I have a lovely little 16gauge Ferlach side by side.It has 3 thin cracks in the butt near the toe.Each is about one inch long , 2 on one side , 1 on the other.They are barely noticable and I have never been concerned .
But recently I broke the vulcanite butt plate and noticed that a dowell had been used to plug a third hole somewhere near the bottom screw .What concerned me was that it was in line with the cracks.
I bored a slightly smaller hole in the dowell thinking I would reduce any expansive pressure on the cracks.
A-Did I do the right thing?
B-should I leave the exposed third hole or plug it with an undersized , better fitting dowell?
I couldnt understand why the third hole was there in the first place as it is a good one inch from the bottom screw hole.
Can I leave the drilled hole exposed or will it crack under recoil? The hole I drilled was 3/16 .
I speculate that the stock has contracted over time at a faster rate than the dowell plug.

Your comments and advise would be appreciated
Thanks

The plug may conceal a void that was left empty or had weight added out of sight to improve balance/weight distribution.

if i'm understanding right, i believe i'd drill out the entire dowel first. then put a clamp on the stock to see if that brings the cracks together or not. this would tell if the cracks were just surface or whether they go through. If they go through I 'd drill out the hole a bit bigger, drop in a load of epoxy glue and then take an air compressor blow gun and blow into the hole. this will force some of the epoxy into the cracks. Clamp until the epoxy is set. then refill the hole

Thanks . Yes , I rather think that a weight has been in place at one time but has now been removed.There is no weight there now as I drilled quite deep.
Why was it removed?
I can only suppose that when the previous owner saw the cracks he realised that the weight (lead?) was creating internal pressure > The lead must have been jammed in quite tight to cause cracks.
I have left the hole open as the cracks are closed and seem stable , although I havent fired the gun yet .
Thank you for your suggestions. I think I have unravelled a detective story .