I need help identifying this rifle that I have.  I think I have determined it is a Krag... which is why I have come to you guys.  Hopefully, you can help me identify it better, give me the style of the rifle, history, where it would have been used, what some of the markings mean, etc... Thanks!

Here is what I have; on the left side it is stamped with:
Haerens Tojhus
1915
M. 89
91370

There ser. # (91370) appears on numerous places.  As well as the shortened ser. number (370) inside on several parts.

On top of the rifle, there is a strange marking that looks like a jB or cursive TB... not sure.  below that (closer to the butt) is a crown-like symbol with 15 below it.  Then farther back right where the metal meets the wood, there is another crown-like symbol.  These symbols actually look like cupcakes or muffins but I am assuming it is a crown.

The bolt action is straight out.

My husband says it has a "bull" barrel.  Really big barrel, but the hole is a lot smaller.

Hope someone can help me with this.  I would like to know more about it.   Grandfather was in WWII and we aren't sure if he brought it back with  him.  He had lots of rifles and some he found remodeling homes in VA, TN and KY.  So, we aren't sure where he found this one.
Thanks!