I am in the unenviable position of not owning firearms to go deer hunting and I am not in the financial position to consider buying a deer rifle at this time.Last year a friend loaned me his 30-30 Marlin which is unavailable to me this season. I have two realistic options of getting loaner guns for the rifle season.
1. 12 gauge shotgun (unrifled I believe) with slugs
2. Older model muzzleloader (not inline) .45 caliber

Both gunshave open sights
I know that there are lots of variables in this equation but generally what would you choose to use in this situation? what would you consider a reasonable effective range for either gun?

Thanks for reading my post

Without a doubt the .45, but let me qualify that with "provided it gives good accuracy"! Be cautious in shot selection and range and it will "make meat" efficiently.
With a PRB I'd limit shots to 75 yards or less, but with conicals you can reach out to perhaps 125 yards. These would be absolute MAXIMUM ranges for me.

"2. Older model muzzleloader (not inline) .45 caliber"

Borrow that muzzleloader. Good luck on your hunt.

If these were my only options I would opt for the shotgun. I don't think anyone should underestimate the capablilites of a slug up to 75 yards even with open sights. Since both guns have open sights you will have a BIG advantage with the shotgun since you will have quicker follow-up shots if necessary. You didn't say if it was a pump, autoloader or single-shot, but either way you will reload much quicker than with any muzzleloader.

I would go with the 12 gauge with slugs provided you can handle the recoil. 12 gauge slugs really knock the snot out of 'em.

Go with the muzzleloader!

If you have the time to get out and shoot the ML and work with some loads at different ranges, that's the one I would recommend. Otherwise, the shot gun.

If the slug gun has a rifled barrel I would try it and see how well it does with several brands of slug some of the better ones are deadly at 100yds; if its not a rifled barrel then you are better off with the 45 muzzleloader, a 50 or especally a 54 cal. would be much better in a PRBthough if the laws where you are allow it you might try a 40 cal bullet in a 45 sabot or if its a 1-48 twist a Real bullet usually works quite well. Lee

If you still have the time and can afford the ammo/powder & bullets, I'd borrow both, then go to a range and see which one works best for you. Probably the easiest would be to borrow the shotgun and buy some slugs. Either way, make sure you check it out at a range to see where it's shooting to avoid being disappointed when that deer walks out in front of you. Borrowing a gun is always a risk, since you don't know where it will hit at any given distance. Either of these choices will take down a whitetail.

Good Luck

Since you are not used to the .45 caliber muzzleloader a shotgun might be easier to learn quickly. While a .45 caliber roundball will more then do the job, a shotgun slug is also very deadly. Both have about the same range, and if all you are doing is trying to fill a freezer for the time being, until you can get a rifle of your own, then the shotgun with fast follow up would be the way to go.

You might still want to get to a range and shoot both of them. I know a couple shotguns that while with shot there were real good, with a slug they were terrible...

Good luck.