I purchased a tac-star side saddle shell holder for the Winchester 1300. The thru-bolt replacement for the pin in the rear of the receiver fits fine, and the side saddle sits nicely on the receiver. however, the clip at the bottom edge of the side saddle does not fit the edge of the loading port on the SXP. I would like to drill and tap a 3/16" hole into the receiver, possibly 2 of them, to attach the side saddle. i have attached an image of the locations where i want to put these holes. the 1st arrow shows the pin that is replaced by a bolt in the standard installation of the side saddle. this works fine on the SXP, as I mentioned above. the 2nd arrow shows the location of one hole i want to tap into the receiver. it would be just in the aluminum of the receiver itself, and would fit a 3/16" short bolt. i could use a 1/8" instead, possibly. this would be the second attachment point for the side saddle the 3rd arrow shows where the second new hole would be. the aluminum of the receiver is about 5mm thick there. the side saddle has a curved flange that hugs the curved top of the receiver (I have an arrow pointing at that from the number 3 also), preventing the saddle from swivelling on the rear pin in the counter-clockwise direction (looking at it in this image). but that flange does not stop the saddle from swivelling up (clockwise). the second attachment point (at arrow number 2) woud prevent this clockwise swivelling, but it is colinear with the rear bolt (arrow number 1), therefore, a third attachment point at arrow 3 would be nice, as it would reduce flexing and generally firm up the attachment of the sidesaddle. OR maybe i only need the 3rd point. what do you guys think? is it OK to drill either or both of these holes? i have the tools and skill to do it right, but i dont know if it is dangerous for the receiver or not. in either case, i would make a bolt that would extend just to the inside of the receiver aluminum, not beyond it. the lower hole (number 2) seems like it would be OK, since that is right next to the open loading port anyway and certainly is not under pressure. the upper bolt location is closer to the action and the chamber, but still not under pressure at firing (i think).