KAC SR15 URX4 16" mod2 + LMT Enhanced Carrier

[BufordTJustice]

Just grabbed my first KAC upper. Life goal.

BLUF: it's absolutely better than I had hoped. Lighter, smoother, more accurate, AND lower recoil than I frankly thought possible with a FH muzzle device, in an upper that is quite light. Not sure how they did it, TBH.

I have a spare current-generation LMT E-Carrier laying around, along with a Lantac Enhanced Carrier, and the std KAC carrier (which is literally just a high quality milspec FA carrier per KAC).

Preliminary observations were that all functioned 100% with PMC bronze 55gr and PMC X-TAC 5.56 55gr. However, recoil impulse was clearly more stout/stiff with the LMT Enhanced Carrier than the other two. The Lantac was the softest shooter. Followed by the KAC. Lantac and KAC felt very close. LMT felt like moving to 2.23/5.56 "+P", such was the obvious increase in sight movement AND rearward thrust. All are FA profile.

Carrier weights:
KAC - 9.4oz
LMT Enhanced - 9.1oz
Lantac - 9.7oz

I would not even attempt to guess these seemingly trivial weight differences by holding them in my hands. I don't know what the driver is for the obvious recoil differences.

KAC's E3 system is a thing to behold. Travis Haley put more than 80,000rds on a standard E3 bolt. This is about 4x the lifetime of any "quality" barrel.

More later.




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[Hammer_Man]

LMT Enhance carrier was designed for use with carbine length gas systems, perhaps that explains the difference in recoil impulse.

[BufordTJustice]

LMT Enhance carrier was designed for use with carbine length gas systems, perhaps that explains the difference in recoil impulse.

Karl Lewis discusses the genesis (and entire story/design) of the Enhanced carrier in this superb interview:

https://youtu.be/p-kSpKYr-Kw

The carrier was designed to address specific problems inherent in the carbine gas M4 to mk18. However, he says it's not only for those systems. It's 1.5hrs but a fantastic interview.


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[BufordTJustice]

LMT Enhance carrier was designed for use with carbine length gas systems, perhaps that explains the difference in recoil impulse.

Also, there are some complex system interactions here. The LMT E-BCG serves to obviously *reduce* recoil on my 11.5" suppressed SBR over a milspec LMT or BCM carrier.

Has the opposite effect here.


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[BufordTJustice]

Updated photo:

-Magpul ejection port cover (weight savings -> 8grams vs 21grams)
-V 7 matte NiB 7075 T6/Ti forward assist (weight savings -> 9grams vs 21grams)
-Geissele SSAE-X (because Geissele)

25grams of weight savings. Zero loss of functionality. A single CR123A is about 17 grams. So this is basically 1.5 CR123A's worth of weight shaved off the middle of the gun. Small, but non-trivial.

The V7 FA looks much darker in person and is non reflective. I manipulated that image in post because my office is so dark. I have the black DLC coated version on two other uppers, but it is actually very shiny. Matte black would be killer.

Lastly, this Geissele trigger is the best I've ever felt. Better than an SD-E or Super TriCon. Hoping to get back out to the range this weekend for a real sight-in.

Up next: hunting for a stripped LMT MARS-L Lower.




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[JediGuy]

What’s this? Not a mag release design I’ve seen before.

[BufordTJustice]

What’s this? Not a mag release design I’ve seen before.

That's the V7 'stendo mag release button. Been around for at least five years, maybe more.

https://www.vsevenweaponsystems.com/...release-button

Founder of V7, Joel, worked with John Noveske at NRW as the lead tech before John passed. I haven't quizzed Joel about it, but it seems like he may have helped John stand-up NRW. They were close. Joel has never run his mouth about it, so I dunno. He left to found V7 after John's passing in 2013.

https://www.thefirearmblog.com/blog/...-manufacturer/

NOTE: I've used their lightweight small parts since 2014, on my duty carbine, prior to retiring in 2020. They have been abused just as much as every other Colt, LMT, BCM, or other part I've got. They hold up. Even though these posts are often so light that they feel like plastic. And, if you can manage to break it or wear it out, they have a lifetime warranty for the original purchaser. They are a good company that also truly supports 2A. In Oregon.


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[JediGuy]

Great info, thanks.

If I can further inquire… How does it set compared to the protective ledges? AKA, is it substantially higher?

[BufordTJustice]

Great info, thanks.

If I can further inquire… How does it set compared to the protective ledges? AKA, is it substantially higher?

Absolutely.

The mag catch comes with the button as well (the don't have it in the images). IIRC, the button is slightly longer than normal spec, but can be threaded down more to compensate for that, if you want.


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[JediGuy]

Thanks!