I have a 1977 Winchester model 70 with the blind mag stock. Caliber is 308 Win. I measured the hole centers and comes to 7 5/8 from back of trigger gaurd bolt to front bolt. I believe it to be a long action stock. The mag well has a spacer for the shorter 308. Is there a supplier here in Canada where i can purchase the bottom metal to turn this blind mag into a hinged drop open style?