# Wildcat cartridge



## prettytiedup (Dec 19, 2007)

I have been thinking about wildcat rifles. One cartridge that I think would be interesting is a .300 win mag necked down to a .270. I'm sure it has been done but can't find any info. Anyone ever heard of this? Also, how would someone go about sizing shells and finding a chamber reamer? Any info from some of you gun nuts would be appreciated.


----------



## Nueces (Jul 22, 2008)

I don't know much about it, but I do recall a guy that had a "wildcat" cartridge a while back. He couldn't find brass, so he was using another caliber loaded with powder and primers ... he would close the bolt and fire blank cartridges to shape the brass to his chamber, then reload.

I just recall him doing that, don't know any details. With the extreme pressures that can be generated with just a 1/2 grain of powder, I personally stick with known loads and cartridges. I tend to be a follower in this particular arena and not a leader. :idea:


----------



## Loke (Sep 7, 2007)

Huntington Dies and Clymer reamers would have the info you are looking for. The basic concept was introduced in 1943 by Roy Weatherby. He called it the 270 Weatherby Magnum, and it started that whole Weatherby thing.


----------



## Frisco Pete (Sep 22, 2007)

As mentioned virtually any wildcat you can think of has not only been done, but as of late has been duplicated in a factory round. As to your "._300 win mag necked down to a .270_" - The above-mentioned .270 Weatherby is basically one, and the .270 Winchester Short Magnum is another version, with its case taken from the .300 WSM, which is very close to the .300 WM in capacity - take your pick, long action or short - but save your money, the PERFORMANCE of a .270-300 WM has been duplicated in two excellent factory rounds.

Speaking of .270 wildcats, on another forum I recently saw a post by a guy that met a shooter at the range that was all excited about his terrific new "wildcat" .270. He explained that he had necked down the 30-06 case to use .277" bullets (.270). He showed the poster the barrel stamp and sure enough it actually said ".270-06 Springfield."

Gotta be the easiest "wildcat" any gunsmith ever did - slap on a .270 Win barrel and come up with the appropriate chambering stamp as per the customer. The hard part would be to keep a straight face through the whole affair as you take the guy's money :lol:

###########################################################

As to:


> a guy that had a "wildcat" cartridge a while back. He couldn't find brass, so he was using another caliber loaded with powder and primers ... he would close the bolt and fire blank cartridges to shape the brass to his chamber, then reload.


That would be called an "IMPROVED" round. For example: You can take a .280 Rem, .223 Rem, 30-06 etc and have it re-chambered for a blown-out "Improved" version. Gunsmith P.O. Ackley (who lived in Utah for quite a while) pioneered this concept. Firing factory ammo in a carefully dimensioned larger chamber straightens out the tapered case body, giving the original factory designs a more straight walled dimension. The Improved chamber would also change the shoulder to something around 30 to 40 degrees. This change would also tend to stop case lengthening upon firing, within reason. It became common to reload those cases 15 - 20 times without having to trim them. Thus, the benefits of the famous Ackley Improved cases became reduced back thrust and elimination of case trimming. Case extraction became easier and more positive and loading pressures could be increased safely, resulting in higher velocities. Another interesting feature of these Improved chambers is the fact that standard factory cartridges can still safely be fired in the rifle - which is what _Nueces_ is talking about. There are some die makers that still offer Ackley dies with the milder shoulders, so when ordering loading dies it is prudent to specifically request the 40 degree shoulder model if you wish to duplicate original AI design.

There are more than 20 Ackley Improved cartridges. The percentage of velocity gain over factory loadings ranges from about 3% up to 17%. When we compare the Ackley Improved cartridges to handloaded standard factory rounds, the velocity gain ranges from zero up to a little over 12%. From this you can see there are a few Ackley Improved cartridges that may not be worth the trouble and expense to chamber for.


----------



## Bax* (Dec 14, 2008)

Frisco Pete,

that was really interesting. Wish I knew more about things like that. The first I ever heard of these "improved" rounds was a 22K hornet


----------



## Lycan (Sep 22, 2008)

Frisco, 

You seem to really know your stuff. What AI cartridges would you recommend against?


----------



## Frisco Pete (Sep 22, 2007)

Currently the most popular and well-thought-of AI rounds seem to be the:
.223 Rem AI
.257 Roberts AI
.280 Rem AI
and the K-Hornet, though not an AI, is an Improved cartridge with large benefits in case life.

I wouldn't mess with any .270 or 30-06 AI, to name a couple I can think of.

In addition, you ought to be aware that the new 7mm Remington SAUM (short action ultra mag) provides identical+ performance to the .280 AI in a factory chambering/round.


----------



## Lycan (Sep 22, 2008)

How about .22-250 AI?

Also, how much is accuracy affected when you shoot factory ammo in an Ackley Improved chamber?


----------



## huntducksordietrying (Sep 21, 2007)

Has anyone ever seen the movie "Shooter"? I'd swear when they casted the roll for the old guy who knows every freaking thing about shooting, the went and saw Frisco Pete.


----------



## Frisco Pete (Sep 22, 2007)

> how much is accuracy affected when you shoot factory ammo in an Ackley Improved chamber?


I don't have any Improved-chambered rifles and have no first-hand experience, but from all the accounts I've read, accuracy doesn't seem to be affected at all, likely because the bullet is in the same relationship to the barrel as it was in the original cartridge.

You do seem to lose velocity because of the larger combustion chamber and the pressure has more room to expand - blowing out the relatively soft brass to form to the new chamber shape in the process.
A velocity drop may affect barrel vibrations, which may affect point-of-impact, but this is totally theoretical.

As to the 22-250 AI, here are a couple of links:
http://www.varminter.com/particles/aifront.htm
http://www.varminthunter.org/downloads/Issue64.pdf
http://www.pittsburghlive.com/x/leadertimes/sports/s_507214.html
and even some discussion on 24hourcampfire.com: http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/213164/site_id/1#import



> ...the old guy who knows every freaking thing about shooting


Hey! You're blowing my cover! :lol: Actually I just spend way too much time reading about gun and reloading stuff and tinkering around with gun-related things. I also know good sources for information. However, be aware that the more I learn, the more I realize the less I know. I am just a student like you.


----------

