Does the thickness of a steel plate determine

1/4” plate would be better, 1/2” plate best. Pellets hit that it’s like bugs against a windshield.

all steels must be secured from allowing them to act like a tuning fork.

If wanting to use steel think shooting against wind chimes vs shooting at an anvil. The non budging anvil will not resonate sound and just be a low thud with pellets.

so far the most quietest I’ve found are the rubber mulch traps
 


so far the most quietest I’ve found are the rubber mulch traps



I have a question on rubber mulch traps, does the pellet hitting the wire mesh make noise?

Heck no!! It’s already “pre holed” and my ammo is flying thru there so fast, and the mulch is right against the screen. So in a fraction of a second’s fraction, the pellets point slices thru the thin wire and is immediately buried into the mulch
 
At Home Depot in the gutter and metal flashing section they sell a 12” wide roll of what I call in my trade “bird screen “, which is typically a 1/4” squared wire mesh. This mesh at Home Depot is patterned out diagonally like diamond shaped openings, about closer to 1/8” in opening size. Good stuff and easy to work with.



it is used a lot in the soffit vents, eave vents, and the same screen tacked on the backside of gable end louver flashings. Main purpose is to properly vent your attic space while keeping the critters out. 
Here it is just to the right of my bench snips-

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