This is what Ruger's curved 20rd mag looks like in my birch stocked 583 Series Mini:



This is what the OE straight 20rd mag looks like in my Mini (after I added a walnut stock):



I have 5ea Ruger 20rd curved mags I got with my Mini-14 Ranch Rifle in 2015, and 5ea OE 20rd straight mags I recently got for it.  I've done a couple fit and feed tests (40rds through each mag).  As far as fit, the OE mags fit much more securely with little to no back and forth and side to side wobble while the Ruger mags have significant wobble.   I feel that the OE brand mag's better mag catch block design (closely resembling the M14/M1A's) is the reason for the better performance.

As far as reliability goes, in my testing I had one failure to feed fully.  It was in a Ruger mag, not an OE which have been 100% reliable. It was on the 1st rd of a new mag and the bolt failed to fully chamber the rd after pulling back the charging handle to it's stop and releasing it. As I learned in Basic Training with the M14, I always tap the rear of the charging handle with a new rd anyway so it was no issue.

You can read my full visual review of the mags in post #1 and my field test review in post #8 of this PU thread HERE.

Here is the pictorial comparison between the OE's 20rd straight mag and Ruger's curved 20rd mag.  Overall, it appears to me that the OE brand mag is a better made, higher quality mag than Ruger's. Something I'm shocked to discover considering that the OE mag cost $12.99 while the Ruger mag cost $28.00:

Side view - OE mag on the left and Ruger mag on the right:



Rear view - OE on the left and Ruger on the right. Note better mag catch lug design providing much better lockup with mag catch.  Ruger's mag body is a 2 piece design and the seaming and welding is poorly done.  OE's body is a one piece design welded only on the front face:



Front view - OE mag on the left and Ruger on the right. Note better, larger spot welds on OE. In fairness, Ruger's dish-out to aid feeding is a step I'd like to see OE do as well:



View of followers - Stock Ruger on left and OE's on right. Ruger's seem more precise, however, many use the OE ones with no issues.  I added Ruger followers I got from Brownells to my OE mags 'just in case':



Bottom line - Ruger needs to review their mag quality and pricing with their current supplier and seriously consider relooking at their sourcing decision.

Mine are all curved and they have been fine.

I like the look of the straight ones better.

Own 10 ea ruger 20's.  A lot of ammo through them.  Never a failure.  But nice to know there is another mag to consider.   Thanks for the post.   Wardawg

Where do we get these $13 OE mags?

Well...see that's the thing...

CDNN has them in stock now and then....briefly.

On the other hand, I can get Ruger factory magazines almost anywhere, pretty much any day of the week.