Lapping powder charge

[Tn Jim]

I'm getting ready to use a LBT lapping kit on my Ruger SBH 44. The only pistol powder I have is W231, Unique and 2400. Also have some Green Dot for my shotgun. I'm thinking the best choice is the W231, but how much? Would 2 or 2.5 grains be too little? I need your thoughts guys.

[5Shot]

I used like 2.5 grains of Bullseye for my 45 Colt. You need a tiny bit of really fast powder. Green Dot is the fastest you have, so I would use it. You also need a brass rod that closely fits the bore and a BIG hammer to get the stuck slugs out...just in case. A few heavy blows vs. lots of light ones.

Load one and try it before you load up a whole bunch and find it is too light/hot.

[Tn Jim]

Thanks 5Shot. My only problem is the range is 37 miles from me. Guess I get to do a little driving for this project.

[tomme boy]

My 9mm was 0.5-.6 gr shot into a bucket of scrap lead. This was with 130 gr boolit. Anything lower and it would not make it out the barrel. I will tell you what, even at that low of a charge, it is moving fast. So be careful where you shoot it. Throw away the brass you use also. The grit will get into the brass.

I did mine in the basement.

[C. Latch]

I used something close to 5 grains of Green Dot for some of the loads I lapped my .45 colt with. I think you could easily go to 4 grains, especially with a .44.

I suspect you could get by with 3 grains, but I'd hate to be wrong and you be an hour from home.

[tomme boy]

You want to go very slow, the slower the better.

[monadnock#5]

Put together a portable reloading press built around a Lee single station press. Prepped brass, prepped slugs and a beam scale with a trickler will get the job accomplished.

[Tn Jim]

Put together a portable reloading press built around a Lee single station press. Prepped brass, prepped slugs and a beam scale with a trickler will get the job accomplished.
My loading bench is portable already (sort of). I built it when I was in the Army and got moved a lot. Since I don't know how many rounds I will need or what powder charge, this makes a lot of sense. I could also use the same six cases to lap instead of trashing my Starline brass, which is all I have at the moment. I've never reloaded at a range before. This is getting interesting.:bigsmyl2:

[pjames32]

I'd pre-weigh some charges at home.

[huntrick64]

I have done about 15 revolvers (357 mag, 41 mag, and 45 colt) with HP-38 (same as 231). I used somewhere between 2.5 grains and 3.2 grains of powder depending on which gun and where I was at in the process. It takes a little more powder the more you lap your barrel because you are creating more friction surface as you smooth out the rough spots. I have lapped out the barrel thread constriction in as little as 36 rounds and on one particular stainless GP100 it took 72 rounds (cringe). I would not drive 37 miles to do this because you are going to end up making several trips due to:
1. bullet getting stuck and not being prepared to drive it out
2. You think your done when you actually are not
3. You forgot something

You can do this in your garage or basement if you are very careful. It is amazing how much even a closed cardboard box can dampen the noise of a lapping load. If you had a metal barrel with sand in one end and a blanket around you wrist you would do well. Keep in mind that powder position is very important because you don't have very much powder in there. The best and easiest lapping I did was on my own land where I could see the bullets with the naked eye against the sky. Yes, I just lobbed them out across the prairie! The bullet is only going about 600 fps so you can see it against the sky, plus the gun is pointing upward which puts the powder against the primer for consistent ignition.

Read up on this quite a bit. You don't want to lap parts of your gun that don't need lapped (i.e. cylinder throats). I will typically size my bullets down to .001 - .002 below what I want my final lapping bullet to be. Then, when you load it up with lapping compound, it will be about the right size.

Shoot 6, clean well, check progress, then repeat. Pin gauges aren't required, but they make the job much easier and more accurate.

Hope this helps.

[tomme boy]

I had to oil the bore after every shot to make sure it did not lead the barrel on my 9mm I did. I tried 2 rounds without oil and the whole barrel was leaded. So after I got the lead out, I started to oil just the rifled part of the barrel.

I was told to not use lubed bullets. So does everyone else here use lubed or un-lubed?

[btroj]

Unlubed, unsized. Powder is just enough to get the bullet out of the barrel.

I did a few in the garage, fired into a bucket of old drywall compound that was almost dry but was moist enough to easily stop the bullets.

[5Shot]

Unlubed, unsized. Powder is just enough to get the bullet out of the barrel.

I did a few in the garage, fired into a bucket of old drywall compound that was almost dry but was moist enough to easily stop the bullets.

I use a thick stack of old newspapers covered with a folded towel. Muzzle on the towel - just a little pop.

[Tn Jim]

My boolits measure .429 and the cylinder throats are .4315, so I should be ok there. No sizing these boolits down because a .430 sizer die doesn't touch them. The main objective of the lapping is to get the "Ruger choke" constriction out of the barrel where it screws into the frame. Smoothing the bore will just be a added benefit. The mold is with Erik at Hollow Point Mold having the driving bands/base enlarged. I've owned this SBH for several years, but if this doesn't straighten it out it is gonna be a dedicated J-word shooter.

