Author Topic: I Need a Bettter Backstop  (Read 727 times)

rsterne

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I Need a Bettter Backstop
« on: December 15, 2018, 01:24:38 PM »
A decade ago I built a target backstop to use when testing my airguns inside my shop, at a distance of 20 feet.... I made a wooden box large enough to accept 12" x 16" pieces of OSB or plywood.... I normally use six layers of OSB, stacked to a depth of 3".... Originally, when I was dealing with low powered guns, I used old magazines, but quickly outgrew that.... Once I started getting into bullet shooting PCPs that were 100 FPE and above, I added a 3/16" steel plate to the back inside of the box, as a precaution.... With the many layers of wood in front of it, I have never had a ricochet.... Bullets impacting the steel flatten on impact, and stay within the box.... Eventually the OSB gets shot up and I have to take the box apart and replace the layers.... This has for the most part, worked great.... BTW, I have three layers of 3/4" plywood that are 32" high and 48" wide behind the box as a safety wall, in case of a miss or penetration of the box.... I feel it's been an adequate and safe setup, although I do inspect it frequently during and after use....

Yesterday I was working on my .457 Hayabusa, which is a 500 FPE gun.... When testing, I often just aim along the barrel of the gun instead of having to install and remove sights all the time, and I'm easily capable of keeping the bullets within about a 3-4" group, centered in the backstop.... Yesterday was no exception, but the OSB was getting torn up badly in the middle, and I was nearly finished shooting, so I didn't bother replacing it.... I kept checking the back of the box, and it was getting pretty big bulge, indicating that the steel plate was bending, something I have seen before.... Every once in a while, after using a particularly powerful PCP, when I strip down the box I pound the steel plate flat with a sledge hammer and reinstall it.... I figured sooner or later it would fail, which is why all the backup plywood and frequent inspections while I am shooting....

I had a few shots more I wanted to take, but I checked the backstop and found a hole in the back, and a bullet stuck in the first layer of plywood, so that was the end of shooting for the day.... When I pulled the box apart today, here is what I found.... The bulge in the steel plate is about 1" high, and you can see the bullet lodged in the plywood above the plate.... both photographed from the back…. :o



Anyways, I thought I would share what the power of a modern PCP can do with repeated impacts to a 3/16" steel plate.... You can bet I'm in the process of redesigning my backstop.... First, I will change to a 1/4" steel plate, and secondly I plan to replace the wood with either two layers if 2x4s, one layer in each direction.... or a layer of them on edge.... in front of the steel plate.... The plan is to have them replaceable by pulling them out a slot in the top, so that laziness is no longer an excuse for making sure there is wood in front of the steel.... Additionally, I can remove the shot up 2x4s in the middle of the box and leave the outer ones, which don't see as much damage, instead of replacing 12" x 16" sheets of OSB where the outer portions are still intact.... Once I have built the new backstop, I will post a photo in this thread....

Bob





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Alan

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Re: I Need a Bettter Backstop
« Reply #1 on: December 15, 2018, 01:56:59 PM »
I used a piece of 3/8 inch 6061 aluminum as a backing plate, thinking that would stop a .25 caliber pellet at about 45 FPE too. But like you, after a few dozen shots, I was surprised at the huge, domed-shaped bulge in the aluminum. That plate is now 3/8 inch, steel boiler plate!
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steveoh

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Re: I Need a Bettter Backstop
« Reply #2 on: December 15, 2018, 05:55:24 PM »
I built my duct seal target out of two by fours on all sides and filled with a double layer of duct seal. Tested my 909s on it with a 2x10 in front. Went through the 2x10, and smashed through the duct seal and spit it’s 2x4 back, and knocked the whole thing off the bench.

So I built a big box again out of 2x boards and filled with 2 bags of rubber mulch. 909s doesn’t phase it, but I haven’t tested the DAQs on it. Thing weighs at least 80 pounds.

So I’m skeered. Bought a 1/4” steel trap on eBay. I think it’ll be ok.

« Last Edit: December 15, 2018, 05:59:08 PM by steveoh »
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sixshootertexan

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Re: I Need a Bettter Backstop
« Reply #3 on: December 15, 2018, 07:43:02 PM »
Sounds like you need to step up to a plate of AR500. ;D
CCS 2300, CCS 2400, Custom Built Regulated .25, Custom Built PRod Clone, .308 Bullet shooter, XS46U .177, Custom regulated .177, 850 Hammerli .177

Nicesurprice

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Re: I Need a Bettter Backstop
« Reply #4 on: December 16, 2018, 12:24:32 AM »
Have this
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Alan

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Re: I Need a Bettter Backstop
« Reply #5 on: December 16, 2018, 05:15:47 AM »
I am jealous! Not just a backstop mind you, but an earthen berm! We should all be so lucky.

Technically, I can't shoot within the city limits, even using an airlift weapon! Imagine what they'd do, if I set up a shooting range in my backyard?
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Alan

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d_boom

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Re: I Need a Bettter Backstop
« Reply #6 on: December 17, 2018, 02:43:45 PM »
I like using ground playground rubber, made out of old tires with the steel removed.  Test have been done
using .22 LR at 25 yards and the penetration was less than 4 inches.  Airguns with higher energy levels will
defeat this playground rubber, you might check into the rubber chunks used by some of the indoor gun ranges.
I was told by one of the ranges the rubber chunks they used would stop a 50 cal. machine gun rounds.  I would
not wish to be around there for that test!
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Nicesurprice

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Re: I Need a Bettter Backstop
« Reply #7 on: December 17, 2018, 10:15:38 PM »
I am jealous! Not just a backstop mind you, but an earthen berm! We should all be so lucky.

