AR15 - Piston vs. Impingment

[eapking]

Opinions please. Main use: target shooting, SHTF home defense.

[Mike]

I own both. The piston is cool, but it does nothing a DI gun can't do cheaper with less weight and a less noticeable recoil impulse.

Mike

[DavidD]

I vote Impingment. Cheap and proven to be reliable, especially in the context you plan to use it. Use the extra $ you would have spent for accessories.

[-boatman-]

I voted Impingment. I just don't see the need for the piston even though I like the idea. Now, if I had to find things to spend my money on.......

[JeffL]

I'm fine with DI. I tried a Sig 556 and the balance just felt off, way too front heavy.

[gunrunner32]

I own both, can't beat the DI but the Piston is just fun and the clean up couldn't be easier. Voted Piston for overall clean up, and it's fun watching my wife shoot it.

[Guest drv2fst]

I like pistons. I have both. Piston's keep your moving parts clean. I like shooting more than cleaning. A piston AR ends the AR/AK debate with the best of both.

[Guest 6.8 AR]

I like the piston, but the DI works fine enough for me to not want to spend the money.

[Smith]

Piston. Some one made the comment about proven reliability. The only thing it's proven is that it was a bad idea and takes way to much maintenance attention to maintain reliability. There is a reason why every new design is a piston design and why there is now an abundance of aftermarket piston makers. True DI is fine for the casual shooter who doesn't really run it hard, but why settle for a 4 cylinder just because it works pretty good?

This is coming from an AK guy who has never dreamed of anyone trying to make a DI AK. haha!

[Jasongar8]

DI for me. Piston guns are ATAS, but the companies who make piston guns think wayyyy to much of them IMO. When I can build a DI gun for less than $1k that will do everything I need, there is no way I'm going to give $2k+ just to say I have a piston gun. All the tacticool guys will tell you that a piston gun is must have, but I doubt anyone stateside really needs a piston gun.

[Reservoir Dog]

Impingement. DI is a proven design, costs less, weighs less, and has fewer moving parts to break.

Piston ARs are overrated IMHO. Keep a DI gun well lubed (as any firearm should be) and it will run even if it is completely filthy.

[Guest Halfpint]

I voted for DI simply because of parts commonality and availability . . . My DI guns run fine, my buddy's piston gun runs fine. We've beaten on both pretty hard, and haven't had a problem yet that can't be directly attributed to mags or ammo. If the S really has HTF, I'm sticking with what I know I can find parts for in a pinch . . . ALL the parts.

*Disclaimer: Yes I want a piston gun, and I will eventually own one. Mainly so my SHTF direct-impingement war-horse can stay clean for when I really do have to use it for serious social interaction.

[TN-popo]

For the given OP situations...DI.

-Less/smoother recoil

-Better parts commonality

-Lighter

-Cheaper

As for reliability, I've run 1000 rounds in 2 days (twice) and 1200 rounds in 3 days with no cleaning in two different DI ARs. Zero malfunctions.

Moot point.

The only time I'd rather have a Piston gun is if I was using a suppressor.

[molonlabetn]

I plan to purchase a piston upper... but only because it will be used exclusively with a suppressor. As far as reliability is concerned, there may be some advantage... but realistically, shooters like us won't ever truly strain the function of a DI weapon, if it's properly put together and maintained. And from that standpoint, a DI gun is far easier/cheaper to maintain.

[Guest FroggyOne2]

Well none of you guys have mentioned anything that answered the mans question.. Which is better for ie "target shooting".. DI is the way to go for "target shooting". You have less moving parts, DI is more reliable. With piston, you would have to deal with getting the gas reduced enough so that the piston don't move till the bullet is competely out of the barrel, movement in the piston would deter accuracy if the bullet is still in the bbl. Another tid-bit. On DI systems, if your brass is landing at 1230 to 230 from the end of the bbl (muzzle being 1200), your gun is cycling too fast. Which means the gas port in your gun is too large. If your brass is landing at 4 to 5 o'clock from the muzzle the your gas system is just right. There are three ways to fix a gun that is cycling too fast. One is have the gas hole plugged in the bbl, then re-drilled a smaller dia. to match the loads that your shooting. Two is to use a carrier weight system, which adds weight to the carrier to slow it down. Three is to use an adjustable gas block. Also, if you intend to do any formal type of target shooting, ie National Match. Your rifle must be the same as an A2 Service Rifle and A2 Service Rifles don't have a piston in it. The Service Rifle I had shot 5 shots at 100 yards, .186 group with Sierra 80gr bulllets, with iron sights. Also, with a piston system, you can not use a National Match float tube on the rifle. A National Match float tube will have the sling loop attached to it instead of the sight tower, so that when you put tension on the sling to hold the rifle, it is pulling on the tube and not the bbl (which would bend the bbl) .

