I have a high wall in 40-70 SS that I just bought some brass for-never tried it previously.  When the breach is closed the action drags very heavily on the cartridge base at 6 o'clock leaving a noticeable furrow in the brass about 1/8" wide and quite deep.  Before I disassemble the gun does anyone have an idea what is dragging and how to repair?

Thanks, John in Wyoming

Easy to take apart.  Remove the firing pin ans make sure the socket is clean and it moves freely.  Check the breech block face for burrs around the pin hole.  Reassemble without the firing pin and see if it is still doing it.

Jack

That was my best Westerner impression.  How did I do Joe?

What old win is describing as the timing is correct. The firing pins in these rifles drag sometimes because of crud in the block, burrs on the parts-either block, firing pin, or both. Also, the action pins or the holes for them get sloppy and cause "delayed" retrieval of the firing pin. If your rifle is an older one, any or all of these things may be the culprit. If it's just a shining up of the brass it is still ok to shoot, but if it is digging a furrow in the cartridge case you may be in for a busted or mis-shaped tip. Also look at the nub on the link and the "wing" on the bottom of the fp for wear. One other thing to check is at the bottom of the barrel, where the rim of the case is recessed. If there is a shiny mark there the pin is dragging for sure. Clean it up and look at the parts, you'll figure it out. When it's good again, don't forget the lubrication. These are easy guns to get going again-usually. Best of luck.

The brass is thick.  This is new brass from Buffalo arms and is made from 30-40 Krag parent brass.  To get the action to close at all we had to file the base thinner to even enter the shell holder.  How thick should the rim be?   Worry about taking too much off and messing up the head space.

I hate to be a dummy but it seems to me the case head at 6 o'clock should never pass over the firing pin, at least not from the primer pocket to the edge of the rim.  I understand that "walls" go over center so the breach block will rise slightly over center before settling into battery.  The mark is 1/8 wide and fairly flat bottomed.  Pretty wide and flat for a protruding firing pin.  Will just have to take it apart and see whats going on.

John

Was it Remington brass?

Aren't you using a shell holder for the .30-40 Krag?  I use that shell holder for my .38-50 Remington Hepburn based on th .30-40 case.

Chris.

One of the problems with the 40-70 brass is that nobody can agree on rim thickness.  There is the rim thickness of the original rifles, the Shiloh thickness, the 30-40 Krag thickness and those now using .405 Hornady brass.  Brass has to be tailored for individual rifles depending on what you have.  Buffalo Arms used to carry 3 different thickneses.   Bob

I've got a C-Sharps in .40-70 SS and It uses .405 Win. Brass. The Rim thickness is about .067"

Terry