This is great info!
Unfortunately I do not have a chrono, but the ammo used is
http://www.luckygunner.com/22-lr-40-gr-lrn-federal-champion-auto-match-target-325-rounds
The centerline of my optic over my bore is 1.5"
That should work. Just want to confirm that is sight-centerline over the
centerline of your bore, right? As opposed to centerline over top of barrel.
40gr is a little on the heavy side for 100 yard shooting because of the steeper arc (as compared to faster rounds). Having said that, if most of your shooting will be
within 100, as opposed to mostly
at 100, then you might be in luck. I plotted the data assuming a velocity just slightly below advertized, and using a ballistic coefficient that I've found to be pretty close for 40gr (0.155) when accounting for the fact that it will be passing from supersonic to subsonic during flight.
I'm finding that you should be able to do a 15/71 yard zero. This trajectory would take you to an apex of 1.25" high at 44 yards and 1.25" low at 83. At 100 you'd be around 3.75" low.
Another option (if you want your apex not to exceed 1" over POA) would be a 16/67 yard zero. This would be an inch high at 43, an inch low at 78, and 4.5" low at 100.
Last option, as I see it, would be a 13/82 zero. This would be the one that would limit your drop at 100, but at the cost of a higher apex in the middle. This would put you an inch high at 25 yards, almost 2" high at 48 yards, an inch high at 70 yards, an inch low at 90, and 2.5" low at 100. So the advantage with this zero is less total drop if you think you'll be doing a bunch of shooting at 100. The drawback is that you need to be more conscious of the exact distance to target because, between your two zero distances, you could be off by a squirrel's head in the middle.
My pick would be the 15/71zero . You go a little over an inch high in the middle, but the trajectory is flatter overall and you don't need to think quite as much about your holdovers as long as you're somewhere between 10 and 85 yards to target. With this trajectory it would be more of a "okay that's somewhere in the middle so I'll hold a little low" or "okay that's getting near 100 yards, I'll hold an inch or so high".
Of course all this is based on numbers and a ballistic table, rather than a crystal ball. Real world conditions will obviously effect what happens in the real world. With a 50ft range you can zero for all the distances I suggested, but because the trajectory is sensitive down to a couple feet (due to the zero being so close), little things can affect big change downrange. You won't know for sure if this is right until you try shooting to the second zero. That said, using this ballistic calculator and the same process for figuring this out, I ended up able to hit a pingpong ball 5 for 5 times at 100, after zeroing my rifle for 19 yards and accounting for the holdover it spat out.