Edited September 7, 2010 by FroggyOne2

[Dolomite_supafly]

Piston. Some one made the comment about proven reliability. The only thing it's proven is that it was a bad idea and takes way to much maintenance attention to maintain reliability. There is a reason why every new design is a piston design and why there is now an abundance of aftermarket piston makers. True DI is fine for the casual shooter who doesn't really run it hard, but why settle for a 4 cylinder just because it works pretty good?

This is coming from an AK guy who has never dreamed of anyone trying to make a DI AK. haha!

When going overseas I would put 300-500 rounds a week for 10+ weeks thru my DI AR without cleaning. Every trip I would put at least 3000 trouble free rounds during training not including actual engagements. The only time I broke the weapon down was when I would get issued it at the beginning of the trip and 10+ weeks later right before I turned it back in. I would run the gun DRY with no oil on it what so ever to prevent collecting the talcum powder dust over there. The reliability issue is just a myth from olden days that people can't seem to let go. Most of the problems people seem to cite are problems from 40+ years ago.

My personal AR is a DI and I have shot at least a thousand trouble free rounds over the course of a year without cleaning it. It never offered to cause any problem at all.

Now onto another note, pistol driven firearms have their merits as well. I do like the fact the bolt stays cool but in the end I do not believe it warrants the extra cost of retro fitting a already proven design. The AK was designed to be pistol driven and that has helped some with reliability but it is the loose tolerances that do more for reliability than the piston.

If you are having reliability issues with your AR it is because something is wrong with your gun or ammo.

Dolomite

[LagerHead]

I like piston. The bolt stays much cooler, which does aid in reliability. It does have one more moving part - the piston - but to say it makes it unreliable I don't think has been proven or substantiated here or anywhere else. On my Sig 556, the piston mates with the bolt and when the bolt moves rearward, the piston comes with it. The spring around the piston compresses and when the bolt reaches its rearward position the spring returns to its original position bringing the piston and bolt with it.

I've shot both, carried M16A1, A2, and M4 in the Army, and I'll take the piston driven gun every day of the week and twice on Sunday. It shoots very smooth, cleans quickly and easily, and has never jammed on me yet. YMMV.

[Dolomite_supafly]

The piston systems are not unreliable, but I do believe the DI is more reliable than what most people realize. It is like any old wive's tale, there are some who cling to it and spread it every chance they get. It is these people who, in an attempt to save moeny, decide to build a AR out of substandard parts then try to shoot crap ammo out of it. This is when the problems arise. At that point they proclaim that ALL DI AR's are crap when in fact it was the crap gun they built or the crap ammo they bought trying to save money.

Now some budget guns run fine but they will not last as long as a quality gun. Quality guns last well into the thousands of rounds without issue yet the cheap guns seem to fail regularly. As long as you have a quality AR and shoot decent ammo you will not have any issues. I have and continue to trust my life to DI AR's and feel more comfortable with them than the piston systems. Now that may change down the road once the longevity of the system on an AR proves itself.

Dolomite

[eapking]

Thanks for the input folks. Most appreciated!

[323ssplt]

When going overseas I would put 300-500 rounds a week for 10+ weeks thru my DI AR without cleaning. Every trip I would put at least 3000 trouble free rounds during training not including actual engagements. The only time I broke the weapon down was when I would get issued it at the beginning of the trip and 10+ weeks later right before I turned it back in. I would run the gun DRY with no oil on it what so ever to prevent collecting the talcum powder dust over there. The reliability issue is just a myth from olden days that people can't seem to let go. Most of the problems people seem to cite are problems from 40+ years ago.

My personal AR is a DI and I have shot at least a thousand trouble free rounds over the course of a year without cleaning it. It never offered to cause any problem at all.

Now onto another note, pistol driven firearms have their merits as well. I do like the fact the bolt stays cool but in the end I do not believe it warrants the extra cost of retro fitting a already proven design. The AK was designed to be pistol driven and that has helped some with reliability but it is the loose tolerances that do more for reliability than the piston.

If you are having reliability issues with your AR it is because something is wrong with your gun or ammo.

Dolomite

Dolomite> you and I have seen eye to eye on several issues in the past, but on the first paragraph of this statement I will have to call bull**** on.

I know, or at least understand it to be true that you have spent considerable time overseas, as have I and many others on this forum. I KNOW there is not a single person who has been in any type of situation "over there" who wouldn't clean their weapon after every range season, much less after several thousand rounds.

I'm not calling you a liar, but......quit stretching the truth. If you want to extoll the virtues of a particular op system, then by all means say so, but please dont do it by saying that you never cleaned your weapon that you used to defend your life with.

[323ssplt]

As for me, I like both systems. The DI system is simple, but the piston system runs much cooler, has less heat related stress on key parts and is much cleaner.

[Dolomite_supafly]

Dolomite> you and I have seen eye to eye on several issues in the past, but on the first paragraph of this statement I will have to call bull**** on.

I know, or at least understand it to be true that you have spent considerable time overseas, as have I and many others on this forum. I KNOW there is not a single person who has been in any type of situation "over there" who wouldn't clean their weapon after every range season, much less after several thousand rounds.

