Is this "leading" - using Ben's Red

[Toymaker]

Hopefully Ben will find this and comment also -

Rifle is a Rolling Block in 45-70. It has been slugged for the first 6 inches from the breech (0.458") and the last 6 inches from the muzzle (0.458").

The bullet is the Hoch 459500 cast in 20:1 alloy in a PID controlled Waage pot using a dipper. They are 1.324" long, 0.459" in diameter and weigh between 506.8 and 507.4 grains. They are put through a Lyman lubrisizer with a 0.459" die and lubed with Ben's Red. There are slight rub marks on the bullet after going through the sizer.

The brass is Starline that was annealed when purchased, full-length sized and trimmed to 2.086". This was the third time they were used. They are cleaned, full-length sized and checked for length after each use.

The load is 27.0 grains of IMR SR 4759, CCI Large Rifle Primer No. 200, no crimp and O.A.L. of 2.896" so the bullet just engraves on the rifling. Velocity testing has been between 1,386.28 fps and 1,403.93 fps with standard deviations between 7.81 fps and 8.83 fps.

The pictures are of patches from a competition today. Temperature was in the upper 60's and humidity was in the low 50's. Each relay consisted of 10 shots after which I wet a patch with Hoppes No. 9 and wiped 6 inches of the bore from the breech with 5 strokes. The "junk" visible on the patch came out at that point. I reversed the patch and repeated the wipe with 5 strokes but nothing else came out. I wet a new patch and stroked the 6 inches of the bore from the muzzle 5 times, but nothing came out. A total cleaning at home yielded no additional "junk".

Previously I used a pure lead bullet. Sometimes I would get some "junk" as seen in the pictures, but not in the quantity shown. This started happening when I changed to 20:1.

I get lead out of a barrel and I freak out. A couple of people at the match said it was an acceptable amount and nothing to worry about. Others said the base of the bullet was being melted and blasted into the rifling. One suggested using a filler to protect the bullet base.

My theory is that the 20:1 alloy bullet is "stripping" as it tries to engage the rifling, leaving shavings of lead behind. The softer, pure lead bullet wouldn't do this.

So:
1. Is it leading?
2. Do I need to worry?
3. How do I stop it? (no, I won't get into powder coating; paper patch either, thanks)
4. I like Ben's Red, but is it doing it's job?

189019 189020

[Gtek]

Just opinion way far away on the other end of a long wire. Pure being much more malleable is scooting/sizing in through the throat a little easier than the 20-1 is. When I have "leaded" a barrel I wish it wiped out in five patches, I seriously doubt you have a lube problem. How many rounds through barrel? What reamer (who's) cut chamber? Throat reamer, fire lapping, bunch of jacketed bullets, paper patching are all options if this is indeed the issue.

[Nueces]

I suggest taking a look at your throat. Some 45-70 chambers have nearly no throat, so present sharp edges to the bullet upon firing. My Pedersoli Sharps gives me flakes like you show here.

[runfiverun]

I suggest you stop wiping the lube out of your barrel after only 10 shots.
if your gonna do something [and I don't know why you would] a single patch all the way through [atf soaked] is more than sufficient.
stripping down to bare steel and shooting it back in each stage can't be good for accuracy.

[runfiverun]

if you think it's alloy related [and it could be 20-1 does usually leave behind some stuff]
try cutting the alloy in half to 40-1.

[Toymaker]

Gtek, I'd have to estimate that I've shot lots and lots and lots of rounds through it. Over 1,000 and probably closer to 2,000. The first 500 were LaserCast to smooth things out.
Nueces ....... (long pause) .... (hmmmmmm) It is, in fact, a Pedersoli Rolling Block. But with all the shooting it has done (above) I'm surprised it hasn't worn. Guess I'll get the casting metal out.
Runfiverun, I run a patch saturated with Ben's Red up the bore before shooting. Then I don't clean it "to bare metal". Just looking for the leading and removing it from the first and last 6 inches of the bore. The middle remains untouched. Haven't noticed any change in accuracy. Today was not a good day, for me. I won't blame the rifle of the load. It sent the bullet exactly where I (unfortunately) was pointing.

[GhostHawk]

No lube is going to work correctly unless the boolit is sized correctly, of the correct alloy for the load, and is not getting swaged down in the loading process.

That being said black on a patch is not my definition of leading.

When I leaded up my Yugo SKS you could just about tell that there was rifling in there. There were however no real grooves as such.

Ben's Red fixed that and from there I moved on to BLL.

That black could be powder residue, unburned powder, carbon stained lube, etc.

Real leading, you can see it in the rifling. It tends to look "patchy" not the same as the steel. Most often down in the grooves.

Not leading in my opinion but I have been wrong before.

