Post by Big Joe on Dec 1, 2017 18:59:30 GMT -5
Lapping a Rifle Barrel - part Sam’s way and part mine. 2012
Ok, begin by disassembling the rifle and thoroughly cleaning the bore. Pull the stock any scope off, you pour melted lead on them and you ruin ‘em. Ask me how I know.
With the bore clean, take a steel cleaning rod with a swivel handle and a metal (brass is ok) jag or patch loop. Push it from the breech end until the jag and about an inch of the rod project from the muzzle. OK, I mark the rod at this point for reference to the throat/chamber with a piece of tape wrapped around rod. Lay the rod on top of the action end just above the throat/chamber and put a mark on it then wrap with tape you only need two wraps of electrical
tape. Take cotton (not synthetic) twine and wrap around the rod just ahead of 6the muzzle (or about 3/4in behind the jag). Use enough twine to form a good seal around the rod. This prevents the melted lead from getting to far down the barrel.
Melt a small amount of pure lead, much easier and softer means better lap, 95% lead and 5% tin or something like that
Use a propane torch to heat the muzzle for 3 or 4 inches. Not real hot, just warm to the touch. This heat helps prevent bubbles in the lap. Also heat the jag a bit.
When you have it hot pull the rod into the barrel until top of the jag is an inch into the muzzle. Pour in melted lead until even with the muzzle. Trying not to over fill it enough that it runs down the outside, a very small puddle on the end is all you want.
Let it cool to where you can touch it. Push so the lap (lead) comes out about 60 - 75% of the way of the barrel. Being careful not to push it all the way out – this is bad and you have to start over with the pouring. With a sharp knife trim off the head so it can go back into the bore.
Use a triangle file to cut 3 or 4 narrow groves around the lap. This is to hold the abrasive grit.
I use silicon carbide “Clover Compound” grits in a factory barrel - slightly rusted stat with 400 grit, good clean bore I start with 600 grit. I use at least different grits each time I lap. I have spoken about the 400 and 600 - also use 800 and then 1200, yes I know I could stop at 800 and be done but I have an anal streak and finish with the 1200.
Smear a little bit on, just enough to fill grooves you filed. Now pull back through the bore. It will be hard to start. Stop as soon as the lap nears the throat, then reverse.
NEVER let the lap come all the way out of the bore on either end or its do over time. Melt the lap off and start over. Run each grit on the lap back and forth until it pulls easy - maybe 20 strokes each direction.
Melt off lap and recast following same procedure as above with same grit. After the 20 strokes melt off, recast and move to next finer grit. So basically its at least two times with the same grit before moving to next finer grit. You can decide if you want to finish at 800 grit or go the extra step to 1200 grit. I skip 1000 grit after I am happy at 800 grit.
When all done flush the bore with mineral spirits swabbing between flushes. Give a final cleaning in your standard method reassemble and go shoot it. I don’t mess with all the hype of breaking it in, I just shoot it.
I know some of my statements will go all through some, but to each his own. I feel that after I go to 1200 grit its pretty much broke in. Its just me and your milage may vary greatly. Hope this helps to some extent.
Where the stuff materials/ tools come from.
Steel Rod — a cheap but sturdy gun cleaning rod with a swivel handle works fine for this.
Jag - same cleaning kit as rod.
Cotton Twine - from the cooking section of grocery market - used to wrap meats.
Lead - my supply - I use roofing lead because its soft.
Lapping Grit - I found my last supplies on eBay – yes I know but you got to do what you got to do.. Its listed under Valve Lapping Compounds. And the best thing is it comes in 2oz cans instead of having to buy 1lb cans
My hand tools supply rest of needed supplies
Update: 2017
I now use brass rods and a different push/pull handle. Its built to a Tee shape using the axle and housing front a front bicycle wheel and a piece of pipe. The rod attaches with a hanger nut rethreaded to the fine thread on the axle. (If you use a newer bicycle part the threads will most likely be metric) and the Jag is cut into each brass rod - one for each caliber group. I use 1/8in for 22 thru 6.5mm cal, a polished 1/4in rod for 270 thru 375 cal, I have a 5/16 rod for everything larger. Each rod has its own axle nut brazed to it. All else it the same as far as the method goes. I built it with steel rods but got worried I was gouging the bore with those and the polishing compound At times I have had to use the steel rods on the first lap session just to break the burrs and make things easier. A note for those who use old Military rifles – a good lapping can make all the difference. I electro scrub mine then lap them.. You will be shocked at all the gunk that will come out of a “clean” old barrel.