I'm not calling you a liar, but......quit stretching the truth. If you want to extoll the virtues of a particular op system, then by all means say so, but please dont do it by saying that you never cleaned your weapon that you used to defend your life with.

You can choose not to believe it but I have went entire 3 month trips with only two cleanings. Once at the begining and once at the end. Other than that the only tiime the weapon was broken down was if there was a problem which was extremely rare and usually related to ammunition. The biggest problems with reliability I seen over there is when people oiled the crap out of their weapons. This only attracted the moon dust type dirt and did cause cycling problems. I for one had that happen on my first few trips but after I was told to leave the gun dry it ran much better. And as long as it ran without issues I never saw a need to clean it so I didn't. It took me a year or two to get to the point where I would feel comforatble not cleaning it but I would in fact go without cleaning for an entire trip. And as a matter of fact this was on my last trip before a helicopter accident that knocked me out of the game.

And yes 3000 may seem a bit much but we would run drills every week and sometimes 2x a week. We would spend probably 4 hours of running drills and going thru at least 10 mags each time we trained.

Now should I have cleaned my weapon more often?, probably, but not doing so had no ill effects for me other than being a pain to clean at the end of a trip. The weapon was, without a doubt, filthy dirty but not to the point it became unreliable for me. I would not advocate someone doing what I did but all I was stating that I have experienced this.

Dolomite

Edited September 8, 2010 by Dolomite_supafly

[Dolomite_supafly]

I give you a few samples of DI AR's going well beyound 3000 rounds without cleaning. None of these are me but I still stand by my statemt that I have fired 3000+ rounds over a 3 month period without cleaning and still had a functioning rifle. It all has to do with quality ammunition being fired out of a quality rifle.

5880 rounds without cleaning and still working You have to have to be a member of AR15.com to go to the link but here are some pictures:

5880 rounds without cleaning, only clp added twice at random times. Not one problem.

They are huge so I linked rather than imbedded them.

http://img38.imageshack.us/img38/1006/p8040023q.jpg

http://img169.imageshack.us/img169/6206/p8040024.jpg

http://img210.imageshack.us/img210/4214/p8040026.jpg

http://img199.imageshack.us/img199/4267/p8040027.jpg

http://img16.imageshack.us/img16/6933/p8040029.jpg

http://img12.imageshack.us/img12/2421/p8040031.jpg

The above is not related to below.

This is from Pat Rogers who runs EAG Tactical:

At 26,450 rds had 3 failures to extract. Replaced BCG and cleaned gun for the first time

"Filthy #14 is the most used, and has (as 12-24-09) 28905 rounds down range. The barrel is original. It has never had a brush put through it. -At 16,400 rounds bolt lug cracked. Replaced the bolt carrier group

-At approximately 26,000 rounds fired a 5 shot 50m group that went into 0.5". This might not be that tight at 100 meters.

-At 26,450 rds had 3 failures to extract. Replaced BCG and cleaned gun for the first time

We use only SLip2000 EWL for lube and Slip 2000 725 to clean.

**All of the rounds were fired during class (at the rate of approximately 1,250 rounds every 3 days)**

I do not recommend allowing the gun to go this long without PM (preventive maintenance). However, we wanted to see how far we could take this particular gun (#14) without being burdened by the myth of meticulous cleaning."

Look for a Pat Rogers's article on EAG Tactical's "Filthy 14" BCM Middy in the October 2010 issue of SWAT Magazine.

Swat magazines has a torture test of a Colt 6920LE in the July 2010 issue. The Colt in question was cleaned once, and not until nearly 15k rounds. Get the magazine.

Dolomite

[TN-popo]

I've always felt that the myth of the DI's lack of reliability was perpetuated by people regurgitating old Vietnam stories or those using crappy or worn out rifles.

My RRA (personal) has went about 4k and my Bushy (issued) about 2k without a malfunction (over 1k each in a weekend more than once) that wasn't directly related to a crappy magazine.

PS. Ammo used...Federal M-193, Federal American Eagle, and Brown Bear.

Edited September 9, 2010 by TN-popo

[LagerHead]

DI for me. Piston guns are ATAS, but the companies who make piston guns think wayyyy to much of them IMO. When I can build a DI gun for less than $1k that will do everything I need, there is no way I'm going to give $2k+ just to say I have a piston gun. All the tacticool guys will tell you that a piston gun is must have, but I doubt anyone stateside really needs a piston gun.

I've always felt that the myth of the DI's lack of reliability was perpetuated by people regurgitating old Vietnam stories or those using crappy or worn out rifles.

My RRA has went about 4k and my Bushy (issued) about 2k without a malfunction (over 1k each in a weekend at least once) that wasn't directly related to a crappy magazine.

PS. Ammo used...Federal M-193, Federal American Eagle, and Brown Bear.

Just remember though, the military weapons are made by the lowest bidder. There is some truth to what they say, though it is relative.