Thanks for all the comments, I will record these comments and give feedback to our R&D department.
I will also post news about this project if any update.
There really is no reason not to have hi CRI.
Is there?
25 year LEO veteran so I have some ideas from experience.
- A single CR123A battery, lots of large doubles already out there.
- Mechanical switch only no parasitic drain. Batteries must be able to work after a couple of years in the light without fail.
- Tough as nails and potted to handle recoil over and over. Revolvers have sharper recoil impulse over semi-auto’s, must handle both.
- 300-500 lumens, needs good spill for peripheral viewing of area.
- Very waterproof, good hinge and sealed.
- Quick attach, tight if a coin screw is used or very low profile if a throw lever.
- 5000k light color, higher gets more glare, less gives lower output.
- Gold plated contact areas. Anodized housing inside and out.
- Removable inserts for UNIV-1, UNIV-2, 1913-1, 1913-2, 1913-3 compatibility.
- Short as possible for use on compact pistols such as Glock-19’s
Battery inserted from a removable light head if o-ringed and still very waterproof possible. CR123A is still the battery of choice as they are extremely reliable. Rechargeable less than 100% reliable batteries turn items from tools to toys and should be avoided.
Sounds a CR123A battery is must. ok. How about compatible with CR123A and 16340, also 16340 can be magnetic rechargeable. Battery replace by unscrew head?
Excellent idea. Hadn’t thought of that. Red would surely help keeping your dark adjusted eyes well, dark adjusted. 
Head unscrews to change battery in this example.
16340 usable probably a good idea by itself. The beauty of the CR123A is that it’s a 1500-1600 mah small battery with a 20 year shelf life that doesn’t mind being stored in extreme weather. Olight built a few good weapon lights and I own a few but rechargeable adds extra complexity. A very small and simple system that always works is wanted in this field. Imagine your police or military sitting down next to an outlet recharging their equipment instead of completing the mission at hand. Like kids at a mall recharging their phones. 650 mah rechargeable vs 1600 mah quick replace. Actually this should not be an issue needing a magnetic rechargeable system. A single CR123A should give well over an hour of run time. This is a weapon light not a flashlight, no body should be using their pistol as a flashlight for extended times. Dark area with a threat that warrants a weapon to be draw only a few minutes.
Streamlight and Surefire built the best switch systems. Two styles both excellent.
The 24mm finned head of your DS series lights with a solid TIR lens would be a good start.
One aspect I forgot to mention - purely from a practicality and marketability aspect… Build it to the same form factor - maybe a touch smaller in one way or another, but not larger - as an established player in the market.
If your light will fit into a holster that is already in production to support another already popular pistol light, that’s one major usability hurdle out of your way. It saves money for buyers, provides a pre-made fit-compatible related accessory market, and frees you from convincing holster makers to add yet another SKU to their catalog.
My question is, could a TIR optic be used to make the light a bit more compact? When it comes to pistol lights specifically, I feel like throw is not that big of a concern compared to a light that would go on a rifle. I personally really like TIR beams but I know some people want throwier lights than that. I know for my purposes, self-defense within the home, the extra throw gained by a real reflector would just go to waste as long as I can push a couple hundred lumens OTF, which any modern emitter can do with its eyes closed with a CR123 backing it up. Throw an SST or a 219C in there for good CRI.
Only thing I want to add to make sure it’s not forgotten, leave the disco function off. Frankly I’m fine with on 100% and off as the only function.
You can include 16340 support, but don’t waste any space on building in a charger.
If you really want to stand out, include red or green laser options. If you can price those models at 100-150 (still potted and stuff), you’ll compete quite well with the $300 Streamlight TLR series 
:+1:
Already mentioned: Potted. CR123 support. Quick unscrew to swap batteries. Mechanical switch, with no modes. It should also be just as waterproof as the pistol. The beam pattern isn’t super important - we know size is limited, so don’t worry about it too much. A TIR is probably pretty good here, if you can get something like the Olight S1 batons do. Otherwise, some sort of shallow orange-peel reflector should be fine. And something neutral (4000K to 5000K) with a bit of high CRI is nice, like a Nichia 219C CRI90 or SST-20 CRI95. That will also stand out from the 7000K 70CRI offerings available.
