Recoil Spring Physics

[jacknast76 2]

Misconceptions about recoil

Hollywood depictions of firearm victims being thrown through several feet backards are inaccurate; if this were the case, the shooter would also be thrown backwards with equal force (see Newton's third law). Gunshot victims frequently do collapse when shot, which is usually due to psychological motives, a direct hit to the central nervous system, and/or massive blood loss (see Stopping Power), and is not the result of the momentum of the bullet pushing them over.[2]

 

Of course this does not apply if the victim is hit by heavy weapons fire, such as aircraft cannon, where the momentum effects can be significant. The recoil from such a weapon is equally enormous, and requires it to be mounted on a weapons platform. An example of the latter would be the Handheld Minigun shown in the film Predator. For example, the gun shown in the movie is based on the prototype XM214 Microgun, a six barrel electric Gatling gun which fires the 5.56 × 45 mm NATO cartridge at a rate of 4000 to 6,000 rounds per minute. Each cartridge accelerates a 4 grams (62 gr) bullet to about 850 m/s (2,800 ft/s); at a moderate rate of fire of 4,000 rounds per minute, a one second burst will accelerate 267 grams (4,120 gr) of mass. Assuming a 100 kilograms (220 lb/16 st) user, and 30 kilograms (66 lb) for the XM214 and ammunition, that one second burst will result in the gun and user being accelerated to 1.7 m/s (5.6 ft/s).[3]

From Wikipedia, See full article

http://en.wikipedia.org/wiki/Recoil

 

 

So the man is now moving backwards 5 ft. OUCH!!

Anyone know what it is for the S12?

 

 

 

I just got my S12 2 weeks ago and at the first outing had the inevitable "Universal" shell crap out hanging up when exiting. Very embarrassing at a full range, with an audience, especially after everyone seeing how bad ass this sgun looks. I've put about 100rds through it of the universal and put 5 slugs through her. 2.75ers, 3 dram. and put 5 slugs through her 2.75ers 3 dram. nice kick about like an sks. The universals felt almost like nothing. Methinks I had the numbersbackwards, butthe manul said it that way. Some minor dinging on the back plate. But disheartening to saythe least. Took her home cleanedher and oiled her.

 

 

Then I came to this website and saw Tromix's article about damage to a trunion and something about, then thetop cover won't aswell as his warning about universal ammo.

 

SoMany thanks.

 

I'm wondering if this is a problem that can be solved with physics. So that this won't happen any more and help prolong the field life and maybe an opportunity.

 

I saw 2 types of gas chamber vent set ups. One when you screw in until just past 1 and one until just past 2.

 

Mine is the just passed 2 job, so does this means that at 2 there is less gas going into the chamber since it is screwed in almost all the way, and when you screw it out 1/2 turn to 1 you allow more gas and a equal recoil. So for the deepest number be it 2 or 1 you have less velocity on the recoil spring and more energy in the barrel to shoot the heavier round. Or You have more force in barrell so lessgas is needed to recoil it. So a 3inchers would have enough force to make the recoil work with a little gas blowback. For the 2.75 birdshot little brass would need more gas to push the spring back in a lighter load.

 

This begs the questions, what is the minimum load? What is the maximum load? And couldn't you just make a gas switch instead of the deally that needs a tool in the field. It would make cycling your loads easier. I've got a plan for one. Could'nt you let even more gas in to allow NL rounds? Couldn't you vent it to near 0??? HA HA the secret snake rear attack blast at the flick of a switch.

 

Anyway I'll be grinning when I win a MD 20rnder.

 

Next postI'll put up some physics stuff so maybe we can caluclate the forces involved, unless someone else already has it? If sopost it up I want to read it.

 

kl8

IJ

[kahrak 2]

Check out Gunfixr's adjustable gas knob (in the Firearms Sales Co. sub forum), it replaces the stock knob and doesn't require tools. It also has multiple gas settings, not just the 2 like the stock one.

[gtnichols 51]

Push the detent pin all the way down and unscrew the gas setting selector and look at it, then look at the ports and the hole in the bottom of the gas block (against the barrel ports) make note of the 45 degree angle that lets more gas into the action, then make note of the completley flat setting reducing the amount of gas allowed,

 

then remember #1 is for AAA #1 grade expensive high power ammunition

 

Setting #2 allows twice the amount of gas to cycle the action and is for lower power rounds,...

[gunnut9 0]

This video shows a guy wearing a ballistic vest being hit point blank with a .44 mag and 7.62mm NATO:

 

http://www.thefirearmblog.com/blog/2008/06...-and-44-magnum/

Edited November 26, 2008 by gunnut9

[Eric86GT 0]

I made up a stupid memory aid, but it works for me.

 

Strong "1"

 

"2" Weak

[twinhairdryers 2]

I made up a stupid memory aid, but it works for me.

 

Strong "1"

 

"2" Weak

 

100 rounds isn't much of a break in for some S-12s. I'd run another few boxes of high brass through it on #1 setting. If you get feed issues, try #2 with the same ammo. Just don't run magnum rounds or slugs on #2. Don't lube the piston or gas areas, just clean and dry. AKs don't generally like lube in these areas as they just collect blow back powders and paste up.

 

Try a few mags of different ammo and find out what runs well without dickering with the gas setting. Then buy some more of the good ammo.

 

And - WELCOME to the fun! These take a few hours of learning and tinkering, and then become too much fun for the ammo storages to hold.

Edited November 26, 2008 by twinhairdryers