I actually own BOTH of these! (I broke down and got the DPMS, 'cause it was a 100% replica of the carbine I used to shoulder.)
What I can tell you about them:
Sport: Out of the box 95% on target. It only took a couple twists and the rifle was dead on.
DPMS: Out of the box, 0%.... I got the actual flip up sights and did the sighting myself. Took all of 20 rounds to get super close, by 30 rounds it was BINGO dead on.
Overall accuracy?? S&W 96.5, DPMS 97.5. It groups about .125" tighter than the S&W Sport at 50yds, carbine firing= standing, no sling, no rest, iron sights, medium fast fire rate. (No more than 3 seconds between shots.) This said, the rifles are both retarded accurate with iron sights.
Construction-
S&W Sport: Properly staked gas keys, all critical parts are staked and straight as sent from the factory. Melonite coating is intact and shows NO WEAR after 3,200 rounds. Rifle looks barely broken in. Fit from pivot pins is acceptable, not too loose, not too tight. Buffer; heavy, might not like weak a$$ ammo; fires WPA/ Wolf with no issues. Accepts and feeds 100% from ALL mags used so far. This includes the cheapo Thermold mags. (10 rnd units for Ca. I have like 10 of them for ??$6 a piece.) Maybe 1 round out of 300 acts up from a cheap mag. STANAG 30 rnd and Magpul 30rnd mags are flawless in the rifle. All fit and cut work is VERY good. Machining in magwell is very good. Upper is very well finished. M4 feed ramps are very well cut and need no polishing.
DPMS: Staking is not perfect. Gas carrier key is staked, but lightly. Rear ring on buffer tube is not staked; buffer tube is not 100% perfectly straight from factory. Easy fix. Gas block is properly set and tight. Rifle pivot pins are Excellent. Tighter fit than the S&W, yet still breaks down and rebuilds with no need to beat on the rifle. Better than even my Deployment Colts. Dust cover?? Yeah. F/A? Yeah. Not concerned with either feature. Been hunting for 34 yrs now and even my duck guns do not have a dust cover; they live in the swamp and have survived MANY marsh swims
( God loves a few things: S&W revolvers, Remington 700 rifles, and Mossberg shotguns!
) If a rifle is feeding properly, the FA will never get used. If the rifle is dirty and FA is needed, then a cleaning is needed. M4 feed ramps: Used to be the DPMS was a .223, with original feed ramps. No longer. It's a true 5.56, and has EXCELLENT M4 style feed ramps. Better cut and fit than the S&W. Nothing is chromed, the bolt is phosphate coated and shows no issues with 800 rnds. Machining is so-so. Mag well machining is a bit sloppy (I am a bit picky
) The DPMS takes all mags well, and Magpul and STANAG mags again work flawlessly. The Thermold cheapos have some issues with the DPMS. I feel the mags do not hold quite high enough and as the mag gets to round #9 out of 10, it fails to feed on 3 of the 10 mags unless I am pushing upward on the mag. AGAIN: This is a cheap mag issue, NOT a rifle issue in my opinion. Buffer seems a touch lighter, and this may account for the slightly better accuracy on the DPMS rifle.
In my opinion, if you are seriously looking between these 2 rifles? I nudge toward the S&W Sport. They are pretty close. The S&W has more attention to detail. it comes with Troy sights; the industry standard. (Also, FWIW, the Troy is what both my deployment rifles had.) S&W has more reputation points FWIW. The S&W has better machining in the magwell, and the slickside upper is very well done. The price is a touch better because the S&W Sport is a complete rifle. The DPMS did not have sights, they threw some in to seal the deal.
If the SHTF, I will not worry which rifle I grab out of the cabinet; they both work very well. And both would qualify for Marksman, not just rifleman. On Sunday, I was able to hit a man size target at 600 yds with each rifle. My younger son did better than I, (He is 16, and has the eyes of youth. I envy him.) also, I am in Ca, and we do not get the Oracle itself. It is renamed the A15. Same exact rifle....just name modified for Ca. communism circumnavigation.
