For all intents and purposes, the 22" barrel won't shoot any different than a 24" pipe, except for a slight decrease of about 80 +/- fps velocity as mentioned by ChesterGolf.
Shooter skill or error is far more important than length of barrel, even though I admit that when shopping for a new 30-06, I went for a Remington 700 stainless SPS with 24" barrel and standard Limbsaver Recoil Pad. I believe the 7mm Mag in this model has a 26" barrel.
Remington 700 SPS Stainless
In short, longer is better, but don't let the barrel's length be a major deal breaker.
Good luck and happy hunting!
P.S. Stainless price at Sportsman's Warehouse for all calibers is $469. Blued is $399.
Anyone who shoots a sabot bullet has had the problem with loading the next round with a dirty barrel we have all struggled with it.
Between muzzleloader shots I have done some research and testing on my own to find out what works for me for the next shot. I have been using a product called bore butter and when the muzzleloader is just sitting around I leave it caked in the barrel for protection. Have also found that if I lube my sabots with bore butter they really slide nicely down the barrel....