A Contemporary Look At Barrel Leading and Related Sixgun Issues


by Fermin Garza

photography by Fermin Garza

January 4th, 2011




Any discussion here should begin with the writer establishing his bona fides as knowledgeable enough to express an intelligent opinion on the matter at hand. I have been shooting sixguns for nearly 40 years. That, however, does not mean I know everything there is to know. BUT, some things I do know. At this point in my career I have been able to take advantage of all the writings of Elmer Keith, Skeeter Skelton, John Taffin, Ross Seyfried, along with many others whom I have studied enthusiastically. By the age of 18 years I was in attendance at The Colorado School of Trades Gunsmithing School. I actually shot in the same pistol league as Seyfried in the early 80's; Ross at the time was already an accomplished sixgunner. I was not aware of this fact, only that the guy could sure shoot a 1911!!! The CST actually awarded me with a journeyman degree in the field of gunsmithing. Nothing more than another way to say that I know just enough to get into some serious trouble. 

During all this time I have been determined to learn to shoot. So I shot. And shot and shot. At 18 I was shooting 1000 rounds a month minimum. This grew to 300 rounds 3 to 4 times a week when we got our first progressive loaders. Much of this ammunition was expended through 1911's but as you might imagine I had to CAST a few bullets to keep up with pace. I also learned the value of a hand fit gun during this time. They last so much longer and can be very accurate. 

I got my first 4 inch S&W Model 29 when I was about 19 or 20, and man that thing stung my tender paws! I loved it. Then I got an Old Model Ruger Super Blackhawk. Of course, the front sight was too short so it saw mostly 180 grain jacketed bullets, but as my hunger for 44 magnum ammo grew, I broke down and sent an Ruger Old Model Flattop to Andy Horvath to have it done up just like John Taffin's Skeeter gun, except in 44 magnum. That was the first of many, many custom revolvers I now own. I have sixguns by Clements, Horvath, Harton, Bowen, John Linebaugh, Stroh, Reeder, Freedom Arms, Morrison, and dream of a Forkin and Dustin Linebaugh creation. 

I have gone so far as to have Alan Harton recreate the Keith #5 44 special only in stainless because, as we all know, The Grand Old Man (Elmer Keith) hated a counterfeiter. At this point, hopefully, we have established that the writer isn't completely clueless regarding the current subject matter. 

During all of this, I have decided that I want my sixguns to be accurate. If they are not accurate, I don't want them. I will pull a suspect barrel in a heartbeat and put on a match grade tube in a flash rather than put up with the aggravation of a troublesome sixgun. I expect sub 2 inch groups at 50 yards handheld or BUST!

Now, I have had barrels by Pac Nor, Shilen, Douglas, and most factory products. I don't give a red rats rear end WHO built the barrel. There is no getting around the fact that some of these barrels will have restriction in the bore. I can also tell you that NONE of the smiths mentioned above make barrels, and they are pretty much at the mercy of the barrel companies. The fact that some of these barrels with less than prime dimensions can shoot quite well is beside the point at hand. 

If you have read this far, let me tell you that what follows is pretty much just my opinion based on my experiences. I do have one close friend who considers me to be a bit on the anal side. Actually, to tell the truth, my buddy Chuck Smith, also a dedicated, knowledgeable, and experienced sixgunner, says that I am about the most anal SOB he has ever met. But, he's always sweet to me like that. Truth be told, Chuck is of the opinion that most factory barrels will shoot lead bullets quite well IF the owner "seasons" said barrel with enough jacketed bullets to smooth out all the rough edges and high spots. I have seen Chuck shoot a sixgun to 650 yards or so, as well as his 100 yard sixgun groups, and simply cannot argue with his success. On the other hand, I'm quite happy to argue with Chuck over the price of bicycles in San Antonio or the best tea in China or whatever it is we are talking about at the time. While I cannot argue with his sixgun success, I am not about to shoot 300 bucks worth of Hornady XTP's to smooth out all of my sixguns! 

I like to firelap my sixguns. Its a bit of a nasty, messy kind of job. It takes time, patience, some careful measuring tools, and a positive attitude to do well. If this isn't you, just quit reading right here. On the other hand, if you like the satisfaction of doing it yourself and seeing positive results, I will detail step by step what and why I do to smooth out a problem barrel. 

