What barrel

[Coldfinger]

I plan to build a 6mm cm or dasher and leaning toward the cm. I have a model 700 sa almost new and was planning a Brux heavy target or heavy Varmint, 30" 7.5 twist. Don't know what bullet weight or distance! I know this will be the first questions but this is all an experiment. I am a Pennsylvania white tail swamp hunter and long range is all new but at 59 I am hoping I can ease into a new hobby in 6 years and have this ready to go!
Please give advise on the barrel, am I on the right track? Advice is appreciated and requested! Thanks

I think you will love any of the 6mm cartridges you choose! I liked the .243 but mine had a short barrel and lots of muzzle blast. I loved my 6XC then got a 6 Creedmoor. My boy kinda took over the creedmoor during deer season and filled my doe tags.

I plan to build a 6mm cm or dasher and leaning toward the cm. I have a model 700 sa almost new and was planning a Brux heavy target or heavy Varmint, 30" 7.5 twist. Don't know what bullet weight or distance! I know this will be the first questions but this is all an experiment. I am a Pennsylvania white tail swamp hunter and long range is all new but at 59 I am hoping I can ease into a new hobby in 6 years and have this ready to go!
Please give advise on the barrel, am I on the right track? Advice is appreciated and requested! Thanks

Unless you are building a bench rest quality rifle I don't think we humans can tell the difference between barrel manufacturers! Some lap more than others all claim to be better than the other. I've got Benchmark, Pacnor, McGowen, Carbon Six, lilja, green mountain, Adams&Bennett and Shaw they all shoot great when I do!

 

[Timeout]

Use

a Norma Dasher design reamer and shoot with no fireforming or neck trimming. Used with a Lapua Dasher reamer just trim the necks back to Lapua Dasher length and shoot with no fireforming or other modifications.

 

[L.Sherm]

He's talking fireforming/hydroforming Norma BR brass, not Norma Dasher brass.
[/QUOi dont want to argue about it, hes talking at the web being smaller than Lapua and stretching more than the Lapua brass therefore stretching primer pockets.
If the O.P wants to read about theres more guys talking about the web be smaller with Norma brass also.
Whether it matters to him or not is up to him I'm just pointing out some BR guys thought it did so they spec Norma Dasher reamers also at the .200 smaller than Lapua brass.
Alex may chime in a give his thought hes certainly got more knowledge than I do about it.

 

[budlight]

I plan to build a 6mm cm or dasher and leaning toward the cm. I have a model 700 sa almost new and was planning a Brux heavy target or heavy Varmint, 30" 7.5 twist.
Please give advise on the barrel, am I on the right track? Advice is appreciated and requested! Thanks

You need to find some articles on barrel length and velocity. Law of diminishing returns with small powder charge and caliber.

IMO. and I have had my share of long barrels. In 6mm all you need is 26 -28 inches and you can get one of the medium contours

https://riflebarrels.com/barrel-contour-data/

Like for instance a number 6 or even 5 about 4 pound 27 inch barrel. I have a #6 with a 2 inch brake for 29 inches in a 243 win. You look at the end diameter of .750 minus .243 and you still have enough barrel diameter for good harmonics. The longer the barrel the thicker it has to be for stability. I go from varmints to antelope with it so I didn't want a special twist for just the heaviest bullet So I kind of only shoot 75 to 105 gr. and the 243 win has enough velocity. So a 9:1 twist is okay. I try to be easy on the barrel and cases so my typical hunting 100 spbt is only heading out at 3100 fps. I use the slowest powder like R-25 or R26 maybe superformance. That will take out a white tail at 400 yards

 

[30BR]

You need to find some articles on barrel length and velocity. Law of diminishing returns with small powder charge and caliber.

This could help

You are being redirected...

 

[30BR]

That is weird, I shoot 26" Dashers and consistently get 40-50 fps more speed than friends running 24" Dashers, and do so with less powder.
Not saying all things are equal, no way can we conduct a test like that.

I think the velocity gain per inch drops off dramatically around 26 - 28"
I had 2 guns done, same barrel type and mfg, same reamer, same smith, and one was 30 fps faster than the other. Go figure.

 

[Truc]

I plan to build a 6mm cm or dasher and leaning toward the cm. I have a model 700 sa almost new and was planning a Brux heavy target or heavy Varmint, 30" 7.5 twist. Don't know what bullet weight or distance! I know this will be the first questions but this is all an experiment. I am a Pennsylvania white tail swamp hunter and long range is all new but at 59 I am hoping I can ease into a new hobby in 6 years and have this ready to go!
Please give advise on the barrel, am I on the right track? Advice is appreciated and requested! Thanks

that is too much of a barrel to hang on a Remington 700, unless you bed part of it or use a barrel block.

 

[Alex Wheeler]

You can hang about any barrel you want on a 700, dont worry about stressing the action, not sure why thats still going around.
You can shoot trimmed Norma cases in a Lapua chamber, the smaller base will loose primer pockets faster as a result. Laupa brass is part of the reason the dasher has gone so far, I wouldnt even consider anything else. Fireforming is not a big deal. Look up the false shoulder method. Or get DJs brass to hydro form it.
In a 700, feeding and extraction will need a little help on any of the br cases, the 6 creed will function with no work, and in a hunting type platform, I think its a better choice.

 

[GCarlton53]

I just did a 26 lilja 8 twist prefit in 6GT. Less than a box through it and it just enlarges the hole on the paper. Got factory ammo from clay's cartridge. Wow

 

[blueprairiedog]

I just did a 26 lilja 8 twist prefit in 6GT. Less than a box through it and it just enlarges the hole on the paper. Got factory ammo from clay's cartridge. Wow

I just did a 26 lilja 8 twist prefit in 6GT. Less than a box through it and it just enlarges the hole on the paper. Got factory ammo from clay's cartridge. Wow

what Bullets are they using

 

[Alex Wheeler]

I just shot my 6 creed this morning, I think this is accurate enough for a hunting gun. Distance, 1008yds. 115 vlds at 3000 fps with rl16. Theres another node close to 3100 as well. As much as I like the 6 Dasher, BR, and BRA cases, I think the Creedmoor is better in this application.

 

[budlight]

When my present disposable 243 win barrel goes I'm really thinking about this because I have 1000's of 243 brass. The 243 AI seems like an even faster barrel burner like the 6mm-06. I really researched the 6XC.

It has a couple grain drop in powder charge VS the 243, but the better shoulder and longer neck. I already download a 243 win with the slowest powders to like 100 - 150 fps less than flattened primers and cases that only get a few reloads before the primer pockets are loose

Super LR

Check out http://6mmar.com!

6mmar.com

 

[GCarlton53]

what Bullets are they using

105 berger, i think the hybrid

 

[30BR]

I just shot my 6 creed this morning, I think this is accurate enough for a hunting gun. Distance, 1008yds. 115 vlds at 3000 fps with rl16. Theres another node close to 3100 as well. As much as I like the 6 Dasher, BR, and BRA cases, I think the Creedmoor is better in this application.


View attachment 194028

Dang!! I would love to shoot that well with my BR gun!!