9mm ammo question

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Does it matter what weight bullet you use for knocking down steel? Does mass or velocity factor into the equation more?
 
Same here. Heavier is better than fast for that purpose.
 
I agree with the above. I've seen a lot of steel plates shot with 9mm. Seems like anything 8" and under will fall with 115s, but bigger plates and most silhouette poppers will move but not necessarily fall. The comps I shoot count hits on target whether the plate falls or not, so I stick with 115s. The 147s do seem to knock over about anything, though.
 
Good question. F=M*A It would seem it's a trade off.

That said, you can only push a projectile so fast (pressure, physics, etc.). Then the mass becomes the important factor.
 
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From my experience shooting steel First, the level of friction applied to the hinge/pivot point to the falling plate is more critical then bullet weight if the plate falls or not. Second, how solid the plate is hit, third how quickly you can get the second, third, fourth round impacting on the steel for the "PITA" plates.

John
 
From my experience shooting steel First, the level of friction applied to the hinge/pivot point to the falling plate is more critical then bullet weight if the plate falls or not. Second, how solid the plate is hit, third how quickly you can get the second, third, fourth round impacting on the steel for the "PITA" plates.

John

Agree, just hit it as far away from the fulcrum point as you can.
 
Bullet hitting the steel I think is more of a plastic collision than an elastic collision, so momentum conservation would probably yield better numbers. Therefore, the more momentum the better.

Momentum = mass * velocity

Lawman ammo in 9mm:

147 grain @ 985 ft/sec. => 0.0095 kg * 300 m/s = 2.85 kg-m/s
124 grain @ 1090 ft/sec => 0.0080 kg * 332 m/s = 2.66 kg-m/s
115 grain @ 1200 ft/sec => 0.0075 kg * 366 m/s = 2.75 kg-m/s

So for knocking down steel targets the 147 gr @ 985 ft/sec would be roughly 7% better than the 124 gr ammo.
 
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Poppers Should be calibrated either major or minor. Easy to do. All the way from 115 to 230 ball. Here when we use poppers they are calibrated to fall with a Center hit with 115 grain ball.
 
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