I shot my Ruger MK2 pistol in a Steel Challenge event today and was using Remington .22 LR 550 Bulk pack ammo and had almost 20 mis-fires in 100 rounds fired...as in the rim was struck very well and no ignition.
I re-chambered them one at a time and rotated the cartridge so that the firing pin would strike the rim in a totally different spot. Still no ignition.
This gun has always been totally reliable with anything. I will try the Ruger with different ammo..Winchester, Federal, CCI etc to confirm that the gun is fine...
Until now I have never had a problem with Remington bulk .22 ammo...looks like things have just changed..