Concentricity
23 June 2025 07:03 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
dime_novel_heroWhen I bought my Rossi 92, it came with a Skinner™ sight, a brand of peep sight. At the first Cowboy Action Shooting match I took it to, however, I was informed that peep sights were not allowed. With the ranges being so short and the targets being so large, it was easy enough to unscrew the brass ring and run with only the front sight.
For the match after that, I had manufactured a sort-of rear blade sight with a machine screw, sighting down the slot. Plenty good enough. By the end of the summer, I had purchased a proper replacement blade sight.
And, for a dozen years running Single Action Shooting Society matches, that was just fine. But recently I have become involved in Brutality Matches and the Cabin Fever Challenge, and with that comes a greater need to improve my sight picture.
You see, what I have been running with is a round bead front sight and a square blade for a rear sight. Using a round peg in a square hole is good enough when the targets are large or close but, putting those targets out to 100 yards or making them smaller, the brain needs a better sight picture. Setting a round dot into a square hole and then placing that over a distant or small target has a level of variability that makes the endeavor inaccurate and inconsistent. The brain doesn’t make the picture quickly and intuitively concentric the way that it would with a blade front and blade rear sight (square peg in a square hole) or with a round peep sight and a round front (round peg in a round hole).
I considered changing out the front bead for a blade as, I am told, that is a slightly more accurate sight picture for more distant ranges (where my shooting needs work), but my front bead sight is integral with the barrel back (a bracket that holds the barrel to the magazine tube). I’d have to buy a different barrel back. The cheaper and simplest solution is to just put the Skinner sight back on.
Or not.
I measured the extant front sight height and got 0.395 inches above the barrel. I measured the rear sight and got 0.3955 inches. That results my hitting high at 100 yards. I measured the Skinner sight at about 0.41 inches. A higher rear sight means I would be hitting even higher at range, the very thing I am trying to reverse.
The only solution to that would be to raise the front sight but, again, that would require me to buy a new barrel band. Except, those aren’t available.
You see, the early Rossi 92s manufactured in the 80s had a barrel band with a sort of notch in the top into which the sight blade was set, with a horizontal pin to hold it in place. Parts for 40 year old models simply are not to be found. Later models had a dovetail notch behind the barrel band into which a sight was set. Those are the models being made today so replacements are abundant. My particular model seems to be a transitional form where the front blade is brass cap crimped on to a very small pin set in the barrel band. I can’t even find photographs of this version, let alone find anyone selling replacement parts.
Going through my gun parts box, I found a rear sight elevator that was a little bit smaller, allowing me to lower the rear sight to 0.354 inches. Theoretically, lowing that rear sight by 4/100th of an inch should lower my point of impact by 9 MOA (9 inches at 100 yards) and that is pretty close to where I want it to be.
And so, off to the range.
Although shooting a foot low might seem like a fail, it is an improvement because using the elevator, it is easy to pull the point of impact further up. But that doesn’t solve my problem with the rounded front sight and the squarish rear sight. And, on top of that, in thinking more about sight picture I turned a more critical attention to what I was actually seeing. It was kind of crap.
With my corrected vision, I can see the target at 100 yards just fine. The front sight is a little bit blurred and the rear sight is a lot blurred. There is no way around that. And, with no way around it, There is no way to improve the sight picture.
Except, maybe, going back to the Skinner peep sight. With that, the fuzziness of the rear sight becomes consistent around the fuzzy front sight, set over the distant target.
Remember though, the measurement and calculation of the Skinner sight suggests I would be hitting higher than I was in the first place but, then again, my measurements were off by a foot for swapping out the elevator. The only way to know was to just do it.
And so, off to the range.
Setting up first at 50 yards I was almost dead on. A little bit to the left but a few taps with the hammer and punch it was looking pretty good. It was time to take it out to 100 yards.
A little over 6 inches low. A half twist of the peep sight brought it up another 3 and a half inches. Another half twist would be only a little bit high but I left it at that because it was a sweltering 95 degrees at the range.
More importantly than being on target at the given range was the sight picture was very much improved. Even with the blurriness I was able to put the front sight intuitively in the middle of the rear sight and put that concentrically over the target. I still need to do some adjusting on the front sight, perhaps blacking it out completely or partially to leave a clean, round dot of brass.
