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Anything else is being improved. Suggestion - option for quality match grade stainless steel barrels would be awesome. Alex, what do you think?
 

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Get rid of the lightening cuts in the rails. It will make the uppers easier to manufacturer and give better accessory compatibility.

Lighter trigger.

medium contour barrel 1/7 twist.
 

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Get rid of the lightening cuts in the rails. It will make the uppers easier to manufacturer and give better accessory compatibility.

Lighter trigger.

medium contour barrel 1/7 twist.
You nailed it. Lightning cut rails and Larue don't mix... that is bad. Medcon barrel with 1/7 twist.. should have been the default. As for the trigger... no excuse. Still... a real decent first show.
 

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Get rid of the lightening cuts in the rails. It will make the uppers easier to manufacturer and give better accessory compatibility.

Lighter trigger.

medium contour barrel 1/7 twist.
You nailed it. Lightening cut rails and Larue don't mix... that is bad. Medcon barrel with 1/7 twist.. should have been the default. As for the trigger... no excuse. Still... a real decent first show.
I ran an EOTech in a Larue mount on my XCR, no problems at all. No marks on the rails, no problem keeping a zero; it fit perfect. The only thing I've heard of that doesn't work is the KAC VFG.
 

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I ran an EOTech in a Larue mount on my XCR, no problems at all. No marks on the rails, no problem keeping a zero; it fit perfect. The only thing I've heard of that doesn't work is the KAC VFG.
My concern is the design of the Larue mounting system... clearly Mark intended full rails with his design...
 

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The lightening cuts being down the center, I don't see how they are going to interfere with the correct fit of a larue mount. The contact points of mount-to-rail are shaped exactly the same unless there are some other cuts I'm not aware of?

I can see how a KAC vertical grip wouldn't work well. I have a Bobro waiting, which has a much larger contact plate.
 

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The lightening cuts being down the center, I don't see how they are going to interfere with the correct fit of a larue mount. The contact points of mount-to-rail are shaped exactly the same unless there are some other cuts I'm not aware of?
Flip your Larue mount over and take a look... the problem is not interference... its the lack of it. Larue designs their mounts to hold fast at the center of the rail cut... the exact area the lightning cuts have milled away...
 

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I'll find out one day, but can't imagine how that would be accurate looking at a larue mount and non-lightened rail. It doesn't look to me like there is any meaningful contact in the center of the rail.
 

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I have Larue mounts on my XCR and there's not a problem. Ipso facto, lightning cuts aren't an issue. More intarwebz bullshit laid to rest.
 

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I have Larue mounts on my XCR and there's not a problem. Ipso facto, lightning cuts aren't an issue. More intarwebz bullshit laid to rest.
Flip your Laure mount over... do you see the locking tits? They are there to prevent forward and rearward movement of the mount during hard use. These locking tits are in the CENTER of the Larue mount... yep... right where the rail is milled away. If you have a Laure mount... flip it over... it is obvious... just look. Of course... your safe queens will not encounter any problems, but hard use...
 

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Are they not wide enough to contact the XCR rail?
They do not go fully across the mount (like ARMS)... the tits are only in the center... they are designed to grab the rail exactly where the lightning cut has removed the rail... thus my reason I would like to see a full rail without the lightning cuts... especially the rail section over the receiver. When I get my camera back... I will post a picture... the concern is obvious once you look at the size of the tits.. and where they are positioned on the Laure mount.
 
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Although it doesn't really need it, an ambidextrous safety might be cool.
It would also be cool if it had an ambi mag release as well.
 

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I'll say this one more time--move your lips if it helps you to comprehend: Larue mounts work fine with the lightning cuts. I have Larues on my XCR and they don't move. Period. End of story.

I know exactly what the things have underneath. It's more than enough to locate the mount. They have about 3/16" total engagement with the lugs. That's enough to do what they have to do, which isn't really very much. Your tensioning--and consequently your return to zero--is from the cam, not the friggin' lug.

Geezus palomino. This isn't rocket science.
 

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I run an LT104 on one of my XCRs. There is enough contact between the existing rail and the larue "cross bar" to prevent fore and aft movement. Full profile rails would give me much added piece of mind however. I don't know where lightening cuts originated but they are showing up in far too many places for my taste. Even the 556 SWAT has them on the forend. Daniel Defense has long proven you don't need them to make a light rail system.
 

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This is the only applicable picture I have on hand; the underside of an LT129:



Eyeballing it from pictures, it looks like the lug is wide enough to me.... but I can't really tell for sure. I will report when my rifle comes in.
 

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Thanks for the picture... as one can see... Larue placed the locking tits in the center... designed to grab the center of the rail lugs and prevent forward and backward movement. With a lightning cut rail... the center is now milled away. Is there enough meat on the side of the tits to engage a lightning cut rail? At the very best... there may be just enough for the corners to barely engage the angle cut of the rail... certainly nowhere near optimal... and certainly not as the original design intended... thats for sure! I will guarantee you this much... Mark Larue designed his mount for a full cut rail, ask him. Is the minimal engagement of the locking tits good enough for a safe queen or very light use range toy, probably... but "good enough" does not cut it for folks with hard use firearms. I for one would certainly prefer a full rail with my Larue mount, especially the top rail... where the optics mount... YMMV.
 

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I shouldn't feed the troll, but what the hell. I've got a free hour.

Again, if you actually look at the Larue mount and the XCRs rail, you will see it engages the rail quite adequately. The lugs engage about halfway into the heaviest part of the rail. That's enough to do what it's supposed to do. Most of the heavy lifting from the mount's viewpoint is done by the cam. This is a .223 rifle. It doesn't require a whole helluva lot to locate the mount. If it were on a .50, I might be concerned. Not on a .223 or something similar.

As for hard use...hah. The only thing getting hard use here is slag's mouth--or fingers in this case. This whole thing is a non-issue born in the fevered imaginations over in the cesspool of arfkom. Personally, I'd rather this sort of thing stayed over there. I get enough idiocy at work and there's more than enough on the internet. We certainly need no more here.
 

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I have Larue mounts on my XCR and there's not a problem. Ipso facto, lightning cuts aren't an issue. More intarwebz bullshit laid to rest.
QFT.

Regardless of your no doubt thorough "Internet Testing" slag (couldn't resist that one), no one has reported any problems with Larue on the XCR. In fact, its the complete opposite, NO ONE has reported a problem.

On a side note, guess what the new KAC PDW has on its top rail? :p
 

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I shouldn't feed the troll, but what the hell. I've got a free hour.

Again, if you actually look at the Larue mount and the XCRs rail, you will see it engages the rail quite adequately. The lugs engage about halfway into the heaviest part of the rail. That's enough to do what it's supposed to do. Most of the heavy lifting from the mount's viewpoint is done by the cam. This is a .223 rifle. It doesn't require a whole helluva lot to locate the mount. If it were on a .50, I might be concerned. Not on a .223 or something similar.

As for hard use...hah. The only thing getting hard use here is slag's mouth--or fingers in this case. This whole thing is a non-issue born in the fevered imaginations over in the cesspool of arfkom. Personally, I'd rather this sort of thing stayed over there. I get enough idiocy at work and there's more than enough on the internet. We certainly need no more here.
Here is a tip for ya skippy... when folks use the term hard use.. they aren't talking bench resting a rifle... and the hard use it gets from that strenuous 5.56 recoil :D ...

Don't think a Larue mount and a lightning cut rail is a problem? Fine.. but don't go asking Mark Larue's opinion... unless you want the straight poop that is...
 
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