2009, 2010 and 2013 G2G Attendee!
I agree with what has been posted. All 5 of my kills this season were with my crossbow. 2@ 20yds; 1 @ 25yds; 1@ 30yds and 1 @ 40yds. They all jumped a little, but I was extremely lucky at the 40yd shot. The buck was very relaxed and not looking my way, otherwise, I might have been more hesitant to shoot that distance. I shot a Ten Point Titan Extreme and it's great, but very loud. I have just purchased a Mission MXB and can't wait to hunt with it. It's so much quieter. But regardless, I think the deer will get a jump.
"I can do all things through Christ who strengthens me."
I've had a very smart mature doe jump my string twice last year. The first night I missed her clean at 17 yards. I am shooting ell over 300 FPS. The second night I missed her again at 21 yards. She presented another shot later that night and she wasn't so lucky.
Based on that experience and others I am going to say heck yes a deer can jump a x-bow at 40 yards. I don't care if it is shooting at a blazing 400 FPS.