Oh ya? I have a cmmg kit id love to run with mine

Yeah reloading is definitely the way to go when playing around with any type of machine gun. Been meaning to get into it myself but just haven’t found the time nor space to set up a proper loading room. Until then, I’m stuck with factory ammo :-(

Wow! This thread has some great info in it for LL users. Can we get it stickied?

I should be getting my approved RLL paperwork in the next week or two. Lots of prep work to do... Im excited! But I’m a seeing a lot of talk in the last few pages here about not letting the link teeter-totter over the safety barrel. Every one of my half-dozen lowers have shelves that sit a bit lower that the top of the selector barrel.

How big of a problem is this?

The shelf heights range from about 1/16” to 1/8” lower than the barrel top just using a machinist scale to judge. Although realistically I don’t plan to bounce the RLL between all my ARs. I really only plan to use the RLL in a non-NFA M4 clone lower with a modded burst FCG probably 95% of the time as the dedicated host. I also have a .300blk PDW SBR with a AR15 FCG that might see occasional RLL use, but .300blk full auto is $$ to shoot F/A. All my other AR setups will likely never see the RLL.

Planned uppers are:
10.3” carbine 5.56mm
14.5” carbine 5.56mm
5” 9mm Radial Delay
7.5” .300blk (PDW lower only)

Its not a big problem if you don't plan on using a protector and/or don't mind milling the rear lug on the upper.

You generally have three options.

1. Don't use a protector and run the link as it was design.
2. Use a protector but mill down the underside of the rear lug on the upper for clearance.   (Not a huge deal on standard uppers but can become unappealing to start grinding on expensive upper like a Shrike, FM9, or original Hk416 upper, etc.)
3. Use a protector, don't mod the rear lug on the upper and instead mill down the selector barrel for the necessary clearance.  (easy to do on a Safe/Full-Auto setup, much more involved on a safe/semi/auto setup)

With the link sitting lower you also get the added benefit of more clearance on the hammer potentially hitting the link as it teeders upward on the disco side when rocking over the selector barrel.

I also always recommend folks run reduced power disco spring(s) as it take a lot less force to pull the disconnector back, which in turn is less strain in the link itself.

Hope this helps.

I just wanted to share some info I dug up since this seems to be the best RLL thread here...

You DONT have to shave the rear lug of your receiver if you plan to use a KNS RLL Protector. If your shelf is low enough, you can simply shave the bottom of your paddle and it will be fine. Credit for this concept goes to a post I read by @coolhand - https://www.ar15.com/forums/armory/_ARCHIVED_THREAD____Safe_to_use_LL_w__9mm_DOE_gun__NOW_with_PICTURES_and_INSTRUCTION/23-392405/&page=1#i3646094

My lower has a shelf that is approx .630 deep. Upper receivers wouldn’t even close on this lower with a protector/RLL installed. I measured about .010” of excess length preventing the upper from even closing, let alone allowing the RLL to move freely.

The tabs on the bottom of the paddle are about .090 tall, so I shaved the bottom by .045, leaving .045 thick tabs. I probably could have shaved less off, but I wanted to make sure it really could freely.  Clearance was fantastic. I ran unmodified Colt, DD, and Fulton Armory uppers on it with zero hiccups. Operation was smooth and reliable. Picture below has about 250 rounds on it and the little tabs aren’t bent at all.

Attached File

Thanks for posting this! I had never seen that prior post from years ago. It follows the rule to always modify the cheapest part. It seems so obvious now!

Esox

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