I have been having a bit of leading with my .38-55 and a Lyman 250 gr flatnosed bullet using bp loads and SPG lube.  I originally thought it might be up in the muzzle where it leads, but now, I'm not so sure.  The amount of lead is very small, and it comes in flakes, not strips.   

I thought I might check bullet size vs. groove diameters, and in doing this, I found something interesting.  First, the bullets are sized, and miked to 0.377".  The breech measures 0.3763" and the bore measures 0.3768" - at least to the best of my abilities to measure.   

To do this measuring, I tapped a sized bullet into the bore for the first three bands and then tapped it back out.  I did the same for the breech.  For the bullet that went up the breech, I found that the rifling marks looked normal with some finning on the backside of each band as to be expected.   

But the bullet that went into the bore, when examined under a 5X loup, showed not just finning but fragments of lead cracked off of the back sides of the bands.  The lead that had been pushed back by the smaller diameter of the bore and grooves was rolling and cracking off the back edges of the bands, and not just where the rifling passes but also in the grooves.  This lead would probably be falling off the bullet as it goes down the bore and may well be the source of my leading problem.   

Both bullets were 25:1 Pb:Sn so I don't think I have excessively hard or brittle bullets.   

My questions to the board are, 
1.  Have any of you seen this?
2.  What to do about it?

I certainly have never seen it but the only solution I can think of to fix it is to switch to paper patched bullets.

Brent

Ed, that's a very interesting suggestion.  I believe my rifle's throat is very steep.  However the bullet put into the chamber did not have these bits of lead cracking off the bands - this happened only on the bullet that I taped into the muzzle.  Of course the muzzle's "throat" is 90 degrees so that may be an even more pronounced effect of the sort you suggest.   

Thanks for the suggestion. It is one I'll think about carefully.   

Brent

40_rod,
Not sure how it could be rattling down the barrel.  There is a 0.0005" taper from the breech to the muzzle.  I'm not the best whiz with measuring devices, but I consistently measured this several times and I can feel a tight patch tighten as I push down the bore.   

Ah, I see, I typed the dimensions in backwards.  The small number is at the muzzle.  Sorry about that.  I was worried that just what you describe was in fact happening.  But it's not.   

Brent

Brent   ! A 25 lead to 1 tin is a pretty solft alloy as is ! this sounds like a new barrel that needs to be broken in or ,  I would fire lap the barrel with  10 pure lead bullets rolled on 600grit and then try to see if it still leads ! If so then try 5 more at a time ! That would smooth up the leading edge of your rifling ! Use no more BP or smokeless then it takes to just push the bullet out the muzzle and wipe between shots !  Use a cream of wheat filler to fill the case with  some compression when the bullet is seated  ! JAGG

Quote:


Longrifle, 
I'd be interested to see that recipe.  I have made a few lubes but none of them have been particularly great stuff.  

I a next trying a 40:1 bullet - which is probably quite a bit softer than I really need to go, but I want to cover that base well.  And, I'll try a larger sizing die.  I'm currently using a 0.377 die but have a .378 in the mail.  If either of these help, then so much the better.

BUT! I think I'm sorta trying to beat a dead horse into a Smarty Jones sprint.  The bullet I'm using is a Lyman flat nose 250 grn bullet.  It has narrow grooves and I think part of the problem is that its 4 narrow grooves just don't carry enough grease.  So, I'm considering finding a new bullet or having one made. 

To that end, I'm going to start a new thread on reloading forum about Garbe's bullet that he published in BPCN's latest issue.  I see a lot to like in that bullet.  

Brent

PS.  I forgot to mention that this barrel is an original #2 barrel that was relined with a Badger barrel.  It's 30" long and has had slightly over 600 rounds down it so far.   

Long Rifle 101;
I went online to look at "Lube Gard". Apparently, there are three different types of "Lube Gard". It will be helpful to anyone who intends trying this lubricant to know which type you recommend.

Dale53

Hello Brent, If you wish I will send you some 120 gr plain base 1-26 alloy bullets lubed sized with a 0.379 die. My rile is a     1-18 inch twist. Just give me an address.
E-mail direct;  richardson 172000 @ yahoo.com
( leave out spaces )  Long Rifle

Just an interesting (to me) update on the leading issue.  This past weekend, using Pete's breech seater, and the same bullet as I use in my fixed ammo, I experienced very little or no leading.  Amazing difference but switching to fixed ammo immediately brought back the lead again.  Both Pete and I have now experienced this difference between fixed and seated bullets.  Both of our chambers were cut with the same reamer and neither has any appreciable taper to the throat.   

FWIW, I also tried reducing velocity with less powder to the point that I had a minimum load of about 41 grs, I tried softer lead (40:1), and a larger sizing die (.378" in a .376" bore).  None of these things mattered although slower seemed to have less lead, but still too much.   

Next up, Long_Rifle send me some sample bullets lubed with his "secret" recipe that he posted above- those bullets arrived yesterday.  I'll load them tonight.  The bullet looks like an RCBS bullet - is that right?  What is the alloy?  Thanks a bunch for the sample - they are very pretty bullets.

Brent