Hypothetical: What Still Needs Fixing?

[Dionysusigma]

The AR design, is (more or less) 60 years old. Since its initial development, it's been frequently and sometimes nonsensically modified, updated, made from almost every possible material, accessorized, accurized, shortened, chambered in as many different calibers as any hunting rifle line, used in every operational environment this planet has to offer, and is still going strong.

Over that time, included in numerous issues that have been addressed are a standard of gas port size requirements; buffer weight; charging handle (from the original "trigger inside the carry handle" to the comparatively-new AXTS); barrel lining, barrel profile, and total barrel composition; trigger/hammer/disconnector/spring group; sights; ergonomics (i.e. furniture options); and countless others. And all have been, more than with any other system ever in such widespread use, cross-compatible with nearly every variant produced. A person could put a BCM GFH Mod 5 charging handle on a Colt 601 (however blasphemous it might seem).

But what, in your opinion, still needs fixing? What glaring (or mildly annoying) issue bothers you? How could it be changed?

To simplify discussion, let's try to limit the possibilities within the following:
- STANAG magazine compatibility
- Mechanically safe (e.g. no paper-thin chamber walls or skeletonized uppers)
- Remain within the "small arms" definition (nothing crew-served, portable and usable by one person)
- Be fully compatible with the majority of another AR - several push this envelope, from the fully ambidextrous lower of the SR15E3 to super-short PDW systems, but may be included because they can still be "mated" with the other half of the system
- Use materials that currently exist (no Star Wars Durasteel bolts or using antimatter instead of H335!)

Edited to add: This is all made from the assumption that the AR operating system (for lack of a better descriptor) is the pinnacle of firearms development. For the sake of argument, let's maintain that bias. The Sig MCX thread comes to mind...

[lysander]

Personally, I think they have been ruining it since 1980.

They started with a rifle that worked, and weighted a tad over 6-1/3 lbs unloaded, and a tad over 7.3 lbs with a full magazine and sling.

But, now they have a carbine that has 5.5 inches less barrel, shoots bullets 300 fps slower and now weighs slightly more, burns through bolts in 5000 rounds, and isn't quite as reliable as the M16A1*. The M16A4 weighs the same as an unloaded M14....



* In 1968 the US Army testing reported a Mean Time Between Stoppages at around 4200 to 4500 rounds (http://www.dtic.mil/docs/citations/ADA953116), the M4 has about 3600 MRBS (https://peosoldier.army.mil/docs/Wea...r-Oct%2009.pdf)

[opngrnd]

http://www.dtic.mil/docs/citations/ADA953116[/url]), the M4 has about 3600 MRBS (https://peosoldier.army.mil/docs/Wea...r-Oct%2009.pdf)

I'd be interesting in how today's mid-length gas system offerings compare with current mags (e.g. Magpul M3) and properly lubed(e.g. VTAC Rand CLP).

[sinlessorrow]

Personally, I think they have been ruining it since 1980.

They started with a rifle that worked, and weighted a tad over 6-1/3 lbs unloaded, and a tad over 7.3 lbs with a full magazine and sling.

But, now they have a carbine that has 5.5 inches less barrel, shoots bullets 300 fps slower and now weighs slightly more, burns through bolts in 5000 rounds, and isn't quite as reliable as the M16A1*. The M16A4 weighs the same as an unloaded M14....



* In 1968 the US Army testing reported a Mean Time Between Stoppages at around 4200 to 4500 rounds (http://www.dtic.mil/docs/citations/ADA953116), the M4 has about 3600 MRBS (https://peosoldier.army.mil/docs/Wea...r-Oct%2009.pdf)

I see people say it burns through bolts in 5,000 rounds. The issue I have with that is the Maintenance Schedule calls for replacement of the bolt at 10,000 rounds.

So who's right? Random internet users or the mandatory maintenance schedule?

[turnburglar]

I see people say it burns through bolts in 5,000 rounds. The issue I have with that is the Maintenance Schedule calls for replacement of the bolt at 10,000 rounds.

So who's right? Random internet users or the mandatory maintenance schedule?

Why can't both be right? 5-10k isn't a very large number to begin with. Some people would be replacing their bolt every year or two. That's hardly ideal.

I think the Arak bolt/barrel extension combo would be of benefit. But really why make these small changes? Why not just build a gun from the ground up that can handle the cartridge we want? The original ar15 was made for 222 rem, and now it appears 556 is pushing the limits of pressure and OAL.

