They are definitely more attractive than the Talley's and they are machined, rather than extrusions. I see them for $85,
so that is a decent price considering the more expensive production methods.
Talleys are machined from extruded alloy....highly likely Leup. also machine those rings from extruded 7075.
DNZ states it uses '7075 billet', which I gather would be an extrusion.
From my time in aerospace machineshops, components were manufactured from 7075 extruded stock
which would be 7075-T6510 or 7075-T6511.
some technical trivia: 7075-T6
7 indicates that Zinc is the principal alloying element
0 means there are no modifications
75 identifies the alloy in 7xxx series.
T6- indicates the alloy has been solution heat treated and artificially aged
without any significant cold working (strain hardening)...., the Talley's are also made of an unspecified 7000 series aluminum. I doubt the Leupold's are any stronger in reality.
7001, 7003, 7004, 7005, 7029, 7046, 7050, 7075, 7079, 7116, 7129, 7146, 7178
7xxx series alloys are the strongest
lower end 7xxx (eg;7004) has significantly less tensile and yield than 7075.
now people don't panic... the old 6061-T6 is a good alloy and still used in aviation and variety of high quality sporting goods.
its tensile and yield strengths can be like half that of 7075-T6.
7xxx series Yield strength can generally vary from 150 -
625 MPa.
Tensile strength can vary from 195-
620 MPa.
Interesting....a reported higher maximum yield strength than the maximum reported tensile strength. From a mechanics of materials perspective that's a challenging design hurdle.7001, 7050* and 7075* are used in high strength aircraft structures (*and hydraulic fittings).
an example of 7075
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=ma7075t6