Never been a big fan of boiled linseed for a gunstock finish...great for protecting axes, shovels and hoe heads and handles.
Kinda looks like part of the wood is still absorbing finish.
I'd try wet sanding you might start with 200 grit wet/dry then a couple of times with 400 grit wet/dry paper with your paper on a rubber sanding block...before the slurry starts to dry give 'one wipe with a tissue paper across the grain.
You need to be sure it's had time to fully cure between wet sandings...could mean over night in a warm room.
Heck what could eYe know I'm no rOcky mountain gunsmurf...
