Has anyone compared a ZM Weapons LR-300 vs. other gas-piston uppers?  

I know HK has the 416, Patriot Ordnance has the P415, and Robinson Arms has the XCR.

I know you can have a folding stock with the ZM LR-300 and the RA XCR, however the others still require a buffer spring.

Are there any other manufacturers with gas-piston uppers in production?

Of the options available, which one is the most reliable, accurate, and cost effective?

The ZM system is NOT a piston system. It is a modified direct impingement setup that allows use of a side-folding stock by negating the need for a buffer tube/spring. It still "shits where it eats".

Other piston systems:
Leitner-Wise
POF
HK 416

Would the ZM LR-300 have more chamber fouling if it's a modified direct impingement as opposed to a gas piston?

It appears the only benefit of the LR-300 would be the folding stock.

How would the recoil of the LR-300 compare to the gas-piston ARs?

Quoted: Would the ZM LR-300 have more chamber fouling if it's a modified direct impingement as opposed to a gas piston?  no It appears the only benefit of the LR-300 would be the folding stock.yes How would the recoil of the LR-300 compare to the gas-piston ARs?its 5.56, if you are bothered by recoil get a .22

"The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website)

Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy.

Besides, the .22 isn't a viable bullet for tactical applications.

If you're saying the ZM LR-300 runs as clean as a gas-piston upper, then it must have a system different from the AR-15's direct impingement.

No.....it doesn't run clean like a piston. The bolt is still acting as the piston and it is still getting a nice blast of propellant ags every round. It's just the action spring has been moved so as to not require a buffer tube.

Simon

Quoted: "The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website) Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy. Besides, the .22 isn't a viable bullet for tactical applications. If you're saying the ZM LR-300 runs as clean as a gas-piston upper, then it must have a system different from the AR-15's direct impingement.

I believe he was saying the "felt recoil" of .223 is minimal regardless of piston/D.I.,

To my understanding, (through reading, I have not employed a ZM rifle) the ZM rifle's folding stock was said to be heavier than a standard butstock. If that information is of use to you...

Hey, who has the picture(s) of the ZM AR-10 conversion?

lord

Quoted: "The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website) Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy. Besides, the .22 isn't a viable bullet for tactical applications. If you're saying the ZM LR-300 runs as clean as a gas-piston upper, then it must have a system different from the AR-15's direct impingement.

Who said the ZM runs as clean as a gas piston upper?  Its just like any other AR.  And "clean" is a matter of perception.  Gas piston systems are just shitting in a different part of the yard, they are still dirty.

I own all three so listen to me.

Obviously the piston upper runs the cleanest in upper receiver and bolt area, the gas system fouling is all contained at the FSB and is pretty easy to clean with a brush.


The ZM is a modified Morris gas system that DOES run cleaner than a direct impingment AR in the upper receiver area.  With the regular AR the gas tube and carrier key interface inside of the upper receiver and when a round is fired and the bolt is back hot gases and fouling are being blown directly in to the upper.

The carrier key and gas tube in the ZM system are always together, even when the bolt is back they are still overlapping. The gas tube is very short and doesn't go into the upper. The gases are fed directly into the bolt and carrier and most of the excess is released through the ejection port through holes in the carrier (of which there are more in the ZM). The bolt and carrier still get dirty just like a DI AR, but the upper runs much cleaner. The upper will still eventually get dirty, but the round count will be much higher than with a DI AR.

The ZM also has a very strong return spring which provides stronger chambering of rounds (this however speeds up the rate of fire). Because the gas system is more tightly sealed it is also more robust than a DI AR. IMO this promotes better reliability even when the rifle is dirty.


Shooting characteristics:

The rifle that controls recoil (or more importantly muzzle rise) the most of any rifle I've shot is the ZM. The ZM basically has very minimal recoil straight back with very little muzzle rise.

The LW piston is not far behind.

Reliability:

I've never experience malfuctions of any kind with either system that was not magazine related. My DI ARs have also been very reliable, but I do keep them much cleaner, you can tell if you are shooting dirty ammo or the round count is getting high, the DI will get sluggish. The others don't miss a beat.

