And I didn’t think it was parallax as much as it was lens distortion.
And I didn’t think it was parallax as much as it was lens distortion.
Thanks, good data.
I ran those numbers (8 yards, 2"; 20 yards, 3.36"; 20 yards, 1.7") through my home brew spreadsheet MOA calculator, to get a consistent metric of MOA:
Since Holosun advertises a "parallax-free" design, it may be that particular optic is not within the specification? It does seem that 507k is accurate but not forgiving with eye movement, however there might be other reasons @GJM alluded to that are contributing to the error as your eye is repositioned. He's got hella more experience shooting/dots than I do. Was the error primarily lateral, or elevation, or both?
Interesting discussion. To the extent I can do it in a hotel room () I'll get my 507c and 507k out and see if I can gueestimate parallax on mine. IIRC Aaron Cowan has a video on this somewhere.
@RJ something doesn't look right with that result.
I'll check back when I have time and give it a closer look.
ETA:
On the Sig, I believe I'm getting g 47.755 MOA
100 yd / target distance in yards (8) * group size inches (4) * .9551
Last edited by CCT125US; 06-16-2021 at 08:49 AM.
Taking a break from social media.
Heck, could be. The calculations are as follows in the spreadsheet:
Minute of Arc (MOA) to Min to Deg (MOAD) = MOA*(1/60) degrees
Minute of Arc degrees (MOAD) to Minute of Arc Radians (MOAR) = D*PI/180.0 radians
Range (In) = Range (Y)*3*12 inches
"MOA", inches, at Range, R = Range (in)*TANGENT(MOAR)
I think this is right?
If I add another computation line, a 48 MOA error will yield 4" of spread, so I think your figures are correct if you are seeing 4" at 8 yards. That's a lot.
Either way that sight parallax seems way higher than desirable. Be an idea for the owner to give Holosun CS a call if they are concerned. I would be.
Last edited by RJ; 06-16-2021 at 09:45 AM.
I’ll let you bug brains do the math but is it just me or does Holosun seem to be “blowing out” their current stock of optics, particularly the 509’s like they are getting ready to drop something new / improved ?
507Ks with the green dot are out. Ordered one from Kenzie’s yesterday. Also have a 509T at Jagerwerks, will have one green dot and one red dot. I think I’ll prefer green as I prefer the green Ameriglo front sights over orange. Time will tell. The price on the 509T was too good to pass up. Of course, I ordered it before the current blow out pricing…
CHPWS is selling 509s for $299.95
https://chpws.com/product/holosun-509t-rd
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