cool..............

About the only difference is the 25x40 has the shoulder set back and it is trimmed shorter. The 25-223 is just necked up in the resizing and then trimmed about 2mm to make sure it does not ride to high on the bullet when it is seated to fit into an AR magazine. This is about as easy as it gets for a wildcat. The advantage to the 25x40 is I think it will fit heavier bullets (over 100 gr.)
If I was a wealthy man I could try them all. (may not get much work done but it would be fun)

If you want to go totally metric it is 6.35x43mm

I wish it was that easy.......

From the start the 25x40 was designed as a work-around for game management areas that did not allow .22 caliber center-fire cartridges....

It was not by luck or fluke that .25 cal was selected for the project, there was close to a decade of previous testing done on small cases similar to a PPC...

There are a lot of BC crunchers here so it was laid out for use up to the more slick 100gr Matchking, although I gravitate more to the 80TTSX as a all-around hunter, currently running over 3,000fps....and that's pretty fast for a slow bullet....usually stay at or under 100gr, point of diminishing return.

The smaller case and geometry offer several advantages that I won't get into here but one being that it accelerates the rise to peak pressure allowing smaller charges of powder and achieving the same or better performance of its full-size cousin in shorter barrels....

With a 20" tube?

In the original thread Kurt cited an 85gr Nosler going 2900 out of a 16", so I bet that is from a 16" as well.

ETA: He beat me to it, but I was almost right.

"I think I've got it narrowed to the .25x40 or the 6.5MPC." I am with you, the 6.5 MPC will be better at longer ranges on deer and hogs(out to 300 yards), but the 25 does not have to be fire formed.

If you're talking about 300 yard killing envelope, why not use either the 6.5 Grendel or the 6.8x43 (SPCII)?

And don't forget brass.

With lighter projectiles some of these 223 based wildcats are getting very close to 6.5G and 6.8SPC performance. I'll grant you that they won't match them, especially with heavier bullets like the 123gr 6.5 bullet, but they only require a barrel change and brass is everywhere. That has merit to me.

The 6.5 & 6.8 both sound interesting to me and I could handle the changing of the bolt and magazines (they are one time cost). It is the cost of brass that kills those two for me. USGI once fired is what makes these wildcats worth the effort.

At the same time, anything past my 150 yd self-imposed limit I'll pick up a .308 Win.

This is very interesting, I will be following this. I have thought about a 6.8 for a couple years now, but the cost of the brass has been the primary thing that has held me back. This may be just the thing. Thanks for the info guys.

How much more life do you get from a annealed case?.

Let's not lose track of the most important issue here...how exactly does an individual like myself, who has neither a machine shop nor a gunsmith as a shooting/drinking buddy, procure a barrel with this chambering?