Below is a qualitative, descriptive comparison. I could not figure out a way to take photos through the optics with an iPhone.
The optics differ in three obvious ways: window size, brightness/clarity, and pincushion distortion. Together, these produced a subjective quality that I'll describe as usability as an aiming device.
Pincushion (least to most): Acro >> SRO > 509t2 ACSS > 509t2
The most obvious "problem" with the 509t2 is the significant pincushion distortion in the top 25% of the window. This is likely due to the angled lens. Interestingly, the 509t2 ACSS has less pincushion. The SRO has some pincushion as well, but because of the large window, it's much less noticeable. The Acro is optically superior, and had no noticeable distortion.
Brightness/Clarity: Acro >> 509t2 ACSS > 509t2 > SRO
Again, the Acro stood out in optical quality, but the 509t2 ACSS was a close 2nd. The SRO was noticeably inferior to the other optics in brightness and clarity.
Window size: SRO > 509t2 (both) > Acro
The huge window and thin frame of the SRO are its main advantages. It's easy to ignore the frame and focus on the target. However, the 509t2's window is large enough (especially in width) that I don't notice it either. By contrast, the Acro's tiny window and thick frame are more distracting. The Acro is tunnel-like.
Usability: SRO = 509t2 ACSS > 509t2 > Acro
Note: this is a subjective preliminary evaluation, and I need more time with the Acro and 509t2 ACSS before I can provide a strong opinion.
The SRO is a popular optic in USPSA CO because it is reliable and has a big window. I still think it's the default choice unless a closed emitter is needed.
The 509t2 ACSS surprised me because it was optically superior to the regular 509t2 (based on a sample size of 1 each). Moving the gun simulating transitions, I found it just as easy to use as the SRO.
If I stare through the 509t2 and concentrate on the top part of the window, the pincushion distortion is distracting. I don't notice it while shooting dynamically. The bright and clear glass and relatively thin frame make the window disappear. For its size, the 509t2 is the winner.
At arms length, the Acro's bright-clear-undistorted yet tiny window with a big frame was less usable than any of the other optics. I'm going to need more time with the Acro, but I don't expect I will be buying more of them. Except for it being possibly more rugged than the 509t2, I can't see choosing the Acro's tiny window in a relatively large optic.
Last edited by Clusterfrack; 06-23-2022 at 12:12 PM.
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Shabbat shalom, motherf***ers! --Mordechai Jefferson Carver
At this point I'd say the 509T's biggest negative is its proprietary footprint.
So the 509t ACSS has a different footprint than a regular 509t2, but the 507 ACSS uses the same footprint as the regular 507?
Thanks
My 509 X2 green died after 100 rounds (mounted on Wright Armory P2000SK). Did fine at range, cleaned gun, was very careful to keep solvent away from void that exposes the underside of the mount plate, but when I reassembled, optic no worky. Ordered new batteries to see if that’s the issue, and if not I’ll go through Holosun CS.