First, we have to understand that there are 3 different things that we need to control. The first is the cylinder throats, the second is the size and hardness of our lead bullet, and the last is the barrel itself. I am going to jump a bit ahead to dealing with the barrel itself and work backwards because its easier for me to explain it that way. 

Next, we have to define what a problem barrel is. Well to me, it is any barrel that leads to any degree when I am shooting a lead bullet. It will rob accuracy, and accuracy is what I am trying to get out of my barrels! I recommend you become a base pin puller. Never go to the range without what you need to pull your base pin. Whenever I get a new sixgun, I measure the cylinder throats and try a load first using the largest bullet I can get into that set of cylinder throats. Sometimes you will encounter a sixgun with cylinder throats that are too small for the bore. These must be opened up to proper dimensions before you can gain any ground here. I like mine .001" larger than the groove diameter. Otherwise you will be shooting lapping bullets that are too small to do any barrel lapping.

This brings us to the first tool we need to precisely measure our sixgun. Some guys like to use lead slugs driven thru and measure them, but let me say that if that is you, at least get yourself a micrometer and NOT your dial calipers. Dial calipers cannot be used to properly measure cylinder throats for their square surfaces on the radius of the chamber mouths. One can also use an inside micrometer which will measure the throats exactly, but I prefer pin gauges and I am going to explain why as I go along here. Keep in mind that the chamber is cut from the rear and some custom gunsmiths ream the chamber with a reamer that will also cut the throat of the cylinder. I believe that the proper way to measure a cylinder throat is from the rear using a pin gauge. The cylinder must be very clean to do this accurately. To this end I have purchased and use a MINUS set of pin gauges. 

Ok, so let's say we are working on a 45 Colt here and our cylinder throats measure a perfect .4525, and we loaded and shot a proven load through the sixgun using a .453 bullet that is a nice press fit into our cylinder throats. Our 25 yard group looks about 2.5 inches or so after 10-12 rounds. We know we can shoot better than that, and while we consider tinkering with our next load we pull the base pin and see the bane of sixgunners; a barrel full of lead. How can this be??? Our bullet is hard enough, we have shot that load through many other 45 sixguns with good success, yet we find ourselves looking at so much lead we might be able to plow it and plant corn! At this point, the next thing to try is a gas checked bullet, for often this is a simple solution to a barrel that has less than ideal dimensions. But first we have to get all that lead out of the barrel.

What we are going to do next is to make a tool that will cut through that lead in your barrel like a chain saw on termite infested wood. What you need is a good brass rod, and since we are working with 45 caliber here, we need a bit of a worn 45 bristle brush and a copper pot cleaner. You can pick them up at the Dollar store or wherever. You take your copper pot cleaner and cut it with a pair of scissors so you can lay it out flat. Wind it tightly around the worn bristle brush so that it makes a really tight fit in your barrel. It cant harm your barrel in any way, its like shooting a jacketed bullet through your bore. Run the modified bristle brush back and forth a few times and it will scrape all that leading right out in an amazingly short time. Be sure you get all the lead out of your barrel. Clean the barrel with a solvent and a patch. You should be able to see a clean patch almost immediately. Avoid using a stainless steel brush on your barrel. 

I cannot stress the next part enough except to say that a set of pin gauges are invaluable to a serious lead bullet shooter. I got a set of Minus Pin gauges for about 80 bucks or so. You have to really be careful here, but what you want to do is to find a pin gauge that will just start in your barrel. Ideally, if it fits in the muzzle, it should just drop all the way through. Your pin gauge like your barrel should be surgically clean, free of any grease or other matter. 

This is different than all these folks who want to beat or otherwise push a soft slug through the barrel and "feel" restriction. A pin gauge is NOT going to lie. Its either going to fall all the way through the barrel or it is not. Some barrels will have a high spot in the middle, some will have a high spot at the threads. The pin gauge will immediately tell you because it will stop in the barrel. DO NOT force the pin gauge in any way. It is very easy to damage your barrel!!! I damaged a 500 dollar custom octagon barrel once because I stuck a pin gauge at the threads and tried to tap it out with a steel Allen wrench and dinged the rifling. The carbon steel barrels are especially soft and easy to ding. If your pin gauge sticks what I do is get a bullet that is smaller than the bore and drop it in the barrel from the breech end and use it to tap out the pin gauge. Be very careful here, and it is easy to find if you in fact have a bore that has restriction.

