LOP on rifles is decidedly different than on shotguns. A good rule of thumb is better a shotgun stock a touch too long than too short, and better a rifle stock a bit too short than too long.
My shotgun LOP w/ straight grip and double triggers is 15 1/4" to the front trigger, and I can do well out to about 15 1/2". On a pistol grip stock, single trigger, 14 1/2 seems right, with 14 3/4 pretty good too.
On rifle stocks, I am happiest with a LOP of 13 1/2"; 13 3/4" is too long for comfort, yet 13 1/4" feels fine too.