More experimentation and practice is in order but I feel I am in a much better position that I have ever been with this gun.
For the match after that, I had manufactured a sort-of rear blade sight with a machine screw, sighting down the slot. Plenty good enough. By the end of the summer, I had purchased a proper replacement blade sight.
And, for a dozen years running Single Action Shooting Society matches, that was just fine. But recently I have become involved in Brutality Matches and the Cabin Fever Challenge, and with that comes a greater need to improve my sight picture.
You see, what I have been running with is a round bead front sight and a square blade for a rear sight. Using a round peg in a square hole is good enough when the targets are large or close but, putting those targets out to 100 yards or making them smaller, the brain needs a better sight picture. Setting a round dot into a square hole and then placing that over a distant or small target has a level of variability that makes the endeavor inaccurate and inconsistent. The brain doesn’t make the picture quickly and intuitively concentric the way that it would with a blade front and blade rear sight (square peg in a square hole) or with a round peep sight and a round front (round peg in a round hole).
I considered changing out the front bead for a blade as, I am told, that is a slightly more accurate sight picture for more distant ranges (where my shooting needs work), but my front bead sight is integral with the barrel back (a bracket that holds the barrel to the magazine tube). I’d have to buy a different barrel back. The cheaper and simplest solution is to just put the Skinner sight back on.
Or not.
I measured the extant front sight height and got 0.395 inches above the barrel. I measured the rear sight and got 0.3955 inches. That results my hitting high at 100 yards. I measured the Skinner sight at about 0.41 inches. A higher rear sight means I would be hitting even higher at range, the very thing I am trying to reverse.
The only solution to that would be to raise the front sight but, again, that would require me to buy a new barrel band. Except, those aren’t available.
You see, the early Rossi 92s manufactured in the 80s had a barrel band with a sort of notch in the top into which the sight blade was set, with a horizontal pin to hold it in place. Parts for 40 year old models simply are not to be found. Later models had a dovetail notch behind the barrel band into which a sight was set. Those are the models being made today so replacements are abundant. My particular model seems to be a transitional form where the front blade is brass cap crimped on to a very small pin set in the barrel band. I can’t even find photographs of this version, let alone find anyone selling replacement parts.
Going through my gun parts box, I found a rear sight elevator that was a little bit smaller, allowing me to lower the rear sight to 0.354 inches. Theoretically, lowing that rear sight by 4/100th of an inch should lower my point of impact by 9 MOA (9 inches at 100 yards) and that is pretty close to where I want it to be.
And so, off to the range.
Although shooting a foot low might seem like a fail, it is an improvement because using the elevator, it is easy to pull the point of impact further up. But that doesn’t solve my problem with the rounded front sight and the squarish rear sight. And, on top of that, in thinking more about sight picture I turned a more critical attention to what I was actually seeing. It was kind of crap.
With my corrected vision, I can see the target at 100 yards just fine. The front sight is a little bit blurred and the rear sight is a lot blurred. There is no way around that. And, with no way around it, There is no way to improve the sight picture.
Except, maybe, going back to the Skinner peep sight. With that, the fuzziness of the rear sight becomes consistent around the fuzzy front sight, set over the distant target.
Remember though, the measurement and calculation of the Skinner sight suggests I would be hitting higher than I was in the first place but, then again, my measurements were off by a foot for swapping out the elevator. The only way to know was to just do it.
And so, off to the range.
Setting up first at 50 yards I was almost dead on. A little bit to the left but a few taps with the hammer and punch it was looking pretty good. It was time to take it out to 100 yards.
A little over 6 inches low. A half twist of the peep sight brought it up another 3 and a half inches. Another half twist would be only a little bit high but I left it at that because it was a sweltering 95 degrees at the range.
More importantly than being on target at the given range was the sight picture was very much improved. Even with the blurriness I was able to put the front sight intuitively in the middle of the rear sight and put that concentrically over the target. I still need to do some adjusting on the front sight, perhaps blacking it out completely or partially to leave a clean, round dot of brass.
More experimentation and practice is in order but I feel I am in a much better position that I have ever been with this gun.
