AR500, what thickness needed for a .308?

Garvey

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May 1, 2010
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Melissa, Texas
I've contacted a supplier that can get the steel for me to build my own targets. (Yes I have a welding/ fabrication shop) I've never had to opportunity to work with this type of steel or shoot it. I know how to treat it when building it into a target. I was thinking I needed 1/2", but if that's overkill It would be cheaper (and lighter) to use a thinner plate.

So what thickness is needed to hold up to a .308 round from short to long range?
 
Re: AR500, what thickness needed for a .308?

We shoot 3/8" ar500 steel at 500 yards all the time with up to .338lm. It only knocks off the paint. This plate are hanging and not mount hard.

It would be best to water jet the plates so no heat get into the edges and changes the heat treat properties at the edges.
 
Re: AR500, what thickness needed for a .308?

Looks like 3/8" would work for me. Thanks guys!

I planned on hingeing or hanging the target and not hard mounting it. I'd like for it to hold up for a long time. I figured the closest it would be fired at would be 200 and that would probably be some of my friends or family doing it just for fun.
 
Re: AR500, what thickness needed for a .308?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KHOOKS</div><div class="ubbcode-body">We shoot 3/8" ar500 steel at 500 yards all the time with up to .338lm. It only knocks off the paint. This plate are hanging and not mount hard.

It would be best to water jet the plates so no heat get into the edges and changes the heat treat properties at the edges. </div></div>

I'm reading you loud and clear. I believe my moderate blacksmithing knowledge tells me that if I did plasma cut it, once it was formed, I could get it to a critical heat, quench, and it should be rehardened.
 
Re: AR500, what thickness needed for a .308?

Well using a torch will leave a heat affected zone which will cause the plate to deform if hit on the edges.

Waterjet cutting will leave little to no enbrittlement on the edges and less of a sharpe edge.

Reheat treating it could cause it to become brittle and end of being worse on the edges.

If you want to plasma cut it I would just use a grinding wheel and knock off the edges and live with it.

My two cents worth:)
 
Re: AR500, what thickness needed for a .308?

I would knock off the edges with a layered sanding disc to make it nice and shiny, reheat, and quench in used engine oil. You are correct a water quench would make it brittle hard provided it got it close to red color during heating. But staying closer to cobalt or peacock blue and quenching in oil or brine will still leave some flex in the steel.

I'm a do-it-yourself kind of guy, but I also don't have a resource to take it to someone with a water jet. If I did have that ability I would certainly take it to them and not worry so much about all this metalurgy.
 
Re: AR500, what thickness needed for a .308?

I have shot my 3/8" LV target at 100 with .308 and .223. The .308 just knocked the paint off. The .223 leaves very tiny peening marks.

At 200 yards you have nothing to worry about. Just make sure it's actually AR500.

AR400 will hole at those ranges. BTDT.
 
Re: AR500, what thickness needed for a .308?

We have a ton of AR500 target.... all cut with CNC plasma. If it is less than a 50BMG, and range is greater than 100 yards, you will be fine. A 338 or 375 at 100 MAY, depending on which batch, slightly cup a 3/8" plate. Turn it over and shoot it until cup is gone. All are hung plates, none solid. Two plates, every 25 yards from 200 to 500, then two plates every 50yards, 500 to 1000. Past 1K, what ever it works out to. Plus a half dozen more UKD ranges with 20-30 targets each.

Do not shoot a 50BMG at less than 500 yards, only because the plate swings madly, sometimes a jacket bit comes back.

Everyone worrying about the edges..... hasn't got a need to worry.
 
Re: AR500, what thickness needed for a .308?

Just a thought but where I used to work we had a cnc plasma cutter that had a water cooling head that sprayed water around the plasma tip. So I would think you could cut and have someone else keep water moving along with the cut being made at the same time. But I'm not 100% sure the cnc machine may have had some kind of special ground or something. I know it had a big tank of something hooked up to it but I think it was just compressed air to blow the metal out of the cut.
 
Re: AR500, what thickness needed for a .308?

I made these targets and they are AR400. I have them set at a 30 degree angle. I shot them at 15 yards with blackhills 60gr VMAX 5.56 just for grins. It puts little pox marks in the plate but nothing major. .308 at 100 yards didn't even leave a mark. These are 3/8" plate. 3/8" is alot lighter then 1/2". All my targets are 3/8" either AR400 or AR500. If you are going to shoot them 50 yards or further 3/8" is all you will ever need, unless you are shooting a .338 Lapua magnum or something equal.
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Re: AR500, what thickness needed for a .308?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">It puts little pox marks in the plate but nothing major. </div></div>

I would take that target "off line" for our matches and no way would I shoot it at 50 with those crators.
 
Re: AR500, what thickness needed for a .308?

Tansinator hooked me up with some 1/2" AR500. So I'm good to go once I build some stands for them.

USPS prolly thought "WTF?" when they had to handle 47 lbs. of plate steel from Tennessee to Texas in their flat rate shipping box on the cheap.

To me, that's some funny shit!