The Shooting Has Begun with the GPR

[Christophero]

I posted a few weeks back of picking up an older but barely used Lyman GP Rifle in 54 caliber, percussion lock. As all the advice read on this forum I took the Scotchbrite to it, bore and crown one evening not long after procuring it. Purchased a length of 100% cotton cloth at Walmart that miced at .017" unwashed. Weave looked pretty tight and the price was negligible. Hand washed last night with hot water and hung it to dry. Put it in the washing machine with a small load of clothes this morning and dried it in the hot air of the tumbler. The micrometer then read .022", pressed down the cloth compressed to .015". Cut patches between work duties and thumbed on bore butter, as it was in the kit and easy to grab.

Stole enough time today to finally load up and shoot a few in the limited range of my back yard (38 yards). As the FFg is in unopened cans I figured may as well use the FFFg (Goex) in the powder horns and proceed from there, only the unmarked horn must have been Pyrodex as there was absolutely no cloud upon firing, twice, a 75 grain and 80 grain loading. Then I went back to the closet in my muddy boots to grab what I know was FFFg black powder. Measured 80 grains, set the trigger, rested the forearm on the cross sticks and proceeded to enjoy the satisfying boom along with the plumb of white smoke we love so well. Spit swabbing between 3 of the 4 shots made loading easy.

Found a couple of the patches 12 steps toward the target from the chair:

Yes, that is a huge hole in the middle of the patch on the right. I strongly believe it is from the 80 grain Prodex charge. Looks to my eye that the lands are still quite sharp on the patch. Would hand lapping the bore with clover compound be a remedy, as I've done with CF rifles?

Had to go to another property later in the day to work on a vehicle. Had a fifth 80 grain FFFg load in the rifle for a shot while I was there. Set out a box 80 yards distant, sighted on where the tape crosses and made smoke:

That is encouraging.

Still, that lone patch isn't too pretty

The patch is laying on the cloth I bought yesterday. Thinking that may not be the correct cloth to use, only the pillow ticking they had mic'ed out at .024" off the bolt, causing me to shy away from it.

I am new, brand new the the 54 caliber world. Owned, shot and hunted with 50 cals for 35 years, PRB for the past 6 or 7 years. This is another skill set to master and enjoy. I could go hunting with it as it is, yet I know eventually the necessity to dial the patch, load and lube will be mandatory for optimum accuracy.
Any words of wisdom are welcome from those who have much experience in the over 50 club.

 

[Phil Coffins]

The calibre doesn’t matter but your patch is failing. Powder charge is in line with what works for most. Unless the barrel feels really bad I wouldn’t use Clover compound in the bore unless you are doing a lead lap. The cloth may not be up to the task so try some others first.

 

[Grenadier1758]

@Christophero, the huge hole in the first patch and the hole in the last patch indicate to me that you have sharp lands and a sharp edge at the crown that is cutting the patch on loading. You should find a benefit from smoothing the crown. This can be as simple as getting some 400-grit wet/dry paper and working the crown using thumb pressure on the muzzle to smooth the crown.

Be sure your patching is 100% cotton. Anything else using synthetic fibers is doomed to failure.

The Lyman (Investarms) GPR is known to have sharp lands new from the factory. It will take from 100 to 200 shots to smooth the edge of the lands. You can speed this up by using a brass brush smaller than the bore recommendation (for example, a 50 in a 54) that is wrapped in 0000 steel wool and running that combination about 200 strokes. Replace the steel wool after 50 strokes.

You will find shooting your GPR quite enjoyable.

 

[SDSmlf]

There are many ways to polish and smooth up a bore. Here is a @duelist1954 video showing the process he used on a difficult to load GPR.



I have used a similar method with Scotch-Brite for some time, but Mike explains his very well. I started doing it after speaking to Don Getz (Getz Barrel) years ago before he passed, and he recommended using the green (600 grit) Scotch-Brite for smoothing up barrels that were cutting patches. Said it wouldn’t hurt the barrel.

 

[Christophero]

I appreciate your replies, Gentlemen. One more shot was loaded today, but with a patch pushed upon the powder charge before ramming home the PRB. That confirmed that the powder alone wasn't the culprit because this patch, too, was found with a big hole out of the middle.
Looking forward to watching the video you posted. Though I have already Scotchbrited the bore and crown I am not above doing it again.

 

[Sixgun_Symphony]

Try using a lubricated felt wad between the powder and patched ball.

 

[Britsmoothy]

Or cream of wheat!

When that is run it it is going to cloverleaf!

