Gotta ask for some advice here.

Have a RR and the lower is solid. Have some uppers that are ok, but thinking of how to best mimic an IAR concept.

LWRC A5 16” upper? Adj gas block, piston, heavy barrel for either 500ish yd accurate area suppressive shots, 0-500+ aimed shots, and everything in between. Have short and longer uppers for some scenarios but would enjoy a breath of fresh air for practicality when ammo is reasonable again. Looking to have some fun at my neighbors place where I have access to 0-500 yards and I can shoot all I want 24/7.

Will be NV capable, would like to try distance shooting with active nighttime aiming.

Id like to go piston so there is less heat and fouling in the upper. Also will be 50/50 suppressed/unsuppressed. Got D60s, might get beta mag, shrike/mcr im not interested in at this time.

I have and enjoy PWS products but they appear to be lacking in the heavy barrel options. Id prefer MLOK, but am willing to deal with LWRCs lack of MLOK adoption.

I am capable of assembling a DI setup with correct parts but fuck all that, both for reasons mentioned above and Id rather throw money at this problem to scratch my itch.

Im gtg for optic and bipod and lasers and lights and shit, concern here is the core of what I want.

1. Am I on the correct track here with L Dub and piston for my concerns?

2. What would you do?

3. Obv focus is FA and I think some PWS stuff is no longer FA so if thats the case have “PWS call me”.

TIA for whatever this topic produces.

FelixJr001

I went with an 18" heavy barrel rifle gas setup, melonite gas tube, standard weight BCG, 13" KAC URX 3.1, Keymo flash hider, Sandman-K, ADM mount and 1-6.5 Bushnell SMRS II on top.

I figure barrels are a wear item and it's easier to replace standard AR barrels than piston barrels.

For mags I have D60's and a SAW-MAG.

I've currently got it on a regular AR lower with FRT-15 trigger, AH52 buffer and sprinco green spring.  I built it for my M16 lower, but it runs so well with the FRT, there's no reason to swap it out.

Awesome post thanks Jaq and congrats on joining the transferrable club. I enjoyed your GD posts about your new purchase. Have lots of spare uppers for mine, 20”, 7”, 14.5” m4 clone, 16” 300, but nothing like an IAR concept and have some fresh accessories for this. I just want an upper to scratch multiple itches and still have the option to ding steel @ 4-500 repeatedly and in the dark.

Have MAWL and Gripstops and bipods and LPVO or dots and magnifiers for whatever new upper I roll with so this is more of a “do all”. Plus having some potential accurate distance shots without melting my barrel parts in between mag dumps.

#closedboltmgs

Thanks. I've always liked light machineguns and automatic rifles. I'm looking forward to seeing what you put together.

Will update this thread and eventually post pics once I know how not to dox myself with them lol.

Eta spelling correction

1) Get the heaviest barrel you can find
2) Piston gas system is a plus but not necessary. The majority of the heat is in the barrel which a piston does nothing to stop. Really only necessary if you plan to run suppressed as the action can dry/gum up after hundreds of rounds suppressed.
3) Go with a heavy duty picatinny rail. I tried a Keymod rail on my homebrew LMG and the bipod and other attachments would come loose regardless of how much loctite i put on everything. M-Lok might be better, never tried it, but picatinny rail will never have issues and on a build like this where you are running big a$$ drum mags and rocking a heavy barrel the weight savings going from picatinny to M-lok is not noticeable.
4) A M27 clone would be fun but probably not worth the money, genuine HK parts are stupid expensive.
5) The MCR is expensive but you get a lot of bang for your buck. Dual feed, piston, heavy barrel, quick change barrels....its the ideal LMG (at least in the transferable MG world where access to modern belt feds is limited). I dont own one as I could never justify the price, for $4k+ I would rather own another MG for that price, but now that entry level MGs like MACs are pushing $8k and non-colt M16s are running in the $20-25k range it doesnt feel as bad. With that said, it does have a history of reliability issues, primarily feeding rounds due to tight links and low power/velocity ammo.

If you ever go that route check out this product from KNS. Allows you to swap out the bolt catch without hammering a roll pin.
https://www.knsprecisioninc.com/product/kns-precision-inc-bolt-catch-retaining-pin/

Thanks for the replies so far fellas.

This is what I did for my IAR build:

That’s fantastic MBell, very nice. My friend has an lwrc upper similar to the concept I had and were waiting on the right place to try it out with some d60s at ranges 50-500m.

Ahhh...why not a 416/MR556/IAR upper?

The MR556 barrel is probably not ideal, but there are chrome lined barrels available.

This is as close as I have to what you are doing. This picture isn’t with my RR but it is pretty fun with a beta mag and the RR. You'll definately want an SSF trigger for the longer range stuff. I was hitting an 8” plate at 300 with cheap 193 ball ammo rapid fire.
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Upper details?

14.7” LWRC piston.  I have a couple of these and this one is my current truck gun with the semi auto lower.
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I went the MCR route and it’s pretty awesome. My M16 is still in jail but I tried it out on another guy’s converted lower and it ran great. I originally bought the MCR for use with a binary trigger and the action is just too sluggish to keep up when feeding from a belt, so legit full auto it had to be.

This is a really great thread, some great advice in here, making me rethink a few things.

I think the most overlooked component of the Colt LMG is the gas tube.  It isn't just 'heavy' but it has a larger ID with more volume than any commercially available gas tube and are basically unobtanium....

