gpr "Jamming"

[cmdrted]

I've been having a problem with my GPR 50 cal percussion "jamming". The problem is from that little patent breech clogging after every 10-15 rounds. I've been patching after each shot, I've tried using a 38 cal bronze brush every 5 rounds, followed by patching on a slotted 22 cleaning rod tip. Drying with alcohol patches and even set up a nifty thumb screw in the cleanout hole so I can remove it easier and swab it with pipe cleaners. even so it still fouls up and doesn't ignite the charge. Changed powder from goex to grafs no dice. anyhows this is getting frustrating especially during our local match here in pa. Any ideas?

 

[R.M.]

What patch (and lube)and ball combo are you using. If your combo isn't tight enough, there could be blow-by and not complete combustion, leaving lots of fouling. More info on what all you're using will help.

 

[cmdrted]

I'm using .490 lee cast roundballs, actually they mic at .493 walyworld ticking, .018 to .020 at rest then compressed they go down to .015. The patches have a nice dark light ring combo with no blow by or scorching. I'm using ballistol 7:1, but this was happening with 6:1 and the homemade moosemilk from stumpy. I moist patch out with a formula on dutch shoultz system. Once when it happened I removed the cleanout screw and used a flint pokeing tool and the stuff was kinda hardened much like the stuff that gathers and gets crsty around the nipple area.

 

[Dave K]

Not only are you possibly sending too wet a patch down when swabbing, you may also be using too tight a jag and patch. Instead of allowing the jag and patch to slide past the cruds and then left them out when you pull the rod out, you are just packing them into the patent breech. Try a little looser jag and patch and try that for cleaning. This is not a normal problem, if done and used correctly with properly fitting tools.

 

[Otter]

I have had this problem with my .54 GPR, but not my .50. First "fix" I did was to go to Goex 3f powder. That greatly improved the problem, but did not eliminate it. I started using my CO2 discharger on the nipple of an unloaded rifle about every 5 or so rounds (just long enough to clear the flash channel) and the problem has disappeared. I feel the problem varied mostly because of the humidity, for whatever reason. I use .530 balls, .015 cotton patch with spit as lube. Don't know if this will help you or not, so take this info for what you paid for it . . . :2

 

[cmdrted]

sounds like you guys are giving me new ideas. The patch jag combo maybe pushing the crud down into the breech and blowing it out with the co2 might be a quick field fix. I am using 3f powder, its giving me the best accuracy so far. tried 2 f the gun didn't like it!

 

[ssettle]

chuck you jig in a drill and make the diameter smaller with a file so the crud doesn't get pushed down the bore. but pulls it out when you pull up on the ramrod.You have to be careful you don't make it too small or it will leave the cleaning patch at the bottom of your bore.SS

 

[Haleh]

cmdrted

I have a GPR .50 and at the range I use a spit patch, wally world ticking (cut at the barrel)70 grains Goex 3f and cast balls. My Lee .490 mold also runs balls a little on the large side like yours. At the range I shoot 50+ shots and never wipe the bore and don't have any problems with accuracy or the charge not igniting. You may want to try not wiping between shots and see what happens. It may or may not work for you.

By the way this only works for me with spit patches. With deer tallow for a lube, which I use for hunting, I can get about three shots off before having to wipe out the bore.

H.Hale

 

[Grenadier1758]

There is a simple fix to clear the gunk our of your patent breech. When you have your last patch down the bore at the breech, pop off a percussion cap. The crud will be blown into the patch and the back pressure will clear out the touch hole. Its worked for me.

 

[Zonie]

cmdrted

I think there is a good chance that your wet patch wiping is shoving a bunch of crud down into the breech area.

When wiping the bore between shots try running your slightly wet patched jag down the bore in one smooth movement until it stops. Let it sit there for about 5 seconds. Then pull it back out of the barrel.
The waiting period is to allow the fouling in the barrels bore to soak up the moisture and soften.
Pulling the patched jag will pull most of the fouling back out with it.
Do not pump the fouled patch/jag up and down in the bore. That only causes the wet fouling to break loose from the patch and the next downstroke will blow it back into the breech, plugging up the whole works.

After removing the fouled patch, run a dry one down the bore once to remove any moisture and pull it back out. Again, no pumping up and down with the dry patch.

Also when loading make sure there is no cap or cap remnants on the nipple and place the hammer to half cock.
With the nipple clear of obstructions and with no wet fouling in the breech your next powder charge will be blown back thru the flame channel hole so that it is easily ignited by the next cap.

