The AR15/M16 gas system problems and the Rhino system

Not open for further replies.
The last two pictures show two bolts wiped after shooting 1340 rounds of high quality maufactured ammunition. One is the bolt with the gas rings as used in the regular rifle, it is completely gunked with carbon, the one without gas rings is used in a Rhino converted rifle.
Last edited:
Stoner went to a gas piston/op rod design on the AR-180. I cannot think of another weapon system that uses the M16 gas system, which shows that it was not highly though of by other design groups.

Converting a AR to an operating rod sounds good, but this system would needs to show more developmental testing.
All I can say is "what problem?"

There's nothing wrong with the AR-15/M-16 the way it is. Hell, my home-built AR-15 was more reliable than my Vector AK AND my Yugo SKS.
Interesting tech, but since it's not broken, why fix it?

Sure the standard bolt is dirty, but contrary to popular misconception the AR15/M16 is a dirty girl, and she doesn't mind being dirty as long as she's wet.
The last two pictures show two bolts wiped after shooting 1340 rounds of high quality maufactured ammunition. One is the bolt with the gas rings as used in the regular rifle, it is completely gunked with carbon, the one without gas rings is used in a Rhino converted rifle.

I have to say I question the honesty of that.

I have fired into the 1200-1400 round range in a weekend carbine class using M193 and my bolt was nowhere near that gunked up after a simple rag wipedown.

That looks more like 10,000 rounds....... or 1340 rounds of Wolf :)
The biggest problem with piston systems is the loss of accuracy due to a large reciprocating mass hung off the barrel. A gas impingement AR-15 can easily be tuned to shoot 1/2" groups or less, something existing piston systems can never do.

To make a piston system accurate, you need to hang it off a free float tube, not off the barrel.
I like it.
Sounds like a wise addition to the AR-15 family. Not big, not clunky, and it's only a simple modification.
Now to solve the forward assist problem...
The AR-15 is a workable rifle. It's good enough to keep using. But it's not the best. The golden jewel would be a rifle with AR like accuracy and the peace of mind of a gas piston rifle.
I believe the biggest problem with the AR is it's inability to function as well as an AK in dirty/sandy conditions due to tight tolerences, which are also what make it such a great and accurate gun compared to the AK. So it is really a trade off between maintenance and accuracy. The DI system doesn't seem like it causes that big of a fouling problem, I mean you should clean and inspect your rifle routinely when you life depends on it right?
i wonder how many times we've had ARs malfunction in combat over the past 5 years or so in Iraq.

Surely some of the people who continue to spread this FUD can provide statistics. I haven't even heard any "some guy my brother knows had his gun jam in teh sandbox" anecdotes.

Seriously, are the M4s in dirty, sandy Iraq malfunctioning at a greater rate than the ones in Afghanistan? or here in the US?
so where can I get this system for trial on my AR15?


-my ar15, for some reason, doesn't shoot very good groups, so I am not adverse to any supposed "inaccuracy" this piston system would impart on my gun.
Most of the people trying to fix the 'problem' of the DI AR don't realize this:

ARs quit working because of external dirt, mud, dust getting into the weapon and binding up the tightly toleranced bolt/bolt carrier/barrel extension system.

How often are ARs FIRED enough to quit working? The piston solves a very minor (stoppages caused by powder fouling) reliability issue with the AR, at the cost of proprietary, expensive, and untested parts. BSW
Guys, you can't get the Rhino system anymore. That article was published in 1981.

There are a number of companies today that offer a more robust version of what they were trying to attempt with the early Rhino systems.

Bushmaster recently announced their gas piston upper. HK has the 416 system which is a gas piston upper and POF USA has a really slick gas piston upper. Unlike the old Rhino system, none of these uppers are "conversions" but are newly manufactured uppers designed to be gas piston driven.

Here's the Bushmaster gas piston setup:


POF is even doing it for .308 AR's... and it looks NICE:

I started this thread as a tribute to a friend and an american patriot.

Sure there are now many available systems.

There is a need indeed;


A December 2006 survey, conducted on behalf of the Army by CNA Corp., conducted over 2,600 interviews with Soldiers returning from combat duty. The M4 received a number of strong requests from M-16 users, who liked its smaller profile. Among M4 users, however, 19% of said they experienced stoppages in combat – and almost 20% of those said they were "unable to engage the target with that weapon during a significant portion of or the entire firefight after performing immediate or remedial action to clear the stoppage." The report adds that "Those who attached accessories to their weapon were more likely to experience stoppages, regardless of how the accessories were attached [including via official means like rail mounts]." Since "accessories" can include items like night sights, flashlights, et. al., their use is not expected to go away any time soon.
US Army Ranger Capt. Nate Self, whose M4 jammed into uselessness during a 2002 firefight after their MH-47 Chinook was shot down in Afghanistan's Shah-i-kot Mountains, offers another case. He won a Silver Star that day – with another soldier's gun – and his comments in the Army Times article appear to agree that there is a problem with the current M4 design and specifications.

