Put one on one of my rifles. It doesn't feed quite as smoothly as the original internal box magazine, but I had to spent most of a night with sandpaper, a dremel tool and some polishing bits to get that(the internal box magazine) to feed smoothly. It feeds reliably and the mags seem to be about the same quality wise as AICS mags other then the follower making it a little difficult to load the first round into the magazine due to it tilting. The mags themselves are not much cheaper then AICS mags, but the substantially cheaper price of the system overall makes it a good system for law enforcement or other shooters wanting to get a reliable DBM system more for quick changes to different ammo types or a quick reload after firing one or two rounds.
As with all "drop-in" parts, it may drop in or it may need a little fitting. I spent an hour trying to install it on my rifle and ended up taking it to my gunsmith who had to file a little off of the rear of the magazine port to allow the magazine to fit into the action.
I am currently in the process of installing the Wyatts Detmag on my Remington 700 SPS. The bottom metal drops right into a B&C stock. The quality of construction and materials is lightyears beyond the factory bottom metal. People need to be aware that it is possible that your bolt wont properly operate without shimming the DetMag (.010-.020 inches) to create sufficient clearance between the top of the trigger guard and the bottom of the reciever. Not many have this problem but as luck would have it, I did...it miffed me off a little at first but I think I have it figured out and will install it as soon as the shims come in the mail. I have to say that the magazine follower is binding pretty badly thus far, which could be because it needs to break in yet (I hope).
So yeah, drops right in but you should really be prepared to do some shimming and tweaking to get correct pillar height (see DIY section for more info) and the mag could bind up pretty bad when brand new but aside from that it seems like a well made product.
I will add to this review once I get some range time and put the DetMag to use. Hope this review helps.