This restriction will cause your lead bullet to crush down to the minor dimensions of the barrel. It will then leave leading as it rattles down the rest of the major dimensions of your barrel. I have measured some barrels that had some serious restriction. Normally you might see .001 or .002, but I have seen .003. This will just devastate your ability to be successful with cast bullets. If you only have a small amount of restriction you can often get by with switching to a gas checked bullet and alleviate any leading issues. However if you are determined to shoot plain base bullets you either have to rebarrel the gun or firelap it.

If you choose to firelap I recommend you get a copy of both Veral Smith's book, "Jacketed Performance with Cast Bullets", and Marshall Stanton's book "Beartooth Bullets Technical Guide". Veral's book is very detailed and full of good information. Marshall's book is a bit easier to read and he also sells a firelap kit that really does not cost very much and I hate to say this but its really very simple to use correctly. I have firelapped quite a few sixguns and every single one dramatically improved lead bullet accuracy. Yes, I damaged one very expensive barrel, but it was fixable and as I stated, I have paid my dues here. My focus here is to help avoid harming your barrel. 

At this point, you need to have your cylinder throats cut for the bullet size you intend to use. Lets say I want to shoot a .453 bullet in my 45 caliber sixgun. I want my cylinder throats just under that at .4525 diameter. If you send off your cylinder to get modified thus you can easily check your smiths work with your pin gauges. Just slide them in from the chamber end. A .452 pin gauge should slide through your .4525 throat but a .453 pin gauge should not. 

You now need to be sure your bullets are the correct diameter. Forget the calipers guys. They measure plus or minus .001 and we need to measure plus or minus .0001!!! You will need a real micrometer, which will also tell you not only what the true size of your bullet is but if its round or not. 

So, we need 3 tools here. A Chore Girl modified bristle brush, a set of pin gauges, and a micrometer. Some guys want to drive lead slugs through and measure them, and that's OK with me, but I have tried that and find pin gauges to be far simpler. I was discussing this same issue with a guy who had an "inside" micrometer. That's a fine tool for measuring your cylinder throats but it will not measure the internal size the entire LENGTH of your barrel!!!! 

Ok, so now we have dropped a pin gauge into our barrel and it stuck inside the barrel. Tap the muzzle on a soft surface and if the pin gauge does not fall out, drop a smaller caliber bullet from the breech side until the pin gauge dislodges and slides out. We now KNOW we have a tight spot in the barrel and since we want to shoot lead base bullets we need to firelap that restriction out. In no way is it proper for the muzzle end of the barrel to be bigger than the breech end. The breech side of the barrel should TAPER down in dimension towards the front. Nor should a barrel have any tight spots in the middle. 

When you get a firelap kit you basically need to get 5 things. A manual of instructions that you should read carefully. A can of lapping compound, 2 steel plates, a large bolt, and some bullets that are the right hardness for firelapping. Pay attention now, I'm going to save you some hassle here. Pull the cylinder on the sixgun to be firelapped and clean it. Tumble some brass that has been fired in the sixgun you intend to firelap. If you are like me and have a bunch of 45's and dump all your brass in one pile, its no problem just tumble more brass that what you think you need. Take your clean fired cases and find 40 or 50 for a blue steel sixgun or twice or even three times that amount for a stainless sixgun. Using your cylinder as a gauge find cases that are a slip fit. You are basically using your cylinder as a chamber gauge here to be sure your firelap rounds are going to work in your sixgun. Any cases that stick should be set aside. I don't happen to own a universal decapping die so for my 44's and 45's I use my 45-70 dies to decap my clean chamber checked cases. Its important that the dies do not touch the sides of your cases at any time. For my 500 Linebaugh I had to use a lead block and a pin punch. Go ahead and prime your cases and set them aside. 

Now comes the messy part. Get a couple of rags handy. I keep one in my lap, one on my bench, and one on my shoulder because that firelapping compound sure does get places you don't really want it to be. Be sure you have already gone inside and hit the little boys room, DO NOT touch any of the wife's clean counter tops or cabinets, and you definitely don't want to be digging around in your snot socket while handling the lapping compound. 

I use my finger to smear a good amount of lapping compound on my steel plates. I lay out about 5 bullets or so and use a back and forth rocking motion to press the bullets in between the two plates until I feel like I have embedded the bullets with compound. At this point the bullets are all sticky and I leave them that way and dump them into a cardboard box. I continue until I have the needed number of bullets for the next step. 

