Direct Impingement Conversion? [Archive] - Glock Talk

PDA

View Full Version : Direct Impingement Conversion?


eaglefrq
12-07-2011, 17:28
I recently got my first AR and it's a direct impingement. I've seen some kits to convert it to a piston and I'm trying to figure out why?

I know the direct impingement have been around since the beginning and the pistons are fairly new.

For a recreational shooter, is there a benefit to converting?

faawrenchbndr
12-07-2011, 17:41
They run cooler.
They have a cleaner bore/chamber.
They are to operate with less lube, because of the above.

I've been shooting the M16/AR15 for 27 years. I AM a DI fan, but,
I do see some pros and cons of a piston upper.

eaglefrq
12-07-2011, 18:24
They run cooler.
They have a cleaner bore/chamber.
They are to operate with less lube, because of the above.

I've been shooting the M16/AR15 for 27 years. I AM a DI fan, but,
I do see some pros and cons of a piston upper.

Other than being fairly new, are there any cons to the piston?

I haven't had a chance to shoot mine yet, the only range around here is about 1 hr away and closes about the same time I get off work. I'm going this weekend to shoot.

mjkeat
12-07-2011, 18:44
Other than being fairly new, are there any cons to the piston?

I haven't had a chance to shoot mine yet, the only range around here is about 1 hr away and closes about the same time I get off work. I'm going this weekend to shoot.

The only cons I know of are from them being proprietary. Some also claim they are overgassed as well.

faawrenchbndr
12-07-2011, 18:50
Other than being fairly new, are there any cons to the piston?

I haven't had a chance to shoot mine yet, the only range around here is about 1 hr away and closes about the same time I get off work. I'm going this weekend to shoot.


Some state they are less accurate than a DI as well. More moving parts,
heavier weight due to the additional parts. Some piston guns suffer from
carrier tilt. Many have fixed this issue.

I am VERY new to the piston upper, I chose an Adams Arms complete upper.
Shown below on a BCM lower.......

http://i30.photobucket.com/albums/c341/faawrenchbndr/BCMwithAdamsArmsupperpic6.jpg

http://i30.photobucket.com/albums/c341/faawrenchbndr/BCMwithAdamsArmsupperpic12.jpg

boomhower
12-08-2011, 07:51
Their are pluses and negatives to the piston system. Do some research and if you want one just get a quality system. LWRC would be my first pick but they certainly aren't cheap. LMT has gotten good looks as well. For the cheaper end AA would certainly be worth a look. If you get a system that isn't done right you'll have nothing but problems.

WoodenPlank
12-08-2011, 08:14
I recently got my first AR and it's a direct impingement. I've seen some kits to convert it to a piston and I'm trying to figure out why?

I know the direct impingement have been around since the beginning and the pistons are fairly new.

For a recreational shooter, is there a benefit to converting?

They are not new in the least. They just never hit mainstream in the AR platform until recently.

They run cooler.
They have a cleaner bore/chamber.
They are to operate with less lube, because of the above.

I've been shooting the M16/AR15 for 27 years. I AM a DI fan, but,
I do see some pros and cons of a piston upper.

However, the piston is often more difficult to access for cleaning, parts are often proprietary, more reciprocating mass over the barrel can (and usually does) affect accuracy, carrier tilt in some systems, less rail systems and gas blocks available for modification/replacement.

IMO, it's a solution looking for a problem. The only time I have seen serious benefit to a piston was with very short (12" or less) barrels, being run with a suppressor, and heavy volume.

I'll gladly stick to my DI gun, and just keep it lubed.

rockapede
12-08-2011, 08:21
While I don't think there is anything inherently wrong with the concept of a piston AR, look up Filthy 14 and tell me if a piston system is necessary. The two most important factors affecting AR reliability are the quality of the weapon and healthy lubrication.

eaglefrq
12-08-2011, 08:32
Thanks to everyone for the info. It was more of a curiosity question than anything else. I think if I went home and told mama I wanted to get a conversion kit, I would have a black eye later that evening. :whistling:

Eurodriver
12-08-2011, 09:55
While I don't think there is anything inherently wrong with the concept of a piston AR, look up Filthy 14 and tell me if a piston system is necessary. The two most important factors affecting AR reliability are the quality of the weapon and healthy lubrication.

I love when people buy piston conversion kits for their DPMS AR15s. :rofl:

rockapede
12-08-2011, 10:16
I love when people buy piston conversion kits for their DPMS AR15s. :rofl:

Of course, a piston converted DPMS will never be complete without an optic worth more than the rifle and every part Magpul makes.

faawrenchbndr
12-08-2011, 14:57
My hunting/go to rifle is a DI 6.8 SPC.......the AA upper'ed BCM is a "fun gun"

WoodenPlank
12-08-2011, 15:07
Of course, a piston converted DPMS will never be complete without an NC Star optic, and UTG rail with matching covers.

Fixed that for accuracy.

mixflip
12-08-2011, 15:13
I say dont convert it to piston because you think you "need" to. Chances are you dont.

Change it because you simply want to.

