I had an ACR. It was one of the first 500 out and it had issues with barrel alignment. I got it out of the box and bore lasered it. I couldnt dial the sight all the way over it was so off. I released the barrel from the trunion and re-seated it...same thing. Try again and again. I ended up sending it in to Bush, they confirmed it was misaligned. I have since sold it namely after I got my KAC. I did really like the ACR. It is incredibly ergonomic...best of any rifle and I had an XCR some years back that I thought was the cats ass when it came to ergonomics however the ACR was what the XCR should have evolved into. My xcr had issues with accuracy (well it just wasnt that accurate) bolts coming lose, didnt open up much for cleaning...and I was tired of waiting for Mr. Robinson to get stuff done...like the stock which is now done DAMN IT! But it took 3 plus years of promises from that guy. Customer service sucked once tara left. And I was worried about that companies survival...still am. Did I like shooting it...yeah...not bad but it felt like a gun frankenstein built. Dont get me wrong it was a tank and that bolt was pretty nice. It never lived up to alex claim of eating wolf ammo for breakfast even after 500 rounds of brass. But it still was a gun I still dig today...just wont buy based on my experience. Back to my ACR, it wasnt bad at all...however there was one significant reason I dumped it...weight...well two and balance. After handling my SR15 the ACR was a PIG! Nose heavy and flat out heavier as well. Not that it is too much to handle but once you handle and shoot both next to each other you quick fell the difference.
So after all this my best friend buys two scars...16S and the 17S. I absolutely LOVE the 17S! for a 308 it is really amazing! It is light and doesnt have the recoil that you would think for a 308. We shot my SR15, his 16S and 17S all side by side. We would go from one magazine to the next gun to gun. Of the 5.56 everyone that did the side by side (500 plus rounds thru each) we all liked the SR15 better. Weight wise they are very similar and balance as well. So this was a wash...however I have an heavier EoTech than he doesnt so if all things equal my SR15 would be lighter. I also have a grip pod on the front he doesnt so between the 16S and the SR15 all things equal...SR15 wins in the weight department. Next was recoil...I put a BC1.0 on my KAC...his SCAR has a FSC556. Mine was quieter and kept the muzzle down better. His has slightly less recoil but once again more muzzle rise. The SCAR has a total different recoil impulse you can feel the BCG travel inside the gun. It feels as if you are firing in slow-mo when you go back and forth between the two guns. It also seems like it cycles slower...these are semi so I dont know if the rate is different but it did seems like the gun was slower. In addition the SCAR had more percussion slap! It felt like someone was slapping you in the face if you stood next to someone shooting it. My KAC...no! My buddies wife shot all 3 and she is as thin as a rail and around 100 lbs. She didnt like the 17S but did like my KAC and ended up shooting it more than we did! The 17S is really awesome it is the only AR style rifle in 308 I have shot...it almost handles like a heavy 5.56...like my ACR...seriously! I have shot alot of different rifles in 5.56 (Colt, ACR, XCR, SR556, SR15E3, SCAR, and BM). The knight is one of my favorites. It has been as reliable as they comes...wolf has been fine in it as well...I dont get it for I put the same wolf in my SR556 and it would get stuck in the chamber...not in the knight., I always though the SR15 was a picky eater. At least mine isnt. My SR556 (which is now owned by one of my buddies) was really quite nice for what it was and what I paid for it. I had the SR556C...14.5" and fluted so it weighted better than the standard SR556. I liked it but dont miss it.
For the money knight is a tremendous buy. I priced out a BCM with as close as I could get fixing and it was more! The Stock (LMT), 2-stage trigger, quad rail, ambi controls, flipup sights, and so on...the BCM was...well more and in the end a lesser rifle. it lacks the E3 bolt, the URX rail with integrated sight (my favorite part of the SR15) and an ambidextrous lower that is so well designed and clean that you forget what an AR is missing from an ergonomics stand point. It is really a great buy for what you get! Sure you could do a colt for 1000 or just under but it isnt a knight. I went thru a ton of rifles before I learned that lesson. Too bad for I always turned my nose up to knight then I got one..and I love it!