That large VOLUME gas tube plays a major role in it smoothness and slow rate of fire.

That is something I don't see discussed on this thread....cyclic rate.

Now I understand everyone is different in this regards but I personally like all my MG's to run in 600's - 700's.  I like to be able to pull singles, double's, triples at will.  It is just too hard to consistently do that once you start going too fast.  (Exception would be 22LR machine guns....I'm just happy if they work).

I have a Shrike as well and have mine tuned to run in the 600's.  However, with the Shrike and any piston gun I personally just find them not as smooth as a standard gas operated setup.

Pictured below shows the smoothest full auto suppressed 556 setup I have.  Custom large volume gas tube on a 16" rifle length gas barrel, Surefire OBC (designed by Jim Sullivan) which uses an improved cam pin geometry to increase bolt lock time, extended stroke length (I don't know if any piston guns have this feature, although most piston guns do have an integral impact lug on the carrier and you may be able to possibly replicate this) and lastly the carrier has a spring loaded carrier weight to increase lock time on the forward stroke and further delay the carrier on the rearward stroke.

Combine that with 556 Tubb flat spring which I have proven on my site also slows down the cyclic rate while also not reducing reliability.
Flat springs provide a more consistent force than round springs. The delta in force between bolt open and closed is less.

The Surefire OBC comes with it's own buffer in order to have an extended stroke intended to be used in a standard carbine length buffer tube.
In my case, I'm using an A5 buffer tube which is longer so now I can use any carbine length buffer plus a spacer equivalent to about 2 quarters.  In my case, I use a custom delrin spacer to prevent the gas key from impacting the lower.

Buffer is a hydraulic Kynshot RB5005 which I prefer over their RB5000 for a scenario that calls for a carbine length buffer and tuned gas system.

Gas block is an old MicroMOA Govnah ported for the optimal size for this suppressor.

End result is a cyclic rate of 576 RPM with LC M855 that is super smooth and no gas to face.  Even my buddies that are lefties said they detected no gas.

I need to give one of the Surefire OBC's a try.

Tag.

I have been exploring this concept but for use in feral hog eradication. I trap them in a Jager Pro trap but I have found the next best way to really put them down in bulk is to condition a group to a bait site where the feed is in one small spot. They have to bunch up real tight and I can normally get within 50-75 yards of them.

I initially started to play around with a LMT MRP, 16” middy and FRT-15. I put 5 small sized pig targets at 50 yards and would do quick sweeps across them to get an idea how many hits I could get per sweep. It was always at least 4 of 5, but most of the time 5 of 5. This is where I differ from you guys on ROF. I really want this as fast as I can control it. I shoot off a RRS tripod with Anvil-30. The more rounds I can dump into a sounder in that 2-4 seconds before they bolt the better off I am.

Here I am practicing sweeping the pig targets.


Here is 10 rounds on a huge rock at ~ 120 yards, shooting off the tripod. Wanted to see what kind of dispersion I would get. I went down and most if not all of those 10 shots would have fell into an adult pig.

If you don’t want to see pigs meet their demise, don’t watch these clips. I don’t hunt pigs like one would deer. The goal here is to kill as many as possible, no different than fireants or rats.

This is generally how it looks. Granted this is only 4 pigs but all were dead within 100 yards. There is no way I could have hit all four with a normal SSA trigger.




Something else I have noticed is usually 556 is meh on a running hog of decent size. But a very quick 2-3 hits even on a huge pig will put them down when they are running.




I found 12 dead ones within 200 yards using the drone after this. Most of the dead ones were from that initial good burst or two. They just ran a bit before falling. This is the big pig that dropped DRT when running that was nearest to me. You can see the 2 impacts in her side.





And here is what a very quick burst on some juvie pigs looks like from the drone. 5 killed that I could locate within 50 yards. I suspect a 6th was hit but traveled some. Drone battery was about to die so I didn’t look.



IMHO full auto or FRT’s have a solid place in hog eradication. I’ve had a HK DLO trigger box in transfer for some time now. I kinda wished I had bought a RDIAS as I have since picked up a HK MR223A3, 14.5” barrel. That thing suppressed would be ideal for what I am doing.

That's the beauty of the M16 platform.  Very easy to change the cyclic rate to your desired needs.  I like the 600-700 RPM range but making it go in the 900 or 1000RPM range is really easy.   Getting them to be slow and smooth is hard.  Fast and smooth is pretty easy.

ETA...I wonder how a drum fed 7.62x39 full auto would do with the hogs?  I've got a 16" 7.62x39 upper setup for hunting that I haven't run yet.  Using modular MGI lower that takes unmodified AK / Mags drums.

Could you use a couple pounds of tannerite & some coffee cans full of nails & other sharp objects to eliminate the group? One well placed shot...

If I were down state or some place like Texas, I guess so. Around where I live, doing so in the middle of the night wouldn't go over that well.

I am sure it would do fine. That is probably the ideal caliber to bust hogs with IMHO. I had looked at getting a 7.62x39 host for my DLO trigger box but the ROF on those is so slow, it is really just a bit over semiautomatic. If the FRT stays legal, that would be ideal. I can use it in areas where noise isn't an issue then I can keep the DLO box and use an MP5 suppressed on pigs up close and near homes (would be super quiet). I've killed a lot of hogs with 9mm. Good JHP's and inside 75-100 yards it will kill them as dead as anything else.

Have been looking to match this guy with an upper for a build.