Maintenance:

Hands down the LW piston system is the easiest to clean and has the most standard parts.

The ZM is easier to clean than the DI, but has many nonstandard parts.

DI has all the standard parts, but requires more cleaning.

Accuracy:  All the systems have been extremely accuate for me with no noticable difference between them (none of them have AK accuracy).

Hope this helps.

Ridge what buffer are your running with your LW set up?

Quoted: Ridge what buffer are your running with your LW set up?

Standard. The recoil/muzzle rise in in NO way harsh it is similar to or better than a DI.
I can't say for sure because I haven't tested the different systems with the same configs.

I've also thrown in one of those black plastic buffers and the recoil was even less (this however was only tested in semi auto and it ran 100%).

Quoted: Quoted: Ridge what buffer are your running with your LW set up? Standard. The recoil/muzzle rise in in NO way harsh it is similar to or better than a DI. I can't say for sure because I haven't tested the different systems with the same configs. I've also thrown in one of those black plastic buffers and the recoil was even less (this however was only tested in semi auto and it ran 100%).

Do you think its possible the Enidine buffer would allow the LW system to have less recoil than the ZM since the ZM has no alternative recoild managment system or is the ZM significantly less recoil/rise than the LW that it would be inpossible to have less rise than the ZM?

Quoted: Quoted: Quoted: Ridge what buffer are your running with your LW set up? Standard. The recoil/muzzle rise in in NO way harsh it is similar to or better than a DI. I can't say for sure because I haven't tested the different systems with the same configs. I've also thrown in one of those black plastic buffers and the recoil was even less (this however was only tested in semi auto and it ran 100%). Do you think its possible the Enidine buffer would allow the LW system to have less recoil than the ZM since the ZM has no alternative recoild managment system or is the ZM significantly less recoil/rise than the LW that it would be inpossible to have less rise than the ZM?

Good question. The Enidine might do it. I need to do a head-to-head comparison on the same day to really be able to report the difference.  The problem is that I need to figure out what to do about the stock, I only have 1 SBR lower and I would have to swap the stock, or I could put some kind of plug in the stock, but I don't know if that would change the recoil characteristics of the ZM.

When you shoot the ZM it's pretty amazing, but it could be similar to the LW w/ enidine (I've heard that is pretty cool too).

.

Quoted: And "clean" is a matter of perception.  Gas piston systems are just shitting in a different part of the yard, they are still dirty.

I have to laugh.  I met Allen Zitta at Shot Show and got a lot of info about the design from the man himself.  He said back before he designed the LR-300 that he had built a number of true piston ARs.  The big complaint back then was how dirty they were under the handguard and that a flash  from burning gas was often visable.  "shitting in a different part of the yard" is the best way to put it.  

Dace-  I think when the question about recoil was asked, it wasn't as general as how much recoil exists but rather whethere it feels different.  The recoil of a DI AR is directly to the rear, inline with the bore.  People have wondered whether a piston driven AR feels at all like an AK with the piston reciprocating above the bore.

Quoted: Quoted: "The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website) Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy. Besides, the .22 isn't a viable bullet for tactical applications. If you're saying the ZM LR-300 runs as clean as a gas-piston upper, then it must have a system different from the AR-15's direct impingement. Who said the ZM runs as clean as a gas piston upper?  Its just like any other AR.  And "clean" is a matter of perception.  Gas piston systems are just shitting in a different part of the yard, they are still dirty.

You did...in your answer to his question:

Quoted: Would the ZM LR-300 have more chamber fouling if it's a modified direct impingement as opposed to a gas piston? no

Must have been a misunderstanding...

Quoted: Quoted: Quoted: "The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website) Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy. Besides, the .22 isn't a viable bullet for tactical applications. If you're saying the ZM LR-300 runs as clean as a gas-piston upper, then it must have a system different from the AR-15's direct impingement. Who said the ZM runs as clean as a gas piston upper?  Its just like any other AR.  And "clean" is a matter of perception.  Gas piston systems are just shitting in a different part of the yard, they are still dirty. You did...in your answer to his question: Quoted: Would the ZM LR-300 have more chamber fouling if it's a modified direct impingement as opposed to a gas piston? no Must have been a misunderstanding...

