Frequently Asked Forum Questions Search the HBO News ArchivesAny All Exact Search the Halo Updates DBsHalo Halo2 Search Older Posts on This Forum:Posts on Current Forum | Archived Posts

 firearms and physics Posted By: rosignol Date: 2/16/01 10:54 p.m. In Response To: Re: point of diminishing returns (SiliconDream =PN=) : Actually, having more gas exit the back is *better* for efficiency. Mebbe when you're talking about breaking wind... but not firearms. {g} : A larger : mass has less kinetic energy, at a given momentum, than a smaller one : (because kinetic energy is proportional to momentum squared, divided by : mass). I was under the impression that mass * velocity = energy... Did you really mean to say that a larger mass moving at the same speed as a smaller mass will have _less_ energy? I'm afraid you have it backwards. : So a larger amount of recoil gas will carry less kinetic energy, : leaving more for the bullet, which means a higher muzzle velocity. Um, no. The energy of the bullet (specifically, the slug) comes from the pressure of the expanding gases released by the combusion of the propellant (gunpowder). It can only expand in one direction, which pushes the slug down the barrel. : Of course, you'd have an even higher efficiency if you *didn't* have gas : vents, This is correct. Any vent will bleed off pressure that would otherwise propel the round... : because then the whole gun (and the person shooting it) make up the : recoil mass. Half the energy pushed the slug down the barrel. The other half pushed against the gun, which then pushed against whatever the gun was attached to (which I think is what sili means by recoil mass). But the recoil mass doesn't have anything to do with the efficency of the weapon, just how much energy is necessary to overcome it's inertia. "For every action, there is an equal and opposite reaction" Okay, I can hear it now- "if half the energy goes to the gun (my hand), why doesn't my hand go bye-bye?" The slug has low mass (most handgun/rifle slugs are between 100 and 200 grains, 7000 grains = 1 pound, I think), compared to the weapon and what it's attached to. The energy that didn't overcome the slug's inertia is transmitted to the gun, where it overcomes the gun's intertia, and most firearms bleed off a little energy into mechanical action (cycling the slide, chambering the next round). What's left is transmited to whatever the gun's attached to (usually a person), where it overcomes that object's inertia (which you percieve as motion). That's the recoil. : But it's entirely possible to raise the efficiency of a : recoilless weapon as close to 100% as you want by adding more and more : recoil mass. The idea of a recoilless (as near as I can tell, it's a totally different scale than I'm used to dealing with) is apparently to give the gases something else to push on besides the slug (vents?). This will indeed reduce recoil, but it also reduces the energy transmitted to the slug, which would reduce the efficency of the weapon.

 Replies:

 Halo weapons should not support recoil Nights 2/15/01 5:58 a.m. To recoil, or not to recoil.. Fernando. 2/15/01 8:17 a.m. Re: To recoil, or not to recoil.. Xero 2/15/01 10:40 a.m. Re: To recoil, or not to recoil.. rosignol 2/15/01 11:00 a.m. Re: To recoil, or not to recoil.. Nights 2/15/01 2:29 p.m. Re: To recoil, or not to recoil.. rosignol 2/15/01 3:10 p.m. Re: To recoil, or not to recoil.. mattd 2/15/01 4:07 p.m. It's not uncommon. Xero 2/15/01 6:59 p.m. Re: It's not uncommon. rosignol 2/15/01 7:17 p.m. Here's a story for you. Tursas 2/15/01 10:02 p.m. Re: To recoil, or not to recoil.. Nights 2/16/01 10:45 a.m. Re: To recoil, or not to recoil.. Mark Levin 2/15/01 5:52 p.m. recoilless rifles... Tursas 2/15/01 9:55 p.m. point of diminishing returns TheRoost 2/15/01 11:51 p.m. Re: point of diminishing returns SiliconDream =PN= 2/16/01 4:33 p.m. firearms and physics rosignol 2/16/01 10:54 p.m. Re: To recoil, or not to recoil.. SiliconDream =PN= 2/16/01 3:53 p.m. Just to nitpick ;-) Pfhreak 2/15/01 3:33 p.m. Just to nitpick some more :-) Tursas 2/15/01 9:49 p.m. Re: To recoil, or not to recoil.. Xero 2/15/01 3:33 p.m. Re: To recoil, or not to recoil.. mattd 2/15/01 4:12 p.m. Re: To recoil, or not to recoil.. rosignol 2/15/01 6:09 p.m. Re: To recoil, or not to recoil.. (USMC)SiLvErB1rD 2/15/01 7:01 p.m. Theta rosignol 2/15/01 7:39 p.m. Re: To recoil, or not to recoil.. Gnocchi 2/19/01 6:11 a.m. Re: Halo weapons should not support recoil Razorback 2/15/01 12:05 p.m. Re: Halo weapons should not support recoil Cipher 2/15/01 12:29 p.m. Re: Halo weapons should not support recoil Andrew Nagy 2/15/01 2:59 p.m. Re: Halo weapons should not support recoil Andrew Nagy 2/15/01 2:47 p.m. Re: Halo weapons should not support recoil rosignol 2/15/01 3:04 p.m. Re: Halo weapons should not support recoil Anaphiel 2/15/01 5:08 p.m. Re: Halo weapons should not support recoil Spytap 2/15/01 5:39 p.m. Re: Halo weapons should not support recoil Nights 2/16/01 10:29 a.m. Re: Halo weapons should not support recoil Xero 2/16/01 10:47 a.m. A way to eliminate recoil foofoohead 2/15/01 8:35 p.m. Re: A way to eliminate recoil Nights 2/16/01 10:33 a.m. Not no recoil, proper recoil Jex 2/16/01 12:12 p.m. Re: Halo weapons should not support recoil Dead Glory 2/16/01 3:54 p.m.