It definately sounds like you have a .22 magnum cylinder or one modified to accept .22 magnum. It could be an original .22 magnum and dry firing would account for the magnum cartridges being tight on a few cylinders. DON'T fire anymore .22 Long rifle, Longs or Shorts in it! Have the cylinder looked at and the bore slugged. Shooting .22 magnum in a .22 LR barrel could be a bad time, just like shooting the .22 LR's in an overbored cylinder. Pressures over the spec's for the firearm could occur either way.
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