March 4, 2002. An RPG tore into the right engine of an MH-47 Chinook helicopter loaded with a quick-reaction force of Rangers in the Shahikot Mountains of eastern Afghanistan. The Chinook crashed atop Takur Ghar, a 10,000-foot peak infested with al-Qaida fighters.
Enemy fire poured into the fuselage, killing Rangers even before they got off the aircraft. Capt. Nate Self crawled out.
“As soon as I got off the ramp, a burst of rounds fired right over my head,” he recalled.
He joined a handful of his men in the open, exposed to enemy fire. An RPG exploded within a few feet of their position.
“We got up and started firing and moving to some boulders 15 meters away,” he said.
Once behind cover, Self tried to fire again, but his weapon jammed.
Instinctively, he tried to fix it with “immediate action,” a drill he’d practiced countless times.
“I pulled my charging handle back, and there was a round stuck in the chamber,” he recalled.
Like the rest of his men, Self always carried a cleaning rod zip-tied to the side of his weapon in case it failed to extract a round from the chamber.
“There was only one good way to get it out and that’s to ram it out with a cleaning rod,” he said. “I started to knock the round out by pushing the rod down the barrel, and it broke off. There was nothing I could do with it after that.”
The Rangers were fighting for their lives. Self left his covered position and ran under machine-gun fire to search for a working weapon.
“I just got up and moved back to the aircraft because I knew we had casualties there. I threw my rifle down and picked up another one.”
Self was awarded a Silver Star for his actions that day.
When even highly trained infantrymen like Self have problems with their M4 it is a sign there might be a problem with the weapon, not the soldier.
The problems had become obvious enough that at the time of the Afghanistan battle, members of the Army’s Delta Force had begun working on a solution. Today, Delta Force is fighting in Iraq and Afghanistan with a special carbine that’s dramatically more reliable than the M16s and M4s that the rest of the Army dependsupon.
Members of the elite unit linked up with German arms maker Heckler & Koch, which replaced the M4’s gas system with one that experts say significantly reduces malfunctions while increasing parts life. After exhaustive tests with the help of Delta, the H&K 416 was ready in 2004.
Members of the elite commando unit — formally known as 1st Special Forces Operational Detachment-Delta — have been carrying it in combat ever since.
The 416 is now considered in many circles to be the best carbine in the world — a weapon that combines the solid handling, accuracy and familiarity of the M4 with the famed dependability of the rugged AK47.
For the foreseeable future, however, the Army is sticking with the M4 and M16 for regular forces.
The Army Times is not a credible source in relation to articles on the M16 and M4 series rifles and has used misinformation in order to sell Heckler & Koch's products. The gas piston is outdated in relation to the M16 series rifle and was considered in the design before the M16 was even adopted for service. Colt originally developed the gas pistol M16 which was turned down.

The only thing that a gas piston set-up does to an AR-15 is makes it a little more complicated and provides another area for carbon-related stoppages and another area that needs to be cleaned and maintained.
The last two pictures show two bolts wiped after shooting 1340 rounds of high quality maufactured ammunition. One is the bolt with the gas rings as used in the regular rifle, it is completely gunked with carbon, the one without gas rings is used in a Rhino converted rifle.
Why do I see rust on the top bolt and what does the gas piston look like? That ammunition you used must be really dirty.

Now to solve the forward assist problem...
I'm sure I'm not the only one who doesn't understand what that could even mean.
“There was only one good way to get it out and that’s to ram it out with a cleaning rod,” he said. “I started to knock the round out by pushing the rod down the barrel, and it broke off. There was nothing I could do with it after that.”

uhh, yeah, there's only one good way to get it out, and ramming a cleaning rod down the barrel is NOT IT.

When even highly trained infantrymen like Self have problems with their M4 it is a sign there might be a problem with the weapon, not the soldier.

if he doesn't know how to clear that malfunction, he's not THAT highly trained.

edit: and he actually took the time while people were shooting at them, to pull out and assemble a cleaning rod?? and jam it down the barrel?? or does he seriously mean all the men in his outfit have deweys zip tied to the sides of their rifles? that seems extraordinarily unlikely.
Actually, Captain Self's platoon sergeant has commented on the matter over at Lightfighteer. From the Lightfighter discussion of the same article Ed DCB posted.

Discussing why the M4s failed (wear issue):
It was a wear issue.

The Ghar was covered in snow and mud, there was no sand.

Nate was talking about the state of our weapons back in the tents getting all gritty. The place that we were at had been cleared by a Mine flailer that left the ground like the surface of the moon with about 4-5inches of powdered silt.

