Post when you've shot one - it's not worth replying until you've done so ...... yawn

Edited to add....Gunzilla - you are so wrong it's not true.  Please take a moment and think about what you have written including what is actually providing the power stroke.  Think now, because the same rule applies to pistons and direct impingement.  

Spend the money on practice ammo.  Then again, people love to spend money attempting to fix something that isnt broke.  
There may be a piston upper adopted by the .mil someday, but until then I'd stick whith what you know works.

Quoted: I have high dollar direct gas AR's and still wouldnt trade my POF M4 for any of them. I will be building nothing but piston AR's from now on. They are the future!

Good point, and a few years down the road you may need replacement parts. Since they are the future, you can just go to any shop and get parts for your POF upper, since all piston upper parts are interchangable.

A customer walks into my store with $1K to spend on a defensive carbine.  Lets say hes a normal, middle class guy, lives in the burbs, but wants to be ready in case something causes a break down in society and its ANARCHY!  
For $1K he can buy a regular "shits where it eats" AR and 1K rounds of ammo.  This rifle will run 100%, and the parts will last longer than the owner will ever actually use it.  If he needs replacement parts, no problem.  

If you want to jump on the latest fads, go ahead, its your hobby, have fun.  If/when a piston upper is ever adopted/standardized by the .mil, that will be the one to buy.  Until then, I'm sticking with what I have. Its not broke, I dont need to fix it.

Well it's a good job they INCREASE the accuracy of the AR platform then.

You know, I really try and avoid getting caught up in these discussions when it is obvious to all that the information being imparted is incorrect.  That said, here are a few FACTS:  

The currently offered AR piston systems give greater reliability than DI weapons in ALL environmental conditions; they require less maintenance, are more ammunition tolerant and run cooler offering less wear.  

They are also more accurate the DI weapons by virtue of the FACT that the barrel is truly free floated.  In the DI weapon, the barrel is not free floated until the carrier group has fully unlocked and has travelled over one inch rearward, well after this can have any positive effect of accuracy; with the piston driven weapons, the barrel is free floated at the moment of firing, which allows the barrel to whip and produce consistant results which are uneffected by barrel temperature.  
While weight may be a factor with some of the piston systems out there, it is not with all; weight neutrality was one of the design briefs.  

Now I'm not saying that DI weapons are crap or unreliable or anything else for that matter, I'm just reporting facts.  The old myths do not apply to the current generation of piston weapons because the designers knew from the outset that they had to improve upon the existing platform otherwise, what was the point?  Most here are not privy to current military thinking; well I meet with these guys everyday and like it or not, DI is a thing of the past.  The only reason Knight's won the SASS solicitation was because HK had not completed the 417 in time, if they had, they would have won hands down.  

Pay your money and take your choice but do so with balanced information and not with rehashed myths that are dead and buried.  

Quoted: As both the DI system and the short-stroke piston push the bolt carrier back with just about equal force (obviously), it shouldn't matter whether the force is mediated by gass or a metallic short-stroke piston, as far as accuracy goes.

Shooting for minute of bad guy, OK.  Shooting in competition, the DI will win everytime.  

Quoted: Quoted: As both the DI system and the short-stroke piston push the bolt carrier back with just about equal force (obviously), it shouldn't matter whether the force is mediated by gass or a metallic short-stroke piston, as far as accuracy goes. Shooting for minute of bad guy, OK.  Shooting in competition, the DI will win everytime.

Not so.  We recently outshot a full up National Match set-up (20 inch barrel) with a 10.3" barrel piston upper - in this instance it came down to the shooters, but bottom line, there is no decrease in accuracy and in the right hands outstanding results can be achieved.  

Concerning the 9mm buffer; the user was complaining about more felt recoil when using this buffer in his system.  

Now that begs two statements:  
If the original DI system is so screwed up you have to use a buffer in in designed for a blow-back weapon, then there must be something wrong?

The piston system is designed to be used with the correct buffers for the 5.56mm round which includes the standard and H varieties - all of the previous "fixes" for the DI system are not applicable to a design that doesn't care about barrel  length.  

As I stated above, pay your money and take your choice, but please don't insult the designers of these systems because they started out knowing that the final execution had to be an IMPROVEMENT over the existing system.  

Any comparisons with the M14 are just asinine.

