fireflyfather
Member
- Joined
- Oct 22, 2006
- Messages
- 807
So, I'm at the range today dialing in new sights for my mosin (mojo microclick snapsights....beautiful sights). I get it all dialed in at 100 yards with 1960's vintage Czech light ball (147 grain). Then as I started generating bullet drop with various reloads using jacketed and cast bullets, I found one load that was a complete anomaly.
All my other loads shot lower than my zero with the Czech ball ammo, as I expected. However, I had one batch of brass set up with Ed Harris' "The Load" of 13 grains of red dot under a 160gr Gas-Checked Lee bullet meant for the SKS (312-160-TL-2R). That load, with it's wimpy recoil, was shooting FIVE TO SIX INCHES HIGH with the sights set to zero. That is, a 1600fps load was shooting six inches higher than a 2850fps load with only a modest change in bullet weight (5-10 grains, depending on gas check weight). I'm pretty sure I wasn't flinching or anticipating recoil, and I went back and forth between the two loads since I had some extra of both lying around, and I was able to repeat the results several times, and it obviously wasn't the sight moving around or being loose, since the zero with the Czech ball was still dead on, and the recoil was what I would expect with full-power military ammo and deliberately wimpy cast bullet reloads.
The BC of the two bullets was .401 for the Czech stuff (http://7.62x54r.net/MosinID/MosinAmmo011.htm), and .276 for the Lee. I'm just scratching my head to try and figure this out. I had assumed that the ball ammo would be the flattest shooting, and I could generate bullet drop data with that as my baseline, and then adjust for each of the different load recipies I have by using the range adjustment dial on my sights. Now I have to hold under six inches or back off on that recipe quite a bit.
I think I've weeded out the other variables like wind, etc, so I have no idea what's going on here. I figured bullet drop at 2.5 inches for the ball, and just under 8 inches for my reloads. The targets however, were showing that instead of being 5.5 inches lower, it was a similar amount higher.
Can anyone give me some insight here?
All my other loads shot lower than my zero with the Czech ball ammo, as I expected. However, I had one batch of brass set up with Ed Harris' "The Load" of 13 grains of red dot under a 160gr Gas-Checked Lee bullet meant for the SKS (312-160-TL-2R). That load, with it's wimpy recoil, was shooting FIVE TO SIX INCHES HIGH with the sights set to zero. That is, a 1600fps load was shooting six inches higher than a 2850fps load with only a modest change in bullet weight (5-10 grains, depending on gas check weight). I'm pretty sure I wasn't flinching or anticipating recoil, and I went back and forth between the two loads since I had some extra of both lying around, and I was able to repeat the results several times, and it obviously wasn't the sight moving around or being loose, since the zero with the Czech ball was still dead on, and the recoil was what I would expect with full-power military ammo and deliberately wimpy cast bullet reloads.
The BC of the two bullets was .401 for the Czech stuff (http://7.62x54r.net/MosinID/MosinAmmo011.htm), and .276 for the Lee. I'm just scratching my head to try and figure this out. I had assumed that the ball ammo would be the flattest shooting, and I could generate bullet drop data with that as my baseline, and then adjust for each of the different load recipies I have by using the range adjustment dial on my sights. Now I have to hold under six inches or back off on that recipe quite a bit.
I think I've weeded out the other variables like wind, etc, so I have no idea what's going on here. I figured bullet drop at 2.5 inches for the ball, and just under 8 inches for my reloads. The targets however, were showing that instead of being 5.5 inches lower, it was a similar amount higher.
Can anyone give me some insight here?