Quacker-Wacker wrote: Alum wears fast and tends to gull the surface especially when a steel bolt is riding on it. Where as the steel on steel of the A-5 tends to polish itself smooth and will last indefinitely.
Metallugurically speaking, that is incorrect. Like metals bearing against like metals (aluminum on aluminum, or steel-on-steel) are the most likely to gall (exhibit metal transfer). Stainless steel riding on stainless steel is notorious for galling, for example.
Dissimilar metals, on the other hand, tend to last longer as bearing surfaces. This means that brass-on-steel, or steel-on-aluminum works very well.
That's why steel shafts ride in brass or bronze bushings, rather than in steel bushings. That's also why 15,0000 rpm Honda engines have their steel camshafts riding directly on aluminum head material w/ the cam bearing caps made of the same aluminum.
If the greatest guns were the ones that last the longest, then my old H&R Topper should be at the top of the Great Guns list. That thing will never wear out.