Don't Shoot. I'm a Friendly !!!

Maddmax

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First. Thanks for all the great info on anything and everything everyone posts on their "Toys". Been doing a ton of research on the M&P 15's (and M&P 15-22's) and 99.9% sold on the 15 Sport & Tactical models. Grandkid is getting almost old enough to start shooting (hence the 15-22),but he'll start out on a bolt action single shot first. I'm already/have been a BIG S&W fan. I own 7 M&P handguns. Looking to add a few more.

Wouldn't touch a Colt AR (old memories die hard). But am wondering about the SR-556 and any good bad things about those and how they compare.
 
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The M&P15's are a DI (direct impingement) and the sr 556 piston operated. So that in itself is a pretty big difference. You can look up the pros and cons by just going to google. I have a friend that has an sr 556 and he loves it and has had no issues to date. I have a M&P15T and really enjoy my rifle and have also not had any issues to date. It really depends on what your price range is and what your plan is for your rifle.
 
The piston operated system will make cleaning your rifle easier, you wont get the gases back into the BCG. As far as I know that is about the only difference.
 
The M&P15's are a DI (direct impingement) and the sr 556 piston operated.

Beg to differ...I have a M&P15 PS which is a piston rifle. The DI guns have been around for 50 years and work well. The piston guns are coming of age as more and more top gun manufacturers are coming out with their new models. My gun is a year old, never has had any malfunction and I am more than satisfied with it.
 
Whereas direct impingement (DI) gas systems use standardized specifications, gas piston systems are proprietary to the manufacturer.

Parts for the gas piston system are different between S&W, Ruger, Sig, etc., etc., etc...
 
All gas piston guns are proprietary. There may be minor exceptions, but I am unaware of any. You break a gas part on your M&P15 PS, you have to rely on S&W for the part. You can't Google AR-15 parts and get them over night from "Bubba's Gun Shop".

Generally speaking, gas impingement systems are more accurate than the DI guns simply because the piston pushes on a small portion of the carrier and causes it to tip. The manufacturers have gone to great extremes to keep the carrier from tipping, but it still happens and when it does the bolt pushes harder on some of the lugs than on others.

The reason the DI guns are more accurate is the bolt, the barrel, and the carrier are all concentric and remain that way when fired. The vibrations are more constant from shot to shot. Bench rest shooters go to great extremes to true their receiver and bolt to assure all recoil force is in line with the bore.

I see JaPes beat me to the proprietary part. Too late at night to type fast.
 
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Generally speaking, gas impingement systems are more accurate than the DI guns simply because the piston pushes on a small portion of the carrier and causes it to tip. The manufacturers have gone to great extremes to keep the carrier from tipping, but it still happens and when it does the bolt pushes harder on some of the lugs than on others.

Just more of the same DI vs PS BS. After 1000's of rounds through my gun my bolt shows no signs of excessive wear. My M&P is the most accurate rifle I have ever shot...better than my neighbor's Colt DI AR.

This target was shot @ 100 yds....by my wife.....a 68 YO grandma to boot.

Let's see yours.......

AR15Target.jpg
 
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Just more of the same DI vs PS BS. After 1000's of rounds through my gun my bolt shows no signs of excessive wear. My M&P is the most accurate rifle I have ever shot...better than my neighbor's Colt DI AR.

It's not the bolt that wears excessively - it's the races in the receiver from the tipping bolt carrier. Although that problem has been pretty much taken care of, any tipping will wear cause uneven wear. Any tipping will cause uneven torquing of the barrel extension and barrel.

We can post target pictures until the end of time, but that proves no more than you have an accurate piston rifle and I have an accurate DI gun.

Again, generally speaking.......... I think the polite thing to do is agree to disagree.

And unlike Gunslinger I don't have any pictures of my wife with any rifle, although she did have high score in the last 100 yard reduced match she shot.
 
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Just more of the same DI vs PS BS.
To you it's BS, to me a piston is a fix in search of a problem. In truth the "DI" system is a coaxial piston system, where as the "piston" AR's are an offset piston system. BTW, I blame the good groups on your wife and not the rifles superiority.

In the long run "run what ya brung". If you want a external piston AR, buy it and have fun. Me, I'll stick with the inline piston system that Eugene Stoner designed.

TECHNICAL NOTE 54: DIRECT IMPINGEMENT VERSUS
PISTON DRIVE
 
Just make sure you get all this stuff to keep it clean. I just use a bore snake, a couple of rags with Hoppes 9 and about 10 minutes time.......

We have a bunch of new members who are new to the AR platform. While we have fun adding furniture and accessories, one aspect of AR ownership that gets overlooked is cleaning.

I don't intend for this thread to devolve into cleaning arguments similar to those I have seen on other forums. For this thread, I think we can all agree on the basics of cleaning.

  • Clean barrel/bore
  • Clean chamber
  • Clean bolt carrier group

This can be accomplished using very basic tools: rods, brushes, patches. There are several YouTube videos that illustrate the basic cleaning process.

There are tools beyond basic tools that can help make the cleaning process easier. I'm going to show some tools I own and tried out. I emphasize that none of these tools are necessary, but the make the job faster & easier.

The subject of lube choice & cleaning solvent choice is for a different thread.