[35 shooter]

Definitely looks like bits and pieces of lead that got cut, melted, or shaved "somehow". I've never shot a 20/1 alloy at that speed, so can't comment on that.
However, i don't think it's lube related as i've pushed Ben's Red with ww alloy to 24,25 and 2600 fps. before without so much as a speck of lead.

The pieces in the pic do look more cut or stripped than anything, coupled with the fact it patched out easily.
As you say, a thousand shots should have had some polishing effect on the bore....just guessing(not much help i know), but i would suspect the alloy, and or, maybe try sizing 2 thou. over the .458 bore size to .460.

[tomme boy]

Is there a reason you are using such a soft alloy?

[Yodogsandman]

I got lead on my patch like that when I decided to try belling the case mouth a little less. It went away when I went back to belling the mouth enough for a gas check width to enter the case. The case mouth was shaving the boolit when seated.

[Wayne Smith]

Is there a reason you are using such a soft alloy?

Tomme, he hardened it from using pure lead! I've never shot pure other cap and ball. However, those pieces of lead are being removed from the boolit somewhere in the loading/shooting process. It is not your lube. Isolating the cause will be illuminating.

[Gtek]

Sized cases, did you chamfer inside and outside of case neck after sizing? Maybe shaving during loading, if you still have unfired or untouched components pop one back out and inspect.

[44man]

Smokeless powder is the reason, You have initial pressure to skid the boolit, too soft. 20 to 1 is a BP alloy. Yet, if the lead is shot out with every load, it is OK. When it builds up is the problem. Ben's Red worked in my rifles. NOT in revolvers.
Black patches are just powder residue, forget it.
Sorry but you can't use BP alloys with smokeless. Works the other way too, smokeless alloys hate BP.

[DougGuy]

Those chunks of lead look like they got knocked or chiseled off the boolit, they don't look like lead that got stripped off from powder gas eroding the side of the boolit. This looks like a mechanical interference of some sort is causing that. Would a chamber cast be in order maybe?

[44man]

Hard to tell. Most leading is mechanical, not melted lead. Even gas leaks do not really melt lead, it forces it off. Not 100% sure of course so does the lead really melt? It would mean the gas has to take lead up to 600° or higher in an instant. I feel it is erosion more then heat.
I use a newspaper wad over the flash hole on some guns. I use wads over powder, from plastic to paper and Dacron filler, None burns or melts, heat is too fast like waving your hand over a candle. If you melt a boolit with powder, I just don't know how.

[runfiverun]

they do look scraped off the boolit.
I'd look at the end of the throat/chamber where the rifling starts.

you might just be riveting the boolit slightly and cutting off the excess diameter.

you could try a shorter oal or a little crimp and see what happens.

[44man]

Most forget about what happens in the chamber and throats. Full pressure before the boolit leaves the brass. Not heat at all. That huge, heavy boolit will not want to spin at first touch to the grooves.

[tomme boy]

Like 44 said. That lead is just too soft. I would add some magnum bird shot or some lino to get the antimony up to about 3% and I think you would be go after that.

Well maybe! Try to get us a picture of your throat on the rifle. That may help to see what is going on. It may not have a tapered throat at all.

[Toymaker]

Thanks to the great ideas and suggestions I've done several things last night and this morning.

1. Took 50 Hoch bullets cast on 2/22 and ran them through the sizer with the .459 die. They were evenly "buffed" from the riding band to the base which means they're casting slightly larger.
2. Took 50 Lyman 457 193 bullets cast on 2/22 and ran them through the sizer also. The mold for these bullets had been "Beagled" to get a larger diameter. They were "buffed" on two sides indicating they were oblong, as would be expected.
3. Took a sized Hoch bullet (.459) and drilled a 5/16 pocket in the base (made it a hollow base). Then I dropped it in the chamber and took a 5/16 dowel and fit it in the base cup. Then I drove the bullet 6 inches up the bore. Reversed the dowel and drove the bullet out. The groove marks were clearly visible. The bullet is seen in the picture below. It was a very good fit.
4. Took a dry cleaning patch and rod and rubbed the breech to see if any chips, shavings, etc. had gotten peeled off. Nothing.
5. Got out my Cerrosafe and cast the chamber, throat and an inch of the bore. I had to do it twice and still got a "wrinkled" casting, but you can see in the picture that the throat is sloped. So peeling off a rifling edge perpendicular to the bore isn't the issue.
189180
A couple of comments:
In the original posting I forgot to mention that the twist is 1:18. I don't think this has anything to do with the issue, but I should have included it.
The black on the patches isn't the issue. That, as pointed out, is just powder residue. The issue is the shiny stuff on the black.
Looking down the bore I don't see "smudges" that would typically indicate real leading.
I only expand the mouth of the case (bell) only enough to let the bullet sit inside the rim.
After trimming I bevel the inside of the mouth and then burnish the outside to remove the wire edge. I once had a problem with shaving (pistol) bullets on the edge of the cases and that was a real mess. So I'm careful about expanding, beveling and burnishing the cases. Then watching as I seat the bullets.