 

[stikshooter]

I posted a few weeks back of picking up an older but barely used Lyman GP Rifle in 54 caliber, percussion lock. As all the advice read on this forum I took the Scotchbrite to it, bore and crown one evening not long after procuring it. Purchased a length of 100% cotton cloth at Walmart that miced at .017" unwashed. Weave looked pretty tight and the price was negligible. Hand washed last night with hot water and hung it to dry. Put it in the washing machine with a small load of clothes this morning and dried it in the hot air of the tumbler. The micrometer then read .022", pressed down the cloth compressed to .015". Cut patches between work duties and thumbed on bore butter, as it was in the kit and easy to grab.

Stole enough time today to finally load up and shoot a few in the limited range of my back yard (38 yards). As the FFg is in unopened cans I figured may as well use the FFFg (Goex) in the powder horns and proceed from there, only the unmarked horn must have been Pyrodex as there was absolutely no cloud upon firing, twice, a 75 grain and 80 grain loading. Then I went back to the closet in my muddy boots to grab what I know was FFFg black powder. Measured 80 grains, set the trigger, rested the forearm on the cross sticks and proceeded to enjoy the satisfying boom along with the plumb of white smoke we love so well. Spit swabbing between 3 of the 4 shots made loading easy.
View attachment 108660

Found a couple of the patches 12 steps toward the target from the chair:
View attachment 108661
Yes, that is a huge hole in the middle of the patch on the right. I strongly believe it is from the 80 grain Prodex charge. Looks to my eye that the lands are still quite sharp on the patch. Would hand lapping the bore with clover compound be a remedy, as I've done with CF rifles?

Had to go to another property later in the day to work on a vehicle. Had a fifth 80 grain FFFg load in the rifle for a shot while I was there. Set out a box 80 yards distant, sighted on where the tape crosses and made smoke:
View attachment 108662
That is encouraging.

Still, that lone patch isn't too pretty
View attachment 108663
The patch is laying on the cloth I bought yesterday. Thinking that may not be the correct cloth to use, only the pillow ticking they had mic'ed out at .024" off the bolt, causing me to shy away from it.

I am new, brand new the the 54 caliber world. Owned, shot and hunted with 50 cals for 35 years, PRB for the past 6 or 7 years. This is another skill set to master and enjoy. I could go hunting with it as it is, yet I know eventually the necessity to dial the patch, load and lube will be mandatory for optimum accuracy.
Any words of wisdom are welcome from those who have much experience in the over 50 club.

See Lee Shavers bore polishing /Ed

 

[Roundball 54]

When l have seen patches that look like the ones you posted , more often than not it has been from using to thin of patch material . Try thicker patches .

 

[Christophero]

Good video. It solidified all the excellent information found on this website. As mentioned, I have Scotchbrited the bore and crown before shooting, but with a bright flashlight it is obvious that the tool chatter is excessive compared to the other MzLdrs in my cabinet. If time allows I'll give it another polishing regimen this weekend. The duelist's information about the micro-burrs makes much sense and it may take more than a cursory polish to clean those up well enough. I like this rifle and hope to have much enjoyment from its use.

The cream of wheat idea has been touted on a number of searched threads. I do have a box in the kitchen to put to use.

Is a .015" compressed 100% cotton patch too thin for a .530" ball in the Lyman GPR? It doesn't start without some force on the ball starter and takes pressure to ram it home. I've loaded easier projectiles in other rifles. What I need to use in one of my 50's is a thin linen or else it is too hard to load. But that is a hand cast ball, whereas this is a Swaged Hornaday ball for the 54.

Edit: that should say it does start out with some force with the ball starter

 

[Roundball 54]

My son shot his Lyman GPR with me last week using .020" patches , .530 Hornady RB ,Moose Milk patch lube , 55 grain fffg Goex . No swabbing between shots . Good accuracy , no problems loading .

 

[Tasbay]

My GPR is doing the same damage to patches as yours and that is after smoothing the bore and crown with fine emery paper. I`m beginning to believe it is too thin patch for the rifle, it is also the easiest to load with the same combo of Ticking and .495 Ball. The rest of my muzzleloaders shoot fine with a Ticking patch and olive oil lube. Only the GPR destroys its patches. All My rifles are shot with 85gr of Black except one which likes 100gr Black and the Ticking Patch. The used patches out of all but the GPR could be used again.

 

[Crow-Feather]

I appreciate your replies, Gentlemen. One more shot was loaded today, but with a patch pushed upon the powder charge before ramming home the PRB. That confirmed that the powder alone wasn't the culprit because this patch, too, was found with a big hole out of the middle.
Looking forward to watching the video you posted. Though I have already Scotchbrited the bore and crown I am not above doing it again.