Technically, I can't shoot within the city limits, even using an airlift weapon! Imagine what they'd do, if I set up a shooting range in my backyard?

We had a oportunity.
Needed a wind brake.
Was not alowed to build a stable.
There was a wind brake once and we had a permit to place it back.

So left side is stable.
Right side backstop.
And the foam will stay on the beer sitting outside.
Everlyone happy.
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rsterne

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Re: I Need a Bettter Backstop
« Reply #8 on: December 19, 2018, 03:59:46 PM »
Well I got all the materials and put together a new backstop today.... The framework is 2x6s with a 3/4" ply back and a 10" x 14" plate of 1/4" steel screwed to that....



The top and bottom rails, fastened to the front, are 2x4s, arranged in such a way that I can slide three layers of 2x4s in without needing to take out any screws.... The front and back layers are 3 pieces each, vertical, and the middle layer is 4 pieces, horizontal.... which left just over 1/2" of space, into which I slid a piece of OSB.... The target clips are taped to that with duct tape....



This means there is 5" of wood before anything can hit the steel plate.... Since all the 2x4 filler blocks are separate pieces, I can replace the center ones, which will get destroyed first, and just turn the side pieces over to put the shot sections out against the edges of the opening.... This should be a lot easier and cheaper than replacing full sheets of OSB.... I guess I'll find out soon how it works, but I'm pretty pleased with it, and I should be able to refill it with about half a 2x4 and a small piece of OSB each time, which will be really cheap to do....

Bob
« Last Edit: December 19, 2018, 04:01:57 PM by rsterne »
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Nicesurprice

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Re: I Need a Bettter Backstop
« Reply #9 on: December 20, 2018, 12:35:34 AM »
Well I got all the materials and put together a new backstop today.... The framework is 2x6s with a 3/4" ply back and a 10" x 14" plate of 1/4" steel screwed to that....



The top and bottom rails, fastened to the front, are 2x4s, arranged in such a way that I can slide three layers of 2x4s in without needing to take out any screws.... The front and back layers are 3 pieces each, vertical, and the middle layer is 4 pieces, horizontal.... which left just over 1/2" of space, into which I slid a piece of OSB.... The target clips are taped to that with duct tape....



This means there is 5" of wood before anything can hit the steel plate.... Since all the 2x4 filler blocks are separate pieces, I can replace the center ones, which will get destroyed first, and just turn the side pieces over to put the shot sections out against the edges of the opening.... This should be a lot easier and cheaper than replacing full sheets of OSB.... I guess I'll find out soon how it works, but I'm pretty pleased with it, and I should be able to refill it with about half a 2x4 and a small piece of OSB each time, which will be really cheap to do....

Bob

Another option.
Cast a plate off lead in the stop.
.5” will be enough.
Once we die a test on a 1 inch plate.
Over 800 Fpe and a 520 grain hard cast spitz.
The only result will be the slugs will become part off the stop.
So you will be able to shoot on the same spot over and over.
And the stop will be quiet

Btw nice piece f work.
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rsterne

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Re: I Need a Bettter Backstop
« Reply #10 on: December 20, 2018, 08:25:02 AM »
I can see how lead, being soft, would work provided the back of the box was strong enough to keep it from bending.... a 1" thick block of lead 10" x 14" would weigh about 56 lbs. and cost about $170 however.... so I think I'll pass....

Bob
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Nicesurprice

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Re: I Need a Bettter Backstop
« Reply #11 on: December 21, 2018, 12:07:37 AM »
I can see how lead, being soft, would work provided the back of the box was strong enough to keep it from bending.... a 1" thick block of lead 10" x 14" would weigh about 56 lbs. and cost about $170 however.... so I think I'll pass....

Bob

Thinkness depends on the rifle you gonna use.
Using scrapp lead will cost less.
For most airrifles a few slaps off roofing lead would be enough ,would cost few dollar.
1 inch will stop hunderds off footpound

There is a catch annyway.
Was testing a kevlar composit once.
It did stop the bullet.
Only all energy will be transfert over the construction you put it on.
The whole wooden construction came down.

We use that composit as safety barrier behind the bullet trap shooting indoors.
When everly fails we have those sheets.
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bdzjlz

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Re: I Need a Bettter Backstop
« Reply #12 on: December 31, 2018, 10:08:54 AM »
Attached is my backstop that works really well.  Have actually shot a .40 caliber pistol at it from 10 yards (only once - the noise was deafening) with no indication of any kind of deformation to the steel panel.

The trick is the angle of the steel plate, directing the projectile into 8" of dense sand.  This takes all of the energy out of the pellet and basically away from the plate.

I use it almost exclusively for airgun shooting though once in a great while I will shoot .22 long rifle projectiles at it. My total indoor range length is 18 yards.

Hope this helps.

DZ
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