GPR lock

[123.DieselBenz]

First let me say I'm no expert! I have never even held a flintlock in my hands, but . . . wouldn't a L O N G E R flint strick the frizzen sooner, and produce more sparks? (I realise that too long will hit the pan)

 

[mykeal]

Yep. But they have a tendency to get shorter...

 

[Trot]

Putting the flint bevel down would also make it hit higher on the frizzen.

 

[BadHorse]

Putting the flint bevel down would also make it hit higher on the frizzen.

gpr's do like bevel down

 

[ebiggs1]

Putting the bevel down, which I have been doing, makes the flint strike the frizzen at a bash the flint angle. In my case, the flint life was unacceptibly short. The problem as I see it is the flint does strike too low on the frizzen. The flint in the picture is about 1/16" from the frizzen and has about 10 strikes on it. It is still very sharp and produces lots of sparks.

 

[ebiggs1]

Since my only refference and experience is my TC locks, which the GPR appears identical, I am using the techniques I use on it. But I am all ears to any advice you guys may have.

 

[jethro224]

I sold my flint GPR, but before I did I found out a few things. The lock has poor geometry as you have noticed. Mine sparked better with the flint bevel down. But, the last couple times I took it shooting, I tried something new, I used a thick piece of flint leather, folded it double under the flint and single on top. Doing that raised the flint about 1/8" and allowed me to place the flint bevel up and still get a higher strike on the frizzen. Try it out, it's free. Might even work for you too.

A lead shim might work even better, maybe even a wedge shaped shim to adjust angle, I sold the rifle and didn't experiment any further. :idunno:, just thinkin'.

 

[ebiggs1]

See great minds do think alike. Thanx for the confirmation on what I also believe is wrong with the GPR. Although the locks appear similar to TC locks, they don't act the same. If I put the bevel down which helps geometry, I get poor flint life because the angle is still off.

But raising it 1/8th inch make a world of better.

 

[ebiggs1]

I got through cleaning the GPR tonite and decided to compare it to an unused TC lock I have. It looks like Lyman copied the TC lock but they copied the old version. Do you suppose a new TC hammer cock would improve the GPR’s geometry? The square hole is larger than TC’s so I could file it to make it fit. Just lining them up, looks like the TC cock would indeed raise the flint to nearly the correct position.
EB

 

[ebiggs1]

Here is the GPR lock with a Thompson Center hammer cock on it.

Here is the modified GPR lock that I shot 25 out of 25 yesterday.

You might ask why mess with it if it was 100%? Well so far the GPR has been rough on my flints and the TC has been frugal. I hope to get a chance to try this combo soon. I want 100% reliability and lots of flint life and accuracy, isn’t too much to ask is it?
The GPR lock also lets the flint get right in front of the touch hole. The TC doesn't. I suspect that would have an effect on flint life, too.

 

[larry wv]

Interesting keep us informed. How much metal did you take off to get it to fit? Wondering about getting into soft metal?? Or is the whole thing hard. :redface: Larry Wv

 

[ebiggs1]

The hammer cock is not hard. It is close to fitting as is, probably just the difference in inches and sillymeters, so very little needs to be filed off. The TC cock is slightly thinner, that is why you see a spacer washer on the screw.

 

[ebiggs1]

Here are the final results. This gun now shoots well, very well, indeed. This is a pic of the flint before shooting and”¦”¦..

Here is the same flint after 25 shoots. It is untouched and I think it will do far more strikes.

This is also the flint I broke and glued back together with super glue!
This Lyman GPR has a lees strong frizzen spring than any of my TCs. I shot 25 times today at 100% firing. Now I am satisfied with how it is working. I am using the 5/64th-coned touchhole with 4f in the pan. Bore butter .018 pillow patch and .530 round balls with 55 grs of 3f BP.

I found these balls in the dirt. I don’t know for sure if they are 54, 50, or 45 cal but look at the expansion on some of them.

 

[jethro224]

Very good experimentin' there. The T/C cock looks like it hits much better. Thanks for sharing.