A failzero coated (nickle boron) bolt and BCG will not need hardly any oil due to its lubricity of its nickle boron coating and carbon fouling wont stick to it much either so cleaning is a since from what I hear?

Look into all options before you buy a piston conversion. For the record, I own a piston gun and I am a big fan of them but I have no illusions of it being technically better. Its different. Period. It has its own share of weakness's.

boomhower
12-08-2011, 15:16
A failzero coated (nickle boron) bolt and BCG will not need hardly any oil due to its lubricity of its nickle boron coating and carbon fouling wont stick to it much either so cleaning is a since from what I hear?


This is true. Mine has never seen a drop of lue, they actually recommend against because it won't stick anyways. Not cheap but very very nice to have.


Outdoor Hub mobile, the outdoor information engine

Javelin
12-08-2011, 15:19
I honestly see no purpose of a piston on an AR. If you want a proper gas piston system there are plenty of other (and better) options out there for cheaper.

:wavey:

eaglefrq
12-08-2011, 16:32
I say dont convert it to piston because you think you "need" to. Chances are you dont.

Change it because you simply want to.

A failzero coated (nickle boron) bolt and BCG will not need hardly any oil due to its lubricity of its nickle boron coating and carbon fouling wont stick to it much either so cleaning is a since from what I hear?

Look into all options before you buy a piston conversion. For the record, I own a piston gun and I am a big fan of them but I have no illusions of it being technically better. Its different. Period. It has its own share of weakness's.

Thanks for the advice. I was just curious if the pistons were better. I have no intention of converting it right now.

Halojumper
12-10-2011, 19:07
The only cons I know of are from them being proprietary. Some also claim they are overgassed as well.

My understanding is that it's actually the DI guns that are overgassed.

Halojumper
12-10-2011, 19:08
Another thing to keep in mind is that the guns Eugene Stoner designed after the AR were piston guns. Apparently he felt it was an improvement FWIW.

WoodenPlank
12-10-2011, 19:43
My understanding is that it's actually the DI guns that are overgassed.

In both cases, it comes down to the individual barrel, gas block, etc.

Eurodriver
12-10-2011, 20:17
My understanding is that it's actually the DI guns that are overgassed.

Yep. Bushmaster, DPMS, etc all have larger than necessary gas ports so fudd shooters can run their WOLF .223 ammunition through their rifles and not call up customer service weekly claiming "It won't feed my ammunition".

Other companies that follow the specifications more closely are not overgassed. But even these, when adding a piston conversion, have too much gas because the gas required to push a piston is less than the gas required to fill the gas tube and push the bolt carrier group to the rear.

Then of course theres that whole issue with locking lugs sheering off and carrier tilt. Remember, on a DI gun the gas enters the bolt carrier group and forces push the bolt forward and the bolt carrier to the rear equally. This makes for a smoother extraction/ejection cycle. When you put a piston (aftermarket mod or a custom gun) into the AR platform you are getting a violent jerk backwards on the bolt carrier group that the cam pin must overcome to unlock the bolt. Since the angle of the cam pin on the AR15 is so steep this creates a stress point on the back of the lugs on the bolt. Add to this what was said above that most piston ARs are overgassed and you have an issue. (If anyone doesn't believe me, go ahead and compare the cam angle on a gun designed for pistons from the get go like the AK47 and FN SCAR. Compare that to an M4 and get back with me)

Of course no one really cares about this and no one will probably even bother to read anything I just said because pistons are the way of the future. They run cooler and cleaner (you say they're heavier and have more moving parts? Thats ok) and the AR15 can't cycle more than 200 rounds without lube because it "****s where it eats"

Oh wait... thats not true either.

http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/

WoodenPlank
12-11-2011, 06:53
Of course no one really cares about this and no one will probably even bother to read anything I just said because pistons are the way of the future. They run cooler and cleaner (you say they're heavier and have more moving parts? Thats ok) and the AR15 can't cycle more than 200 rounds without lube because it "****s where it eats"

Oh wait... thats not true either.

http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/

Two words: Filthy Fourteen.

Spiffums
12-11-2011, 08:42
Why change a perfectly good gun? It's like buying a Colt 1911 and trying ot make it like a Glock.

faawrenchbndr
12-11-2011, 09:11
Why ask why?

One does not NEED a piston upper, one may WANT a piston upper.

Rooster Rugburn
12-11-2011, 09:32
This has been heavily discussed on arfcom from an intellectual and technical perspective, and not from the idiotic "an answer to a question never asked" from knuckleheads, although they have those there too.

If you want it from a logical and technical perspective, find the thread on arfcom and maybe m4carbine.net. You won't get that perspective here.

IIRC, the answer basically comes down to buying an upper designed and built as a piston because the kits cause uneven wear that will have drawbacks in the long term.

But again, find it on arfcom or m4carbine.net. Much better sources of information on the AR.

faawrenchbndr
12-11-2011, 10:34
Very good points Rooster'.......tons of pros & cons on both sides of the fence!

ghostwn
12-11-2011, 15:08
If you want a piston rifle, get the LWRC. There true piston rifle makers. :supergrin: