Gas Piston Kit For New AR....

[SHvar]

The difference between the DI and Gas Piston model is about 2-3 ounces.
The difference in cleaning the 2 models is noticeable, the piston assembly takes a minute to clean, next the barrel is the longest part of the operation.
There are advantages and disadvantages to both, I own both so I can tell you that there is a very minute difference in "percieved recoil", the DI rifle is easier to be more accurate with. The gas piston rifle is louder.
Personally I enjoy shooting my gas piston rifle far more than my DI rifle. I definitelty enjoy the difference in the cleaning process.
Its personal preference, but allow me to say this, there is nothing wrong with a DI rifle and shooting them.
Id much rather have a gas piston rifle designed and built that way by the manufacturer, not using a do it yourself kit that cost as much as buying the rifle built that way, or more.

 

[berettashotgun]

Wow - 1858 has my number.He knows more about the AR-15/M16 than Chuck Norris.
DUDE: lighten up. Were are just expressing opinions, not here to attack each other.
BTW - thought this is THR, Factory specs for my referenced rifle -seems a short barreled and optic enhanced rifle you posted about weighed about 2lbs more than an A2 http://www.4mcd.usmc.mil/AOP/OSOHyattsville/Weapons Handling.htm
OTOH - You do have rather amazing photography skills.
My .02 worth on the piston subject - I have put quite a few rounds downrange out of an A2 and if it ain't broke...well.



About the piston style AR's

I don't know if I'd purchase an add on kit, but a rifle made with the piston in design, tough call.
Real tough call. Not enough range time to make an objective evaluation - ammo prices have caused more keyboard time than trigger time for most of the posters I suspect.
I would reserve my purchase of a piston upper ( or rifle ) for a few years.
I'm positive some need to get the latest and greatest stuff to satisfy some need, heck, I know I do.
As of right now I'd consider most piston upper add on kits to be way overpriced.
My guess is around $100-125 is what I'd consider realistic pricing for a add-on.
BUT - the newer design of rifles and neutered carbines are all together different.
There is some nice stuff available -see 1858's stuff. That guy spent some cash.He has VERY nice weapons.
I THINK ( but don't know ) mfg. customer service would have more influence on my purchase than price.

 

[SHvar]

I was out a few weeks ago in an arctic parka, gloves, and a few hundred rounds. Someone has to hold the line to those "commie paper plates", and keep their heads down in the trenches while the weather is bad.
Heck I might go in a few days again.

 

[Rubber_Duck]

A buddy and I will be building a 5.45x39mm AR-15 soon using a Smith & Wesson upper with the Opsrey Defense gas piston kit. This will be an experiment prior to doing the same with the Colt 6520. My research has led me to choose the Opsrey Defense over anything else out there as far as converting existing DI ARs to gas piston.

I will update in a couple weeks about the performance of the kit as well as a comparison with a DI gun on cleanliness after X number of rounds.

 

[kimberkid]

I just bought the Osprey system to install on a pre-ban PWA carbine I've had for at least a decade ... the kit was here 2/8/10 when I got home.

The little woman said dinner would be ready in 10 minutes ... as I was heading to my man-cave to install the kit.

It went almost as smoothly as shown in the video of the instalation. My only problem was the kit said it was for barrels 11"-16" long and not more than 0.875" in diameter ... mine was exactly 0.875" (not M4 profile like the one in the video) Anyway the spring clip they supply to hold the two pieces of the piston together would not fit between the barrel and the piston so I had to knock out the pins holding the front sight in place and pull it forward about 1/2" to install the piston ... but it didn't matter as I was finished and had my hands washed before dinner was done.

Yesterday afternoon I took off work early and went out and ran 300 rounds through it ...

The good stuff:

No failures at all, so I was pretty happy with that.

I didn't notice any mirage or heat signiture from the gas trap even in the below freezing temp (I was using an Aimpoint in a carryhandle mount.

After blasting through a full beta-mag (rapid fire) the bolt, carrier and receiver were cool!