If you actually hit most of these points, I’ve got a friend who keeps eyeing the TLR-2G that would snatch one of these up, and he’s the kind of guy who basically sells his friends on all the products he likes.
If possible, I’d like one to be short enough to fit underneath a g19. I hate it when lights stick out further than the frame and even past the edge of the barrel. Also I feel like a TIR lens would work well as I would use this for in-home defense where I would value flood over throw. Just my thoughts.
I’m against onboard charging for weapon lights, especially pistol lights. Size matters more, and any additional complexity is another thing that could fail. I also don’t want to leave my pistol connected to a charger and possibly unattended. Swapping the battery and putting the used one on a slot charger is almost always going to be a better solution.
I’ve seen a number of people claim rechargeable batteries are less reliable than primaries, but other than shelf life, I have not seen any basis for believing that. Furthermore, it’s not meaningful to compare capacity in mAh at different voltages. A comparison of mWh is a more meaningful representation of their capacity, and 2665 mWh isn’t that much less than 3239 (1A load used, which again is more power from the higher voltage Li-ion).
I’m going to reiterate my suggestion for 18350 support here. It trounces the other small cells with 4158 mWh - that doesn’t mean it shouldn’t support CR123A. Ideally, the light would support CR123A, 16340, and 18350. The light should be regulated such that they all produce the same power and heat.
Also, I would prefer either CR2 or built-in rechargeable, because I have a personal goal of never adopting more battery types than I currently have (which are: AA, AAA, CR1616, CR2025, LR44, CR2, and 18650). I have a CR2 light already but no CR123s so I don’t want a light that takes CR123s. IIRC, Streamlight makes a weaponlight that takes CR2s.
I’m definitely the only person on this board with this requirement though so feel free to ignore me, but I feel like onboard recharging isn’t the end of the world a lot of people make it out to be, especially if the quiescent current is very low or nonexistent. Quick-charging options could also be explored, as the technology certainly exists, and that would help address the complaints over recharging time. When I look at a flashlight, I look at it as how I would use it. For a weaponlight, it would be on a firearm for self-defense within the home, and in a realistic home defense situation I wouldn’t use it continuously long enough for the battery not being easily swappable to be a problem, unless we’re talking about an absolutely tiny battery here, which we aren’t. I’m good enough about making sure my rechargeables are always topped up and never low enough to be a problem so I would personally much prefer a rechargeable light.
I agree with the suggestions for potting and single mode only - it’s a tactical light for a very specific purpose, it’s there for when you need light and you need it right away. Strobe is definitely off the table. The light needs to be pretty durable, let’s say I drop the gun on concrete from 5 or 6 feet up and it lands right on the light, I want it to survive that, and I’d like to be able to drop it in a puddle, pull it out, and it’s still working - although the latter exists for every light that costs more than $3 these days, let’s be honest.
So a probable plan,
1. Model PT-1, CR2 battery （Pending）
3. Model PT-3, CR123A battery with IR or red, laser maybe.（Pending）
2. Model PT-2, CR123A, 16340 battery.(If size allowed then 18350)
The model PT-2,
Below all “？”are pending to discussion.
- Power: 1 x CR123A or 16340 battery.(If size allowed then 18350)
- No-rechargeable.
- Aluminum with anodized.
-Potted for more reliable.
- Smaller as possible. Fit for more holster.
- Waterproof IPX8
- LED: 5000K, SST-20, CRI95 FA2/FA3 bin
- Shallow OP reflector. (I think TIR Lens will be aging for long time use.)
- Output:
500 Lumen (CR123A),
800 Lumen 5mins? then down to 500 Lumen(16340),
1000 Lumen 5mins? then down to 500 Lumen(18350).
- Big mechanical switch. Push or Press? Which is better? Can the switch have “click” noise?
- No Strobe? No momentary-on? Only on and off?
- Replace battery from head.
