Briley Plasma Choke Tubes ---Aluminum?

I am wondering if these aluminum alloys are holding up. The heat expansion characteristics are different with aluminum. Who has these?

 

I got one of the first sets for my Blaser. My factory contact sent me a set, said to shoot them. Buy them if I like them, otherwise send them back. Give input about them to Briley. I have been an independent Briley Rep for many years, like Briley products, would not promote what I would not use.

I kept them, bought a set of Optima HP's for my SPI back up gun, and have sold several sets.

They don't foul, don't get loose, and seem to break targets HARD for the constriction. Can't see the constriction, even on a Full choke. Get out the inside calipers, it is there. Different geometry, WORKS.

Two Full Plasma Chokes weigh less than one factory Spectrum choke. Made a difference on swing weight.