I am a bit new to the roller operating system, but I am trying to wrap my head around the various locking pieces and how they affect operation, since the 10mm is more powerful than 40cal, would a stronger recoil spring be needed? Especially if using the same locking piece? Or does the system have enough bolt travel to not need the increased spring pressure?
The recoil springs are all the same (although the first 10mm used a different spring, briefly). LP’s are generally ammo dependent. Best thing to do is start with the HI LP and if it ejects sufficiently (I don’t know, maybe 5+ feet or more), then you are good to go. If the casing essentially falls near your feet, or doesn’t eject, you need to change LPs.
Thanks for that info. I just picked up a 40 kit, and I am very fond of 10mm. I have other platforms for 10mm, but a mp5 clone 10mm would be high point of the collection. I may invest in building a 10mm top end, and just swap the bolt group and lower between the 2. Any reason that would be a bad idea. I have alot of dreams but not quite as much cash. Off to find a 10mm barrel and price the parts.
THE only issue about swapping the bolt groups is (besides needing to change out your LP between 40 and 10), would be the bolt gap. Fair possibility that the bolt gap could be different between the two guns, requiring either a specific bolthead for each gun, or you swap out rollers each time you move the carrier group (a real pain).