leading at the end of the barrel

just got done shooting four cylinders out of my new ruger super Blackhawk hunter, 7 1/2" barrel, 22grs of 296, 270 grain keith, homemade moly lube. the potential for accuracy is definetly there, but I am going to back off to 20.5grs for tomorrow, because the last 2 inches or so of the barrel was leading. i am wondering a few things, my boolits turned out harder than I thought, so maybe this is an obturation once the pressure lowered thing, or maybe my lube wasn't up to the task, there wasn't a lube star, so first, I am just going to try the same thing but with the reduced load, then if it still leads, I was going to go to a softer boolit, then, all that failing, work on my lube? maybe add to it to make it a bit harder? before you ask, I couldn't afford to get a hardness tester, but I think it might have been up to 14-15bhn. thanks guys! this isn't gonna dampen my spirits any!

oh, I would like to add that the lube I am using has worked fine in rifles up to about 1700fps, but all of those had multiple thin grease grooves, instead of one big fat one, so maybe the boolit is to hard and the lube is getting blown out before it gets to the end of the barrel? just curious if any of you have had this particular problem...

Leading at the end of the barrel .. indicates lube failure, or you are running out of lube by the time the bullet reaches the end the barrel. Click on the lasc link at the bottom of the page and read from ingot to target, there is info there that will inform and help you.

Billyb is correct. Your lube isn't quite up to the task. What I would do is add a layer of Liquid alox or 45-45-10, or Ben's Liquid Lube over the top of your boolits and that should get you where you want to go.

Another thing your muzzle end of the barrel may have a larger bore/groove then rear end of it. Also too many guns constrict the barrel where they screw into the frame. The earlier S&W's were bad for this.

^^^^^^ This sounds like it could be the problem, barrel constriction at the threads, especially if you can shoot this load and doesn't lead in your rifle.

My recently purchased SBHBH showed some leading toward the barrel also, but not until I had fired a lot through it. The thread constriction will show up with leaving lead in your bore - but usually the telltale sign is lead build up just a little past the forcing cone, tapering off toward the muzzle. This is what I saw when cleaning my gun the other day.

I have a slight constriction and I monitored the build up in my barrel. Leading started to accumulate just past the forcing cone, then eventually toward the muzzle.

I am shooting gas checked and powder coated boolits. I am 100% sure its a hardness issue on my part.

I say all of that to say, if it were a constriction main issue then you'll have more lead at the forcing cone end then the muzzle. If you have more lead at the muzzle, then it's a lube issue more so than a constriction.

This has been my experience at least.

Don't over think it. You answered your own question with; "or maybe my lube wasn't up to the task, there wasn't a lube star".

Your home made moly lube simply wasn't up to the task with that bullet in a revolver with that length of barrel. There's a lot of difference between a revolver and rifle (or closed breach handgun) as to what happens to a cast bullet and its lube. I suggest you use a different lube such as BAC or NRA 50/50 as sold by Lars (White Label).

swheeler, I said I have used the lube in a rifle, but that boolit/ boolits, had 2-3 small grooves, not one large groove, and I have always heard that constriction shows leading at the breech end, maybe an inch or two into the barrel. I re-read a article by frxell about alloys, and he mentions this happening when the alloy is too hard, and towards the end of the barrel as the pressure lowers, obturation quits, and the trailing edge of the rifling isn't being sealed, allowing gas cutting. so I am going to cast some softer boolits today, and test tomorrow. I noticed that it was harder than normal to size these, and I have a feeling that this, and some other alloys, are way harder than I thought they were, especially when I took one of yesterdays boolits, and hit I with a hand held sledge, and it took at least a dozen, maybe more, good whacks before I had it flattened like a coin. so if the soft alloy doesn't work, i'll buy a tube of white lable carnauba blue. I also did end up un-doing one side of the trigger spring, because I was pulling some shots. it isn't causing any hang-ups, and turned out to be perfect. that, with a bit of reducing the load to 20.5 should help too. 22 wasn't too bad, didn't hurt after 4 cylinders, but it was definitely more than needed. I will keep y'all updated! thanks!-Travis

would 20.5-21grs of 296 behind a 270gr keith be safe, or is that too low of a charge??? thanks for all the ideas, im going to check out all of them, one by one of course, so I know what the problem is.-Travis

