Vortex M4 Blowback Spring set Nov 2, 2009 13:39:53 GMT 9 Quote Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by Hazard on Nov 2, 2009 13:39:53 GMT 9 Advertised to shoot 95.95 m/s by just changing the spring.Meron din kasamang recoil springs (soft, medium, hard).3,045 Yen through Yahoo Auction.