Here's a really nice one for sale. Pretty scarce chambering and based on the bidding to date, you'll need to dig deep to win this auction.

https://www.gunbroker.com/item/996771876

I can usually come up with a reason for any rifle in any chambering.
A 44 mag No 1 has me

It would be a nice rifle for deer in states that only allow rifles chambered for handgun cartridges. My late hunting buddy in Indiana used a Ruger #1 in .480 Ruger/.475 Linebaugh. I used a Marlin 1894 in .45 Colt.

I have one of these, it’s a very nice compact take on the #1 that shoots cast or jacketed very well.
.44 Mag loads that sting your palm in a revolver feel like a pop gun going off in the little rifle.

I didn’t pay anywhere near the current bid price for mine.

He wanted it really bad.

First thing I'd do is run my 444 reamer into it and make it more useful.

To paraphrase Ronald Reagan, "There you go again, Tom--being practical."

The 44 Mag #1s must have been produced at the behest of the Ruger Collectors Association.

Dave Manson

$3800 dollars!
He must have wanted it like people in Hell want ice water. That's way over double for what I paid for my #1 in 458 Lott. (And it came with a Cape Buffalo taped to the muzzle)