Why no 20 inch?

[9245]

I’m interested in the M&P 10 but I am NOT interested in a 16 or 18 inch barrel, to me that makes no sense in .308 or 6.5 creedmoor, those are full power cartridges and should have full barrels or else what’s the point? If I wanted a carbine for close/medium range I’d stick to 5.56, it’s better suited for the job. But I am looking for a semi auto precision rifle, there is no need for the velocity drop from a carbine barrel, nor would I use a full powered cartridge for close range work as the extra flash and blast, extra recoil, and reduced magazine capacity would not be worth it over 5.56, so I have no idea why I can only find the M&P 10 in carbine length barrels, it’s like **** on a bull, why?

I’m aware of the performance center version in 6.5 creedmoor, but I’m not ready to spend an extra $800 just for 2 inches of barrel. Why is the non performance center version not offered in 20 inch? Or even better 22, 24, or 26 inch? And why no 6.5 Creedmoor except in the performance center version?

It doesn’t make sense.

 

[sgtsandman]

That's something you'd have to ask S&W about directly. My guess, is that since it is possible to hit targets out to 750ish yards out of the box that S&W thinks it's good enough. Max effective range for .308 when taking game is about 800 yards anyway. 2 more inches of barrel might give you 1,000 yards but even then the limits of the round's capability is being met or exceeded. Punching paper or hitting a steel target is a bit of a different animal since round lethality isn't a concern.

 

[ken158]

The barrel length for a 308 on an AR is well accepted to be optimized at 18”

 

[sgtsandman]

The barrel length for a 308 on an AR is well accepted to be optimized at 18”

I think you may be right from research I had done in the past but it has, admittedly, been a number of years since I did the research.

I'm also trying to get a feel for where the OP is coming from. If he is looking at long range precision shooting, it may be influencing his question.

 

[9245]

I think you may be right from research I had done in the past but it has, admittedly, been a number of years since I did the research.

I'm also trying to get a feel for where the OP is coming from. If he is looking at long range precision shooting, it may be influencing his question.

This, longer barrel gives more velocity, which is better for long range shooting, my goal is a 1,000 yard capable rifle.

 

[LVSteve]

The barrel length for a 308 on an AR is well accepted to be optimized at 18”

I wouldn't say optimized. I would call the 18" barrel the best compromise for .308.

 

[Rodan]

This, longer barrel gives more velocity, which is better for long range shooting, my goal is a 1,000 yard capable rifle.

An off the shelf, mass produced AR in .308 is probably not the tool for that job.

S&W makes a decent rifle at the price point, but it's not a precision instrument. It will certainly lob bullets out to 1k, but expecting any kind of serious accuracy is probably asking too much.

 

[Rodan]

I wouldn't say optimized. I would call the 18" barrel the best compromise for .308.

Agree. It's appropriate to the platform and it's designed mission.

 

[growr]

That's where my M1A SuperMatch shines!!!

Randy

 

[sgtsandman]

I'm pretty much agreeing with the others. The M&P10 is a good rifle but the AR platform in general is generally not the best choice for a precision rifle. It isn't designed for that.

You CAN make it into one but off the shelf, I'm not sure if you will find a factory rifle that will meet precision shooting requirements. At least not without going to a custom made builder.

Generally speaking, AR platforms are 1.5 - 3 MOA rifles. Some will meet 1 MOA but that is the luck of the draw on that. They do exist but are not common and I don't think on purpose. More of a happy accident.

 

[smoothshooter]

That's something you'd have to ask S&W about directly. My guess, is that since it is possible to hit targets out to 750ish yards out of the box that S&W thinks it's good enough. Max effective range for .308 when taking game is about 800 yards anyway. 2 more inches of barrel might give you 1,000 yards but even then the limits of the round's capability is being met or exceeded. Punching paper or hitting a steel target is a bit of a different animal since round lethality isn't a concern.

I would question even remotely thinking of the .308 as an 800 yard game cartridge. To much chance the animal will move while the bullet is en route to the target, resulting in a crippling shot. Bullet performance is pretty iffy at that distance too.

 

[smoothshooter]

An off the shelf, mass produced AR in .308 is probably not the tool for that job.

S&W makes a decent rifle at the price point, but it's not a precision instrument. It will certainly lob bullets out to 1k, but expecting any kind of serious accuracy is probably asking too much.

