Why not more DI guns?

[JoshNC]

What about the Polymer AR-18.

Aka the G36

Don’t forget the B&T APC 223. It is an AR18 derivative.

[patriot_man]

Don’t forget the B&T APC 223. It is an AR18 derivative.

Yes!! Please hurry with the 16" pistols

[crusader377]

It is a shame that more development was not done with the AR18.

Why? The AR18 was not a particularly good rifle hence the extremely limited production and international interest. The whole purpose of the AR18 was build a cheaper rifle than the AR15 for export. The AR15 was briefly looked at by the U.S. military in the late 1960s and its performance wasn't particularly noteworthy. Furthermore, other countries evaluated it yet no one purchased them yet the AR18 was an extremely affordable rifle. Logic would dictate then that perhaps the AR18 wasn't a good rifle for military use despite it being very affordable.

[vicious_cb]

It's a piston rifle with a receiver captured return spring and reciprocating charging handle. Just those points alone makes it a better overall rifle. Sure it's an older design and definitely needs to be updated but all of that could be easily addressed. The SCAR being AR18 esque' could have been that rifle but they dropped the ball with some of the design elements.

How is that "better"? In almost every thread you post in you seem to remark that piston systems are better than DI . Maybe you just dont understand how and why DI specific to the AR15 exists.

To put it even more simply basically echoing what Clint posted but more simply, the beauty of the AR15's gas system is that all the forces are inline with the bore so everything can just float in an aluminum tube. Now I dont need steel inserts to rails because there is virtually no wear on the inside of the receiver making things simpler and lighter.

Crusader is correct, the only thing the AR18 did that was superior was simplify manufacturing for poorer countries that didnt have the technology to make aluminium extrusions at the time. Much like the AK, you could make AR18s with stamped and welded sheet metal receivers. The AR18 itself is a developmental dead end.

[RetroRevolver77]

How is that "better"? In almost every thread you post in you seem to remark that piston systems are better than DI . Maybe you just dont understand how and why DI specific to the AR15 exists.

To put it even more simply basically echoing what Clint posted but more simply, the beauty of the AR15's gas system is that all the forces are inline with the bore so everything can just float in an aluminum tube. Now I dont need steel inserts to rails because there is virtually no wear on the inside of the receiver making things simpler and lighter.

Crusader is correct, the only thing the AR18 did that was superior was simplify manufacturing for poorer countries that didnt have the technology to make aluminium extrusions at the time. Much like the AK, you could make AR18s with stamped and welded sheet metal receivers. The AR18 itself is a developmental dead end.

Maybe I don't understand why DI in a modern rifle exists because in my estimation- it never should have developed past the proto-type stage. On the surface it seems like a beautiful concept as you point out- a floated carrier group inline with the bore to reduce weight and increase accuracy. However when you look at the design closely you realize it's a completely delicate balance entirely dependent on so many strict factors for functionality that it's simply only possible because of our advanced production capability. However any small factor change, be it spring fatigue, gas port erosion, underpowered ammunition, incorrect buffer weight, environmentally incorrect lubrication, magazine issues, or environmental compromise will result in the system failing. I see the AR18 as designed for what it was, a cheap piston fed weapon developed for foreign nations that has now been modernized across several firearms produced today that are superior to DI rifles. Simply, the M16's time has passed, it has served us very well but the military will move on to piston designs as they rightfully should.

[vicious_cb]

Maybe I don't understand why DI in a modern rifle exists because in my estimation- it never should have developed past the proto-type stage. On the surface it seems like a beautiful concept as you point out- a floated carrier group inline with the bore to reduce weight and increase accuracy. However when you look at the design closely you realize it's a completely delicate balance entirely dependent on so many strict factors for functionality that it's simply only possible because of our advanced production capability. However any small factor change, be it spring fatigue, gas port erosion, underpowered ammunition, incorrect buffer weight, environmentally incorrect lubrication, magazine issues, or environmental compromise will result in the system failing. I see the AR18 as designed for what it was, a cheap piston fed weapon developed for foreign nations that has now been modernized across several firearms produced today that are superior to DI rifles. Simply, the M16's time has passed, it has served us very well but the military will move on to piston designs as they rightfully should.

