This will be a welcome new product for owners and users of the SIG SG 55x firearms.
I have a few friends using their SG 552 Commandos who have been asking for these adapters, but had nowhere to go.
GS Designs Canada now offer a magazine adapter for the SG 55x line. Finally your PMAGs can marry your Swiss SGs.
AR Magazine Adapter Kit for Swiss Arms/SIG SG550
This 3D printed Nylon adapter allows you to use modified AR-15 pattern magazines* in Swiss Arms/SIG SG550 series rifles.
It is a simple one-piece design that clips to the front of your existing magazine well. No nuts and bolts, no gunsmithing, and no modifications to the rifle are required.
The kit come with the magazine well adapter, a magazine modification guide, and instructions.
This adapter does not work with the SG540 series rifles. A separate adapter for those may be available soon.
You can find GS Designs here. (Canada). The price is $59.99, which I presume is Canadian Dollars.
Note that the use of steel magazines in combination with this adapter may cause wear on the inside of your SG receiver. It is therefore recommended that you use polymer magazines only.
Below you can check out the YouTube video of the product:
There are plenty of cool pictures of SG 550s from Davos here.