homemade bullet trap / backstop question

[spy231]

I am wanting to make an inexpensive backstop. I have a .270 that I would like to shoot in my pasture. The pasture is about 250 yards long. There are no houses really close by that I am worried about (unless I miss way high I will be ok). I just dont want to chance hitting a cow or ricochey who knows where.
I cant just pile up dirt so that is not an option.
What I was thinking is that I can get 3 pieces of plywood and make a 4ft x 4ft box and and put heavy duty rubber on the front part I will be shooting at and fill the rest of the box with pea gravel and/or sand. I would like to get some steel to make it, but I dont know where I would get any and how much it would cost so I thought plywood would work (maybe double the plywood up also?)
I will be shooting off a steady rest so I think that would work.
Any ideas or links to anything better? I am starting to reload so I am wanting to test out my loads without having to pay $8 per day at the range. (closest one is about 30 min. away) 

[spy231]

I found a test that somebody did online and it showed a .223 and a .308 rifle being shot into sand and no bullet penetrated more than 6 inches into the sand. I think I am going to use the whole sheet of plywood to make the front of my sand stop and then make it about 12 inches thick. This should be plenty to stop my .270 and and it will give a bigger target (more room for error). I guess I will be replacing the plywood up front pretty often. Or, I could cut squares about 1ft by 1ft and put rubber mats over the cutouts to hold the
sand in and I would just have to replace rubber mats every so often and not the whole sheet of plywood. Any thoughts guys??

[alleyyooper]

I use used 16inch truck tires filled with sand.



Al

[frogjake]

I have constructed many ranges over the years...... the cheapest and easiest I have found are tires stacked and filled with sand or clay.  We have a couple different sets up
at camp and two sets have lasted over 10 years!  You can get tires just about any where for free and just stack em and fill em.  I set ours up like the Olympic rings so they overlap.  It takes a little work but you end up with a dandy backdrop that will last a long time.

[Land_Owner]

It is recommended that you DO NOT fill your backstop with pea gravel or stone.  There is too great a possibility that both ricochet and rebound rounds will be experienced.  The sand filled tires sound like the way to go.  Only YOU can prevent missing the target...and sending rounds down range.  This will never happen if you take your time and follow proscribed gun safety rules http://www.nrahq.org/education/guide.asp.

[spy231]

I filled it with sand it is seems to be working great!

[jhm]

A few years ago a good friend SHOT himself with sand filled tires, shot wasnt fatal but he was shooting a 22 cal. pistol of some kind after working on it loaded it with 22 shorts just to check function of his repair and when he fired it at his backstop the bullet DIDNT penetrate the tires and came back and struck him in his belly, he carried the blueish/yellowish/redish baseball sized bruise for a few weeks, no more light loads allowed on that range.   JIM