Decided to trade in my MI Rail I had on my Aero M5 for a new SLR 13" Solo lite series rail.  I really liked the solid lockup between the SLR rail and the SLR barrel nut and my MI Rail didn't exactly fit right (top of rail was a hair lower than top of Aero M5 receiver).  I was also upgrading my Syrac has Block to an SLR Sentry 7

So I pulled off the MI rail this morning and put on the SLR rail.  The SLR rail fit perfectly flush with receiver.  It was obviously that the rail was well made but then I ran into a problem.  I tried to put my sling on and the QD swivel wouldn't lock into the QD socket.  The QD swivel was hitting the barrel which was preventing it from locking in.  I'm running a Rainer 16" select barrel.



I tried grinding down the bottom of my swivel but ground into the hole that holds the swivel button spring and ruined the swivel.  

Then I looked at my old MI rail to see why it had not had the same problem.  MI raised the QD socket a little which added enough clearance for the QD swivel to not hit the barrel.



This just sucks all the way around.  The MI rail doesn't really fit right but the QD socket design works.



The SLR rail fits perfect and is really better in every way except for the the rear QD socket.  I checked the other SLR series rails and it looks like the rear QD socket on all of them is flush with the rail
so I'm guessing that all have this same issue.  

Has anyone else run into this?  Are Rainer select barrels somehow "fatter" than normal?  

If you are running an SLR rail, will a QD swivel lock into the rear QD socket on it?  If so, what barrel are you running?

Not really an answer, but could you live with using an MLOK sling QD mount just ahead of the QD on the rail?  I know it's not as lean and clean, but sometimes ya gotta do what works.

https://www.magpul.com/products/m-lok-qd-sling-mount

FYI... The Rainer barrel is 1.1915" right past the barrel nut under the QD socket.

I've had a few qd stocks , and integrated sockets in handgaurds. My first sling was a paracord home made with uncle mikes swivels. Very different fit between sockets. My magpul ms4 sling fits and locks in every socket I've tried. Maybe try a different sling before ditching the slr

I tried several different swivels, including ALG swivels.  None of them work.  SLR said they think the taper on the Rainer barrel starts further out than normal.

I'm going to try another barrel before I return the rail because I really like the rail if it wasn't for the issue with the QD socket.

Just ordered an 16" QPQ from Aero Precision.   Will have it in a couple days and see how it goes.

Looking at the pic of my barrel on Rainer's site, it does look like the taper starts a ways out



The taper on the Aero barrel in comparison seems to start sooner

Thread title changed until I figure out what's wrong.  Changed to "SLR Rail QD socket won't work with 16" Rainer Barrel".

Fair?

Edit, didn't read the OP well enough first go around.

That looks great!

and this is why I give SLR my business very frequently. WOW.

Wow. Above and beyond customer service !

Maybe I can get a replacement. I've experienced this issue and knew it was because of the taper of my rainier match barrel. I figured that it was just a bad mismatch of parts. Perhaps I'll contact slr

While possibly not optimum, couldn't you just relieve a small amount off the bottom of the QD to give it some added clearance?

Tried that.  A QD swivel actually has a hole drilled straight down into it that almost but not quite goes all the way thru and out of the bottom.
The hole holds the spring under the push button.

If you grind much off the bottom you grind into the hole, the spring flies out.

fyi.  The SLR rail I got worked fine with an Aero 16" barrel.  The new gen rails should work with any barrel.