This is why everyone feels like you dont understand operating systems very well. None of these problems are exclusive to the AR15's gas system.

[crusader377]

Maybe I don't understand why DI in a modern rifle exists because in my estimation- it never should have developed past the proto-type stage. On the surface it seems like a beautiful concept as you point out- a floated carrier group inline with the bore to reduce weight and increase accuracy. However when you look at the design closely you realize it's a completely delicate balance entirely dependent on so many strict factors for functionality that it's simply only possible because of our advanced production capability. However any small factor change, be it spring fatigue, gas port erosion, underpowered ammunition, incorrect buffer weight, environmentally incorrect lubrication, magazine issues, or environmental compromise will result in the system failing. I see the AR18 as designed for what it was, a cheap piston fed weapon developed for foreign nations that has now been modernized across several firearms produced today that are superior to DI rifles. Simply, the M16's time has passed, it has served us very well but the military will move on to piston designs as they rightfully should.

I don't know why people hold onto the myth that the AR18 was good rifle. The only thing it had going for it was that it was inexpensive. Militaries typically like purchasing from the lowest bidder yet no militaries purchased the AR18. You would think such an awesome and affordable rifle would sell well especially during the Cold War where everyone was keen to upgrade their firearms yet the AR18 had no takers. They couldn't even sell AR18s in the third world. So that begs the question why? It is a fact that the AR18 was a very affordable rifle. Therefore the only logical conclusion is that the AR18 wasn't a good service rifle.

In fact, I would argue that the AR18 was probably one of the worst modern service rifles. To further my point the rifle that borrowed the most from the AR18 is probably the British SA-80 and it has the reputation of being probably the worst modern assault rifle.

Also, lets look at its most modern iteration the Armalite AR180B. It could use AR magazines and was less expensive than most ARs, yet it still flopped in the U.S. commercial market which is very price sensitive. It failed to compete effectively with the DPMS, Del-tons and Bushmasters of the AR world even though it was comparably priced and was available when demand for semi-automatic rifles was at its peak. That is not a ringing endorsement to the desirability or capability of the AR-18.

Back to DI vs Piston, Despite it being a 50 year old plus design, the M16/M4 series is still one of the top 5 5.56mm service rifles today. Probably the only rifles that are comparable in overall performance are the SCAR, Beretta ARX, HK 416 (which is more of a cousin to the AR), and maybe a Galil Ace. Lets look at everything else.

Tavor: Goofy ergonomics, Heavy (8lbs empty), worse accuracy than the M4, more expensive, but hey its Israeli it must be awesome.

HK G36: Has a tendency to melt during automatic fire, poor accuracy beyond 200M

CZ Bren 805: A 21st century rifle which no bolt release, Really?, again nearly 8lbs empty weight for a 5.56 carbine, more expensive

Not even going to mention the rest of the bullpups (SA-80, FAMAS, FN2000, etc..) which all have their share of issues

[RetroRevolver77]

This is why everyone feels like you dont understand operating systems very well. None of these problems are exclusive to the AR15's gas system.

Whose everyone? Feelings? What?

I can't honestly think of any other weapon systems that requires such a balance for functionality as the AR15 such that any small deviation of tolerance parameters would render the weapon inoperable. The reason is because nearly all modern rifle systems today are piston designs primarily running over gassed to begin with. A slight deviation from an already over gassed system is not going to cause major functional issues versus one that has to run within a specific range of tolerances in order to function. Hence why I believe the AR18 was an upgrade to the AR15 just as clearly as we see nearly all non AR15 or AK based weapon systems designed today- are essentially AR18 derivatives.

[crusader377]

This is why everyone feels like you dont understand operating systems very well. None of these problems are exclusive to the AR15's gas system.

That is very true. To support your point further, look how many American manufacturers failed to build a reliable AK despite the AK being a 1940s technology rifle that was designed for ease of production.

[MistWolf]

Not sure of the history, but Stoner moved away from it. Aside from that I can only think of 2 or 3 other DI gas designs. I think the piston system is a generally more forgiving system and easier to work around. For example, discussion of gas port sizes are almost unheard of in discussions of piston operated systems. In a DI gun, gas port size is vital.

Eugene Stoner never used a direct impingement system.