Blowback?

[BETH]

was looking a gun said blowback single action, now single action means u have to cock hammer each time what does blowback mean?

[deadin]

Single action on a semi-auto pistol means you have to cock the hammer for the first shot. (or jack the slide if there isn't a round in the chamber.)
Blowback means that the breech isn't locked when the gun is fired.
Almost universal in the lower powered pistols( .22's,.32's and some 9mm's)
Most higher powered guns have some sort of a locking, or retarding action when fired.

[BETH]

i'm sorry but i don't know what the breech is?

[pinecone70]

Blowback is a system of operation for self-loading firearms that obtains power from the motion of the cartridge case as it is pushed to the rear by expanding gases created by the ignition of the powder charge.

[BETH]

u mean like an old powder gun where u have to push ammo in

[pinecone70]

Self-loading and semi-auto are the same thing.

[BETH]

ok but what is the breech, part of the gun?

[BETH]

does it mean the slide on semi is not locked and will slide back and forth?

[LurpyGeek]

The breech is the back end of the barrel that a round goes into before being fired.

I'll try to make sense. Single-action or double-action describes how the hammer or striker is cocked. Although they have "action" in the term, they're not actually describing what kind of "action" the firearm uses. Normally when you talk about a firearm's action, you are referring to the mechanism that loads / ejects rounds.

In blow-back operation, the only thing holding the chamber closed is a spring. When a round is fired, the force of gas pressure pushing the bullet and gases out the front of the barrel pushes the casing and bolt (or slide) to the rear, usually ejecting the case and loading a new round as the bolt (or slide) moves forward again (pushed by the spring).

This works fine for smaller rounds that don't have much power (.22, .380, etc.), but becomes more difficult for larger rounds with higher chamber pressure. Thus, there are other actions like short recoil, gas operated, etc. I won't try to explain all of those here.

http://en.wikipedia.org/wiki/Firearm_action

[BETH]

ok i got it now i just thought all semi's did that, did not know it was called blowback, everyday u keep learning-thanks all

[shootstr8er]

Originally Posted by BETH

i'm sorry but i don't know what the breech is?

beth, google breech guns(ie loaded from the back)

[LDBennett]

Beth:

Blowback guns have the barrel fixed to the frame. Only the slide moves in recoil and is slowed by the mass of the slide and the recoil spring. It works well for low power cartridges and not so well for higher power ones as the mass of the slide has to get huge for the higher power cartridges.

Higher power cartridges use a locked breech. That means the barrel recoils for a small distance with the slide to give time for the pressures in the barrel to subside. Then the barrel stops (usually moves downward to disconnect from the slide) and the slide continues rearward alone.

There are other methods of delaying opening the breech (the junction of the barrel and the slide face or bolt face) that are typically only used in rifles but not always. For common semi-auto pistols the above is all that you have to remember.

But when it comes to buying guns only low power pistols like those below 9mm should be blowback operated. 9mm and more powerful semi-autos need a locked breech operation. So never buy a 9mm blow back operated gun.

LDBennett