The Seneca is such a fine piece of work that I fell in love with it the first time I held one. Its fit and finish, fine wood with brass furniture, light weight and balance, the natural feel of its brass-frame pistol grip, and a set of sights that allows true aiming all combined to make it something I didn’t want to put down. But I did – only to come back about an hour later to buy it. It was to become my all-round hunting rifle for many years: legal for deer yet suitable for smaller game.
Aside from being a percussion cap rifle instead of the older style flintlock, the only modern feature of this rifle is its sights. It has pistol-style open sights, with a U-notch rear sight that is adjustable for elevation. Once that’s adjusted for the individual rifle, there is no need to change it. Right or left sight alignment is achieved with a small screw on the rear sight and/or by drifting (or moving) the front sight in its dovetail groove. Be sure to use a brass punch for this if available, to prevent tool marks. Again, you can set it and forget it.
The front sight seems perfectly sized to provide the right amount of light on either side of it to allow quick and accurate centering within the U-notch. With its flat-top blade that easily aligns to the top of the U-notch wings, there is no question that you have a perfect sight picture. In my opinion, the Seneca rifle can be fired as quickly and accurately as any modern rifle with open-iron sights, within its range.
The Seneca has two triggers. The one nearest the muzzle, or front, is the firing trigger. When the hammer is cocked, this front trigger provides a nice, crisp break that requires the force of “pull” that you normally expect when shooting any conventional rifle. (That trigger has an adjustment screw located between the triggers.) But when you have time to take very deliberate aim, you have a rear “set-trigger” available to enhance your accuracy. Once the “set” is made by pulling the back trigger, the front trigger only takes a slight touch to drop the hammer. Using that set-trigger makes for superb accuracy but care must be taken not to touch it until you’re ready to shoot. Also, I have found that if you are very near your game, the little metallic “click” sound it makes when it sets can spook the game, so it’s best to use that set-trigger only for longer shots or target shooting.
When silent hammer-cocking is needed, the hammer-cocking clicks (similar to the old Colt single-action revolvers) can be eliminated by holding the front trigger down while cocking the hammer. Just make sure that you have a good grip on the hammer and that you release the trigger before slowly and carefully releasing the hammer at its cocked position. Though it has never failed to hold at the cocked position for me, I strongly suggest that you keep the gun pointed in a safe direction if and when you ever try this.
Thompson/Center Arms specifically states in the Seneca literature to avoid the use of sabots. I’m not sure why they advised that other than muzzleloader sabots were new at the time. Perhaps the early plastic sleeves, ca 1978, left a burned-on or melted plastic residue inside the barrel. I fired a few sabots made ca. 2000 to see how they performed on a target and found them to be very accurate. Those sabots used what appeared to be .40 caliber flat-nose bullets inside a plastic sleeve. I expect they may extend my effective hunting range. However, I have no hunting experience with them to relate.
My primary load for this gun has always been a patched .440” lead round ball. It weighs approximately 128-gr. The rifle shoots very accurately using the fully-round Speer lead ball. I also use Pyrodex RS powder and CCI #11 percussion caps. Since my powder flask delivers 30-gr. per neck fill, I can quickly choose to shoot with 30, 60, or 90 grains of powder. However, I find the 30-gr. load is a little puny for hunting and the 90-gr. load (maximum for this gun) tends to be a little erratic with its accuracy. But the 60-gr. load seems to be just right, so that’s my normal loading. If you wonder about the power of this mid-load, just remember: The heavy rifle of the Old West, the .45-70, originally shot a .45 caliber bullet using 70-gr. of black powder.
The Seneca was made in both .36 and .45 calibers, and in cap-lock and (I think) flintlock versions. The .36 is often referred to as a “squirrel gun” and I suppose it is well suited for that. If you can find a Seneca, it will probably cost well north of $300. Just how far north will depend upon its condition.
If you are interested in using a .36 or .45 caliber muzzleloader, be aware that they are not as common as in the early days of the muzzleloader resurgence. Supplies and parts for them are difficult to find and the variety available is quite limiting. I attribute this to the increased popularity of the .50 caliber muzzleloader, which appears to be far more efficient on deer and many states now have a deer muzzleloader season. Since the .45 is so devastating on small game and comparatively less efficient on large game, where does that leave it as a hunting gun? It’s kind of in an “in the middle” category.
All this being said, I still love my Seneca rifle for what it is: A great little all-round gun.