Input on a new 6mm build

[dogz]

With a long action and wanting something a little different and not wanting an ackley I would personally do a 6-06 with a bartlien 7.5 twist and shoot either 105 Berger's or 115 Berger's. The heavier bullets will kill stuff just as dead as the lighter bullets. I don't have a 6-06 but when my 25-06 barrel is done I'm building a 6-06 improved.

Now you're talking long action far and away slam dunk I'd go 6/06 with a 7.5-8 twist on it. I ran thru two 6/06 barrels and it was one incredible beast of a killer

 

[357Mag]

What about the 6mm Remington that I am leaning towards? Is it not a good choice with a faster twist barrel than factory options? Is it never going to be as "good" as the three calibers you mentioned? Will I not be able to get a consistent shooting fast 6 out of it? Not being argumentative, just trying to learn. I don't have a physics degree or anything that will help me to understand what all happens in a chamber and barrel so I depend on you guys to dumb it down to where I can understand.

Just -

Howdy !

I was not intending to sound critical of your 6mm Remnigton choice, not by any means !

A 6mm Rem sounds like it should be able do to accomplish all the shooting goals you mentioned.

As others have mentioned, brass availability will be one challenge.

The 6mm Rem has 1gr more ( H2O) case capacity than the .243Win.
Despite Remington's mis-steps, the 6mm Remington's overall performance and appeal were not enough to keep it alive.

A good, viable cartridge, none-the-less.

With regards,
357Mag

 

[Just a hunter]

Just -

Howdy !

I was not intending to sound critical of your 6mm Remnigton choice, not by any means !

A 6mm Rem sounds like it should be able do to accomplish all the shooting goals you mentioned.

As others have mentioned, brass availability will be one challenge.

The 6mm Rem has 1gr more ( H2O) case capacity than the .243Win.
Despite Remington's mis-steps, the 6mm Remington's overall performance and appeal were not enough to keep it alive.

A good, viable cartridge, none-the-less.

With regards,
357Mag

I didn't take your comments as critical, I just have no experience with the 6mm Remington and wanted to try something different.

 

[Lapua904]

Look up Eagle Eye Shooting on YouTube. Lots of info on the 6mm Arc. Hornady brought it to the market for the AR15 platform Good in that platform but phenomenal in a bolt gun. Kenny in the videos built my 6 Arc custom bolt gun. He runs Desert Precision Gunworks and also shoots really well.

 

[JMW67]

I didn't take your comments as critical, I just have no experience with the 6mm Remington and wanted to try something different.

There is not a thing wrong with your choice the brass is the only fall back and that can be worked around I use 7x57 Norma brass and neck it down and turn the necks works great if you get in a bind for brass I think I have some remington 6mm brass somewhere I could help you out with enjoy your rifle

 

[Just a hunter]

There is not a thing wrong with your choice the brass is the only fall back and that can be worked around I use 7x57 Norma brass and neck it down and turn the necks works great if you get in a bind for brass I think I have some remington 6mm brass somewhere I could help you out with enjoy your rifle

Thank you so much for the offer.

 

[jasonco]

Modern 6mm's, have been conceived using, useful case capacities, where a large part of the combustion potential, happens inside the case. I was looking at my PO Ackley books last night for reference and there's a lot of old wildcat case designs, that look like " modern" cases. The biggest issue back then was, powder selection! So those old designs, couldn't reach their potential, at that time, but move those old designs forward to now and they'd pretty remarkable performers.

 

[PartsJr.]

A good friend has piled up a lot MN whitetail with his Ruger M77 in 6mm using 95gr Barnes TSX bullets with excellent results. He got the Ackley bug and has since rebarelled to 6mmAI 24" #4 or 5 contour as his go to deer gun. He has another, slightly heavier 26" as his coyote gun and yet another heavy pipe(straight tube I think) for his LONG range PD gun. He took a PD at 1143yds this summer (yes it took several shots to get dialed in). I witnessed the shot. Very very close on several shots until eventually a hit. If he was shooting steel, he would have had many hits.
He really likes the 6mm and the 6ai even more.

 

[Ricky C]

Hey Just a Hunter, the 6 Rem will do everything you want in a 6mm cartridge to hunt with. Put the 7 or 8 twist on it and run. With my 6 Rem the 85 TSX likes 47grs of RL 17 with a 22 in barrel it gets 3158fps. The Nos 70gr BT likes 50grs of Superformance for 3351fps. The 85 TSX load is .5 MOA, the 70 BT load needs a little more work, it's just under 1 MOA
Take Care

 

[shortgrass]

6mm AI Hart SS 1-7 #4 contour @ 26" This one is with a 107g Match King 46.5g RL22 just under 3100fps. I'm not sorry I built it. Does wonders on varmints.

 

[Just a hunter]

6mm AI Hart SS 1-7 #4 contour @ 26" This one is with a 107g Match King 46.5g RL22 just under 3100fps. I'm not sorry I built it. Does wonders on varmints.View attachment 314675

Very cool. How hard is it to fire form brass and what dies do you have?

 

[shortgrass]

I have a set of FL Redding dies. Accuracy fireforming is on par with formed cases, just a bit less velocity. I use the same load to fireform as I use to load formed cases. I run my 6mm brass thru the sizing die just enough to make sure the necks are 'right'. Check length of cases, if OK I load them and fire them. After fire forming I size enough for easy chambering (which pushes the spent primer out), tumble, trim to length and de-burr inside and out. They are then ready for loading. Cases don't seem to stretch as much in AI form. The 40* shoulder helps keep propellent combustion in the case and neck, as much as possible. My barrel has been Black Nitride treated (like they do some AR barrels for longevity).

 

[357Mag]

Very cool. How hard is it to fire form brass and what dies do you have?

Justa-

Howdy, again ! Happy Thanksgiving to all.

I sorta rushed my previous response, and wanted to touch on another topic.....

If you want to fully exploit the 6mm Rembias would beington's potential, you should shoot powder( s ) that give you great accuracy, useful vel, safe pressure; and high load density ( IMHO ). For example..... don't shoot a case partially filled w/ Varget.

Powders like H4350 and slower in " burn rate " would marry up well w/ long/longer barrel lengths. There was a time that a 26" barrel would have been considered the " long " barrel length for a 6mm, and a 24" being a common shorter offering. These days, longer barrels exceed 26" in length. And... as heavier bullet weights are used, the natural bias would be to go w/ the types of powders mentioned; above.

The 6mm Remington has a long neck that already keeps the powder combustion " turbulence point " inside the neck. The " Ackley Improved " version features a shoulder diam blown out to larger diameter. This helps offset case capacity that was decreased by the sharpened 40* shoulder angle that Ackley used on the " wildcat ".

The 6mm Remington cartridge was accurate enough that they offered it as a chambering in the " 40X " accuracy/Target rifles.

With regards,
357Mag

 

[Just a hunter]

Okay guys, I have my donor rifle and barrel now. Decided on a Brux 1:8 and a Bergara long action. I'm taking everything to my smith Friday.

I appreciate everyone's input but I have almost talked myself in to going 6mm Remington Ackley improved. Help me convince myself one way or the other. I have quite a bit of brass now, thank you Shortgrass, and a set of standard 6mm dies. I would have to buy a set of custom dies for the AI but is there any other drawbacks? I get that barrel life could be shortened by fire forming and the extra amount of powder the AI will handle. Am I missing anything?