6mm cartridge choices...

[tanks]

I am considering a build of a new long range varmint bolt action rifle and decided on 6mm. It seems like nowadays there are a lot of options.

I seem to have the following options at the very least:

6mm Creedmore
6mm Dasher
6xC
6mm PPC
6mm BR(A)
6 x 47 Lapua
6mm ARC

Doing a peruse of YouTube it seems everyone like the lates which doesn't help though 6mm Dasher is supposed to have a better barrel life than others.

Any opinions from those with experience?

I reload, so availability of factory ammo is not an issue though availability of brass is as long as I don't have to run through a multitude of steps to form the brass.

[Divernhunter]

6mm is the caliber.
What you listed are cartridge choices.

[tanks]

6mm is the caliber.
What you listed are cartridge choices.

OK, Mr. Pedantic I fixed the title.

[DDRH]

All listed cartridges can use 308 bolt, except 6mm PPC and 6mm ARC.

How about 6mm GT?

[RandyD]

I built a long-range 6 mm varmint rifle, and I selected the 6mmbr. It is easy on the barrel. It is used for long-range benchrest matches. The brass lasts forever. The downside is I needed to modify the magazine follower, to get it to load correctly. I am happy with my choice.

[sigstroker]

The Eagle Eye guy has done a lot of work on the 6 ARC. One nice thing is it's a SAAMI cartridge and it's used in AR's, which is good for availability.

He says he's got 4400 rounds down the pipe, so barrel life sounds a lot better than Creedmoor.

[mike.h]

I have a 6BR on a R700 action. It's a nice long range shooter, easy to reload. I did have feeding problems trying to use a magazine conversion kit, but I'm now using a MBT magazine designed for the 6BR, and it works well, no problems.

Good luck, and have fun.

[smoothy8500]

6mmBR in a Rem 700, PacNor barrel. Super easy load development. Basically everything shoots well. I chose to go with the " no turn neck" reamer at .272" to avoid turning Lapua necks.

[MongooseV8]

At the risk of tooting my own horn; I have what I consider to be a significant amount of experience long range varmint hunting. And I know this isnt what you want to hear, but what do you expect out of your rig? My personal examples included:

How far is "long range?" (I am typically at ~200-600yds)
What volume of shooting will you be doing? (couple hundo a day is normal)
Fixed position or walking? (both but mostly fixed)
What are your targets? (ground squirrels, and long ear hares)
What specific bullets will you be using? (lead free Nosler in CA)
What is an acceptable barrel life to you? (~1200)
What level of precision do you need? (I rebarrel at about 5/8 moa)

All the listed options will work great. But as you noted some are harder on barrels, but also usually will gain you performance. Velocity is the name of the game when it comes to varmint hunting. Yes a slower HP will work, but a thin jacket screamer is what really works well. Dont stress too much on a specific chamber. Most people will rebuild or sell a rig waaaaay before the first barrel is worn out. For varmint hunting, your results are going to be more based on your skills, and the bullet you choose. Know your rig, and know your own limitations and you will have a successful time.

After literally dozens of builds, here is what I do:

Main rig is a 28" heavy 243AI that shoots 55 grainers at well over 4k fps. Its a laser that cuts wind, and is easy to quick compensate for drop. Its what most would consider a very high performing rig, at the cost of barrel life.

I use a second rifle usually a 223 or 223AI for closer shots (within ~300yds) and to let my 243AI cool off a bit.


All that said, and I would probably suggest either a 6br or a 6 creedmoor for your first barrel. Brass is really easy to get right now, and will last you a long time. Barrel life is great with the 6 br but you will have to do more planning due to slightly less performance.

[jimmykan]

I have tried 6mm Creedmoor and 6x47 Lapua.

I settled on 6x47 Lapua because I already had a lot of brass. Ruined a handful of cases in the neck-down process, and I don't like that the formed brass has an internal "doughnut" at the neck-shoulder junction.

But the accuracy nodes are wide and velocity is good: 105 grain bullets at 3100 fps from a 26" barrel using Varget.

If I were to do it all over again from a clean slate, I would pick 6 Dasher and use ready-made Peterson brass. And feed from an MDT 6BR AICS magazine.

[hermosabeach]

It comes down to a few simple things...

How far can you shoot? I have to dive 2+ hours to shoot past 1K

So 6.5 CM is an easy answer


What is budget for glass? 1K, 3K or 5K


no need for a round that will reach if the optics don't assist...

[tanks]

...
All that said, and I would probably suggest either a 6br or a 6 creedmoor for your first barrel. Brass is really easy to get right now, and will last you a long time. Barrel life is great with the 6 br but you will have to do more planning due to slightly less performance.

What do you think of 6mm BRA? Seems to provide a bit more velocity. Giraud does support the cartridge so case prep is not going to be an issue as it takes very little time to swap cutting heads.

My main quarry is going to be prairie dogs. Got talked out of my lefty .220 Swift by a friend a while ago and decided to go up to 6mm as a replacement.

[MongooseV8]

What do you think of 6mm BRA? Seems to provide a bit more velocity. Giraud does support the cartridge so case prep is not going to be an issue as it takes very little time to swap cutting heads.

My main quarry is going to be prairie dogs. Got talked out of my lefty .220 Swift by a friend a while ago and decided to go up to 6mm as a replacement.

Yeah a 6 bra would be great too, but I like the 6xc, 6x47, or 6 creedmoor better as they will likely feed better. I would focus on brass to make my decision. Right now euro optic has Peterson 6xc, 6x47, and you can find Lapua 6 creedmoor on gunbroker for about $120/100 shipped. Just secure some brass and dies and dont sweat too much on the chambering. They are all pretty close on performance.

220 Swift are fun but close to the top of the list of throat burners lol.

[Switchbarrel]

6 BR-A has the accuracy/precision (whatever you guys wanna point out), velocity and barrel life.

http://bulletin.accurateshooter.com/2022/02/sunday-gunday-glenn-kulzer-sets-8-1000-yard-records-in-2021/

Alpha OCD or 1 shot fireform Lapua brass.

[SmokeTheClay]

6mm dasher will be easy to tune with tiny groups. Alpha OCD brass is also ready to go