My 25x45 AR
 

Saying hello, basically I am a quarter bore whore myself.

I have a 25x45 barrel made for me by BlackHole and I have been doing lots of work with it. Its a sweet shooter. Just basically re-size, load, and squeeeeeze. Been shooting mainly Sierra 70gr BK's but I did kill a deer a month ago using a 100gr SP. Very accurate so far with just about everything I have shot out of it. Its a 20" varmint contour, crowned. Right now I have it topped with a Nikon M-223. Jewel trigger in it.

Been using quite a few different powders working with it but currently using the New AR-Comp powder from Alliant. So far so good....now that deer season is over I hope to be able to post up some coyote pics as the season progresses. I have only chrono'd a few as I am firmly in the accuracy trumps speed camp but I did get 2926fps with Sierra 70gr BK's and H335 25.3gr.

http://i769.photobucket.com/albums/x...0PointBuck.jpg

http://i769.photobucket.com/albums/x...ghes/25x45.jpg

http://i769.photobucket.com/albums/x...hes/25x45c.jpg

http://i769.photobucket.com/albums/x...ughes/M223.jpg

My Son took a Coyote in New Mexico

http://i769.photobucket.com/albums/x...es/Trip010.jpg

I make 25-223 barrels for a guy in NY.Basically 223 necked up to 25 cal.So they can use their ar's for hunting.Guy says works fine on deer.

I have one of those 25-223's..... I learned a lot from shooting the 25-223. Based on what I learned I went to the 25x45. There is No trimming back the case neck..... just neck up, load, and shoot. It does top out in the 100gr bullet area, I have shot heavier but it is not well suited to shooting them efficiently. The deer above thought the 100gr SP was more than enough.

I would love to talk to you about the barrel I got in 25-223

Welcome to Quarterbore. That's a nice looking buck. What's the difference between the 25x45 and the 25-223 ? Aren't they both 45mm long cases ? I'm looking at a 6x45 AR build since I already load 223, and 243.

looks interesting

Both are based of the 223 parent case. The 25-223 after re-sizing you must trim the neck back from standard 223 case lengths an additional 2mm or so (43mm case) to achieve FFF.

I decided since I wanted to predator hunt with light bullets mainly and I was sick of trimming brass, I decided to go with a 25x45. The 25x45 is simply trimmed to 223 lengths like you would normally do then you re-size, load, and shoot. No extra trimming. I made some changes to the barrel I ordered for it. To me, the 25x45 just makes much more form and function sense for what I am doing. I buy once fired mainly military brass that has been cleaned and trimmed already, place out in Colorado. I have never had to trim one piece of brass after sizing it to .257 yet.......that alone is fantastic.

I also have a 6x45, not going to knock it as it's a good cartridge. I do not shoot it much but I have killed several coyotes with it. I can also shoot 100gr bullets with it also.

Thanks for the information. I don't know a lot about the 6x45 yet, and knew nothing about the 25x45. From what I understood, the 6x45 doesn't need to be trimmed to length after necking up 223. What barrel length, gas length, and twist did you use in your 6x45? I'm looking at carbine probably.

too many choices
 

Hi 7.62 Nato,

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 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 to 25 cal bullets up to 100 g without the case mouth riding up on the ojive of the bullet and still fit the 2.26 length restriction of an AR15 mag. I have been able to push 100g bullets to 2550-2600 fps (16-inch barrel). I have gotten up to 2650 with some combinations of 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 g Hornaday round nose bullet. I have pushed this bullet up yo 2400 fps. It runs through my ARs like a hog eating sxxt. The 117 g Hornaday bullet is designed for the Winchester 25-35 so 2400 fps is right in the velocity envelope for this bullet.

If you want to read more about this cartridge you can find it here:

http://www.ar15.com/forums/t_3_121/4...23.html&page=1

It is over 30 pages of material. So if you want to read about it set some time aside.

The third 25 cal 223REM/5.56x45 based wildcat is the one described here. 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. However you will have a lot fewer bullets to choose from.

Here is a list of the bullets where the case mouth rides up on the ojive.

Nosler 100 BT
bullet length=1.117
shank length=0.576
ogive length=0.541
case @1.7 COL=2.241
case @1.76 COL=2.301

Nosler 85 BT
bullet length=1.000
shank length=0.461
ogive length=0.539
case @1.7 COL=2.239
case @1.76 COL=2.299

Nosler 100 PT
bullet length=1.035
shank length=0.500
ogive length=0.535
case @1.7 COL=2.235
case @1.76 COL=2.295

Barnes 80 TTSXT
bullet length=1.012
shank length=0.456
ogive length=0.556
case @1.7 COL=2.256
case @1.76 COL=2.316

Speer 87 TNT
bullet length=0.916
shank length=0.369
ogive length=0.547
case @1.7 COL=2.247
case @1.76 COL=2.307

Horn 100
bullet length=0.986
shank length=0.459
ogive length=0.527
case @1.7 COL=2.227
case @1.76 COL=2.287

Horn 75
bullet length=0.867
shank length=0.339
ogive length=0.528
case @1.7 COL=2.228
case @1.76 COL=2.288

Sierra 100 MK
bullet length=1.074
shank length=0.516
ogive length=0.558
case @1.7 COL=2.258
case @1.76 COL=2.318


There is a full discussion on this here:

http://www.ar15.com/forums/t_3_121/4...3.html&page=28

Good luck with our project. Wildcating is a very fun hobby/addiction.

320pf

@320pf,
All very good information. Thanks for taking the time to write that down, and the links. Although I don't really plan to get into "wildcatting", I find the information and development fascinating. My limited experience and resources will have to be satisfied by "different" cartridges for now. I'm currrently looking at the 300 BLK and varients, 6x45, and I believe there is a 6x45AI (still need coffee) that is close to the 6TCU. Not sure if the latter will work through unmodified AR mags. I like the other 2 because of simplicity and commonality of parts in the AR.

I consider myself a novice reloader and am still going by the recipes in the books. I just wanted something a little different to play with. I'll see which combinations work best for me.

Thanks again.

After additional reading I've found out the 6x45 is among cartritdges still considered wildcats. At what point are cartritdges no longer considered wildcats? I thought it would be when they are being produced commercially with accepted standards.