It was only 300 rounds but there was no indication of "carrier tilt" wear on the buffer tube or threads ... I'll keep an eye on it.

I put up a few targets but I was cold, fingers were stiff and I think it can do better ... will check group size when it warms up.

It was really nice to be done cleaning in 5 minutes! I was blasting some Silver Bear, not paticularly clean but not terriable either.

The stuff I didn't like:

Besides the instalation problem I noted above with having to remove the front sight which should have been mentioned in the instructions, I didn't like was the rattle of the piston which will slide back and forth. It isn't loud and I found a blurb in the instructions that says its normal.

When stripping the gun and the halves are separated, anytime I pointed the barrel upwards, the bolt carrier will slide back and pop open the trap door ... of course it doesn't fall out because of the charge handle.

Pretty minor stuff.

​

 

[SHvar]

Bushmaster (DI) M-4 6.22 lbs, or 6 lbs 3.52 ounces.

Bushmaster gas piston carbine with much larger double heat shielded handguards, 3 aluminum picatinny rail sections installed, and Yankee Hill Machining folding front sight. 6.5 lbs (6 lbs 8 ounces), for a total difference including extra hardware of 4.48 ounces.

I dont know what the total difference is without the rail sections.
For size reference, heres one of the three.

I would venture to guess that any aluminum quadrail handguard you can get would add far more weight than having a piston system.
I wouldnt mind having a magpul MOE handguard that fits the piston system, heck for the price maybe I can modify one to fit.
Through bushmaster you can get the same heat sink barrel nut, and quadrail that POF installs on some of their rifles.

 

[Rubber_Duck]

UPDATE:

We got the AR-15 built using a Smith & Wesson 5.45x39mm upper, a Rock River Arms lower, and the Osprey Defense OPS-416 gas piston kit.

Had some trouble installing the kit as the roll pin that holds the gas chamber in the FSB was a very tight fit, broke two punches and scratched up the finish on the FSB trying to get it in, but in the end we succeeded.

Ran 150 rounds for test fire, and no malfunctions attributable to the gas piston set-up! The 2nd, 3rd, and 4th rounds were failures-to-fire, I suspect light primer strikes here as we didn't install the extra-power hammer spring included with the S&W upper. All 147 other rounds fired fine. Rifle cycled fine with a standard carbine buffer using Bulgarian mil-surp ammo. The conversion worked as advertised, with significantly less fouling than a DI rifle, and the thin layer of lube applied prior to firing was still present upon disassembly.

It is my understanding that Model 1 Sales makes a firing pin for the 5.45x39mm uppers which protrudes farther from the bolt face for deeper primer strikes to eliminate light primer strikes with surplus ammo, and this is an option we are exploring.

No pics, but I will be posting pics at a later time.

 

[The_Hammer_Man]

I had to look into my back recorder to get the "real" numbers, rather than pulling them outta my butt, here they are...


Bushmaster Retrofit installations: 16
Satisfied customers: : 16 w/only one complaint about it not being adjustable

Osprey Retrofit installations : 28
Satified customers :28 w/ the same guy with the same complaint. Told him to sell his rifle and buy a POF.

To be honest they're nearly identical in performance with only subjective differences. They "feel" different from each other and I think that is because the Bushy sits higher than the Osprey. The Osprey "hugs" the barrel, in some cases VERY tightly, while the Bushy sits nearly 1" above the bore.

They do exactly the same thing, in nearly the same fashion... the only provisio is that the Osprey works a little better with suppressors than the Bushy does. (This last is customer report not personal experience so take it with a largish dose of salt)

Hope this helps,

BTW,,, of the four non-purpose built piston driven rifles I have 3 of them are setup with Osprey's.

 

[Rubber_Duck]

The_Hammer_Man, how many rounds do you have down the tube with the Osprey Defense kits installed? Any issues?