A good bolt gun will perform better at longer ranges and be cheaper too.

 

[Abflyboy]

I have yet to find an off the shelf large frame AR that is truly, consistently sub MOA accurate. I have been through several in a quest to get rounds on target at long range.

.308 was a disappointment across the board. You can't push pressures in a gas rifle like you can in a bolt rifle to get that little bit of extra velocity to get you out to 1k yards without the rifle throwing fits and making problems.

I ended up building my own custom gas rifle and chose to barrel it in 6.5 Creedmoor. It was a lot more money than most production rifles but it is truly, consistently, extremely accurate.

To the OP, if you do get a production rifle with the intent of customizing it down the road, be very careful in knowing exactly what you are buying. There is no mil spec on large frame AR's and most of the manufacturers are having everything made to a proprietary standard so there is zero chance of upgrading or customizing and no parts interchangeability.

 

[sgtsandman]

I would question even remotely thinking of the .308 as an 800 yard game cartridge. To much chance the animal will move while the bullet is en route to the target, resulting in a crippling shot. Bullet performance is pretty iffy at that distance.

It depends on the game. I wouldn't do it. Not that I really have much of a chance anyway. Unless one is on a gas line or power line right of way or shooting from hill top to hill top or at an open field from a hill top, anything more than 300 yards is pretty much going to be the max clear shot range here. Most of everything I hunt is wooded and inside 100 yards.

 

[Tu_S]

Just my opinion on this, and having various pieces of paper hanging on my "I love me" wall, I do over think things, you have to look at what the AR platform was designed to do.

Getting 1 person of angle at the 3 to 4 hundred yards, which makes it good enough to solve the problem of having someone trying to kill you, is what it was designed for.

Of course you can build an AR that does much better than that, but it's going to take some work, which will translate into cost, where there are designs/platforms that can be made for a lot less (Tikka T3x in 6.5 with a 24" barrel is my newest and current favorite.) So for a manufacturer it makes more sense to come up with something affordable, and let the guys who are serious about reaching out farther pay for the custom tuning themselves.

You mentioned the S&W PC versions and the extra cost. When it comes down to it you're paying for more than just 2" of barrel. You could easily swap a longer barrel for less than the PC version, and I would expect it to do better, but I wouldn't expect it to do as well as something that had additional work done to it.

 

[Oldsalt66]

This, longer barrel gives more velocity, which is better for long range shooting, my goal is a 1,000 yard capable rifle.

My guess is that most M&P 10 customers aren't looking to do that with an out of the box AR.

 

[smoothshooter]

It depends on the game. I wouldn't do it. Not that I really have much of a chance anyway. Unless one is on a gas line or power line right of way or shooting from hill top to hill top or at an open field from a hill top, anything more than 300 yards is pretty much going to be the max clear shot range here. Most of everything I hunt is wooded and inside 100 yards.

Be a better hunter and not just a shooter.
Get closer.

 

[Charlie Foxtrott]

The easy fix would be.

This, longer barrel gives more velocity, which is better for long range shooting, my goal is a 1,000 yard capable rifle.

To just get a .243 Winchester upper for the gun.

 

[Yendor357]

If my Magneto Speed Chrono and the ballistics app that I use are correct, the Hornady Superformance 165 SST projectile is still supersonic at 1000. That means that once you’re dialed in, and subject to your ability to judge/guess wind, you’ll make a lot of hits on a 24 inch by 24 inch steel target at 1000. That 165 is going 2665 FPS out of my 16 inch barreled Armalite AR-10. I am of the opinion that a good quality AR-10 from makers like S&W and Armalite will (*eventually) shoot 3 shots around 1.3 MOA or less. Again, that will results in pretty regular hits at 1000. But the catch is, when that barrel gets hot, more than likely, groups open up.

The more you shoot and clean those AR-10 barrels, the better they shoot. My rifle’s groups have shrunk considerably now that I have a few hundred rounds down the tube.

A few days ago I hit a 200 pound, 10 pointer with that 165 SST. When I opened that critter up, it looked like a grenade went off. Impact velocity at 145 yards was 2378 feet per second, carrying 2072 pound feet of energy. DRT.

I don’t need anymore anything. I have a ton of respect for a 16 inch .308 AR.

 

[murphydog]

Almost 2 year old thread and the OP was last here 18 months ago. Hope he found his accurate .308.