Could it be a 22 Savage High Power ? factory loading from Savage. it was rimmed made on the 25/35 case

22's on the 250/3000 Savage rimless .473 head case were a fairly common wildcat back in the day. Current factory  22-250 Remington is about the same cartridge as most of the wildacats. 

Key is rimmed or rimless

Boats

It was an early wildcat varmint cartridge made by necking the 25-20 SS to .22 caliber. G & H had cases made up with their stamp on them. I have one cartridge in my collection. Most folks just necked down the 25-20 SS cases. Most rifles converted to this caliber were single shots.

I was an original case developed by Hervey Lovell, I believe the first CF 22 to hit 3000fps. It evolved into the R2 Lovell to allow for better ballistics, and eliminate case stretch issues that plagued the cases with gentle sloping shoulders . 219 Zipper is another.
Hervey lived in central NY and a while back I met his grandson, a master machinist, that showed me a 1/2 scale high wall that was almost finished, he was making it into an R2 as a tribute.

The original 22-3000 was more like an elongated Hornet.  The R-2 Lovell was a blown out 22-3000.  The Maximum Lovell was a blown out R-2, but most users thought the R-2 was better.

If these are not clear enough, I will make them a bit larger & repost.  They are scans from Landis.

The 22-3000 was designed Harvey Lovell. He commissioned M.S. Reisley to grind the reamer. When Reisley got the reamer print he felt the shoulder was wrong. So he ground 2 reamers the first the way Lovell designed it and the second as he thought it should be done. When Lovell showed up to get his reamer Reisley showed him both and offered him his choice. Lovell stood by his original design. Reisley dubbed the other the 22-300 R2 for his second reamer. It turns out Reisley was correct; you will find many more R2s than Lovell’s design.
  G&H made head stamped cases for the R2 so did J. Bushnell Smith. 

40 Rod

40_Rod wrote on Feb 15^th, 2014 at 9:31am:


I've always thought, from reading all the stuff that Fred Ness wrote, that it was Harvey Donaldson who put Risley up to making the blown-out .22-3000 which became so popular.   ("Practical Dope On The .22" Page 74.)

Then Lyle Kilbourne pushed the shoulder even farther forward, and begot the "Maximum Lovell".  

BTW I have weighed, spindled, folded and mutilated every Lovell case I could get my hands on, so I can say with certainty that the G&H brass, (if that's what the O.P. has) is even thinner in the head area than most of the the old .25-20 cases they used before.   But it was Winchester who made it for G&H, so the quality was pretty good.  G&H cases are collectors items now - I use Captech (nee Jamison) brass in all of mine.  Much thicker heads, so you have to back the loads down a grain or two.

I have the contact info for a gentleman that had a C.C. Jonhson highwall barrel for 22-3000 that he had for sale.
 
Do not know if he still has it but if interested I can give your his email in a private message.
  
Charlie