bercov@bevsun.bev.lbl.gov (John Bercovitz) (06/04/91)
I think a _blowback_ pistol is distinguished by the fact that its barrel is not locked to its breechblock but is, rather, fixed to its frame. A _delayed_blowback_ firearm has a delaying mechanism which delays the breechblock's leaving the breech of the barrel. In the Thompson I think the delaying mechanism was some phony little brake which was later deleted. Some delaying mechanisms have worked fairly well but many haven't. The purpose of them was to make a cheaper approximation of a short or long recoil _locked_ breech. Then there are those firearms which kind of fall in between the definitions, to my way of thinking. Personally, I think of the H&K roller lock as more of a delayed blowback but others would say it's locked breech. Then there was that pistol (who made it, anyway?) that used gas bleed near the chamber to hold the breech shut. I think of that as locked, but most would call it delayed blowback. Part of the confusion lies in deciding whether or not all pistols with barrels locked into the frame are necessarily delayed blowback. I would say it's delayed blowback if a brake or inertia device (a' la roller lock et al) is used to keep breechblock and barrel breech more or less together. In contrast a locked breech firearm would have _no_ relative motion of breechblock and barrel breech during the high pressure part of the cycle. Sometimes delayed blowback is confused with a retarder or an accelerator. These are used to slow down full-auto rate and to speed up breechbolts, respectively, at least in the usual senses. The above was off the top of my head, so I guess I'm fair game. 8-( JHBercovitz@lbl.gov (John Bercovitz)
cash@convex.com (Peter Cash) (06/04/91)
And then there's weird arrangements like the little Detonics 9mm pistol
that was blowback--but had a ring carved around the inside of the chamber.
When the cartridge detonated, the case was supposed to expand into the ring
and hold the case in the chamber just long enough...
I don't know if this worked very well or not. I don't think they make this
pistol any more, so maybe that has something to do with it.
--
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| Die Welt ist alles, was Zerfall ist. |
Peter Cash | (apologies to Ludwig Wittgenstein) |cash@convex.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~cbl@uihepa.hep.uiuc.edu (Chris Luchini) (06/05/91)
In article <35198@mimsy.umd.edu>, cash@convex.com (Peter Cash) writes: #And then there's weird arrangements like the little Detonics 9mm pistol #that was blowback--but had a ring carved around the inside of the chamber. #When the cartridge detonated, the case was supposed to expand into the ring #and hold the case in the chamber just long enough... # #I don't know if this worked very well or not. I don't think they make this #pistol any more, so maybe that has something to do with it. The Seecamp 32 also uses this system. It works for the small round, I have my doubts that it would work very well on a 9mm... The comments I've read about the detonics is taht is stings the hand quite a bit. -cbl #-- #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # | Die Welt ist alles, was Zerfall ist. | #Peter Cash | (apologies to Ludwig Wittgenstein) |cash@convex.com #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | Chris Luchini/1110 W. Green/Urbana IL 61801/217-333-0505 | | cbl@uihepa.hep.uiuc.edu (best) |Cluch@fnald.bitnet (second chance) | no cute sig found. . . thinking . . . thinking . . .