The 6mm-223 — A Wildcat Worth Considering
Intro: Ron Dague wanted a new gun that was similar to his trusty .223 Rem rifle, but which fired 6mm bullets. There is a superb choice of bullets in this caliber, and Ron found that the 95gr Berger VLD could be driven to a healthy 2,604 fps by the small .223 Rem case. This 6mm wildcat based on the common .223 Rem offers excellent accuracy and very low recoil — something very important in the cross-the-course discipline. In addition, Ron’s 95gr load with Reloder 15 delivered an ES of just 4 fps over ten shots. That exceptionally low ES helps achieve minimal vertical dispersion at 600 yards.
By Ron Dague, Sinclair Reloading Tech
From Sinclair’s GunTech Articles Archive
I already had a .223 Remington match rifle, and I wanted the 6mm-223 to be as close to the same as I could make it. I installed the barreled action in a wood 40X stock to work up load data and work out any magazine feeding issues. While I was working on that, I looked for a McMillan Baker Special stock and finally found one to finish this project. I bedded the action and stock, then took the rifle to the range to check zeros on the sights and scope. I was surprised that I didn’t have to change anything on the sights. I thought changing the stock would cause sight changes. The thought went through my head, “Maybe the 40X stock isn’t all that bad”.
Here’s line-up of 6mm bullets. The Berger 95gr VLD is in the middle.
I took the new rifle to the first match of the year, a National Match Course match, and my off-hand score was 83, rapid sitting 95, rapid prone 95, and slow fire prone 197 — for total aggregate 470. This may not be my best work, but on match day the wind was blowing about 15 mph and the temp was around 40° F, with rain threatening. This was a reduced course of fire — we shot at 200 and 300 yards on reduced targets.
I used 70gr Berger bullets for this match, loaded in Remington brass with 25 grains of VihtaVuori N540 and Federal 205M primers. When I worked up loads for this rifle, N540 gave the best accuracy with the best extreme spread — 2,950 fps with an extreme spread of 20 fps on a 10-shot string. The load for 600 yards was with a 95gr Berger VLD bullet, with 23.0 grains of Reloder 15, Lapua cases, and the same Federal 205M primers. This load is 2,604 fps, with an extreme spread of 4 fps over a 10-shot string. I’ve shot this load at several 3×600 yard matches, and the accuracy has proven to be very good. At the last 3×600 match, my scores were as follows: 199-10x and 198-11X with scope, and 193-10X with iron sights. Best 600-yard score so far with iron sights was 198-12X.
6mm-223 Rem Rifle Specifications: 700 BDL action and floor plate, Bartlein 6mm 1:8″ twist, McMillan Baker Special stock in Desert Camo, Centra front and rear sights, Ken Farrell bases with stripper clip guide, Sinclair hand stop, and Jewell trigger. Gunsmith Neil Keller helped me with the metal work and instructed me on the action work and re-barreling.
Similar Posts:
- 6mm-223 Across the Course Rifle Project
- A Worthwhile Wildcat — the 6mm-223 for XTC Competition
- Worthwhile Wildcat — the 6mm-223 for XTC Competition
- Reloder 17 shoots 600-39X in First Match
- New Alliant Reloder TS 15.5 Powder — Outstanding Test Results
Tags: .223 Remington, 6mm-223, Berger VLD, Hornady Dies, McMillan Baker Stock, Rem 700, Ron Dague
While it’s refreshing to see a smaller capacity cartridge featured, this one is not particularly a new find. This certainly doesn’t detract from the performance, it’s just an observation.
The cartridge was brought to light in 1965 and has been a contributor to the field of varminting as well as small game and deer hunting since then. There is even more to acknowledge with the advent of more and better bullets in current production. It is a cartridge which will be at home in either bolt rifles or gas guns.
Don’t forget the bigger brother 6x47mm which is the .222 Magnum case which offers a bit more velocity but in most situations will not run in an AR platform.
Regards.
How is case life compared to pushing heavy 223 bullets? I know guys that push the 223 heavies hard only get 2 or 3 shots per case before primers pockets loosen up.
I built a 6-223 off a savage axis for coyotes. It hasn’t been the easiest to tune a load for but I have 70gr blitzkings moving 3050fps under 1/2 moa and just finished working up a load for 87gr vmaxs at 2880fps shooting under 1/3 moa. Super fun cartridge to shoot and load for.
I considered such a round years ago but dismissed it because it just did not seem to make any sense.
A .224 69 grain SMK has a better BC than a .243 70 grain SMK, plus the 223 case does not have enough powder to hit a sweet spot with much heavier. I mean it will work, sure, but it does not outperform a host of over the counter options.
I’ve always felt the favorite and most popular cartridges have maintained about 3 to 1 bullet to powder weight ratio and that leaves the 223 cartridge with about 26 grains max powder to max out at about 80 grain bullets.
Sure guys run heavier but they struggle with them.
If you want a nice 6mm then I’d recommend a case that holds around 33-38 grains of powder, then you can run bullets between 100 and 115 grains really well.
I have the 6TCU version of this cartridge and cant say enough good about it. Its been used with 55GR noz thru 95 gr Bergs.
Nothing I dont like about it.
Am in the middle of building a 6mm TCU at the moment. Can’t wait to see how it shoots.
The 6mm-223 sounds like just the ticket for my needs because I have buckets of 223 one fired brass that people have given me over the years and I already have a 6mmx 284 for the the long range work so I think I’ll see if I can order a 26″ barrel for my encore rifle and save some wear and tear on my precious 284 brass.
6mm-223 is great. I’m getting 3126fps over 27gr H335 out of 75gr Sierra hp in a 26” barrel with no pressure signs yet. That’s low end .243 velocities!! It’s a great low recoil accurate hard hitting little round. I’m not at all disappointed in mine.