There are a good many posts on this forum mentioning the Lyman GPR. There also some questions about reliable ignition. I just thought I would share some of the things I have found about this rifle over the years.
When I got the gun it only fired about one third of the time. Even with a flash in the pan I got no ignition. I modified the touch hole liner. I drilled it out to .080 then using a .120 round tip carbide cutter, I removed the center of the screw slot down to the flash hole. Using a #1 center drill I drilled out the back down to where there was only about .050 of flash channel between the face and cone. Next I took a tapered cutter and further opened the cone as far as possible.
With the standard Lyman liner you are limited to what you can do as the diameter is so small. An even better solution would be to replace it with one of the newer ones from Jim Chambers.
This modification gives me ignition everytime I get flash from the pan. Lock time is fast also.
I have noticed that the Lyman frizzen is not as hard as it needs to be. Most of them give several orange sparks, not a shower of hot white sparks. There is a difference and it shows up in how fast and reliable your locktime is. To get by I bought several frizzens and tried different ones until I found the best. Case hardening the frizzen with Kasenit is also an option though I haven't tried it yet.
For these frizzens to work to my satisfaction my flint must be very hard and sharp. A crumbly flint won't do the trick. When I get a particularly good one I save that one for hunting.
The trigger leaves a lot to be desired compared to the TC. I dissasembled mine and honed all the surfaces.
For years I used Crisco and tried other stuff, cleaning regularly as your rifle dictates.
Then a friend talked me into using some WonderLube 1000 by Ox Yoke. This is some great stuff. I use it as a lube and rust preventative. My GPR hasn't had a drop of gun oil in over 5 years.
When range shooting if I use half or a little greater charge, then I never clean the bore all day. Accuracy never suffers and crud and clinkers are not pushed down to cover the touch hole. If I shoot a heavy charge it acts just like normal and the barrel must be cleaned every few shots.
When doing a thorough cleaning I use a regular centerfire rifle jag after swabbing the bore with the .54 jag and hot water. This gets a patch down into the smaller powder chamber where the .54 jag and patch won't reach.
Seeing as BP residue attracts moisture, I don't fire a pan or 2 of powder before loading my hunting load. I wipe the bore with a couple of dry patches then using a patch soaked in "Golden Grain" alcohol, I pour a little down the bore then swab it. I like to see some forced out the flash hole. "Golden Grain" is 190 proof with very little water content, compared to rubbing alcohol. It cleans well and evaporates fast.
I also wipe my frizzen and flint with alcohol.
Due to the humidity we have down here I prime my hunting loads with FFFG instead of 4F. I keep a leather frizzen cover on and carry a cows knee.
After taking the time to do all this, if my rifle "Doesn't" fire, then I am surprised.
I have hunted extensively with both the percussion and flintlock and I don't think the flinter will ever be as fast or reliable as a good percussion. But I think doing these things has make my Lyman as dependable as an off the shelf production gun can be.
When I got the gun it only fired about one third of the time. Even with a flash in the pan I got no ignition. I modified the touch hole liner. I drilled it out to .080 then using a .120 round tip carbide cutter, I removed the center of the screw slot down to the flash hole. Using a #1 center drill I drilled out the back down to where there was only about .050 of flash channel between the face and cone. Next I took a tapered cutter and further opened the cone as far as possible.
With the standard Lyman liner you are limited to what you can do as the diameter is so small. An even better solution would be to replace it with one of the newer ones from Jim Chambers.
This modification gives me ignition everytime I get flash from the pan. Lock time is fast also.
I have noticed that the Lyman frizzen is not as hard as it needs to be. Most of them give several orange sparks, not a shower of hot white sparks. There is a difference and it shows up in how fast and reliable your locktime is. To get by I bought several frizzens and tried different ones until I found the best. Case hardening the frizzen with Kasenit is also an option though I haven't tried it yet.
For these frizzens to work to my satisfaction my flint must be very hard and sharp. A crumbly flint won't do the trick. When I get a particularly good one I save that one for hunting.
The trigger leaves a lot to be desired compared to the TC. I dissasembled mine and honed all the surfaces.
For years I used Crisco and tried other stuff, cleaning regularly as your rifle dictates.
Then a friend talked me into using some WonderLube 1000 by Ox Yoke. This is some great stuff. I use it as a lube and rust preventative. My GPR hasn't had a drop of gun oil in over 5 years.
When range shooting if I use half or a little greater charge, then I never clean the bore all day. Accuracy never suffers and crud and clinkers are not pushed down to cover the touch hole. If I shoot a heavy charge it acts just like normal and the barrel must be cleaned every few shots.
When doing a thorough cleaning I use a regular centerfire rifle jag after swabbing the bore with the .54 jag and hot water. This gets a patch down into the smaller powder chamber where the .54 jag and patch won't reach.
Seeing as BP residue attracts moisture, I don't fire a pan or 2 of powder before loading my hunting load. I wipe the bore with a couple of dry patches then using a patch soaked in "Golden Grain" alcohol, I pour a little down the bore then swab it. I like to see some forced out the flash hole. "Golden Grain" is 190 proof with very little water content, compared to rubbing alcohol. It cleans well and evaporates fast.
I also wipe my frizzen and flint with alcohol.
Due to the humidity we have down here I prime my hunting loads with FFFG instead of 4F. I keep a leather frizzen cover on and carry a cows knee.
After taking the time to do all this, if my rifle "Doesn't" fire, then I am surprised.
I have hunted extensively with both the percussion and flintlock and I don't think the flinter will ever be as fast or reliable as a good percussion. But I think doing these things has make my Lyman as dependable as an off the shelf production gun can be.