I just got back from a nice 10 day vacation to my family's farm property in northern Alabama and I had a really great time. I liked it enough that I'm considering moving up there for at least part of each year...the more comfortable parts, that is! (I'm in hot, humid Florida.)
While up there I set up a mini shooting range with a bale of hay (the large round type) as the bullet stop, with six inches of lumber behind that to stop what the hay didn't, in the form of three layers of 2x6's.
I shot 9mm, .40, .380, .45, and .223 into this personal range to the tune of about six hundred rounds or so.
I checked the space between the bale and the boards after every shooting session to recover whatever bullets had made it through, both for the interest of it and because that area has been grazed by cattle before and will again. No sense in poisoning the livestock with lead and copper!
The results of these informal ballistics tests are sort of interesting and I thought I'd post them though they may not really correlate well with real world performance against a live animal or an assailant.
.45 ACP: (Zero 230gr. FMJ bullet, duplicating the Winchester factory loading) About 10 percent of the fired rounds completely penetrated the 4 foot thick bale of hay, but none of them had enough remaining energy to stick in any of the backstop boards or even dent one noticeably. Unless the slugs had bounced off another slug inside the bale, they were recovered in essentially perfect condition except for the rifling marks. I would not hesitate to re-use these slugs if they were run through a resizing die first and then tumbled clean and shiny.
.40 S&W: (CCI Blazers and a few Hydra-Shoks) Full penetration of the bale was VERY rare. I recovered only three Federal Hydra-Shoks, and NONE of them had expanded AT ALL, though their cavities were solidly stuffed with compacted hay. Not even the central posts in the cavities were damaged to any noticeable degree. Penetration was clearly the least of any round fired.
9mm: (115 gr. Zero bullet, duplicating the Winchester factory loading) This was a bit surprising. A large percentage of these bullets (about 30) fully penetrated the bale and lodged solidly in the first layer of the backstop boards, but none of them fully pentrated the first layer of boards. This was the MOST penetration of any round fired. I fired both copper plated (Ranier Ballistics bullets) and the Zero FMJ bullets, and both types responded about the same. The copper plated bullets have remarkably tough copper jackets and they don't shed as easily as the FMJ bullets do when they hit another bullet!
Many were recovered in pristine condition, like the .45 slugs.
.380: Only a handful were fired, and none were recovered. Not enough data available to draw any reasonable conclusion.
.223: (53 grain Sierra Match King hollow point flat base bullet over 23.0 grains of Hodgdon H322, delivering about 3100 FPS out of my 20 inch Bushmaster National Match barrel. Velocity not confirmed as I don't have a chrono.)
The .223's penetrated the bale fully about 10 percent of the time and occasionally stuck in the first layer of boards, usually in a sideways impact. NONE of them showed any expansion at all unless it was a result of hitting the wood backstop! Again , some of these bullets are so pristine that I would reuse them after re-sizing them. This, despite the fact that they are HOLLOW POINTS impacting at over 3000 FPS.
My only real conclusion is that a bale of hay makes a fairly decent bullet stop (I judge that any round I fired that penetrated would not have had enough remaining energy to present a serious threat to life or limb if you were to be hit by it) but it doesn't induce bullet expansion in practically any case. If you want to recover pristine slugs for ballistic fingerprinting or any other reason, shoot them into hay bales.
I also did a few other tests:
.223 straight into 3/16ths inch thick steel I-beam: (a section left over from some project)
The bullet penetrates and leaves a quarter inch hole through the steel without any significant stretching or deforming of the steel. Punches nice, round, even holes.
.223 straight into oak 2x6's stacked: Bullet fragments violently, with all fragments left in the fifth board. Judging by the holes left, the bullet remains more or less intact until it passes into the third board. Reliably penetrates 8 inches of oak.
9mm straight into oak 2x6's, with FMJ bullets:
Penetrates two boards, lodges as an intact, mushroomed slug in the third. Note that the 9mm penetrated MORE in hay than in solid wood, in comparison to the .223 which penetrated more wood but didn't penetrate hay as readily.
.223 into Titleist golf balls:
This is a fun and tricky target to shoot at! The golf balls need to be set up with the hay bale behind them because as I found out, shooting the golf ball with no backstop results in a truly mind-blowing drive with little chance of recovering the ball! All I saw was a white streak heading for the woods!
A golf ball like this is INCREDIBLY tough. Recovered balls show an exit hole that is scarcely the diameter of the bulelt, and an entrance hole that's much SMALLER, only about on millimeter or so. (That's one 25th of an inch, roughly...just a fraction of the diameter of one of the ball's dimples.) I shot one ball with about eight .223's and it's still recognizable as a golf ball and retains more than 90 percent of its mass. The bullets were not recovered but are presumed to be at least mangled and possibly fragmented a fair bit. If I had been inclined to tear apart a bale of hay, I'd know for sure.
I was majorly impressed at the toughness of a modern golf ball. It's the only small target I can think of that has significant reuseability after being hit by a .223 hollowpoint.
The next time I go back to the farm, I'll be shooting at ping pong balls filled with Pyrodex, at 100 yards, just for the fun of it!