wesommer@ATHENA.MIT.EDU (Bill Sommerfeld) (05/03/89)
From: Bill Sommerfeld <wesommer@ATHENA.MIT.EDU> Pardon my ignorance about such matters, but a friend described caseless small arms ammunition to me recently, and I had one question about it which he couldn't answer. I assume that the propellant isn't perfect, and hence leaves some solid residue behind after firing. If the propellent is contained in a casing, and the casing is ejected, then the "gunk" which would be in the way of the next round is ejected along with the casing. Without a casing, it seems that hot residues would tend to build up in the chamber, making it possible that a subsequent round would be set off prematurely (perhaps while the breech was still open), which would be a Bad Thing. Does anyone out there know how this problem is dealt with? Thanks in advance. - Bill
adrian@uunet.UU.NET (Adrian Hurt) (05/05/89)
From: Adrian Hurt <mcvax!cs.hw.ac.uk!adrian@uunet.UU.NET> In article <6186@cbnews.ATT.COM> wesommer@ATHENA.MIT.EDU (Bill Sommerfeld) writes: > >Pardon my ignorance about such matters, but a friend described >caseless small arms ammunition to me recently, and I had one question >about it which he couldn't answer. > >... > >Without a casing, it seems that hot residues would tend to build up in >the chamber, making it possible that a subsequent round would be set >off prematurely (perhaps while the breech was still open), which would >be a Bad Thing. Never mind residues, heat in the breech can do it; and to guns firing cased ammo too. The H&K MP5 can do this; the heat from previously fired rounds sets off the next one, and in extreme cases the entire magazine gets fired while the gunner does his best to make sure they don't go somewhere dangerous (to friendly forces, at least). It's called "cooking off". "Keyboard? How quaint!" - M. Scott Adrian Hurt | JANET: adrian@uk.ac.hw.cs UUCP: ..!ukc!cs.hw.ac.uk!adrian | ARPA: adrian@cs.hw.ac.uk
maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert) (05/11/89)
From: maniac%garnet.Berkeley.EDU@ucbvax.Berkeley.EDU (George W. Herbert) In article <6260@cbnews.ATT.COM> mcvax!cs.hw.ac.uk!adrian@uunet.UU.NET (Adrian Hurt) writes: >In article <6186@cbnews.ATT.COM> wesommer@ATHENA.MIT.EDU (Bill Sommerfeld) writes: >>Without a casing, it seems that hot residues would tend to build up in >>the chamber, making it possible that a subsequent round would be set >>off prematurely (perhaps while the breech was still open), which would >>be a Bad Thing. >Never mind residues, heat in the breech can do it; and to guns firing cased >ammo too. The H&K MP5 can do this; the heat from previously fired rounds sets The G-11 (german issue wpn of near future (now?)) fires caseless ammo. It was based in RDX instead of nirtocellulose, because it's possible to get RDX to both burn cleanly and not cook off too often. It just takes time and effort to get the details right, hence the long delay in perfecting the concept to issuable level. The propellant is balanced in the region where RDX can be made to not detonate but burn (deflagrate) Very quickly: gun propellant speeds. The composition had to be carefully monitored because RDX much prefers to just sorta burn or go all the way and detonate, not good in either case. It also had to be balanced between enough additives not to cook off and few enough that it didn't leave residue. HK believes now that they have it right, and that this is the wave of the future. I'm inclined to agree.