Re: How to adjust to shoot through chrono
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fred_C_Dobbs</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">...And, my name ain't fucking Francis........... </div></div>
We can fix that, ...<span style="font-style: italic">fucking Francis.</span>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: flyrodder</div><div class="ubbcode-body">Hmmm, and to think I just eyeball alongside the barrel to see if I am going to be able to miss it 10 feet away....</div></div>
Except that you can't sight along the barrel unless the barrel is between you and the chrono, which means you're behind it. So you're not 10 feet away, you're closer to 13.
The typical chrono's "sweet spot" is 4" above the sensor and it won't read a shot that's 4" higher than that. Four inches at 13 feet is 92 MoA, which is a degree and a half (1.54°). At that distance, the chrono's sweet spot is about one degree wide (1°). That means if your eyeballs are off by one half of a one degree (0.5°), either you get no reading at all or you blow hell out of your chrono.
So I'm guessing you either don't own a chrono or you have a sizable stockpile of used chrono components. </div></div>
I do own a chrono and I have no used parts other than those in the original setup (with one slightly bent sunscreen support from the afore-mentioned .357).
Maybe I'm not thinking about this enough, but if the chrono is between me and the target, and I have the target centered, it's pretty easy to put the round where I want it. I'm not estimating 0.5 degrees with no reference. Yes, I have to walk back and forth several times during setup, and I check with the scope on low power, but if I see a support rod on each side and I know the straight line between the bore and the target is above the pricey parts, it seems to work. Based on readings with the same load on different days, it seems to be pretty uniform, too.
I am shooting off a bench, so my support point doesn't move vertically, and the target is fixed, so once I am set up my only concern is lateral at my end.