The Garand type action was made automatic in the M2 Carbine and the M14... And it was closed bolt. The M16 types are closed bolts, I am almost certain, all the time. Yet many other machine guns like the Stoner, BAR, or Thompson were open bolt guns.
Advantage to open bolt, as I understand it, is it keeps the chamber cooler longer to avoid cooking off a round with heavy use. The disadvantage is less accuracy as you have the clatter of the bolt after you pull the trigger rather than just release a firing pin. The reverse advantage/disadvantage goes for closed bolt. Those are the big ones, at least.
More than one way to skin a cat when you want to spray lead downrange I guess. And the designed weighs the cost/benefit of the Operating System for what he needs to meet the customer requirements.
You don't see new models of Open Bolt guns available commercially. Probably because the ATF assumes they are too easily modified to fire full auto.
Advantage to open bolt, as I understand it, is it keeps the chamber cooler longer to avoid cooking off a round with heavy use. The disadvantage is less accuracy as you have the clatter of the bolt after you pull the trigger rather than just release a firing pin. The reverse advantage/disadvantage goes for closed bolt. Those are the big ones, at least.
More than one way to skin a cat when you want to spray lead downrange I guess. And the designed weighs the cost/benefit of the Operating System for what he needs to meet the customer requirements.
You don't see new models of Open Bolt guns available commercially. Probably because the ATF assumes they are too easily modified to fire full auto.
The Thompson SMG and the Browning Automatic Rifle are open bolt guns, as is my Uzi. While they are simple and effective, trying to get off one aimed shot is difficult at best due to the weight of that bolt slamming forward prior to ignition of the cartridge.
ReplyDeleteOpen bolts also let a lot of dirt and other crap get into the action because they are...open.
The Sten gun also fired from a open bolt. Open bolt guns are for the most part much cheaper to manufacture since they have fewer parts. The Sten had it's firing pin machined into the face of the bolt rather than being made seperately if my failing memory serves.
ReplyDeleteClosed bolt 'supposedly' offers lower noise when employing suppressors.
ReplyDeleteThe Mp-5 is a closed bolt weapon. HK's intgrally suppressed SD is supposedly one of the quietest.
MAC 10 is also open bolt.
ReplyDeleteIf memory serves me right.
I believe only the M1/M1A1 series of TSMG's fired from open bolt.
Earlier models from a closed bolt.
Anyone remember for sure?
Skul
Per a buddy of mine in the Marines, you also use the closed-bolt weapons to open an ambush, as they're not quite as likely to alert the ambushees if there's a failure to fire. (Back to the clatter of the bolt).
ReplyDeleteOne more open bolt.
ReplyDeleteM3/M3A1
Forgot about those.
Shouldn't have, carried the M3 in Nam for a short time.
Skul
Good bye, sweet friend :)
ReplyDelete