 

[PMROY]

Here is one more for you. I have a Colt 6920 and a Bushy A4. I converted the Bushy using their drop in gas piston retrofit kit. You know what, It works great. At the beginning I had some short stroking problems, ended up being an over site from Bushmaster. I sent the upper to them, they fine tuned it, tested , send back, within two weeks, NO Charge. Discovered the barrel clamp must be tight enough to hold , both loose enough to move back and forth on barrel. Originally not in their install instructions. After that, what a difference, no problems, super clean, (debate coming), bolt temperature dramatic drop right after firing(100 rounds) compared to Colt. Weight difference, Not Noticeable. The Bushmaster kit included everything, and I will recommend to anyone, IMO, based on over 2.5K rounds, no misfires, malfunctions.... Last point, if you instal the Bushmaster Gas Piston, remember , it is meant to run dry, so do not over lube. Awnsering your question, It works great, bolt included is well made and as a bonus, their customer service is exceptional. A4 aand 100 Yd target

 

[The_Hammer_Man]

The_Hammer_Man, how many rounds do you have down the tube with the Osprey Defense kits installed? Any issues?

Combined round count between the three rifles is a little over 9k. I use two of the rifles as "show me's". One 16" and one 12.5 sbr. No problems ever, of any kind, that could be attributed to the piston. No carrier tilt/drag that I've been able to detect. It softens
recoil noticeably and is designed specifically to be used with a normal AR buffer. (sorry you H-buffer guys!)

If you want total rounds fired by my customers I'll have to ask. One of them, "the complainer" is a really active 3-gun competitor. So we can assume his round count is up there in the 3-5k area already.

Fair Warning!!!! If you decide to put a sprinco "red" buffer spring and H buffer in your weapon you will be turning it into a MilSpec ammo ONLY weapon. It will not cycle reliably with lower powered ammunition. By this I mean that you will narrow your ammunition choices to either XM193 or M855. Why? The milspec ammo is a bit hotter than "normal" ammunition and that extra "oomph" will be needed to cycle your weapon.

To be honest the extra power buffer spring/H-buffer combo aren't needed with this kit. So take the money you would have spent on the spring/buffer combo and get a set of fuzzy dice for your car.

 

[GPWASR10]

Dude, really, I went for about 6 mos with just oiling and wiping down the BCG quickly, shooting between 200 and a 800 rounds per session going once or twice a month.... Why even bother with a Piston? They are heavier, have more moving parts, not really tested, and from what I have seen at the range... increase recoil.

Go with DI man...

That is unless you just wanna tinker with a piston gun, even I have been pondering a SR-556, just for craps and grins.

 

[The_Hammer_Man]

Interesting... increased recoil? really?

Out of the 80 plus people who've fired one or the other of my Osprey Piston equipped rifles they've ALL mentioned that felt recoil was radically deminished. All of them.

FYI... the Osprey has one.. count them.. one moving part and that is the piston itself. Everything else is "factory" .. so no new/extra/more parts.

The setup I recommend to customers, and to anyone that'll listen for that matter , is this.

IF your going to retrofit with either the Bushmaster or the Osprey piston kit add these additional items to you rifle:

A good 2 port muzzle brake, I personally like and use the PWS 556.
A Sprinco "red" carbine buffer spring and either use a normal carbine buffer or, for more recoil reduction, install a Enidine.

With these items installed on a standard 16" M4ish rifle you will end up with a rifle that feels like a 10/22 with a bad buffer.

 

[Zerodefect]

Yup, I've seen an increase of recoil and a slight loss of accuracy in the piston conversions as well. I suppose it depends on the brand and gas system type, buffer tune etc.

Theres a guy on arfcom that has come out with a new buffer you should check out. It has an extended front that fits into the carrier to help reduce buffer tilt. You'll still get some tilt but it'll stop your carrier from digging holes in your buffer tube. The aR's rails are too short for piston operation, or at least they act short.

 

[PMROY]

Thats interesting! I have less recoil and the rifle is more accurate at 100Y than before. I guess we all have different expectations and thus different results.

 

[Zerodefect]

How could it get more accurate with a piston bouncing around on the tip of the barrel?
Did you also add a free float forearm at the same time maybe? Or change to a better batch of ammo?