Otis flexible rod cleaning kit:

788293.jpg


It replaces a one piece rod in favor of a polymer coated cable. This makes it easy to clean from breech to muzzle without worrying about dinging up the chamber or rifling. It uses brushes and patches just like we're used to.​

Gunslick AR-15 Bore Guide:

GunslickBoreGuide1.jpg


GunslickBoreGude2.jpg


If you use a one piece rod, then a bore guide makes the process easier with less worries about dinging up the chamber or rifling. The bore guide fits snugly into place. Push the rod through the bore guide. The bore guide has a port that matches to the ejection port of the AR. It is through this port that you can add solvents/lube to the patches, or spray cleaner down the barrel.​

Hoppes Bore Snake

HoppesBoreSnake22Cal_edit.jpg

Boresnake1.jpg

Boresnake2.jpg


The bore snake is a pull through string that has bronze cleaning bristles integrated into it. Put some cleaning solvent on the section before the bristles, & pull through breech to muzzle.

In one pass it applies solvent, brushes, and swabs out the barrel. I usually pull the bore snake through three times. The bore snake can be washed and reused many times.​

Talon Tactical Lug Scraping Tool

TalonLugScraper1.jpg


TalonLugScraper2.jpg


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I use this tool when the lugs are seriously carbon fouled. The tool can clean the sides of the lugs. Gentle pressure and a twisting/pull motion is all that is necessary.

TalonLugScraper4.jpg


It also cleans the face of the lugs that we can't easily see.

TalonLugScraper5.jpg


When contacting the face of the lug, light pressure and a twist scrapes off carbon deposits.

The Talon Tactical Lug Scraper also accepts any standard cleaning attachment on it's tip. It can be used as a cleaning device as illustrated in the next section.​

Chamber Brushes

The chamber is bigger than the bore. I use one of two different tools to clean out the chamber. Both set ups are shown attached to the Talon Tactical lug scraper.

.40 Cal brush

ChamberBrush1.jpg


ChamberBrush2.jpg


I wet the brush with solvent, and scrub out the chamber. I then wrap a clean patch around the brush to swab out the chamber.

AR-15 Chamber Brush

ChamberBrush3.jpg


ChamberBrush4.jpg


Cleans the chamber & brushes the lugs.​

CAT M4 BCG Cleaning Tool

By far the most useful cleaning tool I use.

CatM41.jpg


It scrapes carbon deposits from the bolt tail with a quick and easy twisting motion.

CatM42.jpg


It scrapes carbon from the BCG. Affix a patch to swab out the fouling.

CatM43.jpg


CatM44.jpg


It also can be used to scrape carbon deposits from the firing pin.

CATM45.jpg

Dental Pick

DentalPick.jpg


The good old dental pick. Works like a charm every time. Gets into hard to reach areas to scrape off carbon deposits. Just be careful using it. Use just enough pressure to remove carbon, but not ding up the metal.​

There are also some other tools I find useful to have on hand.

Ejector Spring Installation/Removal Jig

EjectorJig1.jpg


In order to remove/replace the ejector spring on the bolt, the ejector must be compressed. Then a small retaining roll pin must be driven out. The jig makes this job quick and simple.

EjectorJig2.jpg
 
I gotta agree with Kodiac, the DI system has been reliable and accurate for the last 35 years.
As an armorer and gunsmith I have seen issues with the piston ARs that have caused me to shy away from them.
They are finicky, prone to breakage, and a delecate system.
The ONE stand out that I might consider is the Ruger SR 556 entry.
If you want a piston, go with the Robinson XCR, or an AK.
 
Don't Shoot. I'm a Friendly !!!

Don't worry, you won't get shot in this thread. The DI fans have their rifles all jammed up from carbon fouling, and the Piston fans spent too much on their rifles and can't afford ammo. :D

Ruger makes good guns, even their ARs and 1911s are huge winners right now. It's all about features and price point. Buy the gun you want and don't look back.
 
Wow I didnt realize the price difference on the SR556 Wow...not in this lifetime..I can build 3 rifles for the price of one! even without all the spare Parts.
 
I gotta agree with Kodiac, the DI system has been reliable and accurate for the last 35 years.
As an armorer and gunsmith I have seen issues with the piston ARs that have caused me to shy away from them.
They are finicky, prone to breakage, and a delecate system.
The ONE stand out that I might consider is the Ruger SR 556 entry.
If you want a piston, go with the Robinson XCR, or an AK.

I too agree with the good reliability of the DI guns. One of the problems with piston systems is there really is no industry standard for them yet. So every mfgr does their own thing. The piston system also makes the rifle a bit nose heavy....and yes they still have to be cleaned...in two places.
 
I gotta agree with Kodiac, the DI system has been reliable and accurate for the last 35 years.
As an armorer and gunsmith I have seen issues with the piston ARs that have caused me to shy away from them.
They are finicky, prone to breakage, and a delecate system.
The ONE stand out that I might consider is the Ruger SR 556 entry.
If you want a piston, go with the Robinson XCR, or an AK.

Actually, the first M16's were issued in 1962 to the Air Force. That's 50 years. The only major problems were ammo and maintenance issues when first issued. They were rectified when it became the M16A1 in 1967.

Fitting a piston system to the AR system makes about as much sense as what Winchester did to the Model 70 in 1964.
 
Understood, I was going off when NATO standardized the 5.56 round.
The only major problems were ammo and maintenance issues when first issued.
Also, chrome lining the bores and chambers helped a lot too.
MacNamara's folly, he was in such a rush to get it into combat.
 
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Also, chrome lining the bores and chambers helped a lot too.
MacNamara's folly, he was in such a rush to get it into combat.

I believe had they issued cleaning kits with them originally, that chrome lining wouldnt have made that big a difference, But that is just my opinion!
 

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