5.11 holster shirt??

I have one. Trust the sizing guide on their website. I don't know about your XDM 3.8 but it held a 4" 1911 and now holds a XD40sc just fine. I keep the pistol on my left peck and one or two mags on my right peck. It's a little bulky but nice. The material is awesome as well.

I recently purchased the Kangaroo pouch Air marshal holster and really like it. i was suprised at how well it fit and concealed the xdm .40 3.8. Its made here local to me and the guy fited me add allowed me to test it with a xdm mock pistol. I wore it all day Sunday and was happy with it for the $39 i paid.

Kangaroo Carry

I have the 5.11 and have used to carry my XDm 3.8 .40
The shirts fit very tight and need to or it would not work.
You need to have a button down shirt or coat to be able to get to your weapon.
In my opinion it will work this winter with a coat. It makes you look very fat and bulky with regular clothing.
my crossbreed is much better all around.
I will try it again this winter, but not until then.

My wife got me one for Christmas this past year.

It's not something I'd wear everyday, or even prefer to wear, but I'll throw it on if I'm headed to the store.

For the price, I'd go a different direction, unless you prefer to carry in a manor that isn't conducive to a quick draw.

I tried one on recently at a store in TN, and liked it - but didn't have the $ at the time. I like the deep concealment idea - for when carrying in pocket or IWB doesn't work (like weddings, or other formal settings).

I definitely want to get one!

It is definitely a nice option to have, like was said sometimes the IWB or pocket carry is not an option. Not for everyday but nice to have in the holster box.

I had one that I used for my Kahr PM9. It was ok, but the position of the velcro allowed for the gun to wiggle out sometimes if I bent over at the waist. I think they have since put two pieces of velcro to fix this issue.