Thursday, March 4, 2010

Hey! Answer Man!

Hey, T-Bolt! What the difference between open bolt and closed bolt. I'll tell you! But in another upcoming post.

Ok, how the heck should I know THAT? What do I look like? Tam? You have Google. Look it up your own self. You might have noticed that whole 'New' part of New Jovian Thunderbolt. I'm still learning.

Let me take a stab at it for you. But remember, I could be totally wrong headed about this and embarrass myself.

A firearm that operates with a closed bolt is working like a bolt action rifle. The bolt is closed (duh) or pushed all the way forward, with a cartridge in the chamber. All it's waiting is for the trigger to trip the sear releasing the hammer to smack the firing pin (like in a Garand) or release a spring-loaded firing pin like in the Springfield 1903. The firing pin then strikes the primer and we are off to the races.

And open bolt, the bolt is held to the rear and no round is in the chamber. If you pull the trigger you release the bolt, it slides forward stripping off a cartridge from the magazine and shoves it into the chamber, kinda quicklike. Once all the way forward bolt is seated and the firing in is immediately sent forward, bang, then the bolt resets to the rear by the recoil or blowback.

The advantage of the closed bolt? More accuracy, as less stuff is moving around jiggling your aim. Advantage of the open bolt? Some of the heat from firing can escape so you can have a better machine gun that way. (Though, apparently, with the Stoner63, this heavy-ish 5.56 rifle was kinda smooth on full auto. So very good for close range stuff. I'd hate to aim at something 400 yards away even with the smooth Stoner...)

Don't ask about Blowback operating systems versus Long or Short Recoil. All I know is the the barrel moves back on the first and the barrel doesn't move back so far on the second. Sorta. Maybe. (I am pretty sure the Auto 5 shotgun and many machine guns are blowback, while the 1911 and stuff like the Glock are short recoil. Again, take all this ignorance I am spouting with a grain of salt. Wait, maybe I am wrong and it's Long Recoil, that Auto 5.)

Links to explanatory websites, other than Wiki, that bottom line all the firearm operating system types is always appreciated.


Arthur said...

In addition to letting the barrel cool, open bolt also prevents a round from cooking off or detonating from soaking in the heat of a super hot chamber.

Arthur said...

Also, Blowback operation in pistols at least the barrel is fixed in the frame. The fired case acts like a champagne cork and gets shoved out of the chamber by the gas pressure - pushing against the inertia of the slide and the strength of the recoil spring.

And I think auto-5 is listed as recoil operated. Browning Auto-5 :

"Browning Auto-5 shotgun uses recoiling barrel to operate its action. The system is of so-called long-recoil type, as barrel and bolt recoil together for entire length of the recoil stroke"