Broadhead flight
 

I didn't post this here, but I had terrible flight from broadheads on my Killer Instinct 350. I was not using their bolts but Carbon Express, which are fine right? Maybe, but not for my xbow, you can read it all here. Spine matters in Bolts too.

To summarize for those that don't wish to read the entire story, The CE bots are under spined and bend too much and catch air causing planing. I bought KillerTech Pro bolts and a great broadhead flight. I also got perfect field tip flight and got flatter shooting bolts all around.

I out the bolts on my spine tester and found the CE bolts to be twice as soft in spine as the KillerTech bolts!
KillerTeck Pro 20" bolts with half moon nocks – 4°
Wicked Ridge boltsmade by Easton – 6° These have Omni nocks and I could test them on my bow, but they work great on Sonya’s WickedRidge
Carbon Express Pile Driver bolts – 9°

I shoot Carbon express bolts out of my Piledriver 390 and they shoot very well. It is the broad head that usually causes planning.

The broad head causes the planing but the flexing of the shaft allows it to catch air and plane.
I get slight movement with the new bolts but nothing that won't kill a deer at 50 yards. With the CE's on my KI350 some were not good enough at 20 yards, it was awful.

Sounds like you bought the wrong spined carbon express crossbolts, they do make different ones for different powered crossbows. How many deer have you killed a 50 yards with your crossbow?

None yet, I hope to never have to shoot that far. I have a few spots like the top of our access trail where I know i can shoot that far without fear of branches. The deer kind of meander through there and cross over a 120 yard area on 5 or 6 trails. Some places I am limited to 20 - 30 yards because of the cover.

I bought the CE's from Cabelas and there was not an options for difference in spine, just one set of Pile Drivers. Now it would not surprise me they bought the cheapest, softest ones and sold them for the prices as the stiff spines ones. I look on any website and no reference to spine is spoken at all on bolts. I had a terrible time from it and would have liked to know about it. They cover degrees of straightness, not not a word on spine. The CE Maxima is a lot more expensive, thicker wrapped and wording on straightness. I bet that one would have worked.

That is why you should deal with a reputable archery shop to buy your equipment. They make sure you equipment is matched. 20 or 30 yards is where you should be shooting at deer, not 50 with a crossbow.

I don't know who makes them for Cabelas but I use their Hunter Bolts for both my Excalibur and my CenterPoint Sniper and have excellent flight even with Muzzy Phantom broadheads.