From what I've read what causes the stock to split is the battering of the slide on the receiver. A lot of +P ammo ,that you say you aren't using, would probably be a factor. Everyone seems to say to replace the buffer and use a heavier recoil spring to take the stress off the receiver and stock. I changed to a 16 1/2 lb Wolf spring although I've read a 21 lb spring works too especially in 45 acp. The new buffer was from Blackjack Buffers. (They sell both buffers and springs). Others probably make or sell the parts. The original buffer was very brittle and broke when I took it out. I wouldn't have wanted it to break while shooting or when I needed a firearm.