- Quick attach, quick mount like Olight?(Size larger) or like Streamlight need coin?(Size smaller)
- Rail:
Keys for 1913 and Glock compatibility, and any other?
What length for mount can fit for more pistol rail?
How about the slide the rail adapter?
Wait for more ideas and discussion.
Looks good so far. On output 500 lumens is plenty. Many pistol frames are plastic these days. Your lights will only have air flow to bleed heat off. Mechanical switch that “clicks” should not be an issue. As it clicks with a bright light coming on. Momentary with light press, on with full press. Quick attach up to your engineers. Only two keys needed to fit most everything. Rail length for this one should be for full size pistols. Your Model PT-1, CR2 battery for smaller pistols.
This sentence ” How about the slide the rail adapter?” needs better clarity. Are you asking about mounting on the slide of the pistol or making a slide on rail adapter?
I have a variety of firearms and I’m willing to test prototypes if you’re looking for someone.
Disclaimer: I don’t own firearms.
I have a few friends that concealed carry pistols. Two of the three pistols have a light always attached.
Run-time is not a concern. One friend mentioned “Streamlight rates this at a half-hour run time. If I need it for that long, I’m going to need more ammunition than I can legally carry, so I’m also going to need a body bag to go home in.” My impression is that a pistol light will be semi-permanently attached, and only removed for maintenance/cleaning. The battery of course should be changed without removing the light from the weapon. So the smaller option is better there.
Momentary-on is fine as an option. Strobe is a no-go: the user will be looking at whatever is being strobed (because the weapon is pointed there also), so it could disorient the user as well.
1913 and Glock is the standard compatability AFAIK.
I really like what you’ve got down.
Oh, also: the switch can make a click noise. Once someone is turning on a light, they’re giving away their position anyway, so there’s no need for silence.
Ergonomics are key. The switch must be ambidextrous, easily activated by the support-side thumb without changing the (thumbs-forward, presumably) grip, and be easily kept in a momentary mode. As I understand it, low-light pistol tactics are most commonly trained as light on, shoot if necessary, light off, MOVE, repeat. No matter what, we don’t want the shooter to struggle with the UI.
The market is, in my opinion, saturated with high-performing, reliable, and easy to use lights for full-size / “service” pistols. Compact, subcompact and “micro-compact” pistols are all the rage right now, and the existing weaponlights for them totally suck IMO. I would cheerfully pay for a reliable, easy to use, brighter-than-100-lumens weaponlight for a Sig P365.
Mount - A lever throw is convenient, but if you can change the battery without removing the light, it’s not solving much of a problem. As someone else said, once mounted, a light (and especially a light/laser) rarely comes off the pistol. A coin slotted big head screw is fine. Keep it simple, small and light.
Switch - I’m used to switches that move up and down on the side of the light. That is the common operating method for most I’ve seen. I’d like to see Momentary in one direction, and a physical click into ON when moved in the other, with a physical click out of ON when you turn it off. IMHO, don’t reinvent this unless you have to. A lever that pivots in the middle and that can be worked from either side of the pistol is ideal. My olight mini-valkyrie has an odd push type button that seems to act more like a flashlight switch than a traditional up/down lever. I’m not entirely a fan of it. Your weapon light should never turn into something you have to think about when you need to use it. Keep the controls stupidly simple.
Body - anodized aluminum. Nice. Make a heavy Type III. For the home users, maybe even offer runs of differently colored anodizing at some point? As for size, look at a few industry standard competitors with lights similar to what you’re thinking of. Use those dimensions as the outside of your deign envelope so you can fit in their holsters. 
My suggestion is to start with the Streamlight TLR family of lights. Surefire is another major competitor with their x300 and similar lights, but those are a bit on the large size.
Side note - I’ve been a firearms instructor for a while, and can get law enforcement & military opinions on your gear too, should prototypes show up at my door. 
Not a firearm user myself, but some more common sense:
Don’t make it IPX8. Make it IP68. The X means the dust protection either doesn’t exist or isn’t rated, and the light failing because pocket/holster lint or gunpowder residue or dust of any kind fouled it up would be a bad thing.