Having a PSS DM myself, i did a little asking around a while back. I've heard things like the DM problems can't be fixed, to it will misfeed 1 in 20 rounds etc. while other have no problem. I found two solutions I would consider satisfactory (but haven't used myself-yet).
1) HS Precision, the company that makes the stock, has a DM replacement trigger guard with a mag setup that doesn't use the reciever cuts because it is a single stack mag. So, you could even convert a BDL to a mag feed and this is supposed to be a reliable and quality setup. They may even have 10 rd mags. IIRC it was about $165 so it is probably the most cost effective. Drawback-it doesn't displace the stock inletting on the DM so you may have an unsightly gap (which could be filled) where the original mag was wider.
2) The AICS (Accuracy International Chassis System) for about 650 would also solve the problem and considering what you get for that, if you are going to invest in other accessories to get the best out of your rifle, may be worth it in the long run.
Also DD Ross may have something, but you'd have to check.