Andy H Posted August 10, 2009 Report Share Posted August 10, 2009 Here are two more ultra high speed videos of shot leaving the barrel http://www.youtube.com/watch?v=SjYpGnbvhR4 and http://profile.myspace.com/index.cfm?fusea...ideoid=60276871 Quote Link to comment Share on other sites More sharing options...
Gunny Posted August 11, 2009 Report Share Posted August 11, 2009 Blunderbuss I was always given to understand that projectiles were driven by propellants (bullets, missiles etc) and that the definition was propellants were a comparatively slow, controlled burn. I suppose it really comes down to which definition you are working from, much like there is two definitions of a "hardwood", one of which includes balsa ------------------------------------------------------------------------------------------------- Shuck I hope you have been paying attention to this excellent masterclass on internal ballistics. Exam papers will be distributed shortly Quote Link to comment Share on other sites More sharing options...
Shuck. Posted August 11, 2009 Author Report Share Posted August 11, 2009 (edited) Blunderbuss I was always given to understand that projectiles were driven by propellants (bullets, missiles etc) and that the definition was propellants were a comparatively slow, controlled burn. I suppose it really comes down to which definition you are working from, much like there is two definitions of a "hardwood", one of which includes balsa ------------------------------------------------------------------------------------------------- Shuck I hope you have been paying attention to this excellent masterclass on internal ballistics. Exam papers will be distributed shortly Confusion usually appears as the wording 'propellant' is slightly misleading and pictures a solid mass connected to the projectile which would be a missile rather then a concussive force generated from the initial powder charge in say a shotgun cartridge. Black powder I believe is classified as an explosive rather then a propellant, but it is also quite a slow burn when you see black powder pistols and muskets. Edit: Then again there are all different strains of black powder and all vary in acceleration. Edited August 11, 2009 by Shuck. Quote Link to comment Share on other sites More sharing options...
mr salt Posted August 12, 2009 Report Share Posted August 12, 2009 Confusion usually appears as the wording 'propellant' is slightly misleading and pictures a solid mass connected to the projectile which would be a missile rather then a concussive force generated from the initial powder charge in say a shotgun cartridge. what a answer,good god! its like wikapedia(spelling?) Quote Link to comment Share on other sites More sharing options...
Shuck. Posted August 13, 2009 Author Report Share Posted August 13, 2009 Just made it up, dunno if it makes any sense Quote Link to comment Share on other sites More sharing options...
Guest Posted August 13, 2009 Report Share Posted August 13, 2009 That is very interesting indeed that video. I mean when I was first explained how a shotgun cartridge gets fired and how the shot leave the barrel then I had a similar image in mind. To actually see it, with a high speed camera is amazing! Quote Link to comment Share on other sites More sharing options...
Floating Chamber Posted August 16, 2009 Report Share Posted August 16, 2009 (edited) Sorry, this is incorrect. The gas starts to bleed through the gas port as soon as the wad passes it, but whilst it and the shot are still in the barrel. Why would the gas vent down such a tiny hole if there was a big 12 bore hole (the muzzle) it could take instead? There is only enough pressure to allow it to enter the gas port is the short time between the wad passing the port and leaving the muzzle. However in the time taken for the gas to push the piston back against the transfer bars, cam and rotate the locking breech block, the shot and wad have left the muzzle which means the pressure has dropped to a safe enough level to allow the breech to open. Correct. All of this happens in less than a blink of an eye. In gas-operated guns the ejecta (shot/wad/gases) passes the gas-ports and that small amount of bleed-off imparts a sharp impact to the slide via the piston. This movement can be less than a tenth of an inch. This gas ain't going anywhere else at the moment. The slide, now having this energy, moves rearward on its way to unlocking the bolt via a cam. In this 'delayed action', the shot is out of the barrel some three feet or more. Venting then takes place. Edited August 16, 2009 by Floating Chamber Quote Link to comment Share on other sites More sharing options...
Shuck. Posted August 16, 2009 Author Report Share Posted August 16, 2009 Right, my original query was about the consistent force against the gas piston and how much gas/energy would be diverted from the muzzle path.It's a lot easier to understand now knowing only a small amount starts the piston moving, then the rest is done by the transferred kinetic energy of the moving piston. Thats why the first inch or so in the forend is completely airtight, then opens up to dissipate the energy so there's minimal felt recoil of the force of the cartridge firing back on the shooter via the piston Quote Link to comment Share on other sites More sharing options...
neil smith Posted August 16, 2009 Report Share Posted August 16, 2009 Gas operated shotguns require more working parts & linkages than an Inertia driven design, also they get far dirtier & require more regular cleaning to maintain reliability, you can see the difference in the design here... http://www.benelliusa.com/innovations/ N Quote Link to comment Share on other sites More sharing options...
Paladin Posted August 16, 2009 Report Share Posted August 16, 2009 Blinking heck, that reminded me about the time I tried to teach someone to drive, question after irrelivant question, is there realy a differance in propelant/petrol to worry about? Just point it in the direction you want it to go and let it go. Wether it's 21g or anything up to 46g let your instinct take controll, practice If you have missed by a few feet then just put it down to a duff cartridge, they do exist! Quote Link to comment Share on other sites More sharing options...
Shuck. Posted August 17, 2009 Author Report Share Posted August 17, 2009 Blinking heck, that reminded me about the time I tried to teach someone to drive, question after irrelivant question, is there realy a differance in propelant/petrol to worry about? Just point it in the direction you want it to go and let it go. Wether it's 21g or anything up to 46g let your instinct take controll, practice If you have missed by a few feet then just put it down to a duff cartridge, they do exist! The point of the thread indeed had basis for existence, as stated numerous times above. You can use all the instinct you like it's not going to tell you anything about a cartridge/gun combination before a shot is fired is it? I've always wondered about it before and the delayed break was the most recent thing that happened.. I'm well aware of the consequences of duff loads. I don't think there were any irrelevant questions asked, everyone made a valid point and on top of everything, I believe all involved went away with more knowledge then they came with, you wouldn't that knowledge with 'practicing' either. Quote Link to comment Share on other sites More sharing options...
Gordon R Posted August 17, 2009 Report Share Posted August 17, 2009 My goodness, that must have been a VERY high bird, if there was a "few seconds delay" before it broke. The simple fact is, there is no percetible difference in muzzle velocity between a pump, semi auto, side by side, over & under using the same ammo, and that's a fact..............it must all be in the mind..?? Cat. Getting higher. Quote Link to comment Share on other sites More sharing options...
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