 

[paulvallandigham]

YOur cleaning jag( flat on the front end) should be about .030" SMALLER than bore diameter, to allow the soft, loose weave, cotton flannel cleaning patches to slide down OVER the lands , then blouse out on the back stroke to be caught in the grooves of the jag, driving the fabric down into the grooves, and wiping the lands, too.

If you put a wet patch down to clean, you have to follow with a dry patch to clean the dampness out of the barrel. Otherwise, you risk fouling your powder charge, have incomplete burning, and of course, some of the liquid will be pushed through the powder chamber into the flash channel, along with powder, and that is how it " GUMS UP!"

I suggest you try drying the barrel with one or two passes of a dry cleaning patch after you run the wet patch down. Read the Used Cleaning patches when they come back out of the gun. If its damp, and greasy slick, YOU probably will need to run a second damp patch down to clean out more of the crud. If your dry patch comes out with too much crud on it, or looks slick, or " greasy", run another patch down to dry the barrel further.

If you are getting damp patches on the jag when you first run a drying patch down and out the barrel, you really need to use that .35 caliber swab or brush, with another patch on it, to dry that powder chamber, too. This is a PITA for most shooters, but if you shoot one of these Patent Breech guns, with the powder chambers ala NOCK, you have to put up with these problems. This is why a friend who is a long time barrel and gun maker is asked, and does use an end mill to open up those powder chambers to bore diameter, so that the same size ( diameter) bore jag used to clean the rifled barrel, also cleans the " powder chamber". In the process of opening up( enlarging the diameter of ) the powder chamber, the end mill also shortens the flash channel from the chamber to the nipple or vent. That also seems to help cure some ignition headaches, particular for the Flintlock barrel made on this breech system. :hmm: :shocked2: :thumbsup:

 

[Billnpatti]

I recently purchased a caplock rifle that had the same problem. Because the previous owner did not know how to correct the problem, he sold it to me at a very good price. The first thing I did was to remove the breach plug so I could see into the breach and bore. I found a bunch of hard compacted gunk built up in the breach area. Upon further examination, I found the reason why it was there and not being swabbed out with a wet patch. The nipple drum was extending into the breach about 1/16 inch. This allowed the powder to get in and the bullet to seat on top of the powder but the swab couldn't get to the breach plug so all of the accumulating gunk built up on the breach plug and was obscuring the flash hole. I removed the nipple drum, filed off the excessive part that was extending into the breach. I took care that I removed only the extra length and did not remove so much that it would leave a void around the base of the nipple drum to catch more crud. This involved making a few strokes with the file and replacing the drum. Check to see if more needed to be removed and then remove the drum and makiing a few more strokes. Keep doing this until the base of the nipple drum is flush with the bore and the problem is solved.

While I had the breach plug out, I also polished the bore using some fine valve grinding compound on a patch. Hone from the breach so you don't damage your muzzle. I found that a couple hundred strokes did the job and the bore shined like a new dollar.

I also coned the muzzle while I was at it. You may or may not want to do this. I find it beneficial but some folks do not like doing this to their rifle. I found that it makes loading easier and does not affect accuracy at all.

If you have never de-breached a rifle before, it is not at all hard. Be sure to use a large padded vise to hold the barrel and a proper fitting wrench to remove the breach plug. An open ended wrench is your best bet. I do not recommend using an adjustable wrench. Whatever you do, do not try to use a pipe wrench or a pair of Channel Locks. These are guaranteed to damage your breach plug. The darned thing is tight so it will take a bit of force to break it loose but it will come out. Before replacing it, lube the threads with a high temperature grease. Ues the grease on your nipple drum and the threads on the nipple, too.

I think this will fix your problem and you will be able to enjoy your rifle as it should be enjoyed. Good luck!

 

[BrownBear]

The "drum" is integral to the breech on a GPR, so that's not possible and unnecessary. And it's not advisable for the average Joe to remove the breech on a GPR. It can be done with the right tools and care, and it can easily be buggared with the wrong tools and inexperience.

I once "taught" myself to do exactly what you describe cmdrted. When I was starting out with MLs I could feel fouling starting to build right below where the ball was seating, so I started using a sloppy wet patch and pumping between shots just as Zonie advises against. I got rid of the crud ring, but the buildup of crud in the patent breech and flame channel was persistent. I started blaming it on the sub powder I was using, but switching to Goex real black didn't make it any better.