Quoted: Quoted: Shooting for minute of bad guy, OK.  Shooting in competition, the DI will win everytime.   Not so.  We recently outshot a full up National Match set-up (20 inch barrel) with a 10.3" barrel piston upper - in this instance it came down to the shooters, but bottom line, there is no decrease in accuracy and in the right hands outstanding results can be achieved.

Whatever allows you to sell your stuff and still sleep at night

Since there will never be 20" piston upper fired in HP competition, I guess neither of us can prove the other wrong but I know better.

The sad part is, most people don't know enough to know how ridiculous your statement is.  

Bigbore, I guess I kinda expected more of you but your comment sums you up.  

Bottom line, I don't care whether you buy one or not, what helps me sleep at night is knowing that a few of our guys in harms way are equipped with weapons that won't let them down when they really need them; both our's and HK's.  

As I said, buy what you want, I'm not here to sell anything, just report on the work that we and others in the industry are doing so try and take it in the spirit it's given; who knows, maybe you'll actually learn something?

The historical reasons for piston systems not working well witrh the AR platform mostly relate to the earlier designs failing to take into account the shear forces involved with placing the power stroke above the center line of operation of the working parts - I think we can all agree that all the current offerings have addressed that issue.  

I also did not say that gas piston rifles are more accurate than DI rifles; I purely restricted this observation to the current gas piston AR's.

In terms of your thoughts on accuracy they are fundamentally floored by your misunderstanding of the operation of short stroke pistons as employed by both HK and ourselves.  By your account, the forces imparted by the gases on the barrel through the gas tube would be far greater than those of the piston system by virtue of the fact that the moment arm of the gas tube is three and a half times longer.  Clearly this isn't the case.  

The gas tube and gas nozzle are both nothing more than conduits for the propellant force i.e. the gas - they are pipes, nothing more.  The "equal and opposite" forces act on the bolt and barrel extension not any other part of the system and once the piston cup is charged with gas, both it and the operation rod are no longer attached to the barrel but supported by gas and the bushing in the upper receiver.  This is the same for both our system and the HK modified G36 system used on the 416.  

Once these systems are charged, the barrel is as effectively free-floated as a bolt gun which in turn allows the barrel to whip consistantly providing a slight accuracy enhancement.  Now you can choose to ignore this observation but as both we and HK have found the same results and the military end-users have found this also, I think it's fair to say that this is more than marketing b/s.  With the DI system, the barrel is connected to the bolt carrier through the entire firing cycle by the gas tube.  Does this impair accuracy?  Very unlikely, but this factor is not present on ours or HK's weapon.  

Originally, we made no claims concerning accuracy other than that it was unaffected by the short stroke operation.  End-users reported back to us that they were observing improved accuracy in both ours and the HK weapons which led both companies to study this further.  It is worth pointing out that although H&K use a heavier barrel profile and hammer forged production; we use standard government profile button rifled barrels - both systems shoot the same.  

In all practical situations both DI and piston weapons will give identical performance in terms of accuracy.  Benching the weapons in controlled conditions will err in favor of pistons but remember, both systems give more than sufficient accuracy for their intended roles.  

At SHOT 2004, we had not yet received a design brief to develop a gas piston system; that occurred in February/March of that year.  The only change I detect is the fact that we were charged to develop a short-stroke operating system and found it to be so much better than the standard DI system that we moved to it completely.  

In terms of your slight regarding the original .499, please note that the uppers were built by LMT, the magazines were built by PRI and the projectiles were made by West Coast Bullet.  The only company to stand by the warranty on those items was us.  This aspect constitutes a different subject and has no place in this thread.  

In short, you need to look at the substantial engineering and dynamic developments that have been made with regard to taking the DI AR15 and having it operate as a better weapon with the addition of a short-stroke piston system.  This has not been done before and as such, previous observations and experiences are totally invalid when comparing current offerings.  The only way to really experience the difference is to shoot them preferably back to back and then form a balanced opinion.  This is the scientific approach.  

Oh, and by the way; we qualify everything to reliability standards way beyond anything the weapon is unlikely to encounter in real world usage.  I would not allow anything out of the factory doors and particularly into a war zone if there was the slightest doubt as to its functional integrity or long term reliability - please note that the vast majority of weapons we have in-theatre are shorter barrel variants, as such, personal defense weapons and this places a level of trust and responsibility on us as manufacturers to ensure that the above is the case.  

There is still a place for DI weapons but in mine and others humble opinions, that is no longer the front line.  

Attention Ludite DI users - Please try reading the posts - It helps comprehension and avoids repetition.