Vlad G 345 Posted January 27, 2012 Hmm its not like brass is exothermic, the heat comes from burning gases under pressure and that heat has to go somewhere. Quote Share this post Link to post Share on other sites
raz-0 1,259 Posted January 27, 2012 They were not at the range. Everything I am regurgitating was from their booth at the actual show. The engineer's train of thought was that if someone had plastic ammo they would only be firing plastic ammo, and therefore the chamber would not get hot. They have achieved match-ammo accuracy. They did not think about a gun that had just fired lots of brass ammo and then switching to the plastic before cooling down. Hope this clears things up. Ok, I'll change my assessment form stupid and lying, or just stupid. You don't need to fire lots of brass ammo, the heat comes form the gasses. Oddly enough, the barrel is metal and thermally conductive, and the chamber is part of the barrel. It also has every round fired in it while each case only has one round fired from it. The heat comes form the chamber walls. The plastic is an insulator, which means that heat is absorbed more slowly and released more slowly. SO yeah, it might have a lower tendency to cook off a round, but at some point the chamber will be hot enough that even "slowly" means more heat than the plastic can deal with holding, and more than it can shed before it fails. A mag dump to empty isn't the worst case. It's when you have heated up the chamber through rapid fire, and leave a round sitting in the chamber. Quote Share this post Link to post Share on other sites
SpacemanFry 51 Posted January 27, 2012 Not sure if stuff is getting lost in translation so to speak, but that guy doesn't sound like much of an engineer if he said the barrel/chamber wouldn't get hot from firing plastic cased ammo. As has been noted the heat comes from the combustion of the powder. Anyway, that being said there are plenty of composite materials that can withstand the high temperatures in a gun. The key is what other characteristic are they shooting for. Generally I would wager that such a material will be more expensive right now than brass/aluminum/steel. Quote Share this post Link to post Share on other sites
Jon 264 Posted January 27, 2012 I confess that I do not remember word for word what was said. Just going off what I'm pretty sure I heard. I talked to hundreds of people over the course of 3 days. I'm sure an email query to the company in question would yield lots of information if one was interested in it. Quote Share this post Link to post Share on other sites
Ray Ray 3,566 Posted January 27, 2012 I wonder if this crap is made in China since everything plastic is made in China. Pass Quote Share this post Link to post Share on other sites
compujas 21 Posted January 28, 2012 Propellant gasses are not the only place that heat comes from in a gun. Think about a black metal gun sitting in the desert sun for 16 hours. There's a reason they hot/cold/ambient test weapons and ammunition. As for using plastic in cartridge cases, it has been done, but I am not aware of any reasonable-pressure cartridges doing it. In 40mm grenades, the training round and most non-lethal rounds use a plastic cartridge case, but peak pressure in those rounds is only around 3000psi. I would also be very leery of the consistency of plastic cases due to the heat of the gasses likely scorching the plastic and pitting it, changing the volume of the case "randomly" each time. I'd also be surprised if you could still fit enough propellant in the case given how much thicker the wall has to be (aka the inside of the case is much smaller). If many propellant loads are pushing compressed loads with thin-walled brass, how would you ever fit that same amount of propellant in a plastic case. Just my ramblings on the topic. And PS: I am also one of those "munitions engineers", and it really is an awesome job. Ok, so I decided to actually watch the video. It seems like they're low-powered loads. Judging by the .338 Lapua Magnum and .308 Win, there's almost no recoil. The .50BMG is obviously suppressed and sub-sonic, so that explains that. The plastic has got to be some crazy concoction that's going to be really expensive. You can't just take some standard nylon and do this otherwise everyone would've done it ages ago. Anyway, there's got to be something they're not telling (for obvious reasons). It does seem like they've got something, but I doubt it will catch on. If it does and the military picks it up, the soldiers aren't going to have enough pockets to carry all the ammo they're going to want to bring. Half the weight means double the ammo, and they already cram mags in every crevice they can. Quote Share this post Link to post Share on other sites
halbautomatisch 60 Posted January 28, 2012 You clearly have never seen Ray Ray shoot a shotgun. Sounds like I missing a good show. Quote Share this post Link to post Share on other sites
Shocker 151 Posted January 28, 2012 My biggest concern would be how the plastic expands to fill the chamber when firing. It has to spring back afterwards or else it can't be extracted. Polymers can be heat resistant. Or elastic. Or affordable. Getting all of that is the trick. Quote Share this post Link to post Share on other sites
hd2000fxdl 422 Posted January 28, 2012 Went from paper or plastic to brass or plastic. Quote Share this post Link to post Share on other sites
Ray Ray 3,566 Posted January 28, 2012 Sounds like I missing a good show. NICE! Quote Share this post Link to post Share on other sites