The thickness is not so much the thing as the grade of steel. You need a
minimum of AR500 for the rifle calibers, and preferably AR550 (if you can
find it). 3/8" is probably good enough for 5.56 at 100 yards, but not any
closer/, if you want to shoot closer or move up to magnum calibers, you
need at least 1/2". Even 1/2" of AR500 is going to get dimpled at any
range less than 50 yards when shooting rifle calibers.
Not for the tricky part, cutting AR grade steel is a pain in the butt. The
AR designation means that it is abrasion resistant. This is accomplished
via surface heat treating. Cutting AR500 with a torch (and to a lesser
degree a plasma cutter) heats the steel enough to destroy the heat treat
along the cut edge. So for small targets, you can completely destroy the
AR treatment and end up with pain old steel. Laser and water jut cutting
greatly reduces this, but does not eliminate it. Another solution is to
redo the AR heat treat after cutting the parts out. This requires a
specialized fixture that can heat treat the surfaces without hardening the
For this reason, most folks who don't have access to high end metal cutting
equipment just buy already made targets like you describe.
On Mon, Jun 29, 2015 at 11:59 AM, <firstname.lastname@example.org> wrote:
> Is there anyone here that can help me calculate the thickness of steel I
> would need to build something like this...
> But something that could withstand 38 special /40 cal/ and if possible,
> 5.56 Nato rounds?
> I don't know where to look for table that explain steal resistance to
> weapons fire.
> I do know that I will be angling the targets so they will not be square to
> the impact force, which adds another dimension to the calculations that I
> don't know how to determine.
> (If anyone one is in the NJ area and wants to come and shoot once it's
> built, you are more than welcome.)
> Sent from my Commodore 64 on a 2400 Baud Modem.
> Eric P
> "Be as beneficent as the sun or the sea, but if your rights as a rational
> being are trenched on, die on the first inch of your territory." Ralph
> Waldo Emerson
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