Your lube sucks as the ignition is burning through the patch. Sharp lands cut the sides of the patch but do not touch the center. The hole in the center of the patch indicates the patch burning through. I use a mixture of 15-20 percent Napa cutting oil and the rest water with a dash of liquid soap though there are a bunch more lubes that will work. The one described works for me. I soak the patch and squeeze until the patch is saturated throughout. The patch material I use is pillow ticking from .017 to .022 machine washed at least three times to get the sizing out and the material is soft and able to absorb the lube. Once again, lands do not put holes in the center of the patch, that is done by the heat of the ignition and a good wet lube from spit to Moose Milk will prevent that.

 

[Britsmoothy]

I would not got tighter in the ball and patch combo. Just leads to a world of misery!
Once that bore is polished you'll be set.
Do though, for now at least use a firewall.

 

[Roundball 54]

My GPR is doing the same damage to patches as yours and that is after smoothing the bore and crown with fine emery paper. I`m beginning to believe it is too thin patch for the rifle, it is also the easiest to load with the same combo of Ticking and .495 Ball. The rest of my muzzleloaders shoot fine with a Ticking patch and olive oil lube. Only the GPR destroys its patches. All My rifles are shot with 85gr of Black except one which likes 100gr Black and the Ticking Patch. The used patches out of all but the GPR could be used again.

Is your GPR a current production or is it a older rifle ?

 

[Tasbay]

Roundball: My GPR is 2013 manufacturer, previous owner seems to have shot it and put it away uncleaned. barrel cleaned up nice with just rags and elbow grease.

Britsmoothy: Have tried a firewall in mine, made no difference

 

[Roundball 54]

Is your GPR a current production or is it a older rifle ?

My GPR is doing the same damage to patches as yours and that is after smoothing the bore and crown with fine emery paper. I`m beginning to believe it is too thin patch for the rifle, it is also the easiest to load with the same combo of Ticking and .495 Ball. The rest of my muzzleloaders shoot fine with a Ticking patch and olive oil lube. Only the GPR destroys its patches. All My rifles are shot with 85gr of Black except one which likes 100gr Black and the Ticking Patch. The used patches out of all but the GPR could be used again.

My guess is too thin of patches .

 

[johnfrommd]

Investarms barrels have been know to have sharp lands in them for years. I have always recommended bore lapping (when I had my business) which would stop patch cutting much faster than waiting to shoot it smooth. Thicker patches will work but you will have to drive the ball in with a hammer and punch. I don't recommend pushing on a short starter that hard as it can be dangerous if it breaks.

 

[Christophero]

SUCCESS. The other evening after watching the video above I took the Scotchbrite to the bore for another vigorous round of scrubbing. After using up 3 'patches' of Scotchbrite it was revealing all that was coming out of the barrel when tipped upside down that wasn't just particles of the pad. Cleaning it thoroughly with Windex I noticed 3 distinct portions of the barrel that were just a tad tighter than the rest. That stuck with me.
Upon waking up the next morning I knew what needed done. Prepping another Scotchbrite 'patch' I coated it well with fine Clover Valve Seating Compound, pushing and pulling the rod 50 times each direction. This isn't as aggressive as a full lead lap, but I don't have any 54 cal conicals to use and wasn't going to fire up the casting pot. This was an experiment that I expected to show positive results. Then I took the barrel to a bucket of hot tap water for a complete cleaning regimen. Everything looked copasetic until I began dry swabbing the bore with tight patches:

That's what I thought, those tight spots were surface rust areas that a regular cleaning, or even the plain Scotchbrite pads couldn't expose. Kind of easy to tell which was the first swipe down the bore and which was the forth.

Sure of having made a difference the rifle was loaded with the 80 grain charge of FFFg using the same patches from the swath I purchased at Walmart last week that keep shredding. The first two patches were lubed with spit only. Both looked like this when found:

The material held up just fine after the lands and grooves were smoothed out and cleaned up. For an apples to apples comparison two additional shots were fired using the T/C Bore Butter on the patches (same 100% Cotton patch material I've been using since first firing this rifle):

No holes, no shredding to be seen. Next session will be for accuracy on target, but I have high hopes at this point.
Intentionally, no cleaning swabs were run between the shots fired. As experienced in the video of Duelist's shared above the 4th PRB loaded as easy as the first did.
By the way, I sent the serial number to Lyman Customer Service today and they replied this rifle was made in mid 1985. The more this is used the better that bore should clean up for many more years of good use.

 

[Roundball 54]

Good... looks like you are making progress .