Breech plugs.......

[BLAHMAN]

Ok, for everybody that breeches their barrels (like Green Mountain), most breechplugs are 9/16 long, correct? Depending upon caliber, how long, exactly, do breechplugs need to be, minimum, that is.

 

[rich pierce]

I don't see a need for more than 1/2 inch. That works well with most locks.

 

I don't know if there is a formula per see, but I was under the impression the depth should be slightly larger than the bore size. 60 cal. 3/4", 50 cal/ 5/8", 40 cal/ 1/2" 30 cal/ 3/8" etc. and with corresponding threads, and the plug diameter allows for a shoulder. Anyhoo, thats my understanding of it. I generally buy what's recomended by the barrel makers, and leave it at that. Interesting question though Bill

 

[Henry]

Tradition was , in coarse thread `NC , minimum
8 threads .

Om average , with fine thread , same lenght as wight

Your milleage may vary

 

Got to go with Rich. 1/2" was about standard and is still all that is actually needed. 9/16" is overkill and done to avoid liability problems.

six threads is all about anybody shoots for.

Going length to width will give you a really badly proportioned smoothbore in the bigger guages.

 

[BLAHMAN]

I don't see a need for more than 1/2 inch. That works well with most locks.

Yeah, I agree. That extra 1/16" can cause the architecture to be off a smidgen.

 

[Birddog6]

Yeah, I agree. That extra 1/16" can cause the architecture to be off a smidgen.

Yes, and there are days I would be most happy to be just within a smiggen. ha ha !

:huh:

 

[Kaw Trooper]

Does anyone have a picture or diagram of the INSIDE of a breech plug? I'm wondering what it looks like inside.

 

[mikee51848]

Does anyone have a picture or diagram of the INSIDE of a breech plug? I'm wondering what it looks like inside.

Mine measures 5/8 inch.

http://www.trackofthewolf.com/categories/partList.aspx?catID=14&subID=143&styleID=511

 

[BLAHMAN]

Yeah, I agree. That extra 1/16" can cause the architecture to be off a smidgen.

Yes, and there are days I would be most happy to be just within a smiggen. ha ha !

:huh:

Touche'

 

[Herb]

I just fitted a flared breech plug to a B weight .50 cal Green Mountain barrel, and the plug is 5/8" long (10/16"). The threads in the breech were not bottomed. So I just filed off the first two threads of the plug, with smoke fitting, to get it to bottom. Hit the back of the barrel first, lacking about .015" of being down. Filed off the back of the barrel to get the plug to bottom. Name stamp was at the top left flat, not where I wanted it. So I filed off both the end of the plug and the end of the barrel to index the plug two more flats so the name stamp was on the lower left flat. Took about two hours and 45 minutes using hand files. Thought about shortening the plug up to 1/2", but decided I could use it longer for this percussion, Durs Egg, lock.

 

[mikee51848]

I just fitted a flared breech plug to a B weight .50 cal Green Mountain barrel, and the plug is 5/8" long (10/16").

I am curious how you fitted it. Since this is my first kit, I had the plug installed for me. Now I wish I hadn't. How does one remove the plug? I'd like to shorten it an 1/8 inch. It looks almost seemless where the barrel meets the plug.

 

[BLAHMAN]

I just fitted a flared breech plug to a B weight .50 cal Green Mountain barrel, and the plug is 5/8" long (10/16").

I am curious how you fitted it. Since this is my first kit, I had the plug installed for me. Now I wish I hadn't. How does one remove the plug? I'd like to shorten it an 1/8 inch. It looks almost seemless where the barrel meets the plug.

Put it into a vise (the barrel, that is) and get an adjustable wrench, then crank it on out.....it's probably in pretty tight.

What's the barrel?

