The weapon in question is a submachine gun. For the sake of tangibility let's say it's an H&K UMP chambered in .45. A mad hatter is going to burn through as many 25-round magazines as he can. He's not wearing gloves. Full auto, not aiming. 1. Would the barrel morph form heat before the weapon becomes too hot to hold, or the other way around? 2. How many magazines could he get through, back to back, before heat inhibits his spending habit in whichever form above? A friend that knows about these things said two or three magazines before there's an issue, but I want a second opinion (or third or fourth, hopefully). As always, any help appreciated.
theres a video here (around 4minutes) where a guy gets his suppressor glowing hot with not that many rounds - however its a rifle which has hotter rounds than an SMG and also suppressors trap a lot of heat so they get hotter quicker than an unsuppressed weapon
The specs for the ump from H&k's site says cyclic rate is 650-700 rounds per minute. Cyclic is the maximum rate of fire given only mechanical function, not taking into account degradation of function due to heat, wear, or ammunition constraints. Manual reloads of 25 round mags, would not manage that rate. An M60 marine gun team was issued a heat resistant glove for barrel changes. So the barrel would be too hot to touch first. The real question here is can the shooter change mags fast enough in a sustained fashion to heat the barrel. An that would depend on the ammo being used.
I'll say no, unfortunately for him. Wow, didn't realise suppressors trapped so much heat. Yeah that really isn't many rounds regardless. Well, the rate would technically be managed for short spurts. Not sustained for a full denominator minute, of course. Do you think .45 calibre pistol cartridges would generate enough heat in spite of the manual mag changes?
Here's a dude with a full-auto AR-15 (.223/5.56, not 45) torture testing it. Not sure exactly how a .45 would compare but he gets quite a few mags through it before it gives up. One thing to look for is "cooking off," where the chamber gets so hot it ignites the gunpowder within the casings without the trigger needing to be pulled.
crew served weapons are notorious for overheating. Back on the day Gimpy crews were issued with two spare barrels as standard because in fire support roles it wasn’t unusual for barrels to get so hot they distorted but you’re talking about five or six belts of 7.62x51 disintegrating link so about 3k rounds fired more or less without pause to do that
its also worth remembering that the better made guns don't get as hot as the cheap ones - hence the phrase 'hotter than a cheap pistol'... H&K are a quality make, some cheap piece of mass produced crap like the ppsh41 will overheat a lot quicker
Yes, I was trying to contrast that with 25 rnd mags, and the ability to put enough rounds down range for heating to occur.
1. The barrel would be far too hot to hold before it would warp. Just for comparison my favorite personal rifle is a .303 No. 4 Mk 1 Lee-Enfield British rifle from WW2. It has a 10 round magazine and after expending all 10 rounds the barrel is too hot to hold. The rounds are full powered rifled cartriges compared to a pistol-caliber SMG but believe me after a single 25 to 30 round magazine you would leave your skin on the barrel from contact. 2. You could probably get beyond 4 magazines with a UMP. They are pretty well built guns. But...by the end the gun is going be smoking and quite possibly damaged to a point it would take a complete re-build to get back to working order.
Thank you all for the help, guys. Good wisdom here as always. I think it does make sense the barrel would be too hot to hold before it warps. In some of those stress videos the person has to wear mitts. And yeah, 50-75 large pistol rounds being fired that quickly has got to generate substantial heat. So I'll try for around 2 or 3 mags and have him drop it due to the singe.
