Hello
@HogKiller The caliber does not count, it is the fpe ( foot pounds of energy ) that is important.
At 10-meters no more than 30fpe, ( foot pounds of energy )
At 25-yards no more than 55fpe, ( foot pounds of energy )
At 50-yards no more than 70fpe, ( foot pounds of energy )
EXAMPLE: At 10-meters you can use a .177 or a .30 as long as you do not exceed 30fpe. Yes I hate to even say this but there is a "built in" safety factor. I had to calculate this for Pete so that there is a "reasonable" value to protect his build.
I don't need this for me, I am well aware of the allowable "use" of various materials and I know NOT to exceed these values. But for Pete to offer a product to a consumer he MUST apply some limitations. Most ( but certainly not all ) Forum members have and use good judgment when using their air guns, they know from past experience what "should" and "should not" be attempted with various air guns.
I am a retired design engineer and my last project was to design and build three all aluminum supply boats at a cost of 6.65 millions each. I have to realize that not every one has the same experience with various metal as I have had. So it is very important that I do everything within my abilities to help and protect Pete and any other person or company that I offer my services. Pete is a friend, I knew his dad forever and since Mr. Pete has passed Pete Jr has taken over the business and it is my pleasure to help him.
ThomasT