Now I need to charge my cases. I want to use enough powder to be sure I get the bullet out of the barrel, but I don't want to shoot anywhere near 1000 fps, closer to 500 or 600. A fast burning powder works best here, for my 45 colt I use 4 grains of WW 231. Included in the kit is this big ole bolt (7/8x14 TPI). You simply screw it into your reloading press. I like to screw it in until I can see it from the inside of my loading press window so I can clean it off periodically to keep that lapping compound out of my loading press threads. 

Your bullets will have a bevel base or a round nose or both. I set a primed, charged case in my shell holder and lay a bullet on it UPSIDE down and run the lever up until the bolt pushes that greasy bullet all the way into the case. Sometimes it will fall down inside the case and that's OK too. I'm looking to get my bullet as close to my powder charge as I can, and having that greasy bullet sticking out of the case just makes a mess anyway. Once I get all my bullet seated I use my rags to wipe all the lapping compound off my cases. I now have a number of bullets that look sort of like full wadcutters but are in fact going to smooth my barrel and cut out the high spots that are causing me grief. 

Remember I said you needed at least twice the number for stainless steel guns?? That's because the stainless steel that both Ruger and Freedom Arms uses is harder than a whore's heart and will require some serious shooting to get the restriction out. I have firelapped stainless guns in excess of 150 rounds. Carbon steel sixguns don't seem to take anywhere near that number. If I EVER have to do another stainless sixgun I am going to use a more coarse grit before I use the normal compound in an effort to reduce the number of rounds it has taken. 

Now, we are going to the range. You need to set up a target here because you're going to see something you're not going to believe. Start shooting careful groups with your firelap rounds 5 or 6 shots at a time. The first shots will be kind of all over the place, but as you progress you will suddenly see your firelapping bullets shooting a pretty tight group. Something has definitely happened here. It may happen in as few as 15 to 25 rounds, but if not at that point I would stop, get out my new fancy-dancy Chore Girl modified cleaning brush and scrub out my barrel and follow it with a few patches till its nice and clean again and check it again by seeing if the pin gauge that stuck before will now fall all the way though the barrel. If it does, see if the next size pin gauge up will start in the muzzle. Remember, if it starts in the muzzle, it has to go all the way through to the breech end. Be sure to clean your cylinder as well, every 15-18 shots as this will prevent any scoring of the steel. 

If you don't have all the restriction cut out, continue to fire your lapping bullets at your target. I have seen those firelap bullet loads all of a sudden cut a ragged hole! Its a good sign you have made some good progress, but your pin gauges will tell you for sure. Continue to clean your barrel as before and check. Once you feel you have cut out all of the restriction you can try some normal ammunition in your sixgun. 

Remember, we should be shooting the correct diameter bullets in our sixgun and we KNOW we are because we measured them with our micrometer and are NOT going by whatever the box says. A barrel that is properly lapped for lead bullets will never ever need to be cleaned again. You might have some unburned powder residue in the barrel but it should easily wipe out. It is also very important to examine your muzzle. You should see bullet lubricant on the crown of your barrel. This is important because it is telling you that your bullet lubricant is making it all the way out of the barrel. 

Pretty simple, isn't it? Remember to use a target because you want to be sure you don't stick a bullet in the barrel. That's not going to help our project. I have never seen firelapping NOT improve how a sixgun will shoot plain base lead bullets. If you don't care to got through all the trouble of fire lapping, try a gas checked bullet or stick to jacketed. It may solve your problems and shoot pretty well to boot. If you decide to firelap, pay careful attention, clean often, get some proper measuring tools, and proceed with caution. If you follow these simple steps, you may achieve results you only dreamed of before.

Fermin Garza


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Click pictures for a larger version.


A 500 Linebaugh with oversize throats and barrel restriction. Note the tumbling.



A Bowen Nimrod 475 Linebaugh with restriction in the bore.



A pin gauge should fall all the way through a barrel.



A 500 Linebaugh by Reeder with restriction at the threads.



Same gun, note the firelap rounds "stack" at 25 yards.



Same gun, after cleaning, note the pin gauge falls all the way through after 15 firelap rounds.



Freedom Arms Model 97 with a tight spot in the barrel.



If a pin gauge starts in the barrel, it should fall through!



Steel plates with lapping compound.



Five bullets ready to roll!



Five bullets between lapping plates.



Bullets impregnated with lapping compound, ready to load.



Ready to seat, note bolt in press.



Fifty firelap loads. Ready to shoot.