Blown out patches? bore, crown, patching material, lube where to start?

[DillyJamba]

Recently picked up a used Lyman GPR on my first outing I couldn't hit the broad side of a barn (10-inch groups at 50 yards). after about 20 shots down range and adjusting my load, I finally walked down range and immediately noticed nearly every single patch was completely shredded, I wasn't encountering a tremendous amount of force when loading .530 ball and red/blue pillow ticking lubed with 1-6 ballistol/water . It was snug but not crazy tight (I load my pedersoli kentucky with a lot more force on the short starter).

Still learning the ropes with muzzleloading and I've read that GPR's tend to be sharp from the factory, the gentleman I purchased it from included half a box of balls so it's likely that's all it had ran through it prior to sale (Seems in very pristine condition)

So where to start with this problem?

 

[Grimord]

Get yourself a .50 caliber jag and put a 7/8" square of green scotch brite as a patch with a dab of JB bore paste. Give your barrel a good scrubbing (100+strokes or more). This should soften up the edges of the lands so as not to shred the patches, and accuracy should improve.

 

[Grenadier1758]

Sharp corners on the lands would cut holes where the corners of the lands cut the patches. The circular hole in the patch indicates a sharp crown. Doing the polishing with the green Scotch Brite won't hurt a thing and is probably a good idea.

To smooth the crown will take several grades of wet/dry sandpaper. 220, 320 and 400 will be sufficient. Cut several 2 1/2" squares of each grade. Hold the barrel upright and using your thumb holding the square of sandpaper in the muzzle, starting with the coarsest grade, Rotate the barrel back and forth for a count of 10. Rotate a quarter turn and sand on the crown for ten more partial rotations. Continue until you have completed one full revolution of the barrel. Get another square of paper and do it again. Use the next finer grade of paper to do the next polishing of the crown. When you have used the 400 grit paper, try a few shots to see if the crown is still cutting the patch.

 

[DillyJamba]

Hmm this is what I have on hand, no JB bore paste and currently just some red pads think that's safe? also have various grades of sandpaper 220-500-800-1500 and steel wool. I'm slightly hesitant to go out at with any product in fear of damaging the bore.

CZ pictured not relevant just on work bench.

Should I hold off on scrubbing down the bore until I get the paste?

 

[DillyJamba]

Pictures of the gun and bore for refence, seems like a pretty sharp transition after the tapered edge, id basically be working the edge between the rifled section and the tapered area correct?

 

[Phil Coffins]

You’re correct that the only part needed smoothed is the rifling to the taper. And I agree deal with the crown first before attacking the bore. The patch material is where my interest would be.

 

[64Springer]

Fold a piece of 320 in half and thumb polish the crown.

That's all you need to do.

Do not grind away at your crown.

 

[Phil Coffins]

Here’s the crown on my most accurate rifle on the left. The one on the right is excessive. The red ticking I have seen is lighter than the blue that I prefer. JB is for cleaning and has little if any effect on a rough bore.
IMG_0421 by Oliver Sudden, on Flickr

 

[Sam squanch]

Nothing to do with crown polishing, but try a wad between your powder charge and patched ball. It will protect the patch from burning.

 

[DillyJamba]

Here’s the crown on my most accurate rifle on the left. The one on the right is excessive. The red ticking I have seen is lighter than the blue that I prefer. JB is for cleaning and has little if any effect on a rough bore.
IMG_0421 by Oliver Sudden, on Flickr

Wow so not that much needs to be taken off really just breaking the corner I guess or is special care taken when the rifle in the left when loading?

Useful info I was about to at it like a madman, I actually don’t have 320 grit on hand but I’m thinking the 500 I have should work with just a few extra passes.

 

[Larry (Omaha)]

Wow so not that much needs to be taken off really just breaking the corner I guess or is special care taken when the rifle in the left when loading?

Useful info I was about to at it like a madman, I actually don’t have 320 grit on hand but I’m thinking the 500 I have should work with just a few extra passes.

500 is too fine. Might as well rub it with your bare fingers for two days. No disrespect intended, but listen to the boys if ya want to fix your issue.
Larry

 

[Phil Coffins]

Wow so not that much needs to be taken off really just breaking the corner I guess or is special care taken when the rifle in the left when loading?