Pick cartridge

Design gun.

[lysander]

Why can't both be right? 5-10k isn't a very large number to begin with. Some people would be replacing their bolt every year or two. That's hardly ideal.

I think the Arak bolt/barrel extension combo would be of benefit. But really why make these small changes? Why not just build a gun from the ground up that can handle the cartridge we want? The original ar15 was made for 222 rem, and now it appears 556 is pushing the limits of pressure and OAL.

Pick cartridge

Design gun.

The problem was the design of the case was insufficient from the get-go. The original military minimum estimate for effectiveness was a 55 grain bullet going 3300 fps at the muzzle, and required a max pressure of 50,000 psi. The .222 Remington was just a little too small to get that kind of performance, so Armalite moved the shoulder forward .017", and with selected powder loadings, 3300 fps could be reached while staying below the 50,000 psi limit. Springfield Arsenal suggested that the shoulder be moved forward another .030", so the case would be more versatile in powder choices to reach the 3300 fps speed and stay under 50,000 psi. But, Armalite did not feel like lengthening the magazine, so the longer case was quietly dropped. Then later it turned out that you actually cannot reliably get 3300 fps out of a .223 case and stay under 50,000 psi, so they bumped up the maximum allowable pressure, and then had to again when they went to the heavier bullet to keep the velocity up in the shorter barrel.

.222 Magnum (Springfield's suggested case) is more than capable of pushing a 55 grain bullet to 3300 fps with a wide range of powders and stay safety below 50,000 psi, also with the 62 grain bullet get 3200 fps and stay below the 55,000 Piezo/52,000 CUP limit of the original M193.

[Benito]

I'd like to see four particular improvements-
- Easier way to lock the bolt back without a mag
- The charging handle moved to a more convenient location
- A lightweight adjustable buttstock with a cheek piece like that used on the UBR
- The death of metal handguards

What's the issue with metal handguards? The newer M-LOK and KeyMod units are light and strong. Are you thinking of carbon fiber or something?

There are some very good suggestions listed so far.
Stronger bolts (reduced cam pin hole, stronger materials, etc), longer gas systems, not relying on the barrel nut to attach the handguard, etc. No argument here. Obviously a cost benefit analysis is required, but those would all definitely be beneficial in my view.

[BufordTJustice]

The problem was the design of the case was insufficient from the get-go. The original military minimum estimate for effectiveness was a 55 grain bullet going 3300 fps at the muzzle, and required a max pressure of 50,000 psi. The .222 Remington was just a little too small to get that kind of performance, so Armalite moved the shoulder forward .017", and with selected powder loadings, 3300 fps could be reached while staying below the 50,000 psi limit. Springfield Arsenal suggested that the shoulder be moved forward another .030", so the case would be more versatile in powder choices to reach the 3300 fps speed and stay under 50,000 psi. But, Armalite did not feel like lengthening the magazine, so the longer case was quietly dropped. Then later it turned out that you actually cannot reliably get 3300 fps out of a .223 case and stay under 50,000 psi, so they bumped up the maximum allowable pressure, and then had to again when they went to the heavier bullet to keep the velocity up in the shorter barrel.

.222 Magnum (Springfield's suggested case) is more than capable of pushing a 55 grain bullet to 3300 fps with a wide range of powders and stay safety below 50,000 psi, also with the 62 grain bullet get 3200 fps and stay below the 55,000 Piezo/52,000 CUP limit of the original M193.

I'm going to assume that there isn't much room to push the case neck any further forward in the 5.56 case without increasing the OAL of the case?

[skp]

I see people say it burns through bolts in 5,000 rounds. The issue I have with that is the Maintenance Schedule calls for replacement of the bolt at 10,000 rounds.

So who's right? Random internet users or the mandatory maintenance schedule?

Seems like both could be right? The schedule calls for replacement at 10,000 but sometimes they fail at 5,000, presumably due to the hotter loads.
When was the maintenance schedule written anyway? Could have been a long time ago.

[sinlessorrow]

Seems like both could be right? The schedule calls for replacement at 10,000 but sometimes they fail at 5,000, presumably due to the hotter loads.
When was the maintenance schedule written anyway? Could have been a long time ago.

It's the most recent revision for the M4A1. Not sure on the exact date of the revision though.