Armor plate, looking for info

Tororider · Apr 15, 2009

So in an effort to have a bullet trap that won't weigh hundreds of pounds, I have looked into armor plate. There is a place nearby that plates vehicles and has "scraps" that they are selling for $20 a square foot. It is 3/8" bradley armor plate 40100. The 40100 means nothing to me, but I know nothing about armor plate. Will this armor plate be strong enough to shoot thousands of rounds at it when it is angled at 45 degrees? Also, what caliber would it be safe up to? Thanks for any help.

jwstewar · Apr 15, 2009

Would the 45 degree angle just cause the bullet to richochet? I have no clue, just my guess.

Tororider · Apr 15, 2009

Thats how you use a bullet trap. The 45 degree angle deflects the bullet into the ground or sand tray. I am just wondering the strength of the specific type of armor plate vs. steel plate, like 1/2" or 1".

SPYDERLK · Apr 15, 2009

AR 400 and AR 500 are normally used. Im not sure about the #s you listed. Regular cold or hot rolled steel lacks strength and abrasion resistance. Thats the "AR". Google it a bit.
larry

Tororider · Apr 16, 2009

I just talked to the guy, he said it is 46100 not 40100. I think I found some info on that yesterday while googling so I will see what I can found. He also said it has a brinell hardness rating of between 477 and 524.

SPYDERLK · Apr 16, 2009

That is about the same as AR 500 surface hardness then. As I understand it the ARs are not thru hardened. The hard surface gives the abrasion resistance needed. I think your quoted steels will be superior with the implication that they are thru hardened. The price sounds like a good deal.
larrt

LD1 · Apr 16, 2009

The bullet trap that we have used for years is just two 3' x 3' 1/4" plate welded together to make it 1/2" overal thickness. It stands on a 45 and has been shot hundreds of time with .22-250 bullets cooking at 3800fps.

It definatally craters out the steel and demples the backside.

Not sure what effects a larger caliber might have like a .308 or .30-06. It might punch through or the heavier, larger diameter, slower bullet might deflect even better.

There are some places where multiple rounds have hit the exact same spot several times and you can just start to see a little daylight through. But I live way out in the sticks with no worries at all, the only reason we us it is because it's easy to hang targets up, just grab a magnet.

I would say a similar design would be perfect for any handgun and smaller rifle rounds like 22long and 22wmr, on up from that it becomes questionable.

MikeD74T · Apr 16, 2009

Thickness & material strength requirements should be somewhat proportional to the angle of impact ??? How much more would it cost to reduce the angle of impact to 30 or even 15 degrees? i.e. longer plate mounted flatter
Also how about a layer of hardened material backed up with cold rolled? MikeD74T

jimg · Apr 16, 2009

SPYDERLK said:
AR 400 and AR 500 are normally used. Im not sure about the #s you listed. Regular cold or hot rolled steel lacks strength and abrasion resistance. Thats the "AR". Google it a bit.
larry

This. Can only add ar500 is also highly impact resistant in addition to abrasion resistant. Ive built swingers and traps out of 3/8" ar500 and its plenty tough. Ive shot them w/ everything from .22lr to .458 Lott and never had a problem. In fact it doesnt noticeably dent. I bought my stock from the local steel yard as 'drops' which made the entire affair much less expensive. Be certain to check w/ the steel makers recommendations prior to welding/cutting. In my case they recommended a preheat prior to welding + required low H rods.