Lyman GPR .54 charge?

[aragornelessar86]

Ok, I've looked here and on Google and can't find a reliable answer (it's been a few years since I've shot this rifle): what powder charge in a LGPR behind a .535 PRB? Best I could come up with is "between 80 and 100gr". I'm using 777, so I know I'm supposed to back it off 10-15% from real BP. I'm thinking I'll start off with around 70gr and see where that gets me. Is this too small a load? The bottle of 777 says 120gr in a .54, but I know I've never used over 100gr with BP in this rifle. 120gr seems like way too much.

 

[aeatwood]

Well, I would first go by Lyman's recommendation for what is a maximum load.

Secondly, depending on what you want to do with it, I would probably start w/ 60 gr or so and work up if you are looking for target/plinking loads. For a hunting load I would probably start at 80 gr.

The gun will tell you what load it likes. Usually it is best to start with finding the powder charge it likes, then start tweaking patch thickness & lube. Once you determine the best patch/lube combo, try tweaking the powder charge again. Sometimes it takes a couple of iterations to find THE LOAD, but it is usually very rewarding once you have it.

 

[mr.flintlock]

Like AlanA said, Start with 60-65gr.load. Shoot in three shot groups and increase your load by 5gr. until you find your most accurate load.

 

[Loyalist Dave]

Good advice. FYI I shoot 70 grains of BP in all of my .54's for hunting, and wouldn't hesitate to use the same load with a substitute.

LD

 

[BrownBear]

Yup, start in the 60-70 grain neighborhood and work up. I kinda work "backwards" based on my needs for trajectory and experience with 54 cal. I start at 80 grains, with 2f and then 3f black, then go up to 90. If I'm not getting the accuracy I want I'll go up to 100. Still not getting the accuracy? I'll usually drop down to 70 then, but with disappointment. I don't need higher than 100 for my shooting, but by the time I get down to 70 my trajectory is starting to suffer. Most of my 54's like 90 grains of one granulation or the other. I'm currently using 90 grains of 3f Goex in my GPR 54.

My hunting pard is the 777 user in our crowd. His particular rifle just sings with 90 grains of 777 in 3f granulation. That's the rough equivalent of 100-105 grains of 3f Goex, but his rifle likes what it likes.

One thing to watch with yours is patch condition. With that .535 ball you might find .015 patches a little hard to load if you haven't shot that gun at least a couple of hundred times in the past, and you'll be tempted to go to .010 patches to ease loading. In my experience, that's almost a sure formula for torn patches and poor accuracy. Better would be to go to a .530 ball and .015 or .018 patches in that case. But don't complicate things unnecessarily. Go ahead and shoot what you have, then start changing ball/patch if you're getting torn patches.

 

[aragornelessar86]

Yeah, I've shot .535 ball with .015 patches since I got the gun without much trouble, so unless the barrel shrunk or the patches/balls grew, that combo should be GTG. That rifle was dead on at any range I tried it at last time I was shooting it regularly, but I want to try 777 as I hear it's much easier to clean up.

 

[cowpoke1955]

I have two .54 GPR's, one percussion and one flint. My favorite load in both is .530 ball, pillow ticking patch libed with Ballistol oil and 80 grain of FFg Goex. This will give me one ragged hole at 50 yards. Increasing the powder charge to 90 grains of FFg Goex will give me almost the same results at 100 yards. Never found a need to use 100 grains or more.

 

[BrownBear]

Yeah, I've shot .535 ball with .015 patches since I got the gun without much trouble, so unless the barrel shrunk or the patches/balls grew, that combo should be GTG. That rifle was dead on at any range I tried it at last time I was shooting it regularly, but I want to try 777 as I hear it's much easier to clean up.

Sounds like you're good to go. My pard is so pleased with 777 I can't even get him to try some of my black, so I bet you're in the money.

Notice neither of us is using Pyrodex? We both were able to make it work when that was all we had, but it was a little cranky to use in both our GPRs from the care and misfire standpoint. When we both moved away from it, we both swore not to go back unless we had to.