Quote:
Originally Posted by 320pf
This forum was started by my request but I on vacation at about the time that this forum was started and did not have a chance to get any thing posted.
So here is a repost with some additional material that describes the various 223 Rem based 25 cal. wildcats.
There are three variants/wildcats based on the 223REM/5.56x45 case. Some will fit in an AR15 mag better than others. The 25x40 has the shortest case. It goes by the name 25x40mm. It was designed be Kurt. His handle on AR15.com is 7.62x40mm, his first creation. He also post on occasion here on quarterbore. The 7.62x40mm is now being offered by Wilson Combat. Basically, it is a 223REM case shortened to 40mm and the shoulder pushed back. This reduces the case capacity to about 28-29 g of water. The 25x40mm designed is such that you can load bullets up to 115 g Bergers. The case mouth will not ride up on the ojive of the bullet and will fit the 2.26 length restriction of an AR15 mag. The 25x40mm is very similar to the John Wooters 25 Copperhead.
The second 25 cal 223REM/5.56x45 based wildcat is the one I designed with advise from Kurt. It goes by the name of 25-223AR. It has the same shoulder as the parent case but the neck is shortened about 0.06" giving an overall length of 1.70". This cat was designed for 25 cal bullets up to 100 g without the case mouth riding up on the ojive of the bullet and still fit within the 2.26" length restriction of an AR15 mag. I have been able to push 100g bullets to 2550-2600 fps (16-inch barrel).
Various people including myself have been able to push some load to 2650 fps with some combinations of 100 gn bullet and powders, but as with all internet reloads… You are on your own Start low and work up..You must use your own judgement if the loads are safe in your gun/barrel combination. The heaviest bullet that will fit in 2.26 length restriction of an AR15 mag is the 117 gn Hornaday round nose bullet and the 117 gn Sierra GK. I have pushed these bullets up yo 2400 fps. The Hornaday 117 RN runs through my ARs quite well. The 117 g Hornaday bullet is designed for the Winchester 25-35 so 2400 fps is right in the velocity envelope for this bullet.
The third 25 cal 223REM/5.56x45 based wildcat is here on this site under a different forum. It's main advantage is that it is simple to make brass. Run it through a 25-223 Rem die and you are good to go. Because of the longer case neck however, you will have a lot fewer bullets to choose from without the case mouth riding up on the ojive of the bullet.
If I recall correctly, there is also an cat based on the 223 Mag. I believe that "Blackwell???" wrote this up in one of the gun rags several years ago. I think that it was named the 25x47mm.
I have a copy of the original article for both the 25 Copperhead and 25x47mm. I will try and locate them and update the information on these two cats.
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There is another 223 Rem base wildcat based on the .256 Winchester Magnum. I believe Marty of Teppo Jutsu came up with this one. As I understand it, you run a 223 Rem case into a standard .256 Winchester Magnum die and trim to length. Thisis basically a rimless .256 Winchester Magnum.
The Hodgdon reloading manual list load data for the .256 Winchester Magnum. Given that the SAAMI pressure spec is only 50000 psi (~40000-45000 c.u.p.), the Hodgdon data can be used as a good starting point. Based on the data in the Hodgdon manual, I would guess that seating an 87 gn bullet out to AR mag length, the velocity potential would be ~2500 to 2600 fps.
Can anybody think of any others?
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