223 rem rebarreling, what cal would you do?

[clark270]

223 rem in Winchester m70 lightweight should I keep it a 223 and go with a 1/8 twist or 6-223 or 20-223? What would you pick I was thinking about shooting heavier bullets with more twist. I would have to keep the 223 sized magazine and bolt.

 

[BallisticsGuy]

Definitely my choice would be the 6x45mm (6mm-223). It's a hell of a little cartridge. My results were basically 100fps or a bit better better over .223rem with 10grain heavier bullets. More velocity, more energy, better ballistics. Kinda the perfect projo size for that case. So if a 55gn .223 would do 3200fps, I'd get 3300 with a 65-ish grain .243 pill. My favorite load for a long time was 85gn soft points at around 2850fps. It's a little light on case capacity for the heaviest bullets. My normal route is running long throated chambers and single feeding if the gun uses GI length mags so I could hang the bullet out long loaded and get 2-3 grains more capacity in the boiler room.

I'm waiting on a 6x45mm barrel for my MVP rifle at the moment.

 

[J E Custom]

This might help. It gives you some choices with the bolt you have.

http://www.longrangehunting.com/forums/f37/bolt-face-diameters-36661/

I built a 223 AI that is sweet and picked up about 100 ft/sec with the same bullet. It also shoots the heaver bullets as fast as the lighter 55 grain bullets.

J E CUSTOM

 

[newmexkid]

Little lighter bullet choice, I would go with the .20Practical.

 

[Mikecr]

Along the line of 24cal, you could go 25cal with it.
25-223AI

It all begins with a bullet, in this case I suggest BIB's 25cal 80gr FB BR bullets. These run well in 10tw barrels. The AI 223 case would be sufficient capacity yet low enough chamber area(being underbore) to run very high peak pressure loads with faster than normal powders. Lapua brass of course.
It's a little better ballistically than typical 223AI, but way better precision-wise. Expect performance inline with a 30br to 500yds. Barrel life around ~3K.

The benefit of running underbores like/similar to 6PPC, 30br, up to 6.5x47(with the right action/barrel) is that the small chamber to large bore allows viable extreme peak pressure loads(pressure nodes). This is so far into diminished returns that it overshadows nearly every other variable in a load. That is, no matter the inconsistent neck tension, capacities, etc., that powder is going to drive right to the pressure node, and that's where these cartridges shine competitive.

 

[sable tireur]

223 rem in Winchester m70 lightweight should I keep it a 223 and go with a 1/8 twist or 6-223 or 20-223? What would you pick I was thinking about shooting heavier bullets with more twist. I would have to keep the 223 sized magazine and bolt.

Should we assume that you mean a faster twist rate for the longer/heavier bullets?

If that's the case then definitely go with the .223 Ackley Improved. You can match this with the Hornady 75 gr. AMAX and really have a terrific set up. Moderate temperature and pressure with semi-long range performance. This outshines the 6mm-223 or 6x45 significantly when similar bullets are used while maintaining the magazine length you require. It's a great combination for coyote, ground hogs and water jugs out about 600 yards. The rifle doesn't have to be heavy as it's a mild cartridge/bullet combination.

Have fun with the project!

 

[TOM H]

Might want to try 25x45 Sharps.

New, to me, AR caliber .25-45 Sharps. Winner? [Archive] - Calguns.net

 

[MudRunner2005]

Put a 16.5" heavy 1:8 twist barrel on it, and chamber it for .300 Blackout. It is a VERY fun cartridge to shoot, and a very cheap one to reload for (other than the .30 cal bullets). Plus you already have tons of brass for it... You just have to buy a jig and a saw and cut it down and form it.

 

[clark270]

Thanks everyone, if I get a black out it would be for my single shot Encore. I like the 223 AI and 6-45 AI.

 

[Jud96]

My cousin just went through the same decision. He currently has a Remington 700 Varmint with a slow 1:12 twist and he wanted to shoot the heavier bullets and gain performance. I talked him into the .223 Ackley and he's really looking forward to it. He just got a Krieger 1:8 twist #9 contour today and he is going to cut, crown, thread, and chamber it by this weekend. Really looking forward to this hot little cartridge.

 

[TOM H]

Want little more horsepower neck up 204 case got little more case capacity than 223 maybe about what 223AI has. I don't have it twisted for the heavy bullets but I shoot 27" barrel 222mag and I shot 6x47AI couple years. If I do another or rebarrel one of my varmint rifles I'm going to do something off the 204 case.

 

[Kansaswoodguy]

At what ranges do you normally shoot?

 

[clark270]

Just shooting for fun. out to 400 yds. And a few Chuck's, yotes, and deer.

 

[Jerry M]

5.56 mm to be able to shoot mil spec ammo.

Good luck

Jerry