Air rifle moderators

[Porcupine]

Any oil filter will do

[Dellboy]

so my shop contained 300 oil filters which if used as a moderator i needed to be an RFD to sell ??????

on a serious note has anyone seen this idea in action ?

[Porcupine]

From the Firearms Act:

(1)In this Act, the expression “firearm” means a lethal barrelled weapon of any description from which any shot, bullet or other missile can be discharged and includes—

[...]

(c)any accessory to any such weapon designed or adapted to diminish the noise or flash caused by firing the weapon;

While oil filters are not designed to diminish the noise or flash of firing a weapon, if you 'adapt' (which doesn't necessarily need to mean 'modify') an oil filter to that purpose then it becomes a firearm. The same would apply to Coke bottles, pillows, motorbike mufflers, etc.