Travis once a bullet obturates it stays, lead doesn't spring back like many metals with memory.

well, the way he described it, it sounds like he meant more of a continuous obturation though the whole barrel, but I may be wrong, and he may be wrong, I dunno, I thought he was a pretty well trusted gun guy. looks like I will try ordering some lube. wasn't trying to question you, I just thought you might have misread my post. I suppose its all just a part of the learning curve, but today, I tried some softer boolits and saw improvement in accuracy, but didn't shoot as much to tell if the leading was any better or worse. even still though, the boolits still turned out harder than I wanted, I believe my alloy was waay harder than I thought, what shoulda been pure probably wasn't, but in the rifles it didn't seem to matter, so I am only now really noticing. so that is something I am going to work on tomorrow. I do have a good bit of 1.9sb/4-5%sn that I know is soft enough and i'll get to it next. I should have just emptied my pot, and started with that but instead, I just added lead to soften it, now twice, lol. but it should be there now!

I might've missed it, but what are you sizingyour boolits to? A small boolits will lead......430 or .431 may help with the leading, and I'm 99% sure the carnauba blue ( or red) will help.

I shot by pistol last night and remembered to take a few pictures before I cleaned it. I think it should help visualize what a constriction does to a lead boolit. Not the best pictures, but should be good enough.

Attachment 214402

Attachment 214403


Notice there is no lead around the forcing cone and into the bore for a little way. That is where the constriction is. Then, once the boolit clears it, there is a slight moment where there is enough space for the gases to get past the gas check and cut lead off the boolit. Then, when the boolit makes it a little further down the bore it seals once again and there is no more gas cutting.

The picture taken from the muzzle end doesn't show the lead near the forcing cone as well, but it should give you a general idea of how slick the rest of the barrel is. I did not measure just how far the lead cutting happened(maybe I'll remember to do that next time) but if I was to guess maybe between 1"-2".

I think, but will say its just my thought, that if I had a softer boolit then I might not get that leading as bad as I am. That's my theory anyway. The gas check should be doing its job to stop gasses from cutting by, but maybe because the boolit is so hard it does not "slip" past the constriction, but rather "pops" past it. If that makes sense. Does in my mind. :)

newton your pictures didn't work, invalid attachment.

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Originally Posted by swheeler

newton your pictures didn't work, invalid attachment.

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Weird. It looked fine when I posted it, but when I just checked again you were correct. I deleted them and put them back in, maybe it will be fine now.

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Originally Posted by newton

I shot by pistol last night and remembered to take a few pictures before I cleaned it. I think it should help visualize what a constriction does to a lead boolit. Not the best pictures, but should be good enough.

Attachment 214402

Attachment 214403


Notice there is no lead around the forcing cone and into the bore for a little way. That is where the constriction is. Then, once the boolit clears it, there is a slight moment where there is enough space for the gases to get past the gas check and cut lead off the boolit. Then, when the boolit makes it a little further down the bore it seals once again and there is no more gas cutting.

The picture taken from the muzzle end doesn't show the lead near the forcing cone as well, but it should give you a general idea of how slick the rest of the barrel is. I did not measure just how far the lead cutting happened(maybe I'll remember to do that next time) but if I was to guess maybe between 1"-2".

