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Loss of Power

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"he hates semi auto because you lose stopping power in the round."


Now that's funny! Guess the militaries of the world missed that memo (incl. the US selection of the Benelli M4).


Some energy from the firing of a round is used to work the mechanism, but it's so small that it's completly insignificant.


Hey, if your not convinced, just fire 2-3 rounds while he's chambering his 2nd.

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"i was wondering if it is true and if so how much power is lost."


Yes, but not enough that you could measure even with incredibly precise instrumentation.


To test this, get a box of shells.


Shoot 12 of them with your SBE through a chronograph.


Then shoot 12 of them through a pump or a break action gun through a chronograph.


Compare the average muzzle velocity of each set of data.


If they're statistically different, I'll be surprised.

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i would like to take your friend hunting with me. he can shoot what ever he wants. ill use an auto 410, and kill twice the birds in half the time. granted you might lose 1lb of pressure from an auto. but if it makes the difference in him getting his game or not, i would say he is just in need of an excuse for being a sorry shot to start with.:D


i used have a friend that would blame his ammo on his missing. one day dove hunting he started this, i went over to him, my carring 10 birds to his 3. and took his WW game loads, and gave him my federal game loads.needless to say he did not improve. but he did get mad and leave.:p

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Your friend is correct but not to the point where there are major velocity or power differences. Any fire arm that uses gas pressure or blow back to operate will take some power from the projectile being fired. Gas operated systems will use a little more energy but not enough to notice without major testing.

My Glock 21C was a compensated handgun and used verticle slots in the barrel to allow gases to vent upwards to reduce muzzle flip. When compared to a normal non-compensated 21 there is a velocity diference of about 20fps.

When it comes to pump shotgun vs gas/recoil semiauto I think the only way you will see any real difference is when shooting a slug. And even then the difference will be minimal at best.

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I can't speak to possible loss from a gas operated gun, but your SBE uses the RECOIL, not the GAS. Thus there should be no difference between the SBE and an O/U, side-by-side, pump, etc.



Not true. The energy to kick the spent shell and reload a new shell will lower muzzle velocity. Not by much.

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Actually, oldboots is right.


All that stuff happens after the ejecta (wad, shot, gases) has left the barrel.


I thought about that after my original post. The gas guns do use a little of the pressure in the barrel, which would lower, albeit very slightly, and for a VERY short time, the pressure pushing on the back side of the wad.


But a recoil operated semi-auto should be absolutely no different than a fixed breech gun like a pump or a break action.

Edited by timb99
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The amount of "unused" energy expelled as muzzle blast compared to any gas pressure bled off to operate a gas-operated system is, as noted, insignificant.


And yes, the recoil operated system doesn't cycle until the shot column has left the barrel. Amazing all that momentum and kinetic energy can do.

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We should take your friend out with his pump and my M4. By the time he's firing his 2nd or 3rd shot Ill have them all out my semi auto. The gases from the blow back have only a slight affect on the #'s and no real world affect on actually stopping power. No matter what type of shotgun you have semi or pump a well placed shot will knock down almost anything.

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Just ask the guys in Syria that were on the wrong end of the M4....wait, you can ask them cause they are DEAD.

The amount that is lost would never be noticed by you, your shoulder or the bird/bad guy at the other end of your shotgun.

Besides that, like the guy above stated. If for some reason a few feet per second difference makes a difference just squeeze off four or five more rounds.

I would be willing to wager my M4 that I could bang out 4 shots to his One. I am sure others would agree

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