Re: what bases/rings to use?
Please bear with me on this somewhat long-winded and circuitous explanation to your comments on steel vs. AL
Keep in mind that I like steel bases myself under certain conditions, although the steel alloy that the particular piece is made from may or may not be any stronger than the high alloy AL many of the top tier ring makers use. It's also tough to beat AL 7075T6 or 7078T6xxx in what is known as "specific strength".
Specific strength is actually a very useful value to know for evaluating 2 competing materials.
In simplified terms, let's say you have a known load that you need to carry with a certain part. Just for argument's sake, let's say it is 500lbs.
Now, it's straightforward to calculate the geometry necessary to carry that load for any specific material.
Let's look at what that part weighs though.
So let's compare 4340 that is heat treated to have a failure tensile stress of 215ksi. This is pretty common in aerospace for a steel that is still strong, hard, and retains toughness. IE, it's not so hard and so strong that it becomes brittle and becomes prone to cracking during use.
Compare that to 7075 T651 at a failure tensile stress at 93ksi, again, this is relatively common stuff.
Now, if you were to take the same geometry and cut one from 7075T6 and the other from 4340 the steel would be abut 3x's heavier, but only about 2.2x's stronger.
So let's make something where the strength is equivalent. That means, change the geometry of the parts to where you thicken certain parts of the AL and thin out certain parts of the steel so that they can both equally carry that same 500lbs.
Which one weighs more?
In this comparison, the 4340 weighs more because it is 3x's more dense yet only 2.2x's stronger.
Same case with certain scope rings, the high alloy AL rings can be made to the same strength but in an overall lighter design than corresponding, high quality steel rings.
So, in the end, it's a question of "What alloy steel with what heat treat conditions" vs. "What alloy AL with what solution treatment conditions" do you REALLY want to compare?
My personal choice for a while now has been the various stuff built by American Rifle Co. It's made out of 7075, they're very tough, very nicely machined, they repeat well, have excellent grip properties, etc. Pound for pound, they're stronger than the competing steel designs and I've personally seen them last for thousands of rounds on a braked 338LM Imp. and several hundred rounds on a Barret M99 without the scope slipping in the rings.
All in all, an extremely well made and well engineered product.