I think, but will say its just my thought, that if I had a softer boolit then I might not get that leading as bad as I am. That's my theory anyway. The gas check should be doing its job to stop gasses from cutting by, but maybe because the boolit is so hard it does not "slip" past the constriction, but rather "pops" past it. If that makes sense. Does in my mind. :)

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Lap that section through the frame out Newton. You take an old bore brush and push it in the muzzle end of the barrel so it's just barely below the muzzle end after you had put a plug in first say make from tin foil or something that won't let the molten lead or alloy you are going pour over the brush go down the barrel. Then pour your lead or alloy and let it harden and cool. Next don't pull the lap out of the barrel!!! rather push it down the barrel until about 1/2 inch of it sticks out from the forcing cone. Next put your favorite lapping compound on it and pull it back and forth through that frame section of the barrel, pushing it back out again to resupply the lapping compound. Use a very very fine lapping compound. Now when you pull the lap out of the barrel mark it so you can re-orient it back to the same rifling groove if you need to lap that frame section somemore. Clean your bore out and then slug both ends and I feel you know how to do both ends. This will tell you if you got the constriction out.

yeah, mine is the exact opposite of that, thanks for the pics it definetly helps, I can see from the larger "splashes" of lead? that gas cutting makes sense... mine is more like an even coat of lead gradually getting thicker from about 3 in from the muzzle to the muzzle, so you guys must be right about the lube not working, someone asked, I am sizing to 431 and it is a snug fit in the throats. problem is, I have lots of my lube, and not a lot of money... someone mentioned adding lees liquid alox to my boolits after sizing/ lubing. do you think that would help enough to make use of all this lube I have? it stinks because it worked so good in my rifles, I didn't ever have to clean the barrels! but I noticed that I am getting lube "stars" lol on the face of my cylinder, even though the gap is the tightest I have ever seen on a revolver, so maybe I am losing lube there,, if so, would LLAlox help with that?? thanks so much for y'alls help. really apprectiate it... NEWTON- good luck with yours, and keep me up with your progress, and i'll let you know how mine is going. its all part of the revolver learning curve I guess!-Travis

so I was reading a thread about moly lube, and it mentions that it leaves a grey residue in the barrel.... that got me thinking, I hadn't cleaned my gun yet, and since I had no patches left, I ended up using tight wads of paper towel with hopes no.9, in about 5 passes, just in, not in and out, wasn't using a jag, just the tip of the rod, 90-95% of the "leading" or "residue" was gone... so, would you expect leading to clean up that easily, or do you guys think it is more likely that I was seeing this grey wash from the moly in my lube?

I haven’t used lube in years so I am of no help. Sorry.

powder coat?, that seems like a bit too much work for me, not that I don't admire them, especially being able to choose any color you want

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Originally Posted by Oklahoma Rebel

so I was reading a thread about moly lube, and it mentions that it leaves a grey residue in the barrel.... that got me thinking, I hadn't cleaned my gun yet, and since I had no patches left, I ended up using tight wads of paper towel with hopes no.9, in about 5 passes, just in, not in and out, wasn't using a jag, just the tip of the rod, 90-95% of the "leading" or "residue" was gone... so, would you expect leading to clean up that easily, or do you guys think it is more likely that I was seeing this grey wash from the moly in my lube?

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Look at your patch, silver looking sparkles are a dead give away if it was lead?

not that I saw, just looked black... so is this residue a problem? or just something I need to clean when it gets built up, if it does build up, if it IS lube,it may smear like what I saw, but not build up more because succeeding shots would keep it down. still need to find out if lee's alox will help with this, by that I mean applying it on top of the regular lube

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Originally Posted by Oklahoma Rebel

not that I saw, just looked black... so is this residue a problem? or just something I need to clean when it gets built up, if it does build up, if it IS lube,it may smear like what I saw, but not build up more because succeeding shots would keep it down. still need to find out if lee's alox will help with this, by that I mean applying it on top of the regular lube

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It's a problem if it becomes a problem... light fouling can become heavy fouling if long strings are fired without cleaning, especially adding a very hot barrel into the equation. For that, you'll have to try it and see (or just avoid the problem).