[huntrick64]

Those bullets should work fine as long as they are in the BHN range of 12-14. Do you have pin gauges avail to see just how tight that constriction is? My experience has been that .001 or less constriction in the thread area will not affect accuracy, but could cause leading under the right conditions. I have fire-lapped out .002 - .003 constrictions before and it can be quite a bit of work, but well worth it. I have noticed that, once I have a constant choking on the bullet from throats to cone to and through barrel, accuracy is available with many different loads and they are a breeze to clean (no lead). Tomme Boy is spot on regarding oiling the bore. I think it acts somewhat like a cutting oil and I get mo betta cutting with the grit when I oil it down before firing the laps. Also, the biggest factor is making sure you get plenty of grit embedded into the bullet, and not just smearing it on the bullet. You can tell when the lap is fully loaded because when you wipe off all of the lapping compound, the bearing surfaces will look grey like a whetstone where the grit is embedded into the lead. If they are splotchy, get back at it and work more compound into the bullet.

I also like to re-cut the forcing cone to 11 degrees if I am shooting SWC.

When you are done, stop using those .429 casts and get some that fit your throats better. When I see lead on the throats and the forcing cone, it tells me my bullet is too small for the throats. Gas blows by the bullet and softens the lead, which gets smeared onto the throats or cone. When I see leading past the forcing cone for a couple of inches, it is usually a thread constriction.

Hope this helps and look through the old posts. Plenty of good write-ups on the subject on this site.

[btroj]

Only ONE problem with a 429 bullet in 431 throats, what is the barrel dimension?

Lapping a 430 bore with 429 bullets means the top of the lands are lapped but the bore isn't.

I would want .431 bullets for lapping that revolver.

[Tn Jim]

The bore slugged at .429. Just another reason this Ruger is driving me batty.

Also, according to the instructions with my LBT kit, the boolits will increase .0001 to .0002 in diameter once I imbed the compound in them. I just want to lap the bore. The chamber mouths don't need to get any bigger.

[dubber123]

The bore slugged at .429. Just another reason this Ruger is driving me batty.

Also, according to the instructions with my LBT kit, the boolits will increase .0001 to .0002 in diameter once I imbed the compound in them. I just want to lap the bore. The chamber mouths don't need to get any bigger.

I did a Ruger .45, and put at least 100, 320 grit down it, all over cylinder mouth size, and could detect only the slightest increase in diameter. Remember each chamber sees only 1/6th the lapping as the barrel. It made a 6" 50 yd. gun into a sub 2" gun.

[Tn Jim]

I do have some other boolits I could use. I have a Lee .430 push thru sizer that hasn't seen the light of day in years. A quick shot of WD-40 and then push thru and wipe them off. Size wise these may work better than the .429 boolits.

Rick, no pin gauges available. I haven't been able to measure the bore constriction, but I can feel it when I push a slug down the bore.

Also, thanks for the heads up on the oiled bore. I hadn't seen anything on that before.

[huntrick64]

Before you find other boolits for fire lapping, embed a couple of those .429s with compound and then mic them. If you get them fully loaded with grit, I bet they are close to .431. Then when you are done, get some that fit your throats to shoot regularly. Don't forget that your throats are .4315 so you are already pretty sloppy with .429 boolits. Even though there are plenty of people who are negative towards firelapping, it has been the best improvement project I have done on all of my handguns, but I went slow and frequently checked progress. And I kept my gun clean throughout the process. I think that most of today's gun manufacturers are a little sloppy when cutting rifling and screwing down the barrels. Since the majority of people (outside of our group) shoot jacketed bullets, they never really see the need to fix it. You will see the benefits.

[starmac]

Showing my ignorance here, but why does it need to be going so slow that you might get stuck boolits??

[huntrick64]

I can't tell you for sure, but I have my own guess. I would think that an impregnated boolit would significantly increase chamber pressure due to it's resistance going down the bore. And, this pressure increases with each round as it cleans up the barrel and makes more and more surface contact. Slowing that bullet down so that it barely clears the muzzle, is the lease amount of chamber pressure you can generate and still get the lap to do it's job.

Again, just a guess. The real reason I do it is because ALL of the directions that I have read use this method.

[tomme boy]

Slower helps to cut better from all the reading I have done on this. Just going off of what I have done and what I have read. You can go fast than what I posted, but I wanted to also see how slow I could go with my 9mm in case I ever get a low charge on my progressive. So "I" accomplished two things at once. I also was doing this in my basement so I just wanted it to make it out the barrel and that was it. I was shooting mine into a bucket of range pick up bullets and another bucket of scrap brass. Both worked perfect. I set up a couple pieces of cardboard over the top of both to make sure that nothing was going to fly all over the place.

[DougGuy]

Use the largest boolit you can. If it just barely fits in the throat from the front, you are doing it right.

