I got a new Ruger Blackhawk .45 convertible with the 7.5" barrel in 1983. I got the gun with the intent of being able to plink with .45acp ammo and not have to hunt for my brass in the weeds after shooting.
I made one "small" mistake. I decided to try it with .45 Colt ammo, first. Bought a box of Winchester 250gr, the original standard load. Wow!!! with the first shots, I was hooked!!! Over the years, that gun has had maybe 300rnds of .45acp through it, along with a few thousand .45 Colt loads in various power ranges.
Early on, I did polish some internal parts (by hand with stones, no power tools were involved) according to the excellent article about doing so in a Gun Digest annual. And, I did the "poor boy trigger job" by dropping one leg of the trigger return spring off its mounting stud. This resulted in a very light trigger, with no creep, and no noticeable overtravel. There is no "push off" concern. Sear and hammer engagement angles were not touched.
There are no aftermarket parts in my gun, other than the grips. I have never measured the cylinder throats, since the gun shoots just fine, I don't care.
I can put 5 shots in one hole at short range and hit the 200yd gong repeatably as well. (35 years of practice helps..
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I don't use the extra heavy bullets (I have no use for them), and while I did have my time of loading the Ruger to .44Mag power levels (and a bit beyond), I settled on one load 30 years ago, and have been shooting it ever since. 250gr hard cast SWC over 10.0gr Unique.
That load clocks just barely under 1100fps from my gun, and is not unpleasant (for me) to shoot. My .45 Blackhawk is one of my two most favorite revolvers, the other being my S&W M28-2 6".
I might have gotten the 5.5" barrel had Ruger offered it at the time, but they didn't, and I didn't like the look of the shorter one, so I got the 7.5" and I've been very happy with it. So happy that over time, I've gotten a Blackhawk in .357, a Super in .44Mag, and several Vaqueros in .45 Colt.
One of my friends collects Colts, and has several SAA's. nice guns, but after decades with Rugers, the Colts seem small, weak, and stupidly expensive to me. I tease him by telling him that the Ruger Blackhawk is the gun Colt would have made, if they had only known how....