Homogeneous modular rifle

that's why every maker and their mother has a new line of modular multical platforms

>An open bolt AR isn't hard to do
The problem is over time the holes holding your fire control group start to egg out. It's a long-term maintenance issue for the Canucks. The Danes wanted their model closed-bolt, so they don't have that problem.

>qd barrels for the AR platform seems like a no-brainer
There are a couple-three already out there. And every single goddam one of them requires you to be verrrry careful about the gas tube and how it fits in its little hole. They're a convenience for range shooters IMHO.

You're never going to have a belt fed AR, so you may as well save the swappable barrels for a belt-fed weapon. Best you can do is put an aluminum heat sink on the barrel and use a nitrided gas tube, and possibly use one of those sprung-tungsten-weight recoil/ROF reducing buffers. That way you possibly have something that can emulate the performance of an LMG for a few crucial minutes.

Source: I got deeply into the topic a couple months ago and researched the living hell out of every single attempt since the 1970's to turn the M-16 into a support weapon.

Attached: colt lmg fire control function.png (529x765, 249K)

thanks, pedophile

ar's arent very well suited to being a light machine gun. open bolt operation, and quick change barrels are desired in that role to deal with the extreme heat of sustained full auto fire. belted ammunition is also more compact to carry than large drum magazines, and belt conversions of ar's are rarely reliable.

What I was thinking is actually a bit different. I haven't started machining yet, or else I would show you. But essentially, for the qd option, I want to go with an Adams Arms piston set up. The pic rail on the gas block will just slot into a rail that will extend out from the receiver to it. What I've come up with is an extruded rail length, mounted by screws to an upper flat top. Not a picatinny flat top, but with the pic "ladders" cut off of the upper. So it's solidly mounted. The full length rail will also index the piston rod, so it doesn't have to be messed with.
>belt fed
I'm still sorta unclear on this, as far as the automatic rifleman, goes. Mounted, or emplaced, belts make sense. But unless it's hard mounted, you need a third arm to get it all done efficiently, but mags you just pop in and out. With practice, a mag change should take two seconds, tops. If I can find an actual reliable AR beta mag, I think that would have more value if you're moving around constantly with it. Maybe I'm wrong, but either way, it should be a fun summer project. I have a slab sided upper that I bought by accident not realizing that meant it didn't have a dust cover mount either, so if it turns out to be shit, it's no loss.

Im still convinced this can be done, and well. To avoid the key holing issue for trigger group parts, I don't see why an actuating bar that blocks the bolt's forward movement couldn't be recessed in the space behind the mag/bolt catch, in place of using the bolt catch itself.

Attached: open bolt machine gun.png (1348x470, 57K)

>start to egg out
that seems like such a simple problem to fix though, either just enlarge the holes or if that isn't enough have the pins not turn and instead have the components turn on the pins, steel on steel, i doubt you'd see any wear issues.

The M16 and M4 are really good at being infantry rifles, but the nature of the gas system means they're just subpar inherently for something like a squad automatic weapon, and you're basically forced to have an all new receiver for a 7.62mm weapon anyway, so that shits on this idea already.

This. The Stoner 63A would have been a much better gun if it had solely focused on being a belt-fed squad automatic weapon.

Yeah, good at being rifles, with a bit of effort and money they also make great precision rifles, due to how easy they are to free-float and how the fully inline action is inherently good for precision.

For lots of bursts and sustained fire, you will get a very hot gun in not that long time, there was various attempts to make a light machinegun out of the M16 and it just didn't work out.

The bolt gets fucking hot.

fightlite.com/uppers/mcr-1

Belt fed has been done a long time ago....

There is literally nothing left to AR variant that is in a 7.62 or 5.56 caliber.

A short-stroke piston would improve things, but I think for being a SAW, you still want a stronger receiver. There's a reason why the RPKs have reinforced trunnions.

>reliable Beta mag
There is the Armatac SAW 150, which is an excellent piece of kit, holding 150rds, and unlike the Beta mag, it's both highly reliable, and it doesn't break if you sneeze while being in the same postal code. It also makes your gun look like a big cock and balls, which is great.

There's a few issues here though, one is that these are expensive magazines ($400+), they are high quality and the pricetag reflects this, two is that they're fucking heavy (5lbs empty, 8lbs loaded), this will no doubt assist with recoil to a point, but you're still carrying a heavy drum, and some rifles may actually struggle to properly engage and retain the magazine due to its heavy weight, you really want to put your weight on the gun and make sure you hear the magazine catch click.