I must have read it wrong.  I think I thought he was asking would a modified direct impingement system be cleaner then the normal direct impingement system.

Quoted: Quoted: Quoted: Quoted: "The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website) Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy. Besides, the .22 isn't a viable bullet for tactical applications. If you're saying the ZM LR-300 runs as clean as a gas-piston upper, then it must have a system different from the AR-15's direct impingement. Who said the ZM runs as clean as a gas piston upper?  Its just like any other AR.  And "clean" is a matter of perception.  Gas piston systems are just shitting in a different part of the yard, they are still dirty. You did...in your answer to his question: Quoted: Would the ZM LR-300 have more chamber fouling if it's a modified direct impingement as opposed to a gas piston? no Must have been a misunderstanding... I must have read it wrong.  I think I thought he was asking would a modified direct impingement system be cleaner then the normal direct impingement system.

Read my post, the answer is YES whether you said it or not. It does run a little cleaner than a DI. I've explained it above.

LW has a staged vent.  So no flash under the HG or rail.  You will find minimal fouling on your barrel and gas block but you can simply ignore it and it will not effect weapon performance.  This is the important factor that seems to be missed here.

Not every piston system through time is created equally.  Some are short stroke, some long.  Some regulate, some don't, some a piston in tube, some are cup and nozzle.  The HK 416 comes directly off off the Brit SA80, onto the G36, then onto the 416.  

I would rather shit in the yard where I don't have to smell it or do anything about it that shit on the bed.

Shit in a different place? Yup. At least its not in the fucking chamber. I could care less about a dirty handguard.

I've always wanted a ZM system.  I wish I'd purchased one a long time ago...the newer ones produced at YHM just don't seem to be of the same quality.  At least that's the impression I get online.  Does anyone have any real experience with the two to compare?

Quoted: The ZM system is NOT a piston system. It is a modified direct impingement setup that allows use of a side-folding stock by negating the need for a buffer tube/spring. It still "shits where it eats". Other piston systems: Leitner-Wise POF HK 416

The bulk of the carbon and powder residue buildup occurs at the rear of the bolt. It doesn't "shit where it eats" anymore than the AK (which shoots all the primer sealant and gunk everywhere in the action) or a standard recoil action / blowback pistol/SMG/carbine.

Quoted: I've always wanted a ZM system.  I wish I'd purchased one a long time ago...the newer ones produced at YHM just don't seem to be of the same quality.  At least that's the impression I get online.  Does anyone have any real experience with the two to compare?

From what I've heard YHM has always been making the LR for ZM.

Quoted: Quoted: I've always wanted a ZM system.  I wish I'd purchased one a long time ago...the newer ones produced at YHM just don't seem to be of the same quality.  At least that's the impression I get online.  Does anyone have any real experience with the two to compare? From what I've heard YHM has always been making the LR for ZM.

+1

What kind of impression do you get online and how has it really been affected?  

YHM has always made them and if anything, they've gotten better, right?  

RANGE REPORT:

Okay, I compared the LW upper with the ZM upper.  The LW is a 10.3 and the ZM is and 11.5.

The LW actually has a little LESS recoil, but a little more muzzle rise.

The ZM had more recoil straight back and virtually no muzzle rise.

I'd bet an LW piston upper with an enidine could make the LW the same or better than the ZM.

If you look at how the gas systems operate this makes sense.

Both functioned flawlessly with several mags of Wolf.

My ZM is a second generation, it is well built and I do believe was built by YHM.  I have not seen the newer design in person, but I'm sure they are good quality.  To me it appears the upper receiver is less beefy than the older ZM.

Quoted: Do you think its possible the Enidine buffer would allow the LW system to have less recoil than the ZM since the ZM has no alternative recoild managment system or is the ZM significantly less recoil/rise than the LW that it would be inpossible to have less rise than the ZM?

