hey team! just curious to know if anyone has any knowledge as to why the 'sport' works so well w/ steel and polymer coated ammo. its all over several forums, reviews and youtube.

i've always heard/read steel or poly coated is bad, stay away (w/ ARs) but i've witnessed a noveske jam w/ brass. if its going to happen, it'll happen... w/ being able to use cheaper ammo, you'll have a lot more range time, more practice, more ammo and more fun. especially if you're not reloading. i know they aren't the most accurate and can be pretty filthy but you're sending lead down range and supposed to be cleaning after 'every' session anyway again, just curious to know why the 'sport' works so well w/ steel ammo. later!

In years past, there were 2 classes of AR 15 made. 'Mil spec' based guns that were specifically set up for 5.56 and then rifles that were .223
The .223 has a tighter throat, and all in all, less slop built in on purpose than a 'combat based' rifle.
For rapid fire, long duration between servicing, a rifle needs a bit more play in tolerances in the right places. Almost all AR's made today incorporate the best of both worlds. Better accuracy, and better function is the end result.
Not least of all, the new Wolf WPA ammo is a LOT better than it's predecessor from say 5 years ago. Simply put, it is NOT the same ammo. (And thank God!)

Def not the same ammo!

To add to what others have said, I believe there is a correlation between how tight the tolerances are in a firearm and ammo sensitivity. I do not claim to be a firearms expert. My hunch is based on experience with other firearms. I may be oversimplifying.

Competition and target guns are built to tight tolerances. Not factoring in the skill level of nut behind the trigger; tighter build tolerances within a firearm lends itself to accuracy. Firearms with tight tolerances can be ammo sensitive.

For example, a friend has some flavor of super expensive, tight tolerance, Ed Brown 1911. I've shot it. I love it. I understand why folks plunk down the cash for it. My friend had to try different brands and types of ammo to find the ammo that will reliably function with his 1911.

I own a Ruger SR1911. It's considered to be one of the better entry level 1911's. It has nowhere near the tight tolerances of the hand crafted Ed-Browns. My SR1911 will feed, fire, eject any brand .45ACP ball or JHP.

With all conditions being equal, in my hands the Ed Brown 1911 shoots tighter groups than the SR1911. It's just the way it is.

When tolerances are too tight or too sloppy, a firearm will be finicky.

The same stands for the S&W M&P 15-Sport. At the 15-Sport's price point, I wasn't expecting much. What's surprising is that it performs better than it's price point alludes.

My sport mp15 eats the wallmart steel Tula as good as any other ammo and it is not that dirty to clean after a few 100 rounds. The new polymere coating is good and accuracy sub 2" at a 100 yds. Its fine and the steel cases are softer than the bolt and it parts there is no wear. The Tula is very good ammo. I like the Sport better than the Dpms M-4 clones and Bushmaster I used to have. I never used the forward assist on them or miss the cover. The Sport is very reliable.