Do you think your regulation would be the same with something mounted on the muzzles? I'm having trouble with that."

No, I do not.

The barrel mounted chrony is only for sensing the velocity of the bullet.

Since I also shoot a Winchester 1886 45-90 with a 26 inch barrel, I will test my loads in the 1886, not the DR with 26 inch barrels. Any velocity difference should be modest and acceptable for my purpose.

NRA Patron, TSRA, Whittington Center, DWWC,DRSS
Reloading Ballistics App at http://www.xplat.net/