M.g.caps for model guns!

[Mikearfifteen83]

Anyone know where to find some caps for model guns that blowback? there not regular caps like the kind they sell in the grocery store with the 8 caps in the ring. they are used for props and reinactment guns they come in 5mm and 7mm , I just bought a glock 18 blowback cap firer off a friend and would love to try it out.