I noticed some play in my barrel today and realised I had lost the grub screw that goes through the top of the block to secure the barrel in place. There are 2 in the side but with the top one gone it allows a little bit of play, which translates to a lot at the business end of the barrel.

Can anyone tell me the size of the missing screw and where is best to pick one up from?

Any help greatly appreciated.

Cheers,

Darren