Funny, when I firelapped my first Ruger, there wasn't a lot of detailed instruction around, I used a broken bottle of JB bore cleaner, had been sitting for years on a shelf, so without disturbing it, I poured off the oil and used the paste. I had some Keith type LSWC boolits, I boiled the red lube off them, seated them partially in flared cases over 8gr of Unique, then packed the groove full of the bore cleaner paste, seated and crimped the bullets. I think I fired all 50 of them and man that bore was a night and day difference in appearance, and it cut the groups in half. Sure made one heck of a mess!

[dubber123]

Use the largest boolit you can. If it just barely fits in the throat from the front, you are doing it right.

Funny, when I firelapped my first Ruger, there wasn't a lot of detailed instruction around, I used a broken bottle of JB bore cleaner, had been sitting for years on a shelf, so without disturbing it, I poured off the oil and used the paste. I had some Keith type LSWC boolits, I boiled the red lube off them, seated them partially in flared cases over 8gr of Unique, then packed the groove full of the bore cleaner paste, seated and crimped the bullets. I think I fired all 50 of them and man that bore was a night and day difference in appearance, and it cut the groups in half. Sure made one heck of a mess!

Well, not the normal method, but results are what we are after, right? :) I love watching a chatter marked up junk factory barrel clean up and start grouping like a champ. The massive reduction in fouling is a nice side benefit too.. Firelapping is a pain, but the results are so worth it.

[Tn Jim]

OK, so since the weather was nice and very little wind, I decided today was the day to do this. Loaded all my stuff in the truck and went to the range. I started at 3 grains of W231 and started working my way down. 2.2 grains ended up being the magic load, anything less and I had to drive the boolit out with a hammer. The portable bench was a great idea. I used the same six pieces of brass for the entire process. Since I had never done this or even seen it done I was a little apprehensive about whether or not I was doing this right, especially if I had enough lapping compound on the boolits. Now that I am finished I think it was right. I used a LBT lapping kit and rolled the boolits between the metal plates for a good two minutes, 6 at a time, until I had 50 of them. I pulled the cylinder and cleaned the gun after every six.

Now for some notes...
1. That small a charge of fast burning powder leaves a lot of residue. It's hard to see down the barrel with all the soot in there.
2. I started off oiling the bore, but stopped after the first cylinder to see what would happen. I had gotten down to 1.8 grains but the boolits stuck without the oil and I had to go back up to 2.2 grains. Even without the oil I had no visible leading.
3. Checking the groups wasn't even a option. At 25 yards I was over a foot low! So much for using a 12"x12" pistol target. Boolit impact sounded like a golf ball hitting the ground. Every now and then I did see a little dirt fly from the backstop.
4. There were several guys there sighting in hunting rifles. (Gun season opens here in two weeks. Muzzleloader opened yesterday.) A couple guys asked if I was shooting a 22 mag. The look I got when I told them it was a 44 mag was priceless! Trying to explain what I was doing and why got this look.:veryconfu
5. Once I got home and cleaned the gun as clean as I can get it, along with some Chore Boy on a tight brush just to make sure there is no lead, I used a couple of LBT push through slugs to see how it turned out. The bore looks great and is smoother than I ever would have guessed it would turn out. The odd thing is I still feel the barrel thread constriction, even though a slug driven in about a inch and pulled back out and one driven all the way through measure the same. Maybe it's all in my mind. I will know for sure once I get my mould back from Erik at Hollow Point Mold and I pour some new boolits. These will be sized .431 and I think they will work better than the same boolits at .429.

All in all I think everything worked out pretty well. I want to thank everybody that helped me with this project. I don't think I would have had the guts to try this without you guys.:drinks:

[dubber123]

The last Ruger I did took close to 100 to get the choke out, so you may still have a bit left. Now you know how to get rid of it though.. :) It is amazing how smooth the bores come out, isn't it?

[huntrick64]

You might have enough of it out to not matter any more. If it shoots great and doesn't lead, don't get too anal on getting all of it out. The three things I noticed after fire lapping was 1. Drastically improved accuracy. 2. The barrel cleans up so easy (usually just one tight dry patch) and 3. NO LEADING (which was my primary reason for doing this). Glad to hear it worked out. You could have achieved the same results by firing a few thousand rounds of jacked bullets over your lifetime. Then your kids could say "look how accurate my dad's old gun is. Now YOU can say that without having to wait.

[Tn Jim]

Dubber, it really is. It looks like a mirror now. I am considering lapping my Henry 44 rifle, but the idea of sticking a boolit half way up a 20" barrel is a little more intimidating than a 4 5/8" barrel. I can see some tool marks in the Henry bore and I would love to make it look like this Ruger barrel. But the Henry shoots great with no leading or any other problems. You know what they say about something not being broke...

Rick, my reasons for doing this are exactly the same as yours. I should have my mold back pretty soon and after I cast a few and let them season for a couple weeks I will have my answer as to whether or not all this worked or not. I will give a update when all that happens. Stay tuned guys, I'm not done yet!

[dubber123]

I did my Marlin Cowboy in 45-70 with a 26" barrel. Major difference in that one. Of course the bore looked like an old railroad track before I started. :) I did get away without having to pound any out. I find rifles easier to lap than revolvers.