.50cal. Knight Bighorn With Roundballs and a Refurbished Receiver Sight
My .50cal. Knight Bighorn came with fiber optic sights (front & rear), which are convenient since you can really see them, but not quite my cup of tea. The short sight radius, given the 26" bbl. and the location of the rear sight isn't ideal (for me) either. If that's not bad enough, adjustments, especially elevation, are a bit limited as well. To cure those problems, I installed a Williams receiver sight, which worked very well (loads of elevation & windage adjustment too), i.e., until I stripped the bolt that holds the adjustable part of the sight to its base. Reinstalling the original rear sight wasn't a problem, nor was sighting it in, but it just wasn't precise enough for me. After a recent and less than stellar range session, I decided to reexamine the receiver sight to see whether I could find another bolt that would fit. A short search through my parts bin located one and Voila! I was back in business. After remounting the sight and letting the Loctite cure, I took the rifle to the range to sight it in. The results of that are below.
Sighting in usually isn't a problem if you have a large enough, unmarked backer board: I didn't (Shame on me!). What I hoped would be a simple process turned out to be an exercise in futility, at least at first, as I didn't know whether my loads were hitting high or low, or to the left or right @ 50 yd. After moving the target to 25 yd., I found 1 hit very high on the backer (but centered!). Once I got a handle on the elevation, the rest was easy. The rest of my sighting in took place at 50 yd., and exclusively with patched RB's and loose BP, specifically Diamondback FFg.
I had intended to test both .490" (.492") and .495" (.497") balls, with .018" and .014" pillow ticking patches respectively, but ran short of the .490" RB's because of difficulties sighting in. The load was 60grs., which is pushing the accuracy limit of this rifle with its 1:28" twist rate. Btw, the patches were lubed with 1 water : 6 Ballistol and were wet, though not dripping. In short, the 60gr. load was nothing to write home about with either ball-patch combination. I knew from past experience that 50grs. worked well with that fast twist, so why not compromise and try 55grs.? The .490" RB's did better with that "reduced" charge, but the .495" ones did even better with 4 in less than 1" (from a rest, of course) and one 1 1/2" away from the center of that cluster, which I'm sure I pulled.
What's next? I think I'll try thicker patches, e.g, .020" and .022" with the .490" RB's and 55 gr. charges I think it will do well with at least one of them. Elevation will need a bit more adjustment (down) so that the rifle stays 1" high @ 50 yd. Oh, before I forget, I ran 1 dry patch down the bbl. after 12 shots to remove some of the fouling which accumulated on this sunny, but rather dry day.
