Thrunite BSS V4 Flashlight Review

Thrunite BSS V4 Flashlight Review

Here’s the Thrunite BSS V4 – specifically the weapon mount version. This flashlight uses a single 18650 (included) and has Picatinny mounts!


Official Specs and Features

Here’s a link to the Thrunite BSS V4 flashlight product page.

Versions

There are at least two versions of the Thrunite BSS V4 – black, and this Desert Tan version.  And there’s also the Wowtac version, which I have reviewed, too.

Price

The Thrunite BSS V4 flashlight sells for $59.95 and is available now.  The Thrunite BSS V4 weapon mount flashlight bundle (as seen here!) costs a bit more – $89.95.  

Amazon.com even shows some other variations (including camo and grey), so go look there!  Here’s an Amazon (referral link) to get you there.


Short Review

All in all, this is really not all that different from the Wowtac BSS V4 I already reviewed.  The emitter is different, of course, but the Thrunite BSS V4 weapon mount flashlight seems to be cool white only (whereas the Wowtac version was available in neutral white.)  The additional bits (which add a good bit of cost to the package) are very suitable for weapon mounting this light.  So that’s good, too.

Long Review

The Big Table

Thrunite BSS V4
Emitter: Luminus SST-70
Price in USD at publication time: $59.95 (or 89.95 with the kit).  It’s less on Amazon.com, too!
Cell: 1×18650
Turbo Runtime Graph High Runtime Graph
LVP? Yes, with switch warning
Switch Type: Dual
On-Board Charging? Yes
Charge Port Type: micro-USB
Charge Graph
Power off Charge Port with cell: top four modes
without cell: no modes
Claimed Lumens (lm) 2523
Measured Lumens (at 30s) 1988 (78.8% of claim)^
Candela per Lumen 7.9
Claimed Throw (m) 250
Candela (Calculated) in cd (at 30s) 649lux @ 5.101m = 16887cd
Throw (Calculated) (m) 259.9 (104% of claim)^
Claimed CCT Cool White
Measured CCT Range (K) 6000-6600 Kelvin
Item provided for review by: Thrunite
All my Thrunite reviews!

^ Measurement disclaimer:  I am an amateur flashlight reviewer.  I don’t have $10,000 or even $1,000 worth of testing equipment.  I test output and such in PVC tubes!!  Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).

What’s Included

Thrunite BSS V4 Weapon Mount Light what's included

  • Thrunite BSS V4 Weapon Mount Flashlight
  • Wowtac 3100mAh 18650
  • Pocket clip
  • Nylon pouch
  • Replacement switch cover
  • Replacement charge port cover (2)
  • Spare o-rings (2)
  • Lanyard
  • Picatinny rail mount
  • Hex key
  • Remote switch tailcap replacement
  • Red lens to replace crenelated bezel
  • Manual etc

Package and Manual

Thrunite BSS V4 Weapon Mount Light box

Thrunite BSS V4 Weapon Mount Light manual

Build Quality and Disassembly

Thrunite BSS V4 Weapon Mount Light

Build quality is just fine here on the Thrunite BSS V4 weapon mount flashlight.

The bezel is striking.  It’s easy to remove, and the light works fine without it.

This strike bezel unscrews very easily (but not accidentally).

Thrunite BSS V4 Weapon Mount Light strike bezel

This design on the tailcap does little to help with unscrewing the tailcap for cell swaps.

Thrunite BSS V4 Weapon Mount Light tailcap Thrunite BSS V4 Weapon Mount Light cooling fins

The head end has a brass button.  The tailcap has a big thick double spring.

Thrunite BSS V4 Weapon Mount Light contact points inside

The threads on the tail are square-cut, fairly short, and unanodized.

Thrunite BSS V4 Weapon Mount Light threads on tailcap

There’s an inner tube on the cell tube.

Thrunite BSS V4 Weapon Mount Light tailcap spring

 

Thrunite BSS V4 Weapon Mount Light strike bezel removed

The light isn’t designed to be used without a bezel, but the lens didn’t fall out.

Thrunite BSS V4 Weapon Mount Light strike bezel threads

This is why the bezel is so removable:  There’s a red screw-in filter.  The filter precludes the use of the strike bezel.  Unlike the strike bezel, the red filter is flush on the front.

Thrunite BSS V4 Weapon Mount Light red diffuser

Size and Comps

Dimension: 146.5mm x 28mm x 25.4mm
Weight: 98g (NOT included the battery weight)

If the flashlight will headstand, I’ll show it here (usually the third photo).  If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).

Thrunite BSS V4 Weapon Mount Light in hand

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

Thrunite BSS V4 Weapon Mount Light beside the TorchLAB BOSS 35 (custom engraved)

Retention and Carry

First, but probably not most important, is the pocket clip. This is a friction fit pocket clip, which goes only one direction, and only on the tail end of the light.  So bezel down carry only.

Clip hug!

Thrunite BSS V4 Weapon Mount Light pocket clip hug

The included lanyard fits in the tailcap loop.

Thrunite BSS V4 Weapon Mount Light tailcap loop for lanyard Thrunite BSS V4 Weapon Mount Light lanyard installed Thrunite BSS V4 Weapon Mount Light lanyard installed

A nylon pouch is included.  The light will fit in either orientation, but there are no holes in either end.  So the light must be removed for use.

Finally, and most important for the weapon mount aspect of the Thrunite BSS V4 weapon mount flashlight is this Picatinny rail adapter.  This is a very high quality mounting point.

Thrunite BSS V4 Weapon Mount Light Picatinny adapter

The flashlight goes into the loop there.

Thrunite BSS V4 Weapon Mount Light Picatinny adapter

This isn’t a mount you’ll use off and on – it’s more permanent.  That’s because these four screws must be removed fully in order to get the flashlight in and out.  It’s not hard, but doing it on the fly would be unappealing.