Ok, begin by disassembling the rifle and thoroughly cleaning the bore. Pull the stock any scope off, you pour melted lead on them and you ruin ‘em. Ask me how I know.
With the bore clean, take a steel cleaning rod with a swivel handle and a metal (brass is ok) jag or patch loop. Push it from the breech end until the jag and about an inch of the rod project from the muzzle. OK, I mark the rod at this point for reference to the throat/chamber with a piece of tape wrapped around rod. Lay the rod on top of the action end just above the throat/chamber and put a mark on it then wrap with tape you only need two wraps of electrical
tape. Take cotton (not synthetic) twine and wrap around the rod just ahead of 6the muzzle (or about 3/4in behind the jag). Use enough twine to form a good seal around the rod. This prevents the melted lead from getting to far down the barrel.
Melt a small amount of pure lead, much easier and softer means better lap, 95% lead and 5% tin or something like that
Use a propane torch to heat the muzzle for 3 or 4 inches. Not real hot, just warm to the touch. This heat helps prevent bubbles in the lap. Also heat the jag a bit.
When you have it hot pull the rod into the barrel until top of the jag is an inch into the muzzle. Pour in melted lead until even with the muzzle. Trying not to over fill it enough that it runs down the outside, a very small puddle on the end is all you want.
Let it cool to where you can touch it. Push so the lap (lead) comes out about 60 - 75% of the way of the barrel. Being careful not to push it all the way out – this is bad and you have to start over with the pouring. With a sharp knife trim off the head so it can go back into the bore.
Use a triangle file to cut 3 or 4 narrow groves around the lap. This is to hold the abrasive grit.
I use silicon carbide “Clover Compound” grits in a factory barrel - slightly rusted stat with 400 grit, good clean bore I start with 600 grit. I use at least different grits each time I lap. I have spoken about the 400 and 600 - also use 800 and then 1200, yes I know I could stop at 800 and be done but I have an anal streak and finish with the 1200.
Smear a little bit on, just enough to fill grooves you filed. Now pull back through the bore. It will be hard to start. Stop as soon as the lap nears the throat, then reverse.
NEVER let the lap come all the way out of the bore on either end or its do over time. Melt the lap off and start over. Run each grit on the lap back and forth until it pulls easy - maybe 20 strokes each direction.
Melt off lap and recast following same procedure as above with same grit. After the 20 strokes melt off, recast and move to next finer grit. So basically its at least two times with the same grit before moving to next finer grit. You can decide if you want to finish at 800 grit or go the extra step to 1200 grit. I skip 1000 grit after I am happy at 800 grit.
When all done flush the bore with mineral spirits swabbing between flushes. Give a final cleaning in your standard method reassemble and go shoot it. I don’t mess with all the hype of breaking it in, I just shoot it.
I know some of my statements will go all through some, but to each his own. I feel that after I go to 1200 grit its pretty much broke in. Its just me and your milage may vary greatly. Hope this helps to some extent.
Where the stuff materials/ tools come from.
Steel Rod — a cheap but sturdy gun cleaning rod with a swivel handle works fine for this.
Jag - same cleaning kit as rod.
Cotton Twine - from the cooking section of grocery market - used to wrap meats.
Lead - my supply - I use roofing lead because its soft.
Lapping Grit - I found my last supplies on eBay – yes I know but you got to do what you got to do.. Its listed under Valve Lapping Compounds. And the best thing is it comes in 2oz cans instead of having to buy 1lb cans
My hand tools supply rest of needed supplies
Update: 2017
I now use brass rods and a different push/pull handle. Its built to a Tee shape using the axle and housing front a front bicycle wheel and a piece of pipe. The rod attaches with a hanger nut rethreaded to the fine thread on the axle. (If you use a newer bicycle part the threads will most likely be metric) and the Jag is cut into each brass rod - one for each caliber group. I use 1/8in for 22 thru 6.5mm cal, a polished 1/4in rod for 270 thru 375 cal, I have a 5/16 rod for everything larger. Each rod has its own axle nut brazed to it. All else it the same as far as the method goes. I built it with steel rods but got worried I was gouging the bore with those and the polishing compound At times I have had to use the steel rods on the first lap session just to break the burrs and make things easier. A note for those who use old Military rifles – a good lapping can make all the difference. I electro scrub mine then lap them.. You will be shocked at all the gunk that will come out of a “clean” old barrel.