Pro Patria, Inc draws it's name from the 4th Battalion 31st Infantry, "Polar Bears" of the 10th Mountain Division and is were many of it's projects began during the spring and summer of 2001. Below is a breif summury of the lessions learned that have lead to what we offer today.
4-31 Infantry "Polar Bears" Unit Creast
When I returned to the 10th MTN as a Platoon Sergeant in Jan, 2001 I found the division had changed quite a bit since 1998. There was a heavy focus on urban combat due to lessons learned from Somalia and Haiti, with many new things being introduced to our Infantry Companies. One of those were the Halligan tools. After only a few trips to the MOUT site with my platoon I hated those things. Heavy, bulky, and single purpose. Over the next few months among other things I started researching options for introducing ballistic breaching to the division. I looked at the Remington MCS, the Bennelli M-4/M-1013 and some others. In the end I called TACOM Rock Island and asked what was in stock in the Depot. The response? 1,000 Mossberg 500's.
I soon made my case for shotguns for the BN and soon the battalion commander had pushed it up to Division and before I knew it we had one shotgun per squad across the division by the summer of 2001. One BN (+) deployed to the MFO mission in Egypt and one brigade (+)Task Force deployed to Kosovo (one of the justifications for the shotguns was less lethal ). This left 4-31 Infantry at Ft. Drum and 1-87 Infantry training cadets at West Point during the summer of 2001.
Over the summer 4-31 INF used their shotguns extensively in various training events. We experimented with various configurations and first as the BN Operations Sergeant and then HHC 1SG I continued to collect notes from the units on their use of the shotguns. By late August of 2001 I had the results and had outlined the issues that we were having with our shotguns and recommended several configuration changes. I submitted those requirements to the Team leader for shotguns out of TACOM Rock Island and various industry contacts that I had developed working on other projects.
3rd Plt. C Co. 2-87 Inf moving into an Observation Post above Nanglam, Afghanistan Nov, 2003.
Then the war started and I had other issues on my mind, at one point my Infantry HHC had soldiers deployed in five countries with other companies and I was still at Ft. Drum training replacements. We continued to use the 500's that we had, with local purchased bungee slings, ammo pouches and pistol grips. Most, if not all of those shotguns are still in service.

DOD photo, C Co. 2-87 rehearsing VIP extaction in Kabul, Afghanistan fall 2003.
By 2003 I was a 1SG in C Co 2-87 Infantry deployed to Afghanistan. During the course of our deployment we were issued the "Lightweight Shotgun System or "LSS". Today’s version is called the XM-26 Modular Accessory Shotgun System or MASS. We used them over the course of the deployment along side the Mossberg's. At first the LSS was "cool" but over time we found they were less then optimal for our requirements. Unfortunately, only the initial reports were received and the XM-26 MASS program began. 
Light Weight Shotgun System outside Ghazni, Afghanistan Feb, 2004. In 2004 I retired and kept plinking in my spare time at the original requirements I had developed in 2001. We have gone through three Mod's to our orginal specification outlines. Mod 1 and Mod 2 is currently in use by select units within USASOC. Mod 3 is currently being evaluated for wider distrobution.