GPR blowing patches

I have a GPR in 54 using goex fff under .15 pillow ticking and .530 ball my patches lubed with spit or olive oil and all have bottoms blown out. Rifle was used before I got it and have shot it about 50-75 times using 60-90gr of pyrodex and about that many with goex. Every pathch the same except for some new pillow tick that is .19 thick and it takes a hammer on short starter to start and must hammer load all the way (way to tight). Being this rifle was used I have no idea how much it was shot, love the rifle and is grouping ok just blown patch. Ideas how to load easier and not blow patches it shoots 80grs of fff very well.

Some people do not like bore butter, but my 54 has never had problems with it. The .018 pillow ticking is black an the bottom but far from burned through. I would try bore butter you may like it. Requiring a bullet starter is normal a tight fit is required, use of a hammer is to much. Take a caliper and measure the mouth of the barrel, the ball and ticking should be just under this measurement, Ie: .549 barrel .530 ball and .018 ticking for .548.

Try an over powder wad or patch - the only load my .54 GPR will shoot with any accuracy is 100 grs. of FFFg, .015 pillow ticking lubed with bore butter and I have to use a bore button as an over powder wad or the patches are all torn and burned. This barrel has had at least 500 rounds through it, I've tried all sorts of load combinations in different powder ranges and with this near max. load it will shoot cloverleaks at 50 yards. Hard on my shoulder though.

You could also try cleaning/lapping the bore with J&B Bore paste and or/bronze wool, some guys use 000 steel wool, didn't help with my barrel but might with yours.

Check the crown. All my GPRs have had a very sharp crown which wants to cut patches on loading. The cuts mostly go away after 200-300 shots, but there's a quicker solution: Lay a piece of 320 or 400 grit emery cloth across the muzzle and press down firmly with the flat ball of your thumb. Rotate your thumb smoothly back and forth half a dozen times to break the sharp edge. Really quick and easy.

There's another possibility- Depends on how much you and the previous owner have shot it in total, but when newer the bores tend to be a little rough with sharp lands. That goes away and smooths out after the same 200-300 shots, but some guys prefer to lap. I've always just "shot through" the issue rather than lapped, so I can't advise you there.

But here's the deal: When my 54's have first started out they needed that .015 patch with .530 balls. But once I got through those 200-300 shots I started noticing that loading force got a lot lighter with occasional burned patches. A switch to .018 patches firmed up the seating force noticeably, but didn't quite require a mallet. Patches quit burning, and meanwhile accuracy got even better. After several K shots that combo starts feeling a little loose, but I haven't tried a possible next step cuzz accuracy has remained good. Next step in my mind would be to go to a .535 ball and .015 or perhaps even .018 patch, but I haven't tried that with either gun. Don't want to get into Mallet Land, and I'm still satisfied with accuracy.

BTW- Swapping back and forth between Pyro and Goex didn't change anything for me. Ignition after lots of shots is certainly better with the Goex, but you can beat that with a swab every half dozen shots or so when using Pyro.

Great gun, and it'll come around, whether you "shoot through" the issue with more shooting, or with lapping or crown polishing.

A used rifle should have any crown sharp edges worn off. I would suggest trying an over powder wad. If that doesn't fix the problem lapping may be required. Have you tried a bore light and looked for rough spots? :idunno:

I only shoot real black powder in my GPR 54 and .018 patches and 85 to 100 grains of powder.
No problems at all!

Geo. T.

Try using ff instead of fff. 90 grains ff with .535 ball and .017 patch works well for me.

HH 60

I would run 0000 steel wool with oil on a jag and scrub the bore.I do this on all new-to-me muzzleloaders.
My 54 GPR does well with 100grs of FFg,.020 patch,and a .535 RB.

Try using 2F powder. Also use an over powder wad ( folded up cleaning patch will work.) I use a .018 lubed patch over a .530 RB.
Stopped my burnt patch problem and helped in the group size too.

I'd for sure make sure your patches are well lubed. Also as others have suggested, an overpower card would help. Also check your rifling with a bore light for rough spots. One more thing, a .015 and a 530 round all should not produce a super tight load combo like your experiencing ....I wonder if your rifling is lead fouled causing this tight loading issue?

Ringo
I’ve been cleaning lead out of my second hand GPR since I bought it. It is also badly blowing patches. I agree with S.kenton on checking for lead. If the previous owner primarily shot conicals lead could be the problem. My patches are so badly torn up that they are difficult to find. Even with the leading the rifle shoots a tight group. I’ve used steel wool, several different solvents, and some Burchwood Casey cloth and it’s getting better. The lands are mirror bright but I can still see traces of lead in the grooves.
Stan

I will check it for leading and also try a wad under prb to see if it helps. I had carpel tunnel surgery at the beginning of the month and running a ramrod and short starter are out for a few more days even though deer opens tomorrow. I may see if my son will load it for me and my plains pistol just to get out some. Thanks for the help.

JB Bore Paste works good for lead removal.

If its been used extensively with corrosive subs it may never load right due to a rough bore. It ALWAYS pits bores. But most people don't care to see it.
The 530 with pillow ticking should load OK in a 54 unless its a 53. Once in it should be sized to the bore and not require hammering, this simply tightens it every whack, once in the ball should slide down though it may take some pressure to do it. I would try PURE neatsfoot oil on the patches or even Crisco as a stop gap and see if this helps. A true 54 should load a 535 with a ticking patch with little trouble. Unless the bore is pitted.
Crown could be too abrupt causing hard starting as well.

Dan

54 gr of fff is pretty light for any 54 I ever owned.
This can cause blown patches too.

Dan

to thin a patch. Every lyman i have shot loved the .018" patch.

I found Swiss 2f would blow patches at 80 grains but Goex 3f wouldn't on my Deerstalker. Now it gets 3f with Lehigh Valley lube. No blown patch and very accurate.

I shoot a GPR in 54. I would not use over 90 of 3f or even 100 of 2f. The 100 2f puts out less pressure than the 90 3f and I believe both are the recommended maximum loads. I use the 100 2f for hunting whitetails it puts them down quick and 75 2f for target shooting to save powder. I had the same problem your having and I lapped the bore with Steel wool about a hundred strokes, no more torn patches, loads easier, consistent accuracy, whether I use bore butter, spit, moose milk or mink oil. A good cleaning after use is my only other secret weapon. As far as patches go you will just have to experiment. I use 530 ball with .015 patches, you can go tighter but you will just die tired in firefight.

try a 526 rb and thicker patch

Been there done that. Try using 2F I think the 3f is probably too hot and burning the patches. Also with that patch a .530 ball shouldn't be close to tight. I use a .535 and its still not too tight. With loads up to 90gr 2F I don't use an overpowder wad but my hunting load is 120gr 2F and I use a felt overpowder wad for that load.Try it you might like it!!!!