I don't trust Enedine buffers.  Last class I was at had one slip over the retaining pin into the lower.  The instructor managed to get it put back together.  Still...  

.

Quoted: Quoted: Quoted: Do you think its possible the Enidine buffer would allow the LW system to have less recoil than the ZM since the ZM has no alternative recoild managment system or is the ZM significantly less recoil/rise than the LW that it would be inpossible to have less rise than the ZM? I don't trust Enedine buffers.  Last class I was at had one slip over the retaining pin into the lower.  The instructor managed to get it put back together.  Still...   Just wondering how that was possible with the carrier in place - any more details?

yeah, how?  It sounds like someone put their rifle together wrong or something...

I'd also like to hear more Apple versus Orange range reports

Quoted: I'd also like to hear more Apple versus Orange range reports

Okay,  I also shot my 44 mag lever action trapper.  It kicked a lot more, but didn't fire as rapidly.

Quoted: Quoted: I'd also like to hear more Apple versus Orange range reports Okay,  I also shot my 44 mag lever action trapper.  It kicked a lot more, but didn't fire as rapidly.

Thanks for being a sport with my cocky comment

The truth is, most of us don't know anyone who's fired a ZM weapon and it's nice to get a general idea of how they might compare.  

I'm late to this game, so please excuse my ignorance.   Is the ZM system kind of like the Olympic Arms OA style in that the recoil spring is is on top of the barrel?  

Quoted: "The P-415 / P-416 recoil is reduced, allowing for smoother and more accurate operation." (From POF Website) Patriot Ordnance wouldn't be mentioning recoil if it was negligible to begin with in regards to second shot accuracy.

Umm, it is negligible to second shot accuracy.  It is slightly less than negiligible for the speed of a follow-up shot, however.  But only slightly.

But I guess everything is relative.

Has anyone compared a ZM LR-300 to the Olympic Arms OA-93 CAR?

They both have the recoil system in the upper receiver however the Olympic Arms model is much more reasonably priced.

Quoted: Quoted: Quoted: I've always wanted a ZM system.  I wish I'd purchased one a long time ago...the newer ones produced at YHM just don't seem to be of the same quality.  At least that's the impression I get online.  Does anyone have any real experience with the two to compare? From what I've heard YHM has always been making the LR for ZM. +1 What kind of impression do you get online and how has it really been affected?   YHM has always made them and if anything, they've gotten better, right?

I suspected that YHM always made them.

Well, they probably have gotten better-such as the full length top rail.  However, the new plastic HGs look like crap, and I've never been a fan of YHM railed HGs-FF or nonFF.  Also, they don't encorporate a front sight anymore, like  they used to.  Is it me or is the top rail/receiver a little higher than normal?  Would that cause any problems when mounting BUIS?  

I really would like to try one out, but right now I don't have the cash to just TRY something that expensive, especially the way I feel about YHM HGs; maybe if you could change them for something else I would consider it more.  I might just suck it up one year and get the plastic HG version.

Oh yeah, I hate 1/9.  Oh well, maybe I'll try one eventually anyway.

Quoted: Has anyone compared a ZM LR-300 to the Olympic Arms OA-93 CAR? They both have the recoil system in the upper receiver however the Olympic Arms model is much more reasonably priced.

Apples and Oranges again...

I would expect they are not exactly the same system.  

However one must have advantages over the other, whether it is in reliability, functionality, price, etc.

I wanted to know if anyone has compared the two side by side.

If they are about equal, I would go with the Olympic OA-93 due to the price.

Quoted: Quoted: Do you think its possible the Enidine buffer would allow the LW system to have less recoil than the ZM since the ZM has no alternative recoild managment system or is the ZM significantly less recoil/rise than the LW that it would be inpossible to have less rise than the ZM? I don't trust Enedine buffers.  Last class I was at had one slip over the retaining pin into the lower.  The instructor managed to get it put back together.  Still...

Please explain how this could possibly be the fault of the buffer.  I am not following your logic at all.  This is an issue with the pin that retains the buffer, not the buffer.  Its kind of like having a case stuck in the chamber that had the extractor rip though the case and blaming the extractor.