Front barrel leading :cause ?

[chriske]

The other day I tried another new .45 Colt load from my Ruger Blackhawk : 200 gr. .452-sized cast LSWC & 8.5 gr. of VihtaVuori N 320.
I developed this load earlier with a dozen test loads and everything seemed OK : report, recoil, case extraction/ejection, primer appearance, even accuracy was nice. So I loaded a bunch of them.

After the first 30 or so rounds, accuracy dropped, but I blamed myself for that : I had been shooting .38 's DA-wise for more than an hour before switching to the Ruger (and yes, an hour of shooting tires me).

Upon cleaning the Ruger, however, I noticed something weird : usually when leading does occur it is located in the forcing cone & the first inch of the rifling GROOVES closest to it.
In this particular instance, there was heavy leading on top of the rifling LANDS in the LAST two inches of the barrel, closest to the muzzle. No doubt this adversely affected accuracy.

What causes this : wrong bullet ? wrong powder ? wrong load ?

 

[SL1]

It sounds like it was a lubrication failure. That is what typically causes leading at the muzzle end without leading in the forcing cone end.

Another possibility is that your barrel's bore gets larger at the muzzle and there is gas-cutting starting theredue to powder gases blowing by the bullet. But, I would expect that in the grooves, unless it is caused by wear on the lands (only) due to bore cleaning.

If it isn't happening with other lead loads, then I would think it is just the lube in the new load. Are you getting a lube "star" on the muzzle face with this load?

SL1

 

[chriske]

Now that you mention it, the muzzle was dirty, but no "star". (I know what you mean, my rimfire handguns usually show perfect "stars" on their muzzles.)
Is it actually possible to "clean out" rifling lands from a stainless steel Ruger barrel ? I have never used anything more abrasive in it than Remington's Bore Cleaner. Usually I use Hoppe's n° 9 & a copper brush.
The gun was bought new in 2000 and can't have more than 2-3 K lead bullets through it.

 

[Edward429451]

You say its at the front of the barrel, but go on to describe forcing cone leading?
If it's at the forcing cone end, you might have a bullet size problem, or a rough forcing cone.
The leading at the front of the gun (nearer the sight) would be a lube failure.

 

[SL1]

It sounds like a lube issue. I mentioned the lands wearing because you said that is where the lead is, and some folks who overclean their guns can wear the lands near the muzzle in a revolver because they are inserting the rod from the muzzle end. I am no expert on it, but I have read that it is actually the rod that contacts the lands and wears them. Rods usually pick-up abrasive material unless they are the super-hard "non-imbedding" type. Primer residue has fine glass powder in it that is abrasive.

Anyway, if you can put more lube in the bullet's grooves, that would be a good start. If all grooves are already full, then trying a more effective lube would be the next step. What lube are you using now?

SL1

 

[kestak]

Greetings,

+1 SL1.

I am with lubrification failure too. I would suggest you lube your whole bullet in alox or something like that and see if it corrects the issue first.

Lead fouling at the start of the barell is a sign of gas leek and it is usually stronger at the start and almost non existent at the end of the barrel.

Thank you

 

[Unclenick]

You can remove leading one of three ways (these days; the old timers used mercury to amalgamate it and brush it out, but that is a health no-no now).

Electrolytic:
Probably the neatest is with the Outers Foul Out tool. It electrolytically plates the lead onto a stainless rod suspended in the middle of the barrel.

Mechanical:
You can buy the Hoppe's lead remover kit for your caliber which uses a bronze screen to scrape the stuff out or you can just wrap a strand of Chore Boy (a pure copper scouring pad and not a copper plated steel one; avoid anything that a magnet attracts) around a .38 caliber brush until you get a tight fit. Apply some penetrating oil like Kroil, then scrub it out. This can be hard on the muzzle if you aren't careful to keep the cleaning rod centered. There is even a special scouring pad material that Midway sells for the purpose, but it is expensive. There is also an abrasive cloth that will remove leading that I believe Birchwood Casey now sells. The original brand was Lead Wipe, I think? It contains fine aluminum oxide abrasive, though, so use it sparingly.

Chemical:
Sharp Shoot-R is the company that makes Wipe Out copper cleaner, and now has a lead solvent called No Lead. It comes in two parts you mix together. Put a patch in and let it sit for a time, then wipe the lead out with another patch. I bought some recently but have not had a chance to try it yet. The company is dedicated to making it possible to clean bores without brushing. Boretech Elimenator will attack cast bullets slowly. I believe it actually goes after the tin and antimony in the alloy, leaving the lead weak enough to brush out.


As to the original problem, it is likely to be lube failure, as stated by the others. You sometimes see guns whose bore expanded during machining or soldering or brazing of the front sight base or due to the muzzle being contoured much narrower than the breech end. Button rifled barrels, especially, have stress in them that can relieve itself by expanding in that way when you change the contour or heat it. You have to slug the bore with an oiled pure lead slug to feel this. My dad had an old Smith revolver in .45 LC that had the contouring problem and just got wider toward the muzzle. It also had a bad constriction where the barrel threaded into the frame. Lead was impossible to shoot from it. Unfortunately he traded it away before we learned about firelapping to smooth the bore and clear up that problem.

Funneling by a cleaning rod is usually only extreme in military rifles barrels that, at the command of drill sergeants, have often been cleaned much more often than they've been shot. It is especially bad on U.S. rifles cleaned with sectioned steel cleaning rods, but anything can do it, given enough time and elbow grease. Muzzle bore guides are a good idea. If you have a lathe you can make your own from Delryn or Nylon or Teflon stock.

 

[garryc]

Yeah that's lube failure. I had that problem and solved it well. I started using Lyman Super Moly Bullet Lube

http://www.midwayusa.com/viewProduct/?productNumber=461543

Thats a rather soft lube, kind of sticky. So I put about 100 lubed bullets, depending on size, in a plasic pail and put in about a heaped teaspoon and a half of powdered mica.

http://www.midwayusa.com/viewproduct/?productnumber=279094

Just roll it around and get all the bullets coated. Between the moly and the mica those bullets are slick, really slick.

 

[Unclenick]

Or, if these are purchased bullets, just add lube to what's already there. You can supplement it by rolling the bullets around in some Lee Liquid Alox lube in a plastic paint bucket. You can go still further by letting the Lee dry just until it is still tacky and dusting the bullets with motor mica powder, rolling them around a little more, then letting them dry the rest of the way. The motor mica is a dry lube, and it also makes the bullets less sticky to handle after the liquid alox. Graphite would work, but is messier and tends to permeate the gun making everything dirty.