I have two MK25's and am looking at buying a few holsters. With the wider 1913 it looks like a custom holster is the best option. I have read that I can buy the leather Galco P226R holsters and fit the MK25 with heat, time, tough love. I think those two options would cover the leather IWB or OWB holsters.

Another hostler option I have been looking at is a Kydex holster but I want one with a molle attachment. Does anyone have any experience buying/using a non-custom/standard Kydex Molle holster for the MK25? If so, what brand and how was it configured? Or, is my only option custom? With the Kydex I only want the molle attachment, I wouldn't be interested in a paddle/hook option.

I'm not sure if you're looking for a "tactical" holster when you mentioned MOLLE attachment, but I'm a big fan of the Safariland 6378USN ALS Holster, which I think was developed for the Navy for the Sig P226 (but I could be wrong). I've used one for several years as my M9 duty holster, and it's tough and easy to use. The Ranger Green version is in stock at Copquest at that link, but availability of the others is pretty sporadic. It can be attached to one of the Safariland MOLLE locking forks either directly or with their QLS system.

The other option is the Safariland 7TS series of holsters. I believe there's a model specifically designed for the Mk25. They can be used with the same MOLLE locking forks.

Appreciate the options, will look them up right now. Thanks.

G-code makes holsters specifically for the Mk25.