Originally Posted by
steviebee
Hi, iv been down this road also, the older Bsa barrels are 6.3mm , whereas the modern barrels and pellets made mostly on the continent are 6.35mm.
Which is a real bugger, if tried the various pellets & pellet sizers, .243 will undersized the pellet and will actually slip down the barrel.
Iv found good old fashioned marksman pellets very good for my .25 British Bsa. As modern bsa's are made by gamo in Spain.
So if looking for .25 pellets look for 6.3mm ones. Hope this helps a little