Any issues with kac upper on lmt mws lower?

Happiness Is A Warm Gun

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I realize they will fit together, but will it function the exact same as if the lower and upper are both lmt or both kac? Anyone have any issues at all as far as function who put a kac sr25 upper on a lmt mws lower?
 

BEJ762

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I have a LMT MWS lower mated to a SR25 upper (20” 308). Pulled the LMT spring and buffer, replaced with KAC stuff that came with upper. Fits fine. Have around 450rds with no hiccups or funny wear marks on lower.

A buddy of mine has the same set up but with the KAC 6.5 upper. In his set up, there are wear marks on the lower just in front of the buffer tube/buffer retaining pin. I personally contribute this to the KAC 6.5 BCG as it has a different profile than the 308 model. With that said, he has not experienced any failures or hiccups either.
 

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I have a LMT MWS lower mated to a SR25 upper (20” 308). Pulled the LMT spring and buffer, replaced with KAC stuff that came with upper. Fits fine. Have around 450rds with no hiccups or funny wear marks on lower.

A buddy of mine has the same set up but with the KAC 6.5 upper. In his set up, there are wear marks on the lower just in front of the buffer tube/buffer retaining pin. I personally contribute this to the KAC 6.5 BCG as it has a different profile than the 308 model. With that said, he has not experienced any failures or hiccups either.
Thanks. Weird about the 6.5 leaving marks. Is the bcg really all that different? Mine will be for a 308, but I am curious now.
 

BEJ762

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Thanks. Weird about the 6.5 leaving marks. Is the bcg really all that different? Mine will be for a 308, but I am curious now.
You’re welcome.

yes, KAC changed the BCG around. First, the bolt has the split ejector layout like the LMT bolt (vs the 308 bolt with 2 ejectors side by side). Also, the bottom profile of the carrier is different. On the 308 carrier, it has the typical narrow slot for the hammer to access the firing pin. The rear bottom of the 6.5 carrier looks closer to a DPMS style carrier (wider slot for a wider hammer profile). Lastly, the bottom bearing surfaces of the carrier appear to be profiled differently on the 6.5 (which is why I made the assumption about the marks on the lower).
 

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That is very interesting to read. I wonder if kac will change the bcg for future 308s, too?

As far as the 308, yours seems to be working just fine. That is good to see. Hopefully everyone else has the same experience...
 

GUNNER10

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That is very interesting to read. I wonder if kac will change the bcg for future 308s, too?

As far as the 308, yours seems to be working just fine. That is good to see. Hopefully everyone else has the same experience...
I would assume so, KAC is constantly refining their lineup and is why over the past 20 years, you have seen the SR25 development continue. just look at the SR25 Match rifle/mk11, and today's K1/2/3. Almost everything in todays rifles is the results of 2 decades of testing and down range feedback.

If you look at KAC's main competitors on the global stage, HK developed the 417 in 2006 and Fn developed the Scar in 2004, both of these platforms exist pretty much in the same state as they did when they showed up on the battlefield.

Almost 2 decades later, the 13 inch assaulter 417 is Still heavier than the 16 inch ECC/APC. The Scar still has a poorly designed stock and an atrocious trigger and as a 16 inch rifle is now heavier than the ACC/K2.
 

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I would assume so, KAC is constantly refining their lineup and is why over the past 20 years, you have seen the SR25 development continue. just look at the SR25 Match rifle/mk11, and today's K1/2/3. Almost everything in todays rifles is the results of 2 decades of testing and down range feedback.

If you look at KAC's main competitors on the global stage, HK developed the 417 in 2006 and Fn developed the Scar in 2004, both of these platforms exist pretty much in the same state as they did when they showed up on the battlefield.

Almost 2 decades later, the 13 inch assaulter 417 is Still heavier than the 16 inch ECC/APC. The Scar still has a poorly designed stock and an atrocious trigger and as a 16 inch rifle is now heavier than the ACC/K2.
No doubt. KAC is always improving. I think that is part of why their stuff costs so much. I have noticed that most of the negative comments about sr25 tend to be at least a couple generations behind, typically the generation before the EMC/ECC. I was more curious if the new bcg design was more for the 6.5 caliber because of the different recoil impulse, but i guess we will see soon enough.

Do you have any first or second hand info on a current sr25 upper like the cc having any issues working on a lmt mws/mars h lower?
 

GUNNER10

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No doubt. KAC is always improving. I think that is part of why their stuff costs so much. I have noticed that most of the negative comments about sr25 tend to be at least a couple generations behind, typically the generation before the EMC/ECC. I was more curious if the new bcg design was more for the 6.5 caliber because of the different recoil impulse, but i guess we will see soon enough.

Do you have any first or second hand info on a current sr25 upper like the cc having any issues working on a lmt mws/mars h lower?
No issues, The whole reason the KAC started releasing uppers is because LMT made lowers availible. That's was put out by Jack over on arfcom
 

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No issues, The whole reason the KAC started releasing uppers is because LMT made lowers availible. That's was put out by Jack over on arfcom
He would know!

I suppose I am a bit conservative on firearm related stuff after watching things like the Scar program or seeing things like the sig p320 in action. Sfuff that looks great on paper or in testing, but then when actual end users start putting a lot of rounds through it all sorts of strange things start happening.
 

GUNNER10

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He would know!

I suppose I am a bit conservative on firearm related stuff after watching things like the Scar program or seeing things like the sig p320 in action. Sfuff that looks great on paper or in testing, but then when actual end users start putting a lot of rounds through it all sorts of strange things start happening.
Myself along with at least one other member on were and are involved in the organization that does that testing and sometimes one is left really scratching their head on how some of this stuff ultimately was selected. As a matter of fact, over the past 15 years, I think they missed the mark more often than not, by taking end user and program feedback more into account than test data. For example, a number of cherry picked guns are sent to Ft Benning, The guns run great in the field but the test guns are having serious issues after a a few cycles are put on the guns. A decision is ultimately made and the gun gets held up in acceptance testing for years because the gun is nowhere close it being where it needs to be, Prime example is the CSASS/M110A2. I think End user feedback is a great thing, but should only be evaluated as a tie breaker. It should not be the driving factor in selecting a particular piece of gear as it tends to result in a "they will eventually figure it out mindset".

In regards to the Scar, despite its flaws, I always found it to be a solid weapon, and ended up picking one up. I like my MWS and ACC better, but its a good gun. The MHS has been a shit show from the beginning, and to the laughter of my former coworkers, I just picked one up when I was on leave as I really like the Trigger module being the SN'd part and have plans on turning it into a comp'd, RMR range toy. We shall see how this adventure plays out.

What ultimately gets selected,is not always the weapon that preformed best in testing. Generally speaking, I think that anything that makes it out of down deselects tend to be solid choices.
 

GUNNER10

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Generally speaking, optics are not going to be mounted since most of the subtest are going to be done from a mount. You have to remember they are testing the weapon, not the optics or system.

With that being said, I know a friend of mine told me about a aimpoint that was mounted coming apart. Not sure what optic I am going to mount on mine if I even decide to keep it.
 

GUNNER10

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Geeze! I haven't heard of aimpoints breaking. That takes some serious g forces!
In aimpoints defense, I am pretty sure it had alot of rounds on it on pretty much everything we have in the inventory.

I think the scar may have just been the final straw before it goes up the ghost.

I would still consider an aimpoint on mine