Cappy - you may want to rent one or both to see if you have a preference. The .40 was my first handgun - I did develop a bit of a flinch because of the recoil anticipation. With help and more practice using the 9mm, I've been able to correct that problem - even with the .40. It could be said that I was able to correct the problem just using more practice - but I won't know for sure... the 9mm just was easier to manage at that stage. I'm definitely not pushing you away from the .40 - lots of guys shoot .40's and .45's - if they can shoot it and I can shoot it, I'm sure you can too. But just be cognizant of the fact that some folks are prone to develop habits with calibers that give more feedback ( if you are a new shooter like I was.)
And no... I have the locking block without the radius, but it has not cracked at all. If you were to buy a new XD - check the pictures here in the forum and compare it to the gun you are buying... if it has the radius you should be ok.
A forum community dedicated to Springfield Armory XD and XD-M series firearm owners and enthusiasts. Come join the discussion about optics, gunsmithing, styles, reviews, accessories, classifieds, and more!