I've been fortunate over the years to have never experienced a leading problem until a couple of weeks ago.

Shooting a .33-47, load 14.8 grains 4227, Emmert lube. No problem at 60 degrees.

Experience leading at about 75 degrees, temporary cure was wiping each bullet with a stick of SPG lube.

Lubed using SPG and no problems at 75 degrees. Today as the temperature soared, severe leading. Bullets missed the paper. Cleaned barrel, few good shots and then goodby.

Had a .32-40 on hand, load 14.5 grains 4227, Emmert lube, shot well but not enough on hand to finish match.

Suggestions please.

Dick

Dick,

  Probably a lot more ideas than what I've run across with the same problem over the years. What I've found is it's usually a lack of sufficient lube, to large a bullet, not the right alloy, or a slightly rough bore.

  You don't mention where the Leading occurs. If at the muzzle it's lack of lube. Near the chamber the bullet might be to large or the alloy not correct. From you description of the temp. change bringing it on I'd guess it was lack of lube as both Emmerts and SPG have held up to as high a temp. as I care to shoot in. Also when you mention wiping the bullets with SPG that's another clue that suggests a lack of enuf lube.

  I have had guns that would Lead or foul up with certain powders. Ball powders being especially sensitive. But 4227 is a known good powder for Schuetzen rifles with few problems.

  Are your barrels originals? Sounds like it, and could also be a cause for the Leading if even slightly pitted. They usually need more lube than perfect barrels.

  You might check the bullets for both the .33/47 & .32/40 and see how they compare as far as the amount of lube they carry. If the lube grooves are cut shallower than the lands are high, this might also cause Leading as the temp. rises.

  Also a trick I was told about many years ago by an over-the-course shooter who used cast bullet exclusively, was to keep the ammo in a cooler. I've never tried the idea but was told that putting a "room" temp. bullet into a warm/hot barrel would/could melt the lube off. He told me that if he left the cartridge in the chamber for more than 30 seconds he would swap another round in. Don't know how practical that would be for us Schuetzen shooters who breech seat, but something to think about if you're using fixed ammo.

PETE

Very insightful information.  I had a similar problem over the weekend, going from high 60 degree temp range into the low 80's with a new 30-20 rifle, 1-12 twist .308" Pederson cut rifled barrel, 12.5 gr. 4227, cork wad, modified RCBS 165 Sil, plain base, 25-1, Emmert lube.  I was cleaning every 15 rounds, so the buildup never got to where I could pinpoint where it started.  This load had worked well two weeks ago...

These puzzles are what keeps us experimenting, right?

David

Dick
Did you try slowing them down a bit or does your accuracy go to pot at lower speeds.  A little less accuracy is better than missing the paper.
mes

Dick, I have had the same leading problem out West at Raton during the ISSA Match in August.  At that time of year the air is normally dry and the daytime temp can be in the 80's or above.  I switched from Emmert to SPG lube, but still had a fair amount of leading.  I then used Javelina Schuetzen lube and the leading problem disappeared.  I think it's the Alox in the Javelina that makes it work so well.  Using the stuff is not fun--it is very sticky, but adheres to the grease grooves well.

Also, you mentioned the David Mos mold.  I have a .33 mold from David that has narrow, shallow grease grooves.  This bullet always gave me trouble at Raton.  So, David made a mold for the .33 that has wide, deep grease grooves.  This bullet works great--no leading!   

Maybe these two suggestions will help you.  Also, with the Javelina lube I have found it best when pan lubing to heat up the pan the bullets are in prior to pouring the lube in the pan.  Then I put the pan in the frig to cool down.  In about an hour, take the pan out and the cake with the bullets in it will fall out of the pan and you can push the bullets out.  This procedure is a little time consuming, but it works!

Coolhd

Thanks to all who have contributed to this discussion thread. I'll start to work my way through the problem aided by this good information. I hope I can avoid a new mold re: width of grease grooves. The Mos's grooves are about .020, the Hoch about .030.

Dick

Alox/Javelina for smokeless loads, SPG or Black Magic or White Lightning for black, deep & square lube grooves are the ticket in my book. Worst leading I ever had was a few loose flakes that wiped right out with a tight patch.
Good luck, Joe