Thrunite BSS V4 Weapon Mount Light Picatinny adapter Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed

Since you won’t be removing the light frequently from this mount, there’s little point in mentioning that no other carry options can be used while in this adapter.

Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed

The flip side of all the above is that removing or adjusting the apparatus on a weapon is very easy.  That big thumbscrew is useful and easy to manipulate.

Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed mounted on weapon

I’m not completely sure how this remote switch is supposed to mount.  Anyway, here it is.  I’ve seen other WMLs that have a Picatinny holder attachment specifically for holding this type remote switch.  I think this switch will fit in that type (but one is not included).

Thrunite BSS V4 Weapon Mount Light remote switch

Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed mounted on weapon Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed mounted on weapon Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed mounted on weapon Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed mounted on weapon Thrunite BSS V4 Weapon Mount Light Picatinny adapter with light installed mounted on weapon

Importantly, the charge port is not blocked when the flashlight is mounted in this way.  In fact, nothing is blocked when the flashlight is mounted this way.  You can still swap out the tailcaps, you can still access the side e-switch, you can still swap the bezels.

Thrunite BSS V4 Weapon Mount Light charge port access while mounted

Thrunite BSS V4 Weapon Mount Light mounted on Picatinny

Power and Runtime

The Thrunite BSS V4 weapon mount flashlight runs on a single 18650 lithium-ion cell.  A proper cell is included – 3100mAh button top.  However, even the shortest flat top unprotected cell seems to work just fine in the light.

Thrunite BSS V4 Weapon Mount Light beside included 18650

The cell is installed in the usual way – positive terminal toward the head.

Thrunite BSS V4 Weapon Mount Light 18650 installed

Here are a few runtime graphs.

Charging

The BSS v4 has on-board charging too, in the form of a micro-USB port in the head.  This port is opposite the e-switch.

Again, this is micro-USB.  Thrunite definitely knows how to use a USB-C charge port, but the BSS V4 just isn’t there yet.  It’ll be a needed upgrade when that does happen.

Thrunite BSS V4 Weapon Mount Light charging port

An appropriate cable is included:  USB to micro-USB.

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 2523/614 125s/147m 1988 8.44
High 1426/634 130s/150m 1361 2.86
Medium 350 4.5h 343 0.52
Low 33 55h42m 33 0.04
Firefly 0.54 56d 0.5 0.00

Pulse Width Modulation

None of the modes exhibit PWM for mode management.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  Also, here’s the light with the worst PWM I could find.  I’m adding multiple timescales, so it’ll be easier to compare to the test light.  Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, with is 50 microseconds (50us).  10ms5ms2ms1ms0.5ms0.2ms.  In a display faster than 0.2ms or so, the on/off cycle is more than one screen, so it’d just (very incorrectly) look like a flat line.  I wrote more about this Ultrafire WF-602C flashlight and explained a little about PWM too.

User Interface and Operation

There are two switches on the BSS v4.  First is the mechanical tail switch.

Thrunite BSS V4 Weapon Mount Light tail switch Thrunite BSS V4 Weapon Mount Light tail switch profile

This tail switch is very clicky and proud but shrouded on two sides by the tailcap.  This allows tailstanding while also allowing easy access while wearing gloves.

Next is the indicating e-switch on the head.  Note that this one has a metal cover.  (Metal, or plastic, either way, it’s not rubber and soft.)

Thrunite BSS V4 Weapon Mount Light e-switch

Thrunite makes a good e-switch, and this one is too.  There’s even an indicating feature in the center.

A third option, and one not seen on previous BSS reviews, is this remote switch.  This is a complete tailcap replacement.

Thrunite BSS V4 Weapon Mount Light remote switch Thrunite BSS V4 Weapon Mount Light remote switch Thrunite BSS V4 Weapon Mount Light remote switch

Here’s a UI table!

State Action Result
Any (Unlocked) Click Tail Switch Turbo
Any (Unlocked) Tap Tail Switch Momentary Turbo
Off (Unlocked) Click Side Switch On (Memory Mode (LMH only)
Off (Unlocked) Hold Side Switch Moon
Moon Click or Hold Side Switch Off
On (except Moon) Click Side Switch Off
On (except Moon) Hold Side Switch Mode advance (LMH)
Moon Long hold Side Switch Lockout (Switch turns red when clicked)
Lockout Long hold Side Switch Unlock
Any (Unlocked) Double click Side Switch Turbo (Really it’s “previous mode then Turbo”)
Any (Unlocked) Triple click Side Switch Strobe

LED and Beam

Unlike other BSS lights, this Thrunite has a Luminus SST70 as the emitter option.  The reflector is still smooth and deep.

Thrunite BSS V4 Weapon Mount Light emitter Thrunite BSS V4 Weapon Mount Light red diffuser

As stated above, there’s also a red filter option.

Thrunite BSS V4 Weapon Mount Light red diffuser

Thrunite BSS V4 Weapon Mount Light beamshot

LED Color Report (CRI and CCT)

The (single!) emitter is driven pretty hard at over 8A on the highest output level, and we can see the CCT creep toward the blue in that case.  Otherwise, around 6000K for a WML isn’t all that unusual.

Beamshots

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure.

Tint vs BLF-348 (KillzoneFlashlights.com 219b version) (affiliate link)

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.

I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!

Conclusion

What I like

  • The full package with Picatinny mount is great
  • Red filter seems to be very high quality
  • Complete package with high capacity 18650
  • Good user interface
  • Nice remote switch

What I don’t like

  • No non-strike non-colored bezel option
  • Micro-USB charging seems outdated

Notes

  • This content originally appeared at zeroair.org.  Please visit there for the best experience!
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