I think that Magpul 60s are an ok compromise, lighter, cheaper, and still reliable, and 60 is passable for a light support weapon.

Attached: Armatac SAW drum, 150rds.jpg (1920x764, 570K)

>There's a reason why the RPKs have reinforced trunnions.
yeah and that is because the AK has weak as fuck receivers that tend to crack fast, on AR's the receiver almost never breaks, the bolt and cam pin are the weak parts, one receiver can last many many bolts and cam pins worth of shots

Everyone needs to realize that what kept the AR in service so long is the fact that it's too fucking expensive to replace it. There was a M4A1+ program that got shut down simply because the changes that would enhance the M4A1 would introduce parts into inventory that would not be interchangeable with legacy parts.

If you need to change the issued rifle to be able to accept the different uppers then the project is dead on arrival because you're better off just adopting different designs for every purpose.

If the AR derived designs you adopt with the proper changes are not interchangeable... then what was the point of the exercise in the first place?

the holes won't egg out from rotation, it's the reaction force of interrupting a firing cycle that gets transmitted into the pins and therefore from steel into aluminum.

>the holes won't egg out from rotation, it's the reaction force of interrupting a firing cycle that gets transmitted into the pins and therefore from steel into aluminum.
i see, well, up sizing the holes would still help, maybe up size and press in steel collars? i guess they want to use standard lowers though it's not like drilling a single hole a bit bigger ought to be a big deal

lmao what the actual fuck

Larger diameter pins, more wall thickness where the pins fit.

And don't some ARs already use larger diameter pins? I know I've heard of that, but I don't know what they are for.

Because your typical LMG is expected to go through hundreds of thousands of rounds over the course of decades

The AR15 can be a belt fed system, and can be set up to do regular sustained fire, but everything in the lower receiver would need to be substantially beefed up, whivh would drastically increase the costs and make maintenance difficult, while still not performing as well as something thata been from the ground up, designed to be a LMG

Yeah you can have guns like the RPK and M27, but despite what Ian and Carl think, and the Muhreens fucking brain trauma making them think its a good idea, 30 round mags do not make a good sustained fire, suppressive weapon

Its better to make a lightweight belt fed system and let things specialize as they can, diversify rolls and load outs, but cross train such that should the marksman guy go down, nobody in the fireteam is unable to take out a haji popping mortars 500 meters away

>Everyone needs to realize that what kept the AR in service so long is the fact that it's too fucking expensive to replace it.
The M16 and M4 do what they need to do though, and they aren't bad guns, that they have a large industrial base and chain of logistics is just good.

It's like the idea of replacing the M2HB, why do that when it does everything it needs to?

>but despite what Ian and Carl think
I'm wondering if they're coming to that conclusion by thinking about old automatic rifles, like the Zb.26, where a 20rd magazine of 7.92mm Mauser was state of the art, because it was a mobile automatic weapon in an age where people were still doing bolt-action rifles as their mains.
Love Ian, but sometimes he has some crazy ideas.

Russians are using some kind of quad-stack magazine for their current RPK-74M, which gives more than just 30rds, so that seems like it could be viable (the longer barrel does count for something too), even if it's not overall as good as something like a Negev.
The M27 I heard was meant to be used with MagPul 60 drums, but I also heard the M27 wasn't really intended to replace the M249 in reality, but that it was an excuse to have a new rifle.

Attached: RPK74M.jpg (3000x2000, 2.16M)

the M27 IAR program was meant to have a closed/open bolt switch setup

closed bolt in semi auto
open bolt in full auto

but HK spent enough money to have that requirement dropped so that they could win the contract

the LWRC was originally going to win

It's not a dig at the AR design, simply stating that the work involved in trying to refurbish existing inventory so that it can take the beating from a SAW system would suddenly make an AR replacement viable because you're sweeping the existing logistics/supply chain out from under the AR's feet.

From what I understand the Marines want to keep 1/3rd of their SAWs, right?

I know the initial proposition, yeah, but it was supposedly all just a smokescreen so they could have a new infantry rifle, and that they don't use it as a squad automatic weapon at all.

The muhreens are pretty much still holding on to the M249s, yeah. Maybe they're scrapping some of the completely shot out ones, but they're still doing that thing.