 

[Rubber_Duck]

IF your going to retrofit with either the Bushmaster or the Osprey piston kit add these additional items to you rifle:

A good 2 port muzzle brake, I personally like and use the PWS 556.
A Sprinco "red" carbine buffer spring and either use a normal carbine buffer or, for more recoil reduction, install a Enidine.

Funny you mention that because we are also looking to add a Surefire MB556K muzzle brake and an Enidine buffer to reduce as much as possible muzzle rise and movement as well as diminish recoil. Still looking at other options for a muzzle brake as the Surefire is very expensive.

 

[MCMXI]

How could it get more accurate with a piston bouncing around on the tip of the barrel?

First off, the piston isn't on "the tip of the barrel". Second, if the energy of the expanding gasses is moving an XXgr bullet along at almost 3,000 fps, once the gas gets to the port in the barrel, it now has to move a much larger/heavier piston and connecting rod back against the bolt. What's the acceleration of the piston and connecting rod? I bet you don't have those numbers so you can't calculate where the bullet is compared to the piston, connecting rod or bolt as a function of time. My POF P415 has a 16" barrel and my POF P308 has a 20" barrel. It's possible that bullets have left the barrels before any harmonic oddities occur ... possible I say. I haven't found either of my GP POF ARs to suffer in accuracy or recoil compared to my DGI ARs or others. Many piston driven rifles are capable of excellent accuracy e.g. M1A, M1 Garand etc.

 

[The_Hammer_Man]

ok... there seems to be some confusion about how my rifles are setup.

Here they are:

Seekins Precision Billet Lower w/RRA lower parts kit,single stage 5lb patrol trigger
UBR stock w/red spring and Enidine

Mega Billet Upper w/BCM Gunfighter charging handle and Osprey's proprietary piston bolt carrier
MP tested bolt w/ O-ring
WOA 12.5" SS Barrel ,1in7 twist, PWS FSC custom muzzle brake (3 ports)
Osprey piston fitted into a low profile VLTOR gas block
Daniel Defense Omega 9" FF tube
Aimpoint ML3 w/3x magnifier
Troy Tritium Battelsights

How does it shoot? 1-1.5 MOA with this setup. With a normal buffer spring and buffer I get 1.5-2 MOA.

My 16" is nearly a carbon copy of the SBR except it has a Timney 3lb trigger pack in it that I got from 1858. (Thanks again Bro!) And it has a VLTOR CASV-M rail system installed.

How does this one shoot? Even better than the SBR! .5-.75MOA average groups w/little recoil and great second shot speed. If you hold steady you can get "spectacle shots" all day long with this thing.

Now don't get me wrong... a piston is NOT the "golden bullet" where accuracy is concerned. Never was, never will be, it was designed to increase the reliability of the AR platform under stressful conditions where the oppertunity to clean it would be either nonexistant or difficult.

For accurizing an AR you still need to install a good barrel w/a decent muzzle brake/hider, a free float tube, and a decent single stage or dbl stage trigger. Good upper to lower fit is a plus but not as critical as the other three things.

One of the "tricks" to removing some of the jump from your weapon is to "clock" your muzzle device. IE, instead of lining it up at "noon" with your barrel have it set slightly right of noon. This will counterbalance the torque generated by the bullet. You don't need to clock it much.. about 2-5 degrees on average has been my experience.

Hope this clarifies things.

 

[The_Hammer_Man]

Zerodefect says:

How could it get more accurate with a piston bouncing around on the tip of the barrel?
Did you also add a free float forearm at the same time maybe? Or change to a better batch of ammo?

After some thought, and donning my flameproof underoos, I've decided to take a crack at answering this question.

I get asked this one alot by customers and potential customers who are confounded by the fact that my piston uppers outclass their DI setups. Now I am NOT a magician and the only thing up my sleeve is a smelly armpit. What I am is a tinkerer. I have, over the years, had direct user experience with most of the piston drives extent starting with my Dad's M1A that he brought home from Korea.

