still gets spontaneous ignition, he has also eliminated fliers.

I had Epps send me one of his aftermarket breech plugs for a .50-caliber T/C Omega that has always shot reasonably well using No. 209 primers. However, the rifle occasionally had me scratching my head when a shot would print somewhere other than where my cross-hairs had been on the target.

The breech plug I installed uses standard .25 ACP cases, primed with small-rifle primers. These cases can be used 25 or more times.

I also discovered something else: Not only does the Precision Rifle after-market breech plug tame accuracy with the rifle, it also results in keeping practically all of the fouling ahead of the primed case and out of the action. Which leads us to another problem sometimes encountered by No. 209 primer users.

The Fouling Ring

Before using the breech plug chambered for a .25 ACP case, I had regularly experienced another problem when first shooting Triple Seven charges with standard No. 209 primers: the buildup of a crusty fouling ring about where the saboted bullet is seated over the powder charge.

Then, I began hearing from other shooters experiencing the same problem.

Unlike Pyrodex, which is a charcoal-based propellant, Triple Seven is a sugar-carbon based powder. Apparently the added heat of hot No. 209 primers creates a faster peak pressure (and heat) with Triple Seven than when the powder is ignited by milder, small-rifle primers. The result tends to be the accumulation of hard fouling where the pressure is highest and the heat most intense.

When shooting with standard No. 209 primers, I had been running two damp patches down the bore between shots, followed by a dry one. This pretty much wipes away this fouling ring, prevents heavier accumulation, and accuracy remains.

Even though most in-line rifle manufacturers recommend wiping the bore between shots — even with generally cleaner burning modern blackpowder substitutes such as Triple Seven — many hunters don’t want to take that time while in the woods. Most will sacrifice a slight degree of accuracy in order to be able to take a shot, then quickly reload without first wiping the bore.

Western Powders’ new Blackhorn 209 is one blackpowder substitute that permits fast reloading without a significant loss of accuracy. In fact, most shooters are finding that the best accuracy is achieved with this powder after the rifle has been shot once or twice, with the light fouling left in the bore.

One 50-degree summer morning, I shot a .50-caliber Knight DISC Extreme 50 times using a 110-grain charge of Blackhorn 209 behind a saboted 300-grain Harvester Muzzleloading Scorpion PT Gold. I allowed four to five minutes between shots, but never wiped the bore. All 50 shots printed inside of 1.6 inches at 100 yards.

To get this kind of performance with Blackhorn 209 requires using a very hot, magnum-strength No. 209 primer such as the CCI 209M or Federal 209A.

With some breechplug designs that feature a flash hole of around .035-inch diameter, standard-strength primers such as the Remington STS, CCI 209 and Winchester 209 primers usually give excellent ignition of this powder. However, to reduce blowback, some in-line rifle manufacturers have gone to smaller-diameter flash channels in their breech plugs.

Some of the Knight plugs now have a hole as small as .027-inch, and some of the T/C breechplugs have a flash hole that’s around .029-inch in diameter. With these, standard strength No. 209 primers can fail to put enough fire into the powder charge to ensure immediate ignition. However, the use of a magnum-strength primer produces more than enough heat and flame.

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