Rebarrel in 223 or 6mm-223

[bobcat1506]

I’ve got a Remington 700 varmint in 223 (about 3k-4k rounds) and I suspect its barrel is going out. The groups are starting to open up, I’m getting more flyers, and it’s starting to foul faster. I’ve pretty much decided that it’s time to rebarrel it with a quality hand lapped barrel. I mostly use this gun for prairie dog trips and economic practice at the range.

I’ve got other varmint rifles and would like to keep it either a 223 or something that uses the 223 case that can buck the wind a little better that doesn’t need to be fire formed. I’ve read about the 6mm-223 and how it achieves better velocity for the same weight bullets (due to larger space to burn the powder), shoots cooler, and has better barrel life than a 223. There is a good selection of varmint and match bullets available in the 55-80 grain range. Does anyone have any experience with the 6mm-223 that could shed some light on its practicality as a prairie dog caliber?

 

[bheadboy]

i have none with the 6-223 however a great deal with the original 6-47 (222m) and it is a fine round using up to the 70's beyond that the powder capacity is too low. i think you would do well to consider the 6-223ai or 6-204

Bob

 

[Beau]

I think I'd just stay with the .223 with a 1/8 barrel because of reloading die costs. Plus with today's heavy .224 bullets, the 6-223 doesn't have as much advantage as it used to.

 

[Hammer47]

I like the 6 mm better because of the better expansion ratio which leads to less bbl throat wear. There are also way more benchrest type accuracy bullets available in 6mm. You might want to take a look at the 6TCU instead of the 6/223 as the body has less taper and the sharper shoulder is nice too.

Fireforming is a breeze, don't even give it a thought.

I have a tight neck PPG reamer in 6TCU and if you are going to use the small boltface I would recommend it.

It is hard to beat a sporter rifle that groups at a quarter minute using benchrest bullets that did not quite make the grade. You can also buy castoff benchrest 6mm bbls that will easily hold quarter minute but not accurate enough for the benchrest game.

The varmint hunter can REALLY do well buying castoff benchrest gear and apply it to his sport. Ask me how i know.

 

[areaone]

223 AI with a 1/8 twist. Easy to fireform and very accurate when fireforming, almost to a 22 250 with longer barrel life., 69 gr Sierra or 75 Hornady a max. best of all cheap brass, lots of bullet selection.

 

[alf]

I had a 6PPC barrel re-chambered to a 6x47x45 (222RM necked up and improved) that I killed several truck loads of PD's shooting 55 grain Ballistic Tips at 3300. I finally retired that barrel at around the 7500 mark.

Fireforming is a non-issue in a PD rig, but I'd look hard at a 6-204 if it was, neck up and go.

With a dies and barrel life a concern, it'd be hard to whoop a 6x45.

 

[ImBIllT]

6x45 will be at a disadvantage in the wind. It's a little small to shoot bullets with a better BC than you can shoot from a 223. It will shoot the same weight bullets faster than a .223 but those bullets will ave a lower BC. Barrel life should be MUCH longer. For a prairie dog gun i'd go to the 6x45. It will shoot slightly flatter with 55's making range estimation less critical and barrel life will be longer. Also I've noticed heavier bullets seem to make them bounce higher than light bullets moving faster. For an attempt at shooting f-class with that action I'd go with the .223. It will handle high BC bullets better, and with a bipod can be shot in FTR against other .223's and .308's. The 6x45 would have to face a lot of calibers with a huge advantage. You'd still probably be the only .223 on the line because a .308 has advantage over a .223.

Basically, in the field I'd go for higher velocity(6x45), in a match I'd go for less wind drift(.223) because in a match your distance is known and you're usually given some sighting shots. The effect of gravity won't change but wind can.

.223AI is a wonderful round. I absolutely loved mine when I had it. It rivaled 22-250 velocity with 52's
and 55's. I don't know what to say about barrel life and the 6x45 should not be far behind for velocity. It's a cartridge I intend to try one day.

 

[5spd]

I built my 6x45 last year and have about 3k rounds through it. Like you I wanted a .223 cased round since I have 20k of them and 2 other .223s as it is. My McGowan 24" ss bbl still looks new and I cant make out any throat erosion with my borescope yet.
I use it for p-dogs now & then and it does buck the breeze better than the .223 using the 58 & 65g vmax bullets.
The 58g load is at 3232fps and the 65g is at 3053 fps. It will do you good to 600yds with ease as long as the wind is not at 20+ mph. I do not shoot a 55g bullet in it as I built it for Coyote & Antelope first over p-dogs.
I dropped a nice Antelope in its tracks with it last Oct with a 95g nosler HBT at 125 yds.
The caliber is more than easy to reload for & super accurate.