 

[BLAHMAN]

I just fitted a flared breech plug to a B weight .50 cal Green Mountain barrel, and the plug is 5/8" long (10/16"). The threads in the breech were not bottomed. So I just filed off the first two threads of the plug, with smoke fitting, to get it to bottom. Hit the back of the barrel first, lacking about .015" of being down. Filed off the back of the barrel to get the plug to bottom. Name stamp was at the top left flat, not where I wanted it. So I filed off both the end of the plug and the end of the barrel to index the plug two more flats so the name stamp was on the lower left flat. Took about two hours and 45 minutes using hand files. Thought about shortening the plug up to 1/2", but decided I could use it longer for this percussion, Durs Egg, lock.

Herb, do you 'tin' your breech plug face?

 

[Birddog6]

To remove the breechplug you need a very good vice with good wide jaws, & the vice mounted to a solid stable table. I use a modified 15" Cresent wrench I have ground the adjustable jaw to the angle of the tapered breech plug.

When you slip the wrench on the plug to remove, stay up close to the barrel & also do not go over the edge of the tang or you will bugger it up & the tang will not look right.

You can put a thin piece of leather or piece or shim aluminum or brass between the vice jaws & barrel if you are worried of marring it.

Also keep in mind there should be an index mark on the bottom flat of the barrel. If not, put one on there. When you put the barrel/plug back together you will tighten it to this index mark so the mark lines up again as when you made it. You make this index line/mark with a chisel or a graver & you make a mark across the joint of the barrel/breechplug & parallel to the barrel. This is so you know you have tightened the barrel far enough to line up the tang barrel flat & also to know you have acquired the correct seat fit in the breech.

I always put a lil Antisieze on the Inside of the barrel threads. Not near the outside as it is a bugger to get off & if it migrates tbetween the barrel/tang it will not brown there & you will have a silver line there. It is a bugger to was out too.

:results:

 

[Herb]

To remove the plug: Have the barrel in the vise with only an inch or so sticking out to the side. Vise should be smooth jawed, or else with thin cardboard to protect the barrel. If you pad with wood or leather, the barrel may turn in the vise. Vise tight. I use a 14" crescent wrench with the jaws right up against the barrel but not sticking over the top of the tang. Don't want to scar the edges. Adjust the jaws so they are a snug fit. Give the end of the wrench a good bump with the heel of your hand, the plug will break free. To Fit a new plug: I lightly grease the threads and turn the plug in by hand, and then with a small wrench until it resists. Don't force it. Back off and run it up against that bump another time or two. Take the plug out. You'll see a shiny spot on the threads where they hit the end of the inside threads. Lightly file that spot off, following the threads. Smoke the plug up with a candle or string or yarn stuffed into a cartridge case and soaked with oil. You can also smoke up the inside of the breech. Re-thread the plug and lightly bump the resistance. Remove and file off the shiny spot. I had to file off most of the first two threads, going radially around the plug. When you get the plug deep enough, it will bottom on the end of the barrel. If it bottoms inside, all is well. Mine did not, so I filed off the back end of the barrel until both bottomed. I do not tin the end of the plug, nor have I heard of doing this, though I can see that it would fill up a little gap. Had a Colerain swamped barrel that came with fitted plug, and the plug lacked about .020 of bottoming inside. I made a mistake here and filed off the back of the barrel to set the plug two barrel flats deeper. Then the rifle shot about 8" left at 50 yards. I should have filed a dime down and used that as a filler ahead of the plug. (Had worked on the barrel before I found the gap, so didn't think I could send it back to Track). I do not make an index mark, the flats tell me when the plug is aligned. When the plug is fitted, I clean the grease off inside and out. As mentioned, grease will bleed out and prevent browning. The plug can be lubed with graphite or pencil lead on final fitting.

 

[CrackStock]

Kaw,

the pic from Track is a pretty standard plug, but be aware that there are other breaches such as the patent breach which are very different. Think of a breach lug with a hole down the breach face that matches up with a flash channel coming in from the side.

Make a lot of difference in things once you know that you have one of these.

YMHS,
CrackStock