A few months ago I stumbled upon Holosun Technologies, a company out of Florida that makes a range of red dot optics. Nearly all of them employ a solar panel to provide power to the ultra-efficient LED, with a battery backup if it’s too dark. With this combination, the CR2032 battery’s life is up to 50,000 hours (5.7 years). Most of Holosun’s models are available with a 2 MOA red dot only, or like my PARALOW HS503C here with that same red dot inside of a 65 MOA circle and the option to turn the circle on or off. Let’s dive in to check out the rest of the features . . .
In The Box
Many of Holosun’s models appear to come with both low and high mounts. Some of the nicer ones have a good looking quick release mount, but mine uses a standard cross bolt to clamp to any Picatinny or Weaver rail.
Also in the box is the required Torx wrench for the mounts, two battery trays, a CR2032 battery, a handy tool for the small screws that hold the battery tray to the sight, and a good, to-the-point owner’s manual. Oh, and a rubber bikini-style lens cover for this model, while some others have attached flip-up covers.
Perhaps the best feature of most of the Holosun lineup is that you don’t actually have to worry about or do anything. Well, once you have it sighted in, that is. After that and for each time you go to use it, there’s no setup, no adjusting, no configuration. Heck, there isn’t even an on/off button.
Reticle brightness is adjusted automatically thanks to a light sensor somewhere in the solar panel. If there’s enough light to run the LED completely from of the panel — and it doesn’t take much — the optic simply stays on. If it’s dark enough that battery power is being used, the sight powers itself down after a few hours and will wake up automatically with a little light or via a push on one of the buttons. Some of Holosun’s models have a motion sensor and wake up when they’re moved, but my HS503C isn’t quite that fancy.
The above describes automatic mode, in which the reticle will auto-adjust for brightness and, on this model, will always be the circle + dot. By holding the + adjustment button down for a couple of seconds, the optic will switch into manual mode. In this mode the user can switch between circle dot and dot only, and has full control over the reticle’s brightness. There are 9 daytime settings and 2 night vision-compatible settings.
Adjusting windage and elevation is similar to many other red dots. Simply unscrew the turret covers, and click adjust to move point of impact as needed. The bar on the top of each cover fits into the slot on either turret and facilitates easy rotation, and the undersides of the covers are marked so you know in which direction to turn.
The clicks are easy to hear and feel, and each one affects 0.5 MOA of downrange adjustment.
On The Range
My first HS503C unit unfortunately had a defect, and the rear lens wasn’t installed properly and fell out. The sight still worked normally, actually, but it obviously wasn’t waterproof with the lens missing and dirt and debris could get in there and block the LED. The replacement, which arrived rapidly from Holosun with a return shipping label for the broken one [ostensibly] so their engineers can check it out, plus Holosun’s apologies and assurances that this was the first time they’ve seen it happen in over 50,000 units, has had no such issue.
It has now ridden atop my AR-15 for around 1,000 rounds, 500 of which were fired in one sitting as part of the SLF-15 Polymer Lower Receiver review. It also saw a box of .308 while adorning the Century Arms C308 during testing. Primarily, though, it has lived on my CZ Scorpion Evo 3 and works perfectly on that rifle with the low mount, even bottom 1/3 co-witnessing with the factory sights.
The auto mode has been spot-on. Reticle brightness is always correct as long as the target and I are similarly lit, which is where any auto-brightness will break down (e.g. I’m in dark shade so the reticle is dim, but the target is in full sun) and, of course, where the manual adjust mode comes in handy. However, I never actually had to switch it over to manual while out shooting.
I find the circle dot quick and intuitive, and I definitely prefer a fine red dot like the 2 MOA one Holosun appears to use in all of its optics. It allows for more precise aiming than a fat dot, and the brightness capability is more than enough that I don’t think anything is lost in terms of quick acquisition as compared to a larger dot. Plus, the 65 MOA circle with partial crosshairs further draws the eye to the hit zone.
The reticle is nice and crisp. Extremely sharp and clean, in fact, getting only a bit fuzzy on the edges at the very brightest setting or two. Eye relief is effectively unlimited, and the optic really is parallax free at any distance more than maybe 15 or so yards. What that means, of course, is that your eye doesn’t actually have to be centered with the optic for the reticle to be on target. Move your head around and the dot moves as well, going off center in the optic so it’s always right on top of the exact same spot downrange (this is shown pretty well in the video). This, of course, is common to basically all red dot and reflex sights and the Holosun is no exception.
Windage and elevation adjustment were true and the HS503C held its zero for me with no issues. I didn’t really torture test it other than shooting ~1,000 rounds of 5.56, 20 rounds of .308, and a few hundred rounds of 9mm through the blowback-operated Scorpion with it. And, although I’ve taken to tossing optics in their retail boxes down the basement staircase, Holosun #2 took that route as well as the laundry chute. It’s waterproof rated to 1 meter and working temperature rated from 14°F to 122°F, but none of this was put to the test other than shooting it in full sunlight on a 105° day. It did fine, of course.
I think Holosun is offering a lot for the money. The going rate for the HS503C is about $239.95. Some of the models look extraordinarily similar to models sold under at least one other brand name (Holosun may manufacture those), however the addition of the solar panel, the automatic brightness adjustment, and the circle dot reticle option set it apart.
The loose lens was concerning, but the new unit has been fine. The optical system does have a 5-year warranty. Clarity of the reticle rivals that of the most expensive red dots out there, and I think if I could make any one change it would have been springing for an even nicer model. I’d like the quick release mount since I’ve been swapping this thing between firearms a fair bit, and I’d prefer the flip-up lens covers. But then again, the HS503C is smaller, lighter, and less expensive.
Specifications: Holosun PARALOW HS503C Circle Dot Sight
Red Dot Size: 2 MOA Dot; 65 MOA Circle
Eye Relief: Unlimited
Magnification: 1x (zero magnification whatsoever)
Zero Adjustment: 0.5 MOA elevation and windage
Power: Primarily solar-powered with CR2032 battery backup
Battery Life: 20,000 hours for circle dot at mid brightness. 50,000 hours for dot only at mid brightness.
Housing Material: 6061-T6 aluminum
Operation: 11 brightness settings. Automatic or manual, push-button adjust. Circle dot or dot only reticle.
Mount: High and Low riser mounts included
Dimensions: 133x54x72 mm
Weight: 120 grams (4.23 oz)
MSRP: $282.34 (street price ~$239.95)
Ratings (out of five stars):
Build Quality * * * *
Being a little bit generous and assuming that loose lens truly was a complete fluke, the Holosun is otherwise very nice. Clean machining, flawless anodizing and lens coating, perfect and precise fit of all parts including the mounts, good button feel and turret adjustment feel, and it holds zero.
Optical Clarity * * * *
Just about as clear and bright through the optic as around it. I’ve played with a lot of sub-$100 red dots and reflex sights and this is a star above the vast majority of those for sure.
Adjustment & Controls * * * *
Automatic mode is going to suit you just perfectly a good 95% of the time. Doesn’t get easier than that. Switching to manual mode and using the adjustment buttons is simple, and the buttons are sleeker than a large dial.
Overall * * * *
Solid features and quality, particularly the reticle’s sharpness and the extreme battery life, at a price that’s half that of the battle-ready competition. Sure, if I’m actually going into battle or otherwise making a living with my firearm I might spend the extra few hundred dollars, but for any sort of recreational use — even rough use — and possible defensive use the Holosun should continue to serve admirably. Well, maybe not the first one I got but apparently every other one on earth, and certainly my replacement unit.