Finally Shot the Gemmer Hawken

Back in January I got a .54 caliber flint Investarm Gemmer Hawken. It's the current version of the Lyman Great Plains Rifle that was sold for almost 50 years here in the US. I bought this rifle for a couple reasons. First, I wanted something a bit shorter than my longrifle for hunting. Second, I wanted the power of a .54. The deer we hunt up in Tioga get big and I would really like a complete pass-through to maximize blood trails. The huge doe I shot in 2022 stopped the .50 caliber ball I shot and the blood trail was very hard to follow. Bigger holes and two of them mean more blood out and air in, so hopefully blood trails will be a lot shorter.

Anyway, life got in the way and I didn't not shoot he rifle until today.

This is my first five shots, fired off the bench, from 50 yards. My point of aim was 6:00 on the top bullseye. As expected, it shot low because these rifles come with an extra tall front sight.

The lowest shot was the first, with the rest clustered into a couple inches. This is about as good as I can shoot from the bench with open iron sights, even with a cartridge gun, much less a flintlock. I'm quite happy with the group.

The load consisted of:

• Hornady .530" round ball
• 0.018" ticking patches lubed with October Country's Bumbling Bear Grease
• 80 grains of Scheutzen 2Fg black powder

Ignition was perfect the whole day. As long as I got spark there were no flashes in the pan and ignition was quick. I had to reverse the agate flint that came with the gun after 5 shots, and it last another 5 after that. I then replaced it with a real flint.

To raise the point of impact I needed to shorten the front sight. The file I had with me was too fine to remove enough metal in a reasonable amount of time so after awhile I gave up on it. After I got home I took the barrel out to my shop where I had a coarser file and took some off the top of the front sight.

If you know the sight radius of your gun, the distance to the target, and how much you need to move the point of impact, you can use this formula to determine how much to move an adjustable sight or file a fixed sight:

(Sight radius / Distance to target) (POI change needed) = Adjustment needed

All units must be the same. E.g., my rifle has a sight radius of 21.125" and 50 yards = 1800 inches. I needed to remove a bit over a tenth of an inch from the front sight to bring up the point of impact.

Something I noticed is that with this powder charge, ball size, and patch/lube combination, I can load a second shot without wiping but it's tough. After I get it zeroed I'll try with a liquid lube to see if that makes it easier. But I may look into a thinner patch for reloads while hunting, or bring a jag and patches wet with rubbing alcohol in my shooting patch when hunting. 

Tomorrow I'm planning to get together with a friend for some shooting and I'm bringing the Gemmer Hawken. Hunting season is coming up soon so I want to verify the zero get some practice in.

Investarm Gemmer Hawken Rifle

With Lyman getting out of the black powder business, Muzzle-loaders.com has taken over as an importer of Investarm guns. I had a 10% off coupon from them that expired at the end of last year, so on 12/26/23  I put it towards a left handed .54 flintlock Gemmer Hawken. It arrived this past Wednesday. The Gemmer Hawken is the current incarnation of the Lyman Great Plains Rifle, which for decades has been very highly regarded for a production muzzleloader.

Back in the 1990s I had a LH flint .54 Lyman GPR but sold it off after a few years. At the time I wasn't hunting and my shooting interests were more along the lines of milsurps and S&W revolvers. I wish that I had kept it. Let's just say that the Investarm rifles made today are not as nice as those made even 10 years ago, much less my old GPR. In particular, the triggers were horrendous. Rough, difficult to set, and so heavy when unset as to be unusable. So, I ordered a Davis Deerslayer from the Log Cabin Shop and it arrived today. The Deerslayer was originally designed for use in  the T/C Hawken and Renegade, rifles but it also works in similar guns like the GPR/GH.

Installation was painless and while the instructions mention removing wood, that wasn't required. (Doing so may be required on a T/C.) The rifle now has an easy to set trigger that would be usable even when unset. Dry firing it feels like I'm holding one of my custom muzzleloaders. In my opinion the Davis triggers are worth the $80 asking price (although it shouldn't be necessary to replace the triggers on a factory rifle to get something usable).

Pic before installing the new triggers:

Yesterday I added a couple coats of clear Watco Danish Oil to the stock, which is some unspecified European hardwood that was lightly finished. Older Investarm guns, including the Cabela's Hawken I took a big doe with in 2022, had walnut stocks. I also replaced the vent liner with an RMC unit that uses an Allen wrench for removal. It's coned internally as well on the outside so it should help ignition.

The lock sparks well even with the cut agate flint that it came with. L&R now makes left handed RPL replacement flintlocks to fit the GPR/GH but I'll give the factory lock a solid workout before thinking of replacing it.

The only other modification I have planned it to put slots in the barrel keys and install pins held in by the escutcheons so they can't fall out and get lost.

I may not be able to shoot it until next weekend, due to the weather. I'm hopeful that it will shoot well with 70 - 80 grains of 3Fg and a patched .530 ball. I'm also going to try some .526 balls which should make for easier loading in the field. My reason for getting a .54 is to improve my chances of a complete pass-through on the large whitetail deer up in Tioga County, compared with the .50s I've been using.

As an aside along those lines, I'm hoping to work up a good conical load for my percussion Cabela's Hawken .50 that I can use during the early antlerless season. I have some Hornady Great Plains bullets that should shoot well in the gun and be really effective on deer.

Aside from the larger ball, the Gemmer Hawken will give me a flintlock rifle that's easier to handle inside a deer blind, since it's significantly shorter than the longrifle I toted last week.

More to follow after I shoot it ...