KAC's New BIS for SOPMOD...

KevinB

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Well as I posted the pic on ARF.com

BIS2.jpg



Click to switch from CQB to Long Range Aperature.

Locks up and down like their front sight gasblock combo.
 
I handled one when down at KAC.

Its a rock. Worst case it wont lock - but has the same ball detent assembly as the KAC 300m and 600M BIS's that are part of the SOPMOD kit already.

The small aperature is mostly used for zeroing (at least the 300m BIS's insert was there for that) - and I doubt any will use the long range aperature off a range setting. Everyone was always loosing the plastic insert from the 300m BIS - so this way it cannot be lost.

Hoddie with the 300M - harder to hit target at 400m with the large aperature...
DownloadAttach.asp
 
I'm a mechanical engineer IRL and from a design standpoint I have to say I don't like it. That little rotating apeture pinion is going to be fun to use when it's full of fine sand. That slotted screw holding it on the RAS will probably look like it was attacked with a jackhammer once you've installed/uninstalled it a few times. A Torx or Hex head would be better. Also seems they haven't dealt with the biggest complaint the Matech and early KAC sights have had: the placement of the windage knob and its liklihood to interfere with the charging handle when wearing gloves.

Lastly that throw-lever lock seems like another un-needed part to manipulate and break. Why was that needed? If it was just spring loaded it would have worked just as well, been cheaper and easier to produce and would be less likely to cause malfunction.

Even without having one in hand I can tell I don't want one. Doesn't seem like much of an improvement over the old KAC design, or even the Matech for that matter.

I wonder if the designers have thought about how a gloved operator will manipulate that little aperture flipper when the sight is locked up and an Aimpoint CCO with a dead dot is in the way? In a firefight not everyone will have the time to spin off their aimpoint mount click-torque nuts so that they can properly use their BUIS...

Lastly, I'm sure it will have the usual unrealistic KAC pricing...

To my eyes the Troy is still a superior sight, as would be the ARMS40L and even the GG&G MAD for that matter.
 
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Well the Aimpoint was replaced in the SOPMOD kit - so now worries there :D

With the EOTECH (or Aimpoint) you just use the body as a big ghost ring and keep shooting till the threat is gone.

The locking mech was required by SOCOM as a lessons learned from the #40's spring has seized in the dust of Afghan and Iraq.

The lock mechanism is the same as KAC's flip front sight gasblock combo -- that has severed admirably on the USMC SAM -- and on my rifle :p -- I have no issues manipulating it with flight gloves on.
USMCUppers.jpg


Leave it in the open position if you worried about it seizing.
 
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KevinB said:
Well the Aimpoint was replaced in the SOPMOD kit - so now worries there :D

With the EOTECH (or Aimpoint) you just use the body as a big ghost ring and keep shooting till the threat is gone.

The locking mech was required by SOCOM as a lessons learned from the #40's spring has seized in the dust of Afghan and Iraq.

The lock mechanism is the same as KAC's flip front sight gasblock combo -- that has severed admirably on the USMC SAM -- and on my rifle :p -- I have no issues manipulating it with flight gloves on.

<<<IMAGE DELETED BECAUSE IT WAS TOO HUGE!!!>>>

Leave it in the open position if you worried about it seizing.

Kevin,

Again, my observations are from an engineering standpoint and not a soldier's viewpoint as I'm not in the CF. That being said, I still don;t like the design. It looks overly complicated for the simple function it has to perform and looks prone to wear and breakage. Time will tell if my concerns are justified or not, but if I were running the KAC R&D team, that sight would NEVER leave the design shop with my PEO stamp on it and that's a fact ;)

Re: Aimpoints being replaced in SOPMOD, yes, I agree the Eotech has "officially" supplanted it, but from what I've heard, the sales of AIMPOINT to the US forces has not slowed. Both Eotech and Aimpoint and Trijicon are making and selling thesesights to the US forces as fast as production will let them. I suspect that no matter what the standard SOPMOD kit is, there will be an Aimpoint substitute standard for some time to come and also it will likely be years before the aimpoints in the system are withdrawn from service, if ever. I should think the odds that field armorers will install the new KAC BUIS behind a few AIMPOINTS is 100% and then some :) I also understand they were not happy with the ARMS once sand is introduced, but I've not heard that complaint about the KAC 300m nor the Matech which are both spring loaded sights. In fact only complaints I've heard about those sights are that the Matech is too heavy (subjective), that the arm retainer can wear out leaving the sight "permanently deployed" and that is has a fixed aperture and that the KAC's aperture reducer (a plastic insert) is too easily lost.

If US spec is calling for the new lock mechanism then I can understand its inclusion, but personally I think it's dumb to mandate it when only the 3rd substitute standard BUIS (currently the ARMS) seems to be missing it. But hey, what do I know about beurocracy? :eek: My gloves comment was about the aperature selector flip anyhow, not the (IMHO useless) lock. I think a better design would have been a GG&G type aperture selector which is easily manipulated, or even better an A2 style flip on the end of the post.

As for the front sight, personally I like hte KISS method of just using the fixed front sight and getting used to part of it being visible in the optic. Oh well, if cowitnessed properly it shouldn't matter :)
 
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KAC 300 and 600m BIS's are NOT spring loaded - they have a detent ball that hold them upright - but are positioned by hand.


SOCOM and The Big Army are too different things -- the Army (non SOF) uses the Aimpoint (both CompM and M2 versions).

The BISII (and BIS - KAC300M) are SOCOM SOPMOD (Special Operations Peculiar MODification)
The Army has no official BIS - but units have procured KAC 300M, ARMS #40 and Matech units.

The KAC 600 and ARMS #40's are from the SOCOM Mk12's (SPR) and the 600m as well on the Mk11 (SR-25).

USASOC (Army Special Ops - read D boys and their Ranger support) have bought Troy and other BIS as well.


The BISII is the replacement sight in SOCOM for the SOPMOD BlockI device BIS the KAC300m - and who ever wants a BIS.
 
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