FIRELAPPING STAINLESS STEEL RUGER HANDGUNS IN 36 ROUNDS.
Firelapping is a very effective way to improve the barrels on handguns and rifles. I have been firelapping handguns and rifles for about 10 years now. I have successfully firelapped over a dozen firearms. This tech note is not really about firelapping. That has been done. Rather, this article is about how to do it a lot faster with much fewer lapping bullets going down the bore.
A full and accurate description of firelapping or barrel lapping can be found in Marshall Stanton’s book, “Beartooth Bullets Technical Guide”. Before you seriously consider any of my suggestions, you need to thoroughly read the procedure of firelapping in “Beartooth Bullets Technical guide”. This Tech Notes article is only to add to Marshall Stanton’s extensive work. I am not reinventing anything here. If you want to firelapp successfully, the Technical Guide book needs to be your guide.
If you are new to all this and wondering if firelapping is worth your while, here is a post I recently put on the Beartooth forum describing some successes with the process.
” I have firelapped well over a dozen handguns & rifles in the last decade. The results varied but were never negative. My 30-06 M-70 went from a 1 1/2" shooter at 100 yards to a 1/2" shooter with the same load. A friends identical M-70 went from 2" groups to 1" groups. That was just after the initial firelapping with no other work done. I have a S&W 629 that shot heavy bullets well but sprayed 240gr swc all over the paper. After firelapping it shot those 240gr lead swc into under 6" groups at 100 yards (the edge of my skill level with iron sights and a 5" barrel).
In recent years I do not do an assessment first. Once I know the firearm is in good shape, I firelapp it. Invariably they are either very accurate or tack drivers. There is less leading and fouling of any nature. Like Marshall said, you have to do it by the rules for it to work right but the gains have always been worth the small effort. I have found the Beartooth lapping compound to be easily the best I have used. Marshall has it down right. I am hooked on all those benefits!”
The reason for this article is that I have found a way to dramatically decrease the number of lapped loads necessary to eliminate the high spots/constrictions and convert the barrel into a lightly tapered and very smooth bore. This article is about Ruger stainless steel handguns, though it applies in part to any firearm being firelapped. It has been common to take up to 200 lapped rounds to get the constrictions out and taper a stainless steel Ruger revolver. I found a way to do it in 36 rounds. It’s all very simple and pretty logical (which is why it took me so long to figure it out!). Do everything the Tech Manual says but apply these three additional rules. You will be simply amazed at the results.
1. CYLINDER THROATS, (revolvers)
A couple of months ago I firelapped a stainless Ruger GP-100. I only lapped 36 rounds but in this case, it reduced but did not eliminate the constriction where the barrel is screwed into the frame. It shoots great. It is very smooth etc but I did not achieve the tapered bore I was seeking. Why??? Simple. The cylinder throats measured .358 against a .357 bore. The BTB lapping bullet diameter is .360. That means the lapping bullets were using up most of their cutting ability on the cylinder throats instead of the barrel constriction. It is interesting to note that after 36 lapping rounds, the cylinder throats opened up .0005 to .3585. I just had David Clements open the throats on the Ruger so I will firelapp again.
On the same night I firelapped my new stainless Ruger Redhawk in 44 mag. This Ruger had .4325 cylinder throats against a .429 bore. The BTB lapping bullet diameter is .435. The lapping bullets spent most of their cutting ability on the bore constriction instead of the cylinder throats. At the end of 36 rounds, I had a constriction free bore with a slight taper toward the muzzle. Exactly what we want. There is more below, but you will not get far with smaller cylinder throats. I think that smaller lapping bullets would work better here but that’s only a guess.
2. BEARTOOTH LAPPING COMPOUND
Apply it per directions. Compared to others, the Beartooth lapping compound is “slicker” and appears to lubricate better. My impression is that it causes A LOT LESS LEADING in a barrel. For at least that reason, it cuts better and faster. There are lots of lapping compounds out there but the BTB lapping compound seems ideal. The lubrication of the lapping bullet seems equally important as the abrasive!
3. BRISTLE BRUSH THE BORE A LOT!
We have been taught to clean any lead out of the bore while firelapping. That is, any lead we can see. In my experience, that is not how to judge lead in the bore. It’s too hard to see anyway. If you get any lead built up on a barrel constriction, you’ll take forever getting through the very buildup every previous lapping bullet caused. When I firelapp a revolver, I use a tight fitting copper bristle brush every 6 shots. Start with a new one and figure to throw it out when you are done. You do not need to look if there is leading. Just assume there is lead and get the brush working. I use lots of Break Free to keep the particles loose and push them out. It generally makes a pretty big mess before it’s all over. Be very generous on the lapping compound and work with a bore lightly lubed with Break Free or equivalent. You will not believe how fast the lapping will go if you do this. If I observed the bore to be very rough, I would brush the lead out after every round.
I use lead sinkers to test for constrictions. I test when I start (with a very clean and lubed barrel) and every 18 rounds. Of course the barrel is brushed clean & lubed every 6 shots.
If you are firelapping a rifle or single shot handgun, I highly recommend you remove the lead after every shot. No matter if you can see it or not. In this case, I would simply Firelapp 10 shots, break in the bore and go shooting. There is a good chance this is all you will need. It’s a lot easier to take more metal off than to put it on.
That’s about it. In the last year I did this to 2 stainless Ruger Redhawks (44 & 45) that way and got 100% of the constrictions out and achieved a tapered bore. All this was done in a total of 36 shots per gun. I have achieved these results before but never in under 100 lapped rounds. To no ones surprise, these guns are total tack drivers. Do it by the book and you’ll love the long term results.
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