Stoner AR Operating System Technical Detail

**HansTheHobbit** · 09-24-15, 04:59

Originally Posted by thx997303

Hans the Hobbit, this is the last I'll say on the subject. You are wrong. Let it go. Stop digging holes.

Ron, what kind of lube schedule do your rifles get?

Hmmm, that's not a very convincing argument, but I see I've hit a nerve. Sorry my facts are getting in the way of the group think. Tell me your definition of direct impingement, and I have a feeling that will pretty much end this whole thing. I've asked you DI revisionists to give me the "proper" definition about three times now, and no one has come forward. So maybe you'll step up to the plate.

**Belt Fed** · 09-24-15, 10:59

Hans, Hans, Hans.

**Thesandstonefiles** · 10-20-15, 09:52

Originally Posted by HansTheHobbit

No, I call it a magazine because that's the correct term. Look, I don't know where this idea came from that an AR isn't a DI gun, but it's wrong. If an AR isn't DI, then DI doesn't exist. And just because the bolt has gas rings doesn't make it a piston. The movement of the bolt is caused by the carrier, and then by direct blowback after it is unlocked. At no time does the bolt act as a piston. Again, a piston is a moving part, it's movement is directly caused by an expansion of gas, and it does work on other moving parts.

With the Hakim, you could argue that in some strangely philosophical way it's a piston gun. The gas key is functionally a very short long stroke piston. But anyone with a lick of common sense can see that it's really just part of the carrier, so it's a DI gun because there's nothing substantial that moves between the carrier and where the gas comes from.

Again, the definition of DI is any gun in which the gas is piped directly to the carrier without a piston in between. You can get all philosophical about what constitutes a piston if you want, but you can't get away from the definition of DI. Just out of morbid curiosity, what is your definition of DI???

You're wrong. You've been told why, in great detail, as to why you're wrong.

The has pushed the BCG back and that impacts the trigger. Just like the piston in an engine turns the crank shaft after the gas from the explosion pushes it down.

It's the same thing. Period.

**HansTheHobbit** · 10-20-15, 17:04

Originally Posted by Thesandstonefiles

You're wrong. You've been told why, in great detail, as to why you're wrong.

The has pushed the BCG back and that impacts the trigger. Just like the piston in an engine turns the crank shaft after the gas from the explosion pushes it down.

It's the same thing. Period.

Give me your definition of direct impingement.

**HansTheHobbit** · 10-21-15, 00:41

If you folks will remember, I didn't start this, and I'm not the one who just won't let it go. I very innocently asked a question about DI vs piston ARs, and a bunch of people started lecturing me about how ARs aren't DI. First of all, it's the accepted terminology that everyone understands. If I had referred to them as stationary piston vs conventional piston, NO ONE would have had a freaking clue what I was talking about. Quite frankly, I'm pretty pissed off. Everyone knew exactly what I was talking about, because it's the universally accepted terminology. Just because Armalite used the term stationary piston doesn't mean that the AR is a piston gun. That argument is absolutely absurd.

For the last time, someone give me their definition of direct impingement, in one sentence, or drop this altogether. There seem to be about ten of you DI reformists out there, yet not one of you can come up with a simple definition. Why is that?

**Failure2Stop** · 10-21-15, 01:13

https://en.m.wikipedia.org/wiki/Direct_impingement

Actually covered decently here.

Please read all of it.
Wouldn't be a bad idea to read Stoner's patent as well.

**HansTheHobbit** · 10-21-15, 01:45

That article contradicts itself.

Direct impingement is a type of gas operation for a firearm that directs gas from a fired cartridge directly into the bolt carrier or slide assembly to cycle the action.

Sounds to me like the AR falls into that category.

As we've gone over already, and as has been pointed out many times before, Stoner was trying to demonstrate that his design was unique to get patents. If we start calling ARs piston guns, then we'll have to call everything a piston gun, as the gas must impinge against something, and that something will thus qualify as a piston. Like I've said many times already, the gas key on the Ljungman is functionally a long stroke piston.

A piston gun means that the carrier is actuated by a piston. DI means that the carrier is actuated by gas. If you try to bend that definition then it loses all meaning. Again, I accept that the AR is a unique type of DI, perhaps even deserving its own terminology. But it's not a piston gun by any stretch of the imagination.

**HansTheHobbit** · 10-21-15, 04:06

It also seems that I can't say anything without someone turning it into a federal case. If you guys want to call ARs piston guns, then have at it. What pisses me off is that everyone knew exactly what I was talking about, yet they felt the need to hump my leg anyways. And then I'm the one who gets blamed?

I didn't start this thing, but I'm more than happy to finish it. So please, someone give me a one sentence definition of direct impingement that logically places the AR in the category of piston guns, yet somehow still includes the Ljungman. I've scoured the various firearms dictionaries, and I can't find a single definition that even remotely supports that position. It seems this nonsense was started by Wikipedia, which now makes perfect sense. Like teachers tell the kids these days, Wikipedia isn't to be trusted.

**Failure2Stop** · 10-22-15, 00:14

In recent times, the exact definition of the operating system found in AR-15/M16/M4 type platforms has come into question.

Paramount to this is what is exactly is the definition of "direct impingement" as detractors and enthusiasts alike refer to the patented Stoner system.

Reference the actual patent:
http://www.google.com/patents/US2951424

Key point of discussion:

It is a principal object of this invention to utilize the basic parts of an automatic rifle mechanism such as the bolt and bolt carrier to perform a double function. This double function consists of the bolts primary function to lock the breach against the pressure of firing, and secondarily, to act as a stationary piston to actuate the automatic rifle mechanism. The primary function of the bolt carrier is to lock and unlock the bolt by rotating it and to carry it back and forth in the receiver. The secondary function of the bolt carrier is to act as a movable cylinder to actuate the automatic rifle mechanism. By having the bolt carrier act as a movable cylinder and the bolt act as a stationary piston, the need for a conventional gas cylinder, piston and actuating rod assembly is eliminated.

The preceding posts are in reference to this, though not necessarily in direct reference.
From here forward, the discussion beings.

As always, please be courteous and technical in the discussion.