Leading

[MacRob46]

I have some questions regarding leading in BPCR barrels. I have been hand loading for over forty years but only three years for BPCR. Up until recently I have not had any significant leading but suddenly I do. Here is what I have been doing.
Until last week, I used only black powder in my .45-70 cartridges. Because I am going to try to shoot some short range matches in the area, which allow smokeless loads, I decided to load some of those. A friend of mine who owns a couple of Pedersoli rifles shoots strictly smokeless and loaned me some cartridges to try. These are the rifles I currently own:
Original #5 Rolling Block action with new Green Mountain barrel
Pedersoli 1874
Shiloh 1874 LRE
Shiloh 1874 #1 Sporter
All are chambered for .45 – 70
When I tried my friend’s ammo in my two Shilohs, it would not chamber. It easily chambered in the Pedersoli and the Rolling Block. Consequently I decided not to shoot them at all. They were loaded with a Penn Bullet, 500 gr .459 RN bullet. Since these bullets seem to shoot well in his two Pedersolis (I know from personal experience) I decided to order 100, unlubed, to try. Got them, pan lubed them with SPG. The bullets looked just fine and miked to .459. Then I attempted to load them in some Starline brass with 25.1 grs of AA5744, WLR primer. The brass was annealed and the case mouth belled with a .457 sizing plug. Initially I left the first driving band exposed and taper crimped the case mouth back to pre-sized specs. Finished rounds chambered in the RB and Pedersoli but not in either Shiloh! So, against my better judgment, I seated them a bit deeper, so the driving band was in the case mouth. No change. The bullet is seated about 1/10” deeper than the 535 gr rounds I load for the two Shilohs – which chamber perfectly in all four guns. Those are black powder rounds with a money bullet from John Olsen and have never caused more than a tiny bit of leading.
Thursday at the range I fired 35 rounds in the RB. Every round went off without issue but accuracy began to decline the more I shot. When I got home and wiped out the barrel, I discovered heavy leading just ahead of the chamber. I have gotten most of it out with Shiloh bore solvent and have some Montana Extreme Cowboy Blend, heavy duty stuff which I will use to get the rest out, if I have to.
Can someone tell me what I have done wrong, besides using smokeless!? Western Powder’s reloading guide indicates I should be getting around 1200 fps out of this load, probably more with the 30 inch barrel on the RB. I understand that smokeless loads are known to not obdurate lead bullets as bp does. Could the deeper seating be causing the leading, given that most of it is just ahead of the chamber? I will be very appreciative of any advice you can give me. “Deleading” a barrel is not fun.
Thanks in advance for your help. Also, if you have ever used them, what do you think of Penn Bullets?

[DAVE ROELLE]

Pull one of the bullets you loaded in brass opened with the 0.457 sizer and see what the diameter is after seating

Quite possible you have swaged the base of the bullet down from 0.459 to a diameter thats allowing blow by with smokeless

Dave

[Coltsmoke]

What type wad did you use under the bullet?

[MacRob46]

Don't use wads with smokeless.

Thanks Dave, for the tip. I had considered that too and will take a look and let you know.

[Lumpy Grits]

What alloy is this lead?
Which version of SPG did you use?
What's your fouling control procedure? Wipe, BT???
There may well have been lead in the bores you didn't know about from the past.
NEVER EVER use wads with smokeless
Gary

[MacRob46]

Gary...

The barrel is brand new. First time on the range.
20-1 according to the bullet caster
Smokeless propellant
Original SPG, not the tropic stuff
I said above, there are no wads involved...I know better

[bpcr shooter]

my guess would be that the bullet is too small for your chamber and when the cartridge is fired there is gas cutting til it builds enough pressure to seal the bore....I tried 8 different bullets in my rifle and they ALL leaded to some extent and it didnt matter what I did, sooooo PP it was. No more leading and they look damm good!! I would look for some .460 dia bullets if you are stuck on greasers....

What are you barrel dimensions?? .450-.458?? whats the dimensions of a fired case?? trim length??

[MacRob46]

I miked a bullet and the top driving band was between .459 - .460. The base was about the same.

Trim length is 2.095". The head of a fired case was .500 and the exterior of the neck was .485."

The barrel is brand new, or was until Thursday, and was installed by Dave Higginbotham the summer before his tragic accident. Dave was, of course, a competent smith and well known for his quality work so I would think the chamber itself is OK. Also keep in mind that the rounds loaded with these bullets fail to chamber in two Shilohs, one of which is only 3 years old yet would drop into the RB chamber and the Pedersoli chamber as well.

Thank you for the reply and your suggestions.

[Lumpy Grits]

Who made the BBL?
Shiloh cuts their bores and chambers to minimum specs. About the best made barrels out there.
You should slug the bore of this rifle.
5744 is a very dirty burning powder.
Might want to give either tropic SPG a go or try DGL.
I live in the Mojave and use DGL year round.
G.

[MacRob46]

As I said originally, it is a Green Mountain barrel. I have two Shilohs so know what you mean about their barrels.

The SPG Tropic mix is not recommended by the maker for pan lubing which is what I have to do. It is hot here in NC but not has hot as it gets for you and the original SPG seems to work OK. I don't think that is my problem as I had a grease flower at the muzzle after I fired the rifle. Yes, 5744 is filthy powder for sure.

I will slug the bore as soon as I get a minute.

[Lumpy Grits]

My CRS is in full bloom.
DGL was formulated from the get-go for pan lubing. I only pan lube.
Look forward to hearing the results of the 'sluging'.
G.

[Coltsmoke]

I'm not geared for smokeless.

[Coltsmoke]

Do you need one of those copper thang a majiggies on the base of the bullet, I think it is called a gas check or something like that? Is that thang a majiggie made for shooting lead bullets with smokeless powder? Just asking, I don't know.

[Coltsmoke]

Do you need one of those copper thang a majiggies on the base of the bullet, I think it is called a gas check or something like that? Is that thang a majiggie made for shooting lead bullets with smokeless powder? Just asking, I don't know.

[Woody]

I've shot a lot of rounds using my black powder alloy, soft black powder lubes, and smokeless powders. Including 5744, Unique, Bullseye, and other powders. I would be looking at something besides the powder, alloy, or lube. Bullet diameter, seating depth, case length, and velocity, all can cause leading issues. I've shot hundreds of rounds of 45 ACP without any accuracy loss or leading using 25 to 1 alloy, soft lube, and 4.0 grains of Bullseye.

Woody