Two Questions on Ballistics

[Guest Bassman17SC]

Recently I bought a 1911 and have been shooting it with various ammo to break it in. Last weekend at the range, i noted some 'odd' things on the target after I finished. So here goes...

I began my shooting with precision (using the sights only) with two mags of JHP ammo (14 rounds total). Below is what the target looked like -

Sorry about the crummy iPhone pic, but oh well. Anyways, look at all the nice round holes (from 25 feet)! Now, when I shoot my 9mm with JHP ammo, I see star-shaped holes in the target.

Question #1: Does the .45 ACP JHP round need more substantial material in which to expand (as compared to the 9mm) because the bullet is traveling much slower (850 fps versus 1100 fps)?

I then spent the remainder of my range time practicing my point shooting exercises (about 200 more rounds - mostly ball ammo, from 20 feet). When I finished, this is what the target looked like -

Please note the holes in the 10:00 position; the one just below the 7 at the the 8:00 position, and the ones between the 4:00 and 6:00 positions. They all seem to have ragged "spikes" that lead to the actual hole.

Question #2: What would cause this phenomenon? Are the bullets tumbling? Or could it be that I am shooting before the pistol comes to a full rest (my point shooting regimen is bringing the pistol up from the "ready position" to the firing position and shooting single and double taps).

Just being curious as to the physics.

Thanks to all answers.

[LngRngShtr]

1. bullets don't reliably expand at handgun velocities into the classic mushroom and certainly not on just paper, however the .45 has a larger cavity which may offset the slower velocity unless you are running +P which run nearly 950 or 185 JHPs which are usually faster than that more like 1000 fps +/-

45 ACP Ballistics Chart | Ballistics 101

2. looks like the cardboard backer may have backed away from your paper target ( possibly due to muzzle blast from being closer or range vent fans ) and the kind of paper they use for that target is prone to tearing look at an NRA competition target the paper is designed to cut cleaner than a longer fiber white paper most folks shoot at...next time get a can of "spray tack" cement and glue your target to the backer,or staple the corners ..those tears will disappear due to cardboard supporting the target some bullet styles (round nose) tend to star the target as they push through, pointier calibers like a 9 more radial tears a .45 tends to be rounder in profile so a little less radial tearing, Semi-wadcutters much less and or full wadcutters look like you used a hole punch

Shooting before pistol comes to full rest would just move point of impact, tumbling is an ammo or firearm problem either the barrel has an issue with the rifling or you ammo is undersized or too fast and doesn't take the spin from the rifling like it should I don't see any "key holing" so your bullets don't appear to be tumbling.

Here is something to help you "read" the targets to self diagnose why the shots go where they do.

single handed (right hand)

http://www.targetshooting.ca/docs/Pistol_Shot_Analysis.pdf

or if 2 handed ( right hand)

http://www.neshooters.com/awerbuck.pdf

John

[Jonnin]

expansion is related to lots of things, velocity is 1. The softness/hardness of the bullet/lead, velocity, bullet design, jacket thickness, material of the target, and more. As noted, paper does not generally expand anything, even the softest lead from a rifle like 223 does not expand much from paper (though it may tumble after the impact). If you want to study expansion, shoot into gel/jello/wet paper/etc in a thick jug. You can buy faster moving .45 ammo; it will have a lighter grain bullet weight pushed as high as 1200 fps for the really light ones in +p loads. The buffalo bore 185 grain for example is billed at 1180 FPS.

Edited December 6, 2011 by Jonnin

[Guest Lester Weevils]

I used to prefer shooting cheap JHP reloads in 9mm rather than even cheaper FMJ reloads because it was easier to see the holes in the target at a distance. The JHP would cut distinct holes in the target and the round FMJ would more often cut "flaps" that were harder to see. I was mostly printing targets on the laser printer or using the cheap-as-possible store-bought paper targets.

But Caldwell stick-on Orange Peel targets are not too expensive bought in bulk from MidwayUSA, so lately I just try to keep Orange Peel targets in stock to use. Those are easy to see even with FMJ, though a JHP still makes an easier to see round hole. Its more expensive than homemade laser-printed targets but its worth it to me to see the shots easier without walking out and looking at the paper real close.

Wasn't that the original idea behind wadcutter bullets, flat topped cheap bullets that would make a more easily visible hole in the paper?