As a gunsmith one of the biggest parts to my work with the AR platform have been fixing problems caused by user error. Usually those errors are in cleaning/maintenance of their weapons. If you've ever been a gunbunny/cage monkey for a law enforcement agency or company armorer for a military organization you'll get what I mean. After a few trips down this road you start looking for ways to make your life and your customers life easier. This is what started my initial investigation into piston driven AR's and retrofit kits.

The trips been a long one with stops along the way to experiment with most, if not all, of the piston retro kits available. Adams Arms,Ares/Bushmaster,CMMG,Osprey to name the most, IMHO, reliable piston retrofit kits on the market today.

After LOTS of testing, on my own rifles, as well as customer weps, I've narrowed my retrofit choices to three. Adams Arms, Ares/Bushy,and Osprey with Osprey earning top spot for patrol rifles and Ares/Bushmaster earning top spot for SPR rifles that require narrow FF tubes like the ERGO or DD. (The Osprey won't fit under the ERGO for love or money. DD's have to be modded so that they'll fit.) Adams Arms gets my vote for building Suppressor equipped rifles, also SBR's The other two sometimes, not always, have issues with either overgassing or undergassing with all the attendant issues. So, for reliabilities sake, I chose to go with the AA kit for this class of rifle.

No, these are not perfect choices.. they're MY choices... go get/make your own!

If, in the future, someone points out a better product I'll probably use it. If, when,,,, maybe .

The biggest reason I chose the Ares/Bushmaster and the Osprey Defense retro kits is the big two.. ease of maintenance and user confidence. They work, all the time, everytime and they are easy to clean and maintain. The reason I recommend them for patrol rifles is, believe it or not, officer boredom. If there's a button to push or a knob to turn someone is going to push it or turn it and forget that he/she did. This means that if/when the SHTF the weapon will not be in a ready condition. This is bad... very muchly bad! The nice thing about these two kits is that under normal circumstances the user, that bored guy/gal remember, can't readily get at the working parts of the piston drive in order to muck it up. This is known as a GOOD thing . (At least to law enforcement administrators)

Ok, so what other benefit besides ease of maintenance does the end user get? How about reduced recoil? Yuppa,, unlike some piston drives these two systems do reduce, not drastically, the felt or subjective recoil noticeably. This is a major plus with smaller/less experienced shooters. It is my very strong belief that anything that increases shooter comfort and confidence is a GOOD thing. I am not into self abuse and most of the folks who I do work for aren't either. So, why make it worse by adding weight and increasing recoil? Seems kinda dumb to me.

If I'm building an SBR shorter than 12.5" I'll use the AA kit. Especially if the end user is going to suppress it. Yes it's heavier... yes recoil is slightly heavier than the other kits..but it IS adjustable and reliable. And, to be honest, most of the end users that get my builds actually go to a gym now and again and actually work at upper body strength so an extra 1.9 lbs isn't a big deal to them. I use Surefire or PWS brake/adapters only...my choice based on experience with them and other brands and not subject to debate.

Now the second part... yes, I always recommend free floating the forearm whenever it's within the POU (philosophy of use) for the weapon.

Patrol rifles have to fit into racks in squad cars and thus have to be uniform in the profiles in order to fit. The solution to freefloating these is simple. Compass Lake Engineering makes a CMP free float tube that "hides" under a normal set of hand guards. For a norminal fee they'll shorten their stock rifle length tube to carbine length and weld on the round carbine forecap and even mod your forearm caps for you. Nice people who are easy to work with.

Special Purpose Weapons,,,, IE, toys for SWATTIES/CERTS,ERTS and so on are generally very very mission specific and require lots of head scratching on the end user and smiths part. Too big a subject to go into here,,,, might start a different thread.

 

[chiken36]

Osprey Defense Piston Kit

Here is my M&P 15 with the ops-416 installed in it.
Magpul Equipment: ctr stock, pmag, and moe handguard (modified).
Simple yet killer looks on my AR15!!
The piston kit performs flawless, about 1k shot with it, recoil is reduced.