I have a 243 that I bought for a longer range varmint project rifle. It was a beater when I bought it but it cleaned up pretty nice so I have been shooting it as a 243.
If I decide to go to a wildcat 6mm, which simple, short action friendly, variation would the experienced wildcatters here go with?
I read about one that pushes the shoulder back and forms a longer neck and 30 degree shoulder on the 243 that sounds interesting. What do you all think? DW
ps. this will only the the second cat I have owned. I had a 6mm 30-30 barrel for one of my contenders but sold it like a fool.

6x47 Lapua, 243 AI, 6 Dasher, 6 Creedmor, 6x250

6mmX284!If it shoots good just rechamber your barrel.

For what you are looking to do, you should look at this site. Just go to CARTRIGE GUIDED (shows red box of 223 Rem)

http://www.6mmbr.com/index.html

I like the 243AI
the 6mm-284 is too long for feeding in a short 700 action..

m

metric: My data shows the 6x284 Win and the 260Rem-308Win all having the same OAL of 2.800". It will work in a short action but a longer actiom would be a better choice as you could uses long high BC bullets set out in a throated chamber. If the gun was going to shot as a single shot there is not a need for a longer action as the chamber could be just throated longer.

Sure, Albert
but the benefit of a 6/284 over the 243AI is the ability to push a long heavy bullet with high bc a bit faster..
If you want to shoot 75HP's the 243AI is just as good!

M

I think the first question you need to ask yourself and for us to help you choose, is how much case forming are you willing to do? Next is what level of performance are you looking for? Are you trying to re-use the original barrel (false economy)? How much are you willing to spend on the chambering and dies? Wildcat dies can be 2x-4x the cost of standard calibers and finding a smith with the reamer you want could be a callenge. If you are single loading, it doesn't really matter what you go with as far as cartridge length.

A little more detail. The rifle will be used for coyotes, prairie dogs and maybe an antelope. I bought a bunch of Barnes old varminator lead core 72 grain bullets, (thousands), when they were clearing them out. I was thinking about a wildcat listed on 6mmbr.com called the super x. It is a 243 that has the shoulder pushed back and forms a 30 degree shoulder. The 6 x 47 Lapua also is interesting. 243 AI is ok but want something different with a longer neck. I have a good friend who used to chamber all of Barnes test barrels who will clean up the action and chamber the new barrel. I think a Shillin #5 contour from the Barrel Man. I also think I'll cut it back to 24 inches. DW

6-250.
Easy to form and will feed from the magazine.

Since the 6-250 was brought up, I'm going to suggest the 240NMC which is the 6-250 with a .243 body taper and the original 28 degree shoulder and headspace. Super easy to form from 22-250 cases and has slightly more capacity than the 6xc. I shoot one in highpower XTC and LR competition and it will throw a 105-107 at 3000+ fps out of a 28" barrel. I haven't pushed the 70's at all but I imagine they should do 3200-3300 at full tilt. Dies are reasonably priced from Hornady and I can point you to a very good gunsmith who developed the cartridge and has the reamer and everything else you need.

I have done the 6X47Lapua. It feeds great and is very accurate. The dies will neck it down with out any form dies.
Butch

Ream for a 6x284 and don't look back. If you are going to change barrels, then get a long action, but if you want extra performance, then go with the 6x284, and simply run 6.5x284 cases through your resizing die. I have done this several times, and it works well.

A lot of the cases mentioned are fine tuned for target work and you won't see the difference in a stock 700. If you start doing major remodeling work, you will end up with a full custom, along with its cost.

By the way, several of the wildcats mentioned here use 223 or ppc head sized brass. A new bolt is not an easy thing to find used, and can cost as much as a cheap rifle.

I did the 243AI on a 28" long barrel.

Read this
http://www.6mmbr.com/243win.html

For simplicity ... 6x250. I wouldn't look at anything requiring custom dies. If your going to be using the lightweight pills that you have in abundance, a smaller case will almost equal the 243Win. For absolute simplicity, true the action and throw a match grade barrel chambered to 243Win back on the rifle. No flies on a 243Win built to match grade specs.
Cheers...
Con

How about the 6mm AI?

Art S,
Which mentioned cartridges on this thread is 223 or PPC based? New Remington bolts are very reasonable from PT&G if needed.
Butch

Butch

You're right. I read quickly and didn't notice the Lapua after 6x47. I have owned 3 or 4 461's in either 6x45 or 6x47, and just didn't register the difference. The other mistake was that I haven't followed the development of some of the newer 6's like I used too, and didn't realize what the 6 Creedmore was. A couple of friends of mine were playing with the 220 Russian case around the same time the PPC came out, and they called their chamber the 6mm Creedmoor.