Someone wise here on the site (could have been Zonie, as a matter of fact) advised swabbing with a patch that wasn't so wet, allowing it to sit for a few seconds at the bottom of the single stroke before withdrawing, and following with a single stroke of a dry patch. Problem solved.

Thanks again to Zonie or whoever set me on the course to redemption! :hatsoff:

 

[Dphar]

I've been having a problem with my GPR 50 cal percussion "jamming". The problem is from that little patent breech clogging after every 10-15 rounds. I've been patching after each shot, I've tried using a 38 cal bronze brush every 5 rounds, followed by patching on a slotted 22 cleaning rod tip. Drying with alcohol patches and even set up a nifty thumb screw in the cleanout hole so I can remove it easier and swab it with pipe cleaners. even so it still fouls up and doesn't ignite the charge. Changed powder from goex to grafs no dice. anyhows this is getting frustrating especially during our local match here in pa. Any ideas?

This is the disadvantage of buying a gun designed to be sold for a certain amount by people with little or no idea of what it should be. It just has to be easy to make and put together and go bang most of the time.
If you are shooting FFG switch to FFFG. Swiss powder might help if you are already using FFFG.
A properly designed percussion breech can't even have a clean out screw installed. It is possible that the breech is as cast or roughly machined internally. If the breech could be removed and the passages polished it might help. But I have never had one in the shop so I don't know the internal layout.
The best breeches have a short threaded portion that screws into the barrel with a "cup" machined in it. The flash channel ending under the nipple is then angle drilled. If done right this will work very well but some new breeches need some tuning of the flash channel diameter or finish. Having a large channel under the nipple is not a good idea either so all this needs to be carefully done. Guns that sell for less than the cost of a good set of parts have some corners cut.
Its impossible to make a GOOD traditional ML rifle for what most bolt action CF rifles sell for.
The bolt gun is designed to be mass produced and requires very little fitting to work well. Traditional MLs and even 19th Century breech loaders like the side hammer Sharps are much harder to make and have them work right. This is why an American made Sharps or a custom ML costs at least 2-3 times what a decent bolt action 30-06 does. To make the complex gun sell cheap requires corners to be cut.

Dan

 

[William O.]

Make sure that your thumb screw is not blocking the channel under the nipple hole. You might also want to use a nipple pick every three or four shots as well. I use a scraper to dislodge the fouling that cleaning patches can leave behind, see if that helps.

 

[longcruise]

I too think you are pushing gunk into the breech area. All suggestions made so far to remedy that should be followed.

But, You might also consider your nipple. If it's the one that came with the rifle it's not a very good one. It may have an undersize flash hole. That's not a good thing because you need a bit of blow back through the flash channel and the nipple in order for it to self clear with each shot.

Get one of the nipples with the hole drilled across it. The cap will just cover it and the blow back will help clear the nipple and channel and will also make your cap easier to remove after fireing.

Some of the old guns had a tiny hole drilled at an upward angle in the front of the drum (you don't have a drum) to serve this same purpose. I'm not suggesting that you start drilling holes. Just pointing out what has been done in the past to solve the same problem.

Changing lube, powder brand, granulation, etc., etc., may help alleviate the symptoms, but like cold medicine, it's only hiding the problem and not solving it.

 

[Billnpatti]

Whoeee!! Do I ever have egg on my face. I got so wrapped up in expounding on my solution that I didn't carefully read the question. You are absolutely right that the patent breach is made completely differently from the regular caplock ignition design. In this case, my "solution" was no solution at all. Thanks for catching that and sparing a fellow shooter from trying to make the wrong "fix". Next time I'll try reading the question a bit more carefully.

 

[kbuck]

Hope this request isn't too late. I had these same problems with my 54 GPR and others, both flint and percussion. Finally resolved the "gunk" build up by using a variety of methods - soaking, under-size bore brush, carburetor cleaner, etc. Now, however, I can shoot all day with no misfires nor excessive wiping. Can't say exactly which method actually did the most good. Don't want to repeat that process again. My question is, does anybody have the dimensions of the breech face inlet so that I can shape a brass bore scraper to fit?

 

[kbuck]

Just got the Cain's catalog and saw that they list a steel brush with 10-32 or 8-32 threads. Maybe that's the answer.

 

[William O.]

You might take a look at the Mag-spark set up which replaces the nipple/cap with a 209 shotgun primer ignition system. It will touch off the most stubborn powders.
http://www.warrencustomoutdoor.com/mag-spark.html http://www.octobercountry.com/products2.php?categoryid=356
Or you might look at the musket cap nipples. http://www.cabelas.com/p-0006779213451a.shtml