General Holosun pistol optic thread

[JCN]

And I didn’t think it was parallax as much as it was lens distortion.

[RJ]

Let's begin with the fact that the gun is zeroed. B8 at 20 yards, firearm in Jorgensen clamp, dot centered on X.

Move head up / down, left / right. Observe where the dot deviates in relation to head movements.

The Sentinel M stayed within the 10 ring (3.36"), the MPRD stayed within the x ring (1.7").

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.

[CCT125US]

@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

[RJ]

@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

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.

[HCM]

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 ?

[RJ]

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 ?

Yeah, I definitely get that feeling. I'm not in tune with the major shows. Is there something coming up, like an annual NRA show or SHOT in Vegas or whatever it is?

[davisj]

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…

[HCM]

Yeah, I definitely get that feeling. I'm not in tune with the major shows. Is there something coming up, like an annual NRA show or SHOT in Vegas or whatever it is?

No, I think the release of the ACRO P2 is forcing them to up their closed emitter game.

[RJ]

509T on sale at Big Tex Ordnance today for $333.99:

https://www.bigtexordnance.com/produ...red-dot-sight/

EDIT: Sorry, didn't see it was out of stock already. Wow.

Back in stock, 25 available a/o 11:10Eastern at $333.99.

[Lon]

CHPWS is selling 509s for $299.95

https://chpws.com/product/holosun-509t-rd