The 405 is listed at 36,000 cup and the 30/40 Krag at 40,000 cup.  The Rolling Block was offered in the 30/40.  The base diameter of the 405 case is significantly smaller than the 7mm that was loaded at the time to something close to 39,000 cup it seems so it would seem that the rifle is a good candidate for a 405.  The main thing is to reload to less than these maximum pressures.  I have a Hepburn rebarrelled to a 40-70 SS that actually uses full length 405 brass.  If the rifle was used for black powder and or cast bullets there would never be a problem.  I believe that the rifle would handle factory ammunition but I would not fire it when it is easy to pick out a slow powder and reload to a good velocity at 35,000 cup or less.  This is based on the assumption that the rifle is tight and the pins are well fitted.  My two cents.  Tom:

If the rifle is a #5 action it will handle the pressure, they were chambered in 7X57 which SAMMI shows at 51,000. If its a black powder action it would probably be best to chamber it to a black powder cartridge.

The rifle in question has a matte or bead blasted finish and only needs the new wood fitted and finished. The barrel is only 22” long and is marked 405 Win. The person building it passed away before finishing it according to the seller. Their idea of a hunting rifle I guess. The tang is marked with the 1901 patent date so I am assuming it is a #5?

Dave - -  I certainly agree with you that too hot of a load in the rolling block can mess up your face.  My comment was that the gas/brass is coming from the firing pin, not the gap between the barrel and block as that would be deflected sideways.  The action is "springy" and even with the smokless actions (1897 and 1902) loads have to be held down to 40,000 psi or less.   The original 7mm  chambering was the 7 mm SPANISH  not the 7mm  Mauser.   There are some subtle differences between the two besides the SAMI rated pressures.   Long ago I learned that case mortality with commercial 7mm brass was high so switched to necking down military 30-06 brass for use in my    7mm rolling blocks.   Theoretically, the 405 in it's original loading would be safe in a late rolling block.   BUT, I wouldn't care to test that theory.

Like someone else said; call it a 40-70, load it with black powder and be happy.  A 405 with a 22 inch barrel would probably kill on both ends.

George

The barrel face, the action face and the block face are like the sides of a billiard table. The high pressure gases can bounce back and forth and exit at odd angles. It would be very difficult to get perfect exit at 90 degrees to the bore line between the block and barrel.