Barrel lapping

[LRB]

I would like to get some input from anyone out there who laps barrels. To pour a lap, which is best, pure lead or alloyed? How tight should the lap be after pouring? I have never poured one that I thought good enough to go with. What are your methods of operation? I have two Colrains with tight spots in the bore. Neither shoots well with any load. I did improve one by using a target minie ball screwed on the end of a machine gun cleaning rod, and hammering it in tight from the muzzle, but it needs more, and I would rather pour the lap. I do not need to hear about using steel wool, that is not lapping, and only good for removing burrs. These bores have definate tight spots.

 

[BLAHMAN]

Wick, this is how I do it. It may not be the best way, but I have found it to be simple, fast and easy.

Say, for instance, I have a 50 caliber gun with a very rough bore. I take a 490/495 round ball and wack it a few times to swedge it out.

Then I drill a hole through (the flat part) with say a number 27, 26 drill.

Then I take an old lock bolt that is 8x32 and put it into an 8x32 die (which is in my vise) and I screw it through the die untill I shoulder it. At that point I cut off the remaining screw sticking out of the die, thus keeping the head and what is left in the die.

I now have a small 8x32 screw that I can screw into my cleaning rod. Before I do so, I get a couple of small washers to sandwich the flattened roundball which now I will pass the screw through and attach to my cleaning rod.

I tap (gently) the whole thing into the muzzle of the barrel and push it through to the breech, just comming to the end, but not going out. A mallet helps, with lite little taps. I add some valve grinding compound and pull it back through the barrel.

I keep doing this untill I feel it loosening up, upon which I crank a turn on the cleaning rod handle to tighten it back up and I keep pushing/pulling untill I feel I've smoothed things up a bit. I don't need to do it much, because I use aggressive valve lapping compound.

In short, I am not pouring but swedging the lead into the barrel. The idea behind the small screw is that when I turn the cleaning rod handle, the screw will draw into the rod end exerts force against the lead and squashing it outwards. The washers act as a bearing surface, otherwise the head of the screw will just tear out the hole in the lead ball.

You don't needs to use a lock bolt, but any screw from the hardware store will do.

Hope I didn't confuse you any.

 

[rich pierce]

Good advice; I'll have to try the "no pour" technique. Maybe for tight spots in a clean new barrel, a longer lap would work well too. I pour a hard mixture, not pure lead (scrap lead I rejected for balls), get the barrel hot as the Dickens, make the lap 2" long. If it does not pour well, melt it right off in the pot and give it another try. The barrel will be that much hotter now since the pour. Don't be afraid to get the lead hotter than you would for casting. A little frsotiness is no problem.

Oftentimes on old guns the muzzle is more worn and puring a lap at the muzzle results in a lap that has poor to no rifling, but that will not be the case here. I think a long lap will cure the tight spot. I hope it's not at a dovetail.

 

[LRB]

Rich, how tight are the laps you cast? I did pour one that I almost used, but thought it was a tad loose.

 

[rich pierce]

I have lapped with a lead lap on worn and rough barrels, not new ones. In old barrels which were hand-cut, these laps are tight enough that I have to index them (know which flat is up) because they will not fit if I rotate them (at first). They are tight enough to be hard to remove. Old barrels are not always symmetrical and can have some heinous spots in them. Rough as a cob. The lead lap fixes that and they become loadable and shootable.

The lap gets loose pretty quickly, perhaps 20 strokes, and In the spring I had to pour 3 times on a .36 barrel that was really rough and it's surprising how well it loads now even though looking down it, there's no "mirror" effect! There's still lots of pits.

I really like the idea of using a threaded system and tightening it as it wears. I HOPE that would also cram the lead down into the grooves (furrows, if Wallace is listening in!). I am looking to make a sort of "jag" that could be used this way for most any barrel.

 

[Zonie]

Blah! Humbug!! ::

I bet you are describing something like this?

I made this little picture for a post a here a year or so ago and thought I would add it to this Post in case people are having difficulties picturing your description.

 

[BLAHMAN]

Blah! Humbug!! ::

I bet you are describing something like this?

I made this little picture for a post a here a year or so ago and thought I would add it to this Post in case people are having difficulties picturing your description.

Yeah Zonie! That's a perfect description of what I use when I need to lap a barrel.

In my case, I rifled a barrel and I didn't do to great a job. When I ran patches down the bore, the were all cut up like crazy.

With Olie's help, I made this and used it to smooth out them rough spots, and it took very little effort and time. That unto itself really surprised me!

 

[joseph mcdonough]

well here are my thoughts
first wire cloths hanger straighten as well as possible
cork like on a wine bottle put on end or cloths hanger then bend the end in a u shape and bring that end backthrough the the cork with some sticking out cut cork to size you must have a tight fit push cork down just far enough to put some lead in let cool when cold start lapping
can also sub screw rod and nuts for cloths hanger rember to tape the rod.
the lead plug is supposed to follow the rifleing so the rod is supossed to rotate while you lapp

 

[fho]

Wick Ellerbe:
I have made two lapping rods. One is a 5/16 rod and the other is 3/8 rod.
I put them in a lathe and turn the end on the 5/16 rod to 1/4 inch, the 3/8 rod to 5/16 straight for about 1/2 inch. Then I taper them for about 4-5 inches from the straight part. Then I taper thread them with a 24 pitch thread. this how I make the lapping rods. I use about 2 to 3 inches of the tappered part to hold the lap.

To use them, I wrap string around the rod (tappered part)till it is tight when you push it down the barrel on the muzzle end. Then I push The rod down in the barrel and wrap string on the rod at the breech end. This helps to center the rod in the barrel.

When I get ready to pour a lap, I push the rod out of the barrel at the muzzle end till some smooth part sticks out, just a little. Then I heat the barrel and pour hot soft lead in the bore. When it is cool you are ready to lap. I use 240 & 320 lapping compound that I get from Brownell.

I also made a handle that rotates to hook on to the lapping rod. I had trouble pulling the lap out of the barrel so I tied a string on one side of the handle around the vise (I hold the barrel in a vise)to the other side of the handle long enough so the lap will just come out at the breech end.

When you use the lap if it gets loose turn the lap rod a little and it will tighten up.

That's all
Olie :m2c:

 

[fho]

Wick Ellerbe:
I forgot to tell you that you can not lap the grooves in a gain twist barrel. You can lap the tops of the lands in a gain twist barrel only.
Olie

 

[swifty]

check out beartooth[url] bullets.com[/url]
the sell a boar lapping kit-it contains bullets that you seat on the black powder that have been rolled in an abrasive. You fire the number of shots-cleaning between shots until the tight spots go away.
www.beartoothbullets.com

 

[BLAHMAN]

That's fire lapping. You can get the same effect with a patched roundball that has the patch lubed with a polishing compound.