S&W M&P 15 barrel choice

[willymc]

Thinking about getting a S&W M&P15. I'm stuck between 2 choices. The one with the chrome 1in9 twist barrel, and the Sport, $300 less, with the 1in8 twist Melonite coated bore with 5R rifling. Consistant accuracy is important to me. Any info on difference between the 2 would be most appreciated. Also, I'm from Cali so I'd be getting one that is California compliant.

 

[bgrav321]

I can't speak for the chrome lined, but I have the melonite and my rifle has been a consistent 1-1.25 MOA shooter with PMC Bronze. Great rifle, I certainly love mine.

 

[CharlieDeltaJuliet]

I have the 1 in 9 twist M&P 15, it shoots about the same as bgrav321 states his 1in8 shoots. I have heard more say the melonite will wear better. I have even heard that others state that the melonite barrels are more accurate. I don't doubt that a bit. HK does not put the chrome lined barrel in their MR556. They clame the unlined is more accurate.

 

[willymc]

Thanks for the replies on the barrel lining! Anyone know what the "5R rifling" thing is all about?

 

[jim243]

Anyone know what the "5R rifling" thing is all about?

5 grove right hand twist. As to the chrome or no chrome, the chrome will last a little longer, but the non-chrome barrels SHOULD be a little more accurate since the rifling is sharper than a chrome barrel. If you shoot a lot and fast then get the chrome, if you shoot slow and accurate then the non chrome.

Just my opinion

Jim

 

[TurtlePhish]

Anyone know what the "5R rifling" thing is all about?

5R rifling is rifling with five grooves, and the lands having more sloped sides than ordinary rifling.

 

[willymc]

I'm not much into rapid fire, but I don't want to wait five minutes between shots for my barrel to cool either. I'll check out a few more accuracy reviews on the Sport and ORC before I decide.

 

[Warp]

I believe the chrome lined barrels will probably have less accuracy. The chrome lining is for durability and longevity, not accuracy.

If you are buying an AR15 to put on the bench (or bipod, or sandbag, or whatever) on shoot for groups, the S&W Sport should serve you well.

 

[willymc]

And I can buy a lot of ammo with the $300 savings. Thanks!

 

[gunfighter48]

I have a Sport and it's very accurate with factory ammo. I shoot mostly Fed m193 and PMC 55 gr ammo. Here's a 100 yrd target shot with M193 55 gr. The red bullseye is 1.5 in in diameter and these were 3 shot groups.

 

[meanmrmustard]

Melonite is a "beyond the surface" metal treatment, one I find superior to chrome lining. The durability isn't a factor with either: you'll most likely never wear out either lining, but melonite will be better for accuracy.

5r is a rifling consisting of 5 lands and grooves, eliminating the opposing forces of any 2 lands direct surface friction on the bullet. The lands are also radiused to eliminate unnecessary contact on the bullet. It isn't a gimmick, it works.

I'd go Sport. I have gone Sport, several times. It isn't just a bench rifle. I've fast fired with them, beat em up, shot crap ammo, hunted in freezing temps, carried on woods hikes, shot long range, mag dumped at short range, and it doesn't quit. Matter of fact, I may have just talked myself into buying another!

 

[hardluk1]

If both barrels are the same lenght or maining a high velocity that a longer barrel can give is not that imortant . I would and did go with the sport. With a good scope the sport is a sub moa rifle. The melonite treatment will have a more consistent bore diameter as nothing changes in diameter when compaired to a surface applied chrome coating. Long term wear will not matter.

 

[bgrav321]

Right on meanmrmustard. Right on.

 

[wriggly]

Another vote for the Sport here. The absence of the dust cover and forward assist are no deal breaker for me, and the weapon is very accurate. The $350 or so saved enabled me to buy a WMD Nickle Boron BCG and I had a little left over for a Larue LT 135-1 SPR/M4 scope mount so I can switch between my scope and red dot.

I also spruced mine up pretty quickly with Magpul furniture.

 

[willymc]

Thanks all! I think I'm sold. Now I'll see if I can find one at my LGS for a decent price. I've seen them on-line for under $700. I'll pay a bit more if my LGS has one in stock. Thanks again for all the replies!

 

[willymc]

Well, I just came back from my LGS. I bought the Sport. $699 + tax and transfer fees. I have another question. Does the Melonite barrel need the regular break-in procedure that I've used on my Hunting guns? My regular breakin is 1 patch each round for the 1st 20, 1 patch every 5 rounds for the next 20, and 1 patch every 10 for the next few 20's.

 

[allaroundhunter]

It's an AR.....just shoot it, shoot it some more, and don't worry about break in or anything

 

[CraigC]

Melonite is not a coating or plating. It's a surface hardening treatment, identical to Glock's Tenifer treatment. It does not alter dimensions and thus, the bore is more consistent from one end to the other. Hard chrome is a plating. Manufacturers have to take into account the thickness of the plating when cutting the bore and rifling. Problem is, chrome does not disperse itself evenly over the surface. So you end up with irregularities, which is why chrome lined bores are typically less accurate than unlined bores.

 

[Warp]

I have a Sport and it's very accurate with factory ammo. I shoot mostly Fed m193 and PMC 55 gr ammo. Here's a 100 yrd target shot with M193 55 gr. The red bullseye is 1.5 in in diameter and these were 3 shot groups.

For comparison:

Prvi M193 at 100 yards in my 6920 with red dot site. (only target I shot, not hand picked best or anything)

 

[hardluk1]

Work on the price with your LGS as lower prices are still out there. Gunsamerican has atleast one for 639.oo. May LGS has one for 595.oo

 

[chris in va]

I will also add the Sport uses a 'gain twist' rifling, meaning the rifling starts out at something like 1/12 then tightens up to 1/8 toward the muzzle.