Bullets and steel

Ry and I were at the Boomershoot site in Idaho this weekend when Sebastian sent me an email asking about steel penetration by bullets. I was pretty sure I gave him off the cuff correct answers but I was in a good position to do some of the tests. The next morning Ry and I found a piece of 0.5” mild rod and I shot it a few times.

The question was, “Could a pistol bullet severely damage the mild steel rod? Or is severe damage proof that AP rifle rounds were used?” I said, “I don’t think 1000 FPS pistol bullets will do that.” But I also said that a rifle, even relatively low powered lead core rounds, would go right through. Ry said, “The pistol bullets will only polish the metal.”

Here is the photographic evidence:

Entrance of a .223 52 grain JHP from 30 feet.

Side view of the .223 shot.

Left to right are Winchester Ranger 180 grain .40 S&W, hand loaded 180 grain polymer coated lead, .223 exit.

The Winchester Rangers were probably going about 1015 fps and polished the metal a little better than the handloads going about 950 fps. I don’t have any chronograph data of my own for the .223 rounds out of my gun but Black Hills says to expect about 3250 fps.

This shows why those who wish to ban ammo that penetrates police soft body armor are actually proposing to ban all hunting ammo.

7 thoughts on “Bullets and steel

  1. Yup, ban that overpowered hunting ammo and your “sniper” rifle… Ted K wanted .30-30 banned because it would punch through body armor, in reality nothing is truly bullet proof, not even planets!

  2. Penetration is largely a function of velocity, and seems to occur at velocities >2400 FPS. Some years back I tested 5.56 ammo from a 20″ barrel in various projectile configurations – FMJ, AP, soft point, hollow point – against 1/4″, 3/8″,1/2″ mild steel and and 5/8″ hardened steel at distances from 25 to 100 yards. Against 1/4″ and 3/8″ out to 100 yards bullet type made no difference – a clean hole. Against 1/2″ at 100 yards AP penetrated but the others did not – just a 1.5 caliber depth divot on the front and a projecting welt on the back (150 grain FMJ 7.62X51 did barely penetrate 1/2″ at 100, but failed at 150 leaving 2 caliber divot & back side welt, At 300, the same but smaller divot and welt.). Against 5/8″ hardened (a discarded CO2 high pressure gas cylinder) there was a difference: clean hole in the front face and a visible welt extending from the back of the cylinder (5.56 only, didn’t see any point in trying it with 7.62). I assumed that the hardening increased the brittleness and found it interesting that enough off the bullet held together (probably along with some of the cylinder steel, I have no idea as to how much of each) after penetration to raise the welt 6 inches later.

    All penetrations indicated a raised ring of bullet jacket material on the front face surrounding the hole. No effort was made to determine the quantity or effect of spalling behind the plates but I’m sure there was a fair amount.

    IIRC, Ripley’s Believe it Or Not museum in Niagara falls, NY has an example of straw being driven through a tree by a tornado, probably more an example of linear momentum than velocity. I recently ran across a photo of what looks like a pine 2X6 fully penetrating a 6″-8″ palm tree (can’t paste it in here, but Joe I can email it to you if you’d like) which I assume is another tornado result.

    As to penetration from handgun rounds, a private indoor range I occasionally used at the time had a 1/4′ mild steel backstop set at 45 degrees and while 20 years of use dished the backstop in the area behind the target suffiiciently to require the addition of J-Plate panels to correct (lead bullets only, in .22 through .45), there was no penetration. I’m confident, though, that any of those lead pistol bullets at >3000 FPS would probably penetrate.

  3. Years ago a local gun store, now closed, had a small piece of 1/4″ steel with a large hole through it. About 1/2″, I think. This was from a handgun, .44 AutoMag, IIRC. One side had a raised rim of displaced metal around the hole.

    • Interesting about that raised rim.

      That ties into a comment I saw on the website of a company making steel targets. They argue that your steel targets should be hard steel, so they stay flat when hit, rather than building up raised ridges like that. The reasoning is that an uneven target is likely to send ricochets off into unexpected directions.

      I have no experience with steel targets so I can’t tell if this is a valid concern or just marketing hype.

      • A number of ranges have learned the hard way that unless steel targets are hardened (AR500 is becoming a favorite, despite the added expense) they will eventually dish out from pistol rounds. Once dished to any visible degree the amount, direction and distance of ricochets, including bullet fragments, becomes unpredictable.

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