Thread: 22 Squib load

Put a new scope on my little Brno 2e this morning and picked up a box of CCI mini mag when I was in town earlier. This wee rifle has always been deadly accurate and will stack everything on top of each other at 50yds. Anyhow.. went out to sight it in, boresighted by eye then got into it, got it near enough and shot a group, yeap still shoots mint as.
Then I decided to shoot another group at 75yds, fired first shot, then second shot was just a dull thud, I should have checked the barrel but proceeded instead to fire another shot, the thing actually recoiled unlike a normal 22 and didnt even hit the target fullstop..
I think it had a squib in it because now its shooting all over the show ( anywhere from 5-10" at 50yds) and when I removed the bolt and look down the barrel I can see this ring that looks like it cuts through all the rifling about 4" from the end of the barrel.
Tried cleaning etc, ring is still there and really pronounced like something has cut a ring with a dremel from the inside.
Sound like a squib? Might have to get it cut right back short I think to restore accuracy? Shame as it aint cool chopping up these cool little guns.