Powder change causing leading?

89240 · October 31, 2009, 08:27 PM

Can changing powders cause leading if other variables are constant?

I shoot .357 magnum and .38 Special from a S&W 66 and S&W 60. I have never seen much leading in either barrel before today. When I got back from the range today, both guns had a good bit of leading in the first inch or so of the barrel, just past the forcing cone. I shot a total of 100 cast lead rounds, about 60 from the M66 and 40 from the M60.

This was my first couple of boxes loaded with Hodgdon Clays. I had previously been using TiteGroup. I liked TiteGroup, but my guns and hands ended up filthy after shooting, and I wanted to try something reputed to be cleaner.

On my most recent previous shooting session, I used the following load:

.357 case
Winchester small pistol primer
4.5 grains of TiteGroup
158 grain RN cast lead bullet from Missouri Bullet Co.

I had zero leading shooting 100 of these from my M66.

This time, I shot the following:

.38 Special case
Winchester small primer
3.1 grains of Hodgdon Clays
158 RN cast lead bullet from Missouri Bullet

Could the powder change have caused leading? This load is close to the max .38 Special load recommended on Hodgdon's website. However, I have shot these same bullets from both guns with +P and Magnum charges without any issues.

Other things worth mentioning: I shot 50 jacketed bullets before shooting the lead ones, about 25 in each gun.

I also cleaned the bores of both guns with JB Bore paste after my last range trip. (I was using it to scour some tough residue out of the cylinders, and I ran a few patches coated with the stuff through each barrel as an afterthought.) I'm wondering if maybe I didn't clean it out of the bores well enough, and some residue got the leading started.

Thinking back, I remember getting some leading in the barrels with commercial ammo when I first bought the guns. This seemed to lessen each trip out, and I chalked it up to a break-in period as the barrels gradually smoothed out. Maybe I roughed the surface up a little with the paste. Seems unlikely, but...

Any suggestions?

Josh

Sport45 · October 31, 2009, 08:54 PM

It's possible the powder change made the difference. The Clays might have more pressure or hotter gasses as the bullet moves into the forcing cone and the gasses jetting around the bullet would take some lead along for the ride.

It might also have been the jacketed bullets you shot first. The little bit of copper fouling they left in the bore might have given the lead something to hang on to.

Try the Clays load again without shooting jacketed bullets first and see what happens.

LHB1 · October 31, 2009, 10:06 PM

Quote: "It might also have been the jacketed bullets you shot first. The little bit of copper fouling they left in the bore might have given the lead something to hang on to. Try the Clays load again without shooting jacketed bullets first and see what happens. "

+1 AFTER cleaning the barrel thoroughly again. Some disagree but I clean the barrel thoroughly before switching from jacketed to cast lead bullets or vice versa.

It's noteworthy that the leading is in the first inch or so of barrel. This tends to indicate that the bullet may be undersized or not obturating quickly to fill the barrel/bore. Are the bullets in both loads from same or different batches? Same alloy, diameter?

Sarge · October 31, 2009, 10:20 PM

I'm convinced that faster powders contribute to leading, to the extent that I don't load anything faster than W-231 anymore.

89240 · October 31, 2009, 10:32 PM

These bullets are from the same batch that I shot previously, so the size and composition should be the same.

I'm kinda wondering about the jacketed bullets myself. I don't normally shoot them, but I was at the store and grabbed a box without realizing that they had copper all over them. :barf:

Josh

October 31, 2009, 08:27 PM	#1
89240 Registration in progress Join Date: August 14, 2009 Posts: 63	Powder change causing leading? Can changing powders cause leading if other variables are constant? I shoot .357 magnum and .38 Special from a S&W 66 and S&W 60. I have never seen much leading in either barrel before today. When I got back from the range today, both guns had a good bit of leading in the first inch or so of the barrel, just past the forcing cone. I shot a total of 100 cast lead rounds, about 60 from the M66 and 40 from the M60. This was my first couple of boxes loaded with Hodgdon Clays. I had previously been using TiteGroup. I liked TiteGroup, but my guns and hands ended up filthy after shooting, and I wanted to try something reputed to be cleaner. On my most recent previous shooting session, I used the following load: .357 case Winchester small pistol primer 4.5 grains of TiteGroup 158 grain RN cast lead bullet from Missouri Bullet Co. I had zero leading shooting 100 of these from my M66. This time, I shot the following: .38 Special case Winchester small primer 3.1 grains of Hodgdon Clays 158 RN cast lead bullet from Missouri Bullet Could the powder change have caused leading? This load is close to the max .38 Special load recommended on Hodgdon's website. However, I have shot these same bullets from both guns with +P and Magnum charges without any issues. Other things worth mentioning: I shot 50 jacketed bullets before shooting the lead ones, about 25 in each gun. I also cleaned the bores of both guns with JB Bore paste after my last range trip. (I was using it to scour some tough residue out of the cylinders, and I ran a few patches coated with the stuff through each barrel as an afterthought.) I'm wondering if maybe I didn't clean it out of the bores well enough, and some residue got the leading started. Thinking back, I remember getting some leading in the barrels with commercial ammo when I first bought the guns. This seemed to lessen each trip out, and I chalked it up to a break-in period as the barrels gradually smoothed out. Maybe I roughed the surface up a little with the paste. Seems unlikely, but... Any suggestions? Josh

October 31, 2009, 08:54 PM	#2
Sport45 Senior Member Join Date: May 25, 1999 Location: Too close to Houston Posts: 4,196	It's possible the powder change made the difference. The Clays might have more pressure or hotter gasses as the bullet moves into the forcing cone and the gasses jetting around the bullet would take some lead along for the ride. It might also have been the jacketed bullets you shot first. The little bit of copper fouling they left in the bore might have given the lead something to hang on to. Try the Clays load again without shooting jacketed bullets first and see what happens. __________________ Proud member of the NRA and Texas State Rifle Association. Registered and active voter.

October 31, 2009, 10:06 PM	#3
LHB1 Senior Member Join Date: March 25, 2005 Location: Houston, TX Posts: 1,545	Quote: "It might also have been the jacketed bullets you shot first. The little bit of copper fouling they left in the bore might have given the lead something to hang on to. Try the Clays load again without shooting jacketed bullets first and see what happens. " +1 AFTER cleaning the barrel thoroughly again. Some disagree but I clean the barrel thoroughly before switching from jacketed to cast lead bullets or vice versa. It's noteworthy that the leading is in the first inch or so of barrel. This tends to indicate that the bullet may be undersized or not obturating quickly to fill the barrel/bore. Are the bullets in both loads from same or different batches? Same alloy, diameter? __________________ Good shooting and be safe. LB Last edited by LHB1; October 31, 2009 at 10:22 PM.

October 31, 2009, 10:20 PM	#4
Sarge Senior Member Join Date: May 12, 2002 Location: MO Posts: 5,457	I'm convinced that faster powders contribute to leading, to the extent that I don't load anything faster than W-231 anymore. __________________ People were smarter before the Internet, or imbeciles were harder to notice.

October 31, 2009, 10:32 PM	#5
89240 Registration in progress Join Date: August 14, 2009 Posts: 63	These bullets are from the same batch that I shot previously, so the size and composition should be the same. I'm kinda wondering about the jacketed bullets myself. I don't normally shoot them, but I was at the store and grabbed a box without realizing that they had copper all over them. :barf: Josh