Window Weight Pellet Trap / Backstop

A few years back, I came across some flat cast iron window sash weights at an auction, and for some reason my mind immediately went to "pellet trap." These weights are marked with a "12" as in pounds, so there's 72 pounds of cast iron in total. There were pulleys at the top of each weight attached with with a steel frame which I discarded. The edges of these weights are tapered, so when I alternate them, there is virtually no gap in between.

The initial design has worked well, with the trap evolving over time. Initially, it was just the wood base with a single black iron pipe frame attached that I would place on a couple of sawhorses. It now has its own dedicated folding steel sawhorses with custom fit wood tops and a catch tray spanning the pair. I recently added some drain holes to the tray so it doesn't fill with rain water if I leave it out. Most of the pellets get caught in the wedge formed where the weights meet at the rear, forming large clumps that make for easy collection and recycling.

My latest additions have been a second set of iron pipe frames to hold the cardboard target boxes in place. Before this, I had an aluminum profile frame at the front to hold single flat pieces of cardboard, but it only took a few errant shots to bend the profile and make it difficult to use. A few days ago, I added some more iron to hang a string and a plumb bob from to check the reticle on my scopes for proper positioning, and I'm sure this won't be the last modification I make as this trap evolves.

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I installed windows for 22 years. I have never seen flat weights in windows, the windows we took out were always round cast iron weights.
I could never figure out what to re use them for.

Great find and re purpose !
Right...as an auctioneer, I've seen hundreds of the round weights, but very few flat ones like these. I've kept my eyes out ever since, but haven't come across any more. The flat ones must have been much more expensive or used only in specialty applications.

Here's a picture of some 7 pound flat weights I found on eBay showing how the pulley was attached...

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How loud is it when shooting ? Does it ring ? Awesome set up you know it’s not passing through .
I do most of my target shooting at 100 yards and I've never noticed any sound from the trap. I'm sure there's some sound from the impact, but I've never really listened for it. I sometimes shoot until almost midnight, so it's nice that it's quiet.
 
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I installed windows for 22 years. I have never seen flat weights in windows, the windows we took out were always round cast iron weights.
I could never figure out what to re use them for.

Great find and re purpeose !
Same. Canoe anchor. Net weight.

Tarp holder downer . Door stop ..lol...

Them flat ones are pretty unique to me as well . Like the idea as a back stop too
 
I do most of my target shooting at 100 yards and I've never noticed any sound from the trap. I'm sure there's some sound from the impact, but I've never really listened for it. I sometimes shoot until almost midnight, so it's nice that it's quiet.
I use old breaker boxes with stall mats stacked in them I’ve never had a pass through and have shot .35cal at 10ft away . I like how while they are for back yard shooting . Only issue is the trap lead over time