Army arnament r28 pistol mag O ring

[Lm90]

Hi guys, I own an army arnament r28 pistol and completely destroyed the O ring where the gas nozzle is at the bottom of the mag, looking at heading to B&Q this eve as was told to head there for some replacement O rings but because the old one has been completely destroyed is there anybody here who has any information on what size I need as I can't size it up with the damaged one ? cheers guys 

 

[Cipher-032]

Wouldnt be able to tell you. The R28 might be KJW compatible. So you might be able to buy a spare one that way.

Failing that, buy some silicone sealant, and use that to make a new gasket. Will last longer and be a far better seal