Useful info I was about to at it like a madman, I actually don’t have 320 grit on hand but I’m thinking the 500 I have should work with just a few extra passes.

I load that rifle without a short starter and no special care. The ball is placed on the patch and the knife blade is layed over it and given a modest smack with my hand then the butt of the knife handle push’s the ball just a bit lower then the same knife cuts the patch. I use the wood ram rod to seat the ball on the powder. This sport can be as complicated as you like but I prefer simple.
IMG_0200 by Oliver Sudden, on Flickr

 

[DillyJamba]

500 is too fine. Might as well rub it with your bare fingers for two days. No disrespect intended, but listen to the boys if ya want to fix your issue.
Larry

It’s 500 or it’s 60 there’s nothing else in stock! ( in my tool box )

You’re right better to do it right the first time! Will update tomorrow.

 

[coupe]

Looking at the patches I believe polishing the crown, as they said, is the best way to start. It seems to me the patch is put under max stress when loaded stretched out and weakened easily burned. A wad might help but try a empty lubed patch over the powder then your ball and normal patch, if all-goes well shoot for best group. Wads in mine don’t help but the sacrificial patch does best till the bore settles down. I have a 54 renegade that has a scruffy bore polished n petted n rubbed that eats patches till I use the patch over powder and it does it with only 70 grs of powder! .530 ball n .019 pocket drill patch TOW mink oil lube.

 

[nchawkeye]

It all starts with the patches, you start "polishing" without knowing what you are doing and you may screw up your barrel..

How old is your patching material? Was it prelubed? Lube can break down cotton patching...Start there, then as someone suggested, put a wad, even another patch between your powder and ball to keep patches from burning...Also, what powder are you using?? 777 and other subs can burn through patches, use only real black powder for most consistent results...Also, change lubes, try SnoSeal, it's worked for me for over 40 years...Also, what is your powder charge? Too heavy a charge can burn through patches...For a hunting load 75-85 grs in a .54 is plenty...

 

[Steve Wagner]

Dilly, lots of good advice here. When I got started, someone on here told me about polishing the crown with progressive rounds of wet/dry paper starting at 200 up to 400 or 600 using your thumb at the muzzle. That helped a good deal. Someone else pointed out that it is safe to polish the entire bore with the finest steel wool [000 I believe]. I started w a Traditions 50 cal Hawken and it really helped, with the same problem you are having, by removing some burrs. I also stepped down from .015 lubed patches to .010 and it made no real difference in accuracy, but it did allow my grandson to load the rifle by himself. For plinking, the thinner patches are much easier to load. Works for some rifle and not others. Give it a try. I still use .015 for hunting. SW

 

[R Ellis]

It’s 500 or it’s 60 there’s nothing else in stock! ( in my tool box )

You’re right better to do it right the first time! Will update tomorrow.

Go get the grit that everyone said will get the job done only a couple of dollars

 

[DillyJamba]

It all starts with the patches, you start "polishing" without knowing what you are doing and you may screw up your barrel..

How old is your patching material? Was it prelubed? Lube can break down cotton patching...Start there, then as someone suggested, put a wad, even another patch between your powder and ball to keep patches from burning...Also, what powder are you using?? 777 and other subs can burn through patches, use only real black powder for most consistent results...Also, change lubes, try SnoSeal, it's worked for me for over 40 years...Also, what is your powder charge? Too heavy a charge can burn through patches...For a hunting load 75-85 grs in a .54 is plenty...

Noted on the polishing, holding off on scrubbing the barrel and just hitting the crown before going out today.

Pre lubed patches lubed with 6 parts water 1 part ballistol the day prior. Schuetzen 2F powder.

Focus right now is more of a target load.

 

[wiscoaster]

View attachment 252528View attachment 252530

Pictures of the gun and bore for refence, seems like a pretty sharp transition after the tapered edge...

Ouch, that looks really sharp, even in a small photo. Agreed with the reccos to smooth out the lands and grooves to crown edges. Good luck on the range trip.

 

[45man]

I see burned out patches. The GPR has deep rifling so I would use a .535 ball and a patch that is tight. looks as if you have a gap for gas to escape.