More and more I'm agreeing with those that believe this is a mechanical shaving of the bullet as it attempts to engage the rifling and begin its spin. But why more so with a harder alloy than with pure lead?
Being a mechanical issue (general consensus) I think my next step is Lyman #2. The fewer shavings when I used pure lead must have just been an aberration.
(Maybe I'll check with some friends and see if I can talk them out of a couple of jacketed .459 bullets to reload and see if I get copper shavings )

[DougGuy]

Looking at the casting, I can see the neck of the chamber, and the chamfer that goes from the case mouth to the throat, but I am not seeing any freebore. It looks like the rifling leade in is going right to the edge of that chamfer where it begins groove diameter. You should usually have some freebore which is tapered into the groove diameter, and then the leade in starts where the groove diameter begins. If this is the case, lead can become shaved off by the boolit being forced into the barrel and then subsequent shots carrying it further into the bore.

This is a Glock 40 caliber barrel that I throated, but I am going to post it here to illustrate the freebore, which is on a 1 or 1 1/2 degree taper, so the section before the leade in is larger than groove diameter by .0025" or so, and it tapers into the groove diameter as the reamer gets smaller going towards the nose of the cutting flutes, anyway, this freebore is what I am not seeing in the chamber cast.

http://i1202.photobucket.com/albums/bb374/DougGuy/Cylinder%20Services/Glock%20Throating/Glock19-640_zpsv5rzqop5.jpg (http://s1202.photobucket.com/user/DougGuy/media/Cylinder%20Services/Glock%20Throating/Glock19-640_zpsv5rzqop5.jpg.html)

*OR* are my old eyes fooling me, and there actually is some freebore, which ironically enough the two wrinkles in the casting below the leade in to the rifling there, almost point perfectly at the section of freebore?

Also, this section of bore directly in front of the chamfer at the end of the chamber, MUST be greater than boolit diameter, or it will without a doubt shave the excess diameter off the boolit and this is where your lead is coming from. I took the liberty of editing your photo to show the area of the throat that is the topic of this discussion..

189188

[Toymaker]

How'd you do that picture? Messing with my camera and my cell phone and I can't do it.

In your picture there is a dark, heavy line where, I'm guessing, the chamber ends. Then there is a space to a second, thinner line. From there the rifling appears to be a ramp beginning at 0 and going to the full depth of the rifling.

189190 Looking at my casting the chamber ends and slopes down toward the bore. The slope is about 0.05" long. Then there is an area that is almost void of anything. It is about 0.119" long. Then the rifling begins.

In the area between the end of the slope and beginning of the rifling (0.119" long), using a magnifying glass I can see marks on 6 of the 8 that start very faintly at the end of the slope and connect to the beginning of the rifling.

Tell me how you did that photograph and I'll see if I can do one too. Unless it took special equipment.

[DougGuy]

I used a Sony camera with macro mode to take the pic of the throat. That throat is on a taper, and the other thinner line is where the taper runs out and the reamer just quits cutting because the diameter of the flutes drop below the dimension of the groove diameter in the barrel.

According to your pencil drawing, your barrel has .119" of what we call "freebore" in it. This can be parallel or tapered, depending on the design of the throating reamer used to create it. The freebore, MUST be larger than the boolit diameter at the beginning of the throat, or it will shave lead because you cannot shove .459" worth of boolit (or anything else for that matter) into a smaller diameter hole, without SOME of the boolit going somewhere, in this case it is shaved off by the throat *IF* your throat is smaller than boolit diameter.

It looks to me like the freebore in the barrel, i.e. the throat, is not large enough in diameter which is causing the lead shaving. Look in the Gunsmithing section of our forum, or do a search for a thread on doing a poundcast. If you do a poundcast of the throat, you need a decent mic to measure it a caliper will not be accurate enough. You want to basically expand a soft lead ball at the end of the chamber where it will be driven outward until the walls of the barrel confine it, then remove this and mic the freebore directly in front of the chamber. The diameter at the beginning of that .119" section is what you are after. If this diameter is smaller than your boolit, *there* is the reason for your leading..

Personally, I would say throating the barrel would stop this leading. I see nothing else in there that would cause it other than trying to shove too much boolit through too tight of a throat. Same with all the autopistol barrels I throat daily, no difference, and they work great afterwards..