December 31, 2011, 02:12 AM
I am trying a wildcat consiting of using the 25'20 case necked down to 5mm
Any input

If you enjoyed reading about "20/20" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
December 31, 2011, 02:32 AM
seems an awful lot like the .218 Bee to me, and that might be a better case to work from depending on what your looking for. I dont really think it would serve any practical purpose that other rounds dont already fill, but hell if only practical mattered we wouldnt have so many cool rounds to play with.

What sort of rifle ( i assume its for a rifle) are you going to be using it for? I think it might make a really neat little project in the right gun.

December 31, 2011, 01:08 PM
I am going to try it in a Remington 571 5mm rem mag modify the chamber to the 25 20
I use a 204 now but sometimes its too much gun(noise) and think this should fill the ticket. The 5mm mag is okay but it is rimfire and the shells are 25.00 for box of 50.

December 31, 2011, 02:29 PM
It is also a rim-fire, and the firing pin in the 571 Bolt will not hit a primer in a 25-20 centerfire case.

You would also have much greater bolt thrust at the same pressure level because the 25-20 WCF rim is much larger = Bigger Piston.

I would question if the bolt handle locking lug would be strong enough to hold it.

It won't feed from the magazine either.

I think you might save a lot of time and potental injury if you just rebarreled it to .22 WMR.


December 31, 2011, 02:36 PM
Im unfamiliar with the 571 rifle so i cant say anything towards specifics, and my generalizations might well be wrong. That said if it can handle the pressure, having the bolt modified from rim fire to center fire and modified for the larger rim diameter would likely cost more then picking up another rifle in .22hornet or .218 bee and going from there.

As for the cartridge itself, id actually forgoten about the .204. An improved version of the bee with its shoulder moved forward might be a really neat little round.
http://i14.tinypic.com/3yfktg3.jpg much like the killer bee or Hebee, just necked down to .204

RC beat me to the post lol, and made a good point i hadnt thought of. The .22wmr is a great round for smallish (and some times not so small) stuff out to 200yds or so.

December 31, 2011, 03:37 PM
Try an internet search for "5mm Craig". Years ago someone made a centerfire conversion for the 5mm rimfire. I have no exposure or experience with this round. I can speculate that it was not real successful and that the re-introduction of factory 5mm has reduced demand for the conversion.

December 31, 2011, 05:23 PM
Cooper Arms also had several small center fire hot shots. It seems to me that one of them was a 20 caliber. That was some years back.
rcmodel; do you remember any better than I do?

December 31, 2011, 05:27 PM
Go for it ignore these negative nannies there whole purpose in life is to ruin good ideas that could have potential.

December 31, 2011, 08:11 PM
I dont think anyone was being negative, just pointing out some facts, and offering opinions.

Jim Watson
January 1, 2012, 12:24 AM
I would question if the bolt handle locking lug would be strong enough to hold it.

That series of Remington rimfires, both the 5mm and .22LRs, had six locking lugs, pretty much a 2/3 scale model of the 788. It would surely stand some level of .20-20 WCF load. But can the OP find it? Does he care that he would be in single shot mode? Not much chance of making a 5mm RM magazine take a .20-20. Does he have a good deal of money to sink into a centerfire conversion and new extractor/ejector (the 5mm is kind of weird there) in addition to having custom reamers ground to cut the chamber and loading dies?

These Internet Bright Ideas are usually more complicated and expensive than they appear at first glance.

January 1, 2012, 02:26 AM
You are right about the extractor and ejector on the 571 both are junk that is the problem with the rifle iam thinking of using a different action and just the barrel on the 5mm. The 5mm looks to be close to just a22wmr necked done. the cartige is good but I cant reload the rimfire to tune loads to the gun It is equivalent to the 22wmr which is just not quite enough. The 204 is fine it is just too loud in certain situationsI could use some inputy on what action would be compatiable with the 571 barrel.
I just think the 218 Bee would ok but I am wanting to stay in the sub calibers (.20 >17)
Hornady just introduced the .17 Hornet which is the ....22 hornet necked down. I guy doesn,t have a chance to come up with new cartiges when the bullet manufacterures and gun manufacterures(Rugert) are thebiggest wildcatteres it the business now

January 1, 2012, 02:38 AM
The 5mm Craig is where I started but if we all did the same thingh nothing would chang
As isaid the action is not too desirable in the firsrt place The218 Bee is wherte I started it is a 25/20 necked down to .22 I just think a .....20 cal version mjght be interesting .Just about every combination and modification has been trird on the..22 to .460 calibers therte are very few .17 or.20 cal ibers and it is an open field for unchartered waters

January 1, 2012, 02:46 AM
I love the 204 .I shot a cyote at 75 yards with a 40 grain polymer tip, she jumped ran 10 feet and dropped. There was aclean .20 entrance wound and no exit wound no pelt damage I am in the processof suppressing the .204 but there will always be noise especially with a supersonic bullet 4100 fps It would be fun to have a unique rifle of your own design. Anybody can buy anything they want but it is rewarding to build what you want and be unique

January 1, 2012, 01:37 PM
I've never heard of a Remington 571 in 5mm mag.?? Am i confused or are you guys?

All the 5mm's i owned were 591's and 592's...

BTW, the Rem. 5mm mag. is a much bigger case than the 22WMR, at least in diameter...


January 1, 2012, 01:52 PM
You are correct it is a 591 My mistake and yes the 5mm is a bigger diameter than the 22wmr.

If you enjoyed reading about "20/20" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!