Wayne, It looks like they attached a handful of Parker matted ribs around the breeches. The guy must have thought they'd really catch on and everyone would just have to have one...the new big thing...not.

Harsh o so harsh. Unusual and rare may translate into value? probable not.

The 'Diana' breech is very likely to be from Pieper
http://www.picturetrail.com/sfx/album/view/24302405

How big is it?

Isn't that the patented "reinforced breech" by Pieper,I believe?

I just called my buddy and he thinks it's a 12 bore. I asked him to take photographs of the bottom of the barrels and the water table. He's taking the photographs now so when he emails them to me I will post them here.

My J. Stevens A&T Model 360 has the mono-block and even today I believe Beretta continues it's use.

Manton Under Barrel & Watertable:
 

Belgian.

Drew, If you blow up the barrel photo there is a lot of information you can decipher for us. I appreciate you thoughts.

It was made 1910-1921 (12 in a diamond and no Lettre Annale )
PeteM's list does not have a 'DJ' (receiver) but it could be a Dumoulin
The right barrel may have a 'LD' in an oval and could be Lambert Dumoulin
The left barrel bore is .720 with a choke constriction to .693
It probably has a steel breech and clearly Damascus barrels
Other Belgian makers copied the Pieper 'Diana' breech
It was not of high quality when new, and of less quality now