technetium-99m
Mighty Righty
They all work.  But for the love of God load to at least 132-135 PF.  It's only 9mm and there is no reason to skirt the minor or major PF floor anyway.
9mm bullet weights for steel
- Thread starter argyle64
- Start date
FortyMikeMike
Well-Known Fanatic
Actually, during the last match at USSA a guy in my squad struck the plate with his .45 in such a way that it knocked it off the stand. Whatever was fastening it broke and we had to get a replacement. Complete accident but hey, never say never :good:
Nerd alert: all others skip to the boldface..
As it happens, I noticed erratic results on the falling steel poppers at the ITPSC range and did some calculations of the various bullet momenta with various types & sizes of steel.
(For those that don't know me, I'm the resident physics prof, and this is a serious post)
Bottom line is the problem is the WIND, which at ITPSC hits the targets full on with our famous SW "breeze" and requires adjusting the poppers so not to fall just from the wind. With no wind, a 9mm will knock down any properly adjusted steel falling target.
The wind produces a force ( in pounds) on a flat surface of 1 sq ft = 0.00492 times (wind speed in mph) squared
So a 30 mph gust on an approx 1 sq ft full size pepper popper produces a force of about 4 1/2 pounds, which is MORE than the force produced assuming total momentum transfer from a minor power 9mm bullet. The power factor is a pretty good predictor (not exact) of steel knockdown force. There are reductions from the max theoretical based on bullet composition, and the angle you hit the steel is critical.
So what I though I was seeing when shooting pepper poppers with 9mm was predicted from the math:
If a pepper popper is adjusted not to fall in a wind gust over 20mph, you better hope you get some help from the wind when you shoot with 9mm. If the wind suddenly drops, the 9mm may not knock it down by itself.
Based on this, I have stopped using the full size pepper poppers in IDPA at ITPSC, particularly since most guns shot in IDPA are minor power.
The mini pepper and mini classic poppers are small enough that the wind would have to gust near 40mph for the same effect, and trying to use poppers in that much wind is a total PIA, as anyone who has tried it knows. Not to mention the paper targets flapping around and coming loose.
We did shoot one IDPA match with the wind gusting over 50mph, using no steel, and quadruple stapling the paper targets: most of the target heads were ripped off by the wind, and half a dozen paper targets still got ripped off and disappeared.
As it happens, I noticed erratic results on the falling steel poppers at the ITPSC range and did some calculations of the various bullet momenta with various types & sizes of steel.
(For those that don't know me, I'm the resident physics prof, and this is a serious post)
Bottom line is the problem is the WIND, which at ITPSC hits the targets full on with our famous SW "breeze" and requires adjusting the poppers so not to fall just from the wind. With no wind, a 9mm will knock down any properly adjusted steel falling target.
The wind produces a force ( in pounds) on a flat surface of 1 sq ft = 0.00492 times (wind speed in mph) squared
So a 30 mph gust on an approx 1 sq ft full size pepper popper produces a force of about 4 1/2 pounds, which is MORE than the force produced assuming total momentum transfer from a minor power 9mm bullet. The power factor is a pretty good predictor (not exact) of steel knockdown force. There are reductions from the max theoretical based on bullet composition, and the angle you hit the steel is critical.
So what I though I was seeing when shooting pepper poppers with 9mm was predicted from the math:
If a pepper popper is adjusted not to fall in a wind gust over 20mph, you better hope you get some help from the wind when you shoot with 9mm. If the wind suddenly drops, the 9mm may not knock it down by itself.
Based on this, I have stopped using the full size pepper poppers in IDPA at ITPSC, particularly since most guns shot in IDPA are minor power.
The mini pepper and mini classic poppers are small enough that the wind would have to gust near 40mph for the same effect, and trying to use poppers in that much wind is a total PIA, as anyone who has tried it knows. Not to mention the paper targets flapping around and coming loose.
We did shoot one IDPA match with the wind gusting over 50mph, using no steel, and quadruple stapling the paper targets: most of the target heads were ripped off by the wind, and half a dozen paper targets still got ripped off and disappeared.
TerryKendell
Well-Known Fanatic
Bullet Weight in Grain times Velocity Squared divided by 450,240 Equals Foot Pounds of Energy
Weight X Velocity x Velocity Divided by 450,240 = Foots Pounds of Energy
Power Factor was invented originally to give the 45 ACP the advantage over the 9MM
Weight X Velocity x Velocity Divided by 450,240 = Foots Pounds of Energy
Power Factor was invented originally to give the 45 ACP the advantage over the 9MM
poopgiggle
B Class Nobody
I'm glad you dragged this thread back up. Shortly after it was posted I drove cross country with a guy who did his undergrad in physics and now has a MS in mechanical engineering and we talked about this.Old Gun said:
Long story short is that momentum determines steel-knockdown ability, not KE.
hunter_dmw12
Well-Known Fanatic
I have only shoot steel challenge twice and power factor was never checked. Just a thought 100 grain bullet..... if pf is not checked.
TerryKendell
Well-Known Fanatic
poopgiggle
B Class Nobody
http://en.wikipedia.org/wiki/Inelastic_collisionOld Gun said:
Stranger
Fanatic
Well, I learned something today. If you knock down a steel targets in Steel Challenge you are WAY overpowered. 
Corey
Well-Known Fanatic
For steel challenge I always wanted to load a revolver light enough so I could get the second rd off before the first bullet hit. I had a black powder pistol when I was a kid and the load I started with was extremely slow, the bullets would not penetrate a thin metal, for rent sign
Banga1time
New Fanatic
I'm using 147gr fp from Missouri bullet company
Brinell 18 seems to be working fine
Brinell 18 seems to be working fine
DC4OU
Well-Known Fanatic
Hey, I am not sure about this because I have never seen it in steel challenge, however in ArGyLe64's defense, it appears there might be poppers in steel challenge. Look at Falling W and Outsider.
http://ipsc.okcgunclub.org/steel_chal/sc_stages.pdf
http://ipsc.okcgunclub.org/steel_chal/sc_stages.pdf
drmitchgibson
The white Morgan Freeman
You better have some poppers out there for us today!