It kicked up like pig pen from the peanuts when you walked. There were no solid floors when we got there and the silt tracked in all over our gear.

The 6 color chocolate chip ruck covers made good weapons bags.

Anyway, a couple of our M-4's were approaching 7 years old at that point (this was before we started replacement every 24 months).

Those rifles had an unknown number of rounds because there was no requirement to run round counts on rifles then either, but I can tell you that they all had at least 1,000 rounds per month through them.

CQM shooting tables were shot monthly and the ammo load was 1,000 rds per rifle, per day.

If we blew an extractor or whatever, we would only get the actual part that broke. IE: faliure to exctract got you a new spring, NOT a new extractor. Only if you had more problems, would you be able to get it replaced.

Like the rest of the Army, the Clinton years had worn hard on our equipment and our Armorers were not about spending money unless they had to.

Three of four SAWs went down that day (one was hit by enemy fire). The SAWs were my biggest problem for keeping up, but we started DXing them after three turn ins for the same problem. We called it the Three strikes and you are out plan(the commander accepted some risk..... I will leave it at that).

We pretty much figured out that the military standard for a "shot out" unrepairable weapon was not good enough. If you followed all the rules and only replaced a weapon when it met the Army criteria, you would have weapons that would have horrible malfunctions and eat up brand new parts for lunch.

I called this "getting sloppy". When a gun gets real loose (even though it might meet guaging standards for servicable) it creates extra wear on parts, so you end up pissing away good spare parts trying to keep an old tired weapon in the fight.

We affectionately called this "polishing a turd".

There were lots of hard lessons learned that deployment that started the ball rolling on the transformation of the RGR REGT to the organization that it is today. It looks almost nothing like the organization that I left in 2003. Thats all I will say about that.

Discussing why they were carrying rods zip-tied to the handguards:
Nate had a rod on his rifle because I was his PSG and I made him do it, just like I made all of the M-4 guys do it.

These were not actually sectional cleaning rods. Sectional rods were carried by Saw gunners in an extra pouch.

The secional rods were being phased out by the Army and we were only getting OTIS bore snakes at this point, so we went down to Home Depot and purchased alluminimum metal dowels. These came in like 12 foot lengths or something.

We cut them down to the size that we needed. the length that we wanted was only long enough to push a round out of the chamber with about an inch left sticking out of the barrel.

After the Rods were cut, the edges were rounded with a dremmel tool. A Handle was made with a heavy duty rubber band wrapped around the end.

The rod slid down the gap between the 9 O'clock and 12 O'clock rails the tip of the rod extended back to the middle of the upper. Guys that had the M-68 could wrap another rubber band around the "clicky knob" on the Aimpoint mount to hold the tip of the rod in place.

The main body of the rod was attached to the rail with two small zip ties, one behind the front sight post and one at the delta ring. The "handle end" would stop about a half inch behind the flash supressor so that it would not heat up during firing.

We had been using this technique for years with Simmunition upper recievers because they get rounds lodged in the barrel. When our batch of M-4A1's started crapping out on us, I started making guys carry rods on their rifles as well....

So you all haerd it here on, The 1st PLT Aco 1/75 RGR malfunction rod technique.

Also worth noting that the original author of the article is Matthew Cox. You'll find his byline on many a glorious review of various H&K products such as the XM8 (now with plastic melting barrel trunion).

As to the Rhino, it is an old system. Even if you did have a problem with direct impingement, you could probably find a better design.
Last edited:
ahh, that makes much more sense. there's a world of difference between a case stuck in the chamber and a bullet stuck in the barrel.
I agree that there are now improved design gas piston systems, this thread was meant to be a tribute to a friend and an american patriot who contributed to this great rifle.
Am I the only person on the face of the earth that does not see a problem with my AR-15 gas system? My Colt National Match HBAR has thousands and thousands and thousands of rounds downtown and it's only jam can be attributed to early Wolf laquered ammo - period. I just got off the phone with my buddy, (whom I sold it to). He reports a round count now approaching 5,000 and like me, he has NEVER cleaned the gas tube with those fancy-schmancy pipe cleaners....Did/does Colt make their gas tubes with some magic metal, or have other makers not caught on? I'm being a little sarcastic, but I really don't see the problem....
I've always heard that Nate Self's gun failed because the extractor broke. Is that incorrect? Doesn't matter what the gas system is, if the extractor breaks the gun ain't gonna work.

I'm more concerned about the problems with the M249. IIRC, one of Self's SAW gunners had his SAW bend an op rod as they charged the enemy bunker and the guy was reduced to just being a grenade tosser. It seems like I hear a lot more complaints about the M249 than the M16/M4.
Not open for further replies.