More on "Patent Breech" Muzzle Loaders.....

[oldracer]

Well as I have been posting, I started working up loads and such for my Pedersoli Gibbs rifle. Last fall I also bought a Pedersoi Tryon muzzle loader which is supposed to be good out to 500 or 600 yards. The first time I took it to the range I was indeed shocked to find the first 5 shots touching at 100 yards! This was with Pedersoli's 490gr molded grease groove 0.551 diameter bullet, plain card wad and 80gr of FFG. Next time was about the same and I was happy. Then last April I took it out and it did not want to hit a barn door? Same bullets, wads and powder load, everything! I experimented with all sorts of things and every now and then could get 3 or 4 shots close but nothing like before? So what to do.......last night I though well maybe this Tryon has a patent breech and it is gooped up and not giving me good powder burn.

This evening I pulled the barrel off and ran the bore scope in and what did I find......a patent breech about the same size as the one in the Pedersoli Gibbs! The fire hole come in at the same location as the Gibbs also, right in the side, half way in the patent breech. So I scrubbed it out with Windex and a 22 caliber brush and patches and wow did the goop come out! I finished up with a little Breakfree and will wash the bore and breech out with Windex before I take it to the range in a week or two and try out the same load settings as I'll try on the Gibbs and I just bet the grouping will be back to what it was.

[45/70fan]

Check the flash hole in the nipple, if it is burned out any at all the the erratic pressure curves will give you the results you saw. Once happed to me and I sold a perfectly fine hand built hawkens on the cheap when it went south, so I thought. New owner demonstrated what a new nipple would do for accuracy.

[oldracer]

If I remember correctly, the nipple I started with came on the gun. I have a very small drill bit that will not go through the flash hole of a new or good nipple but will sometime later. When I pull it to do the cleaning I check with the drill bit and if it goes in then I toss the nipple.

I did not mention that I tried one of the 209 primer adapters for several shots and they put out tremendous amounts of spark, etc. I took it off when I saw no difference.

[451 Pete]

Oldracer ,

If you are shooting black powder in your rifle's you will not need a primer hotter than a # 11 cap to get it to go off. `( Black ignites at around 450 degrees. ) You are correct in that a patent breech will sometimes build up fowling and need a bit of special attention.

Outers company used to make a small bottle with a short piece of tubing attached thru the cap that ran to the bottom of the bottle. The idea of this is to put solvent or cleaning solution in the bottle and then slip the tube on to the percussion nipple to flush solvent in and out of your bore with a mop attached to your cleaning rod thru the percussion nipple. You can easily make one of these from a piece of the right size rubber tube and an old shampoo bottle .. just remember to drill a small air hole in the cap also as a vent to relieve the pressure in the bottle. I made one modification to this in that I took an old shot out nipple and drilled it out to better allow the flow of the solvent into the bore and allow more goop to get out of the barrel when pumping the mop up and down in the barrel.
One last comment. A standard percussion nipple will wear very rapidly in these rifles ... I have had one open up in as few as 20 shots to where I began to get fliers out of a group. The " traditional " remedy in the old days to cure this nipple erosion was to install a platinum lined nipple ... something that is very costly and hard to come by today. Some on this site are experimenting with machining nipples from space age stainless steel materials and hopefully the source of a better lasting nipple for these rifles will be available in the not too distant future. ( Read the post on when rocket scientists and muzzle loaders get together by Boz )

Hope this helps .... Pete

[Junior1942]

I did some rough measuring on the patent breech in my 50 caliber Lyman Plains Pistol. A brass-bristled brush .315" in diameter, i.e., probably for 30 caliber, is an easy push into the breech and works well to clean it. A guess says the diameter of the breech is about .308". A rough measurement says the length of the patent breech is about .730". So its volume is about 1cc. For sure, a 30 caliber brass brush will forever be in my 50 calibers possibles bag. I suspect the patent breech of my 50 caliber Lyman Great Plains Hunter is the same or nearly so. I'll check it soon.

[Boz330]

Racer another thing to check is the barrel channel on your stock. Not familiar with the Tryon but on the Gibbs you look for shiny spots in the barrel channel. This is where the barrel may be contacting the wood where it shouldn't be, usually around the tenon or at the fore edge of the barrel channel. This could be caused by shoot in or maybe some swelling of the wood. I had this same problem with my Gibbs and lowering these areas along with tightening of the hooked breech brought everything back right. Lee Shaver can give you an idea of how to solve the problem. It doesn't seem to take much in these precision instruments to muck it up but Lee is probably the foremost smith on these guns.

Bob

[oldracer]

Hum, hadn't thought of that but I'll take a look next time I pull the guns out. The Tryon uses two wedges so I'll measure them to make sure they are straight and also measure the under lugs to make sure they line up. I should be able to see if there is any pressure points on the wood and I'll also check that in my Gibbs too. The hooked breech on both guns has a very tight fit, so tight that on the Tryon I generally have to tap the barrel with my rubber mallet to unhook it. I'll let everyone know what I find.

[fouronesix]

A too tight hooked breech can be good or bad. If it stresses the barrel as the barrel is pulled down to fully engage wedges it may negatively affect accuracy. Generally the idea is to provide a secure, stable platform for the barrel/tang with no undue stress. Achieving that for best accuracy is easier said than done though. Some of it is trial and error and may be more art than science. Sometimes barrels shoot best with a little up pressure somewhere along the channel. However, predicting all that or second guessing the barrel harmonic node pattern then relieving wood in the right places to accomplish better accuracy is usually a carp shoot. Lots of experimenting, relieving wood in the right places along with bedding compound can help- predicting with certainty is the unknown. In the end, the target tells the tale.

[Boz330]

My buddy has done several Gibbs hooks for guys and he said mine was probably the tightest he had seen. All of the rifles benefited from tightening the hook and relieving the bearing spots. The Gibbs is supposed to seat on the sides of the stock not the bottom. Modern bedding is not allowed in the international rules so that is out. If the sides don't support the barrel you can add some paper or card stock to shim it.
The guys who shoot these seriously, don't pull the barrel very often so as not to change the bedding. I have a nipple with a plastic tube attached for cleaning and all I use is hot water to clean. When done I turn the rifle barrel down and then use WD40 to displace the moisture. I do follow up the next 2 days and then oil with the Mobile 1.

Bob

[Junior1942]

I did some rough measuring on the patent breech in my 50 caliber Lyman Plains Pistol. A brass-bristled brush .315" in diameter, i.e., probably for 30 caliber, is an easy push into the breech and works well to clean it. A guess says the diameter of the breech is about .308". A rough measurement says the length of the patent breech is about .730". So its volume is about 1cc. For sure, a 30 caliber brass brush will forever be in my 50 calibers possibles bag. I suspect the patent breech of my 50 caliber Lyman Great Plains Hunter is the same or nearly so. I'll check it soon.The patent breech of my Lyman GPH 50 caliber is ~.425" in diameter and ~.750" in length. A 44 caliber brass brush cleans it just fine and a 45 caliber brass brush is too tight.