6ARC Tikka

[The Guide]

I'm confused. How does the bolt face support the case head? I'm not sure why firing a 441 case on a 473 bolt face would be an issue at all.

I'm definitely not talking about firing a 6aec round in a 308 rifle. Only using the 308/473 bolt.

I am under the impression that the bolt face diameter is sized close to the diameter of the case to provide support during firing. As in prevent outward growth of the brass and provide the back stop for the chamber during firing. If that's not the true and the bolt face doesn't have a role in supporting the case head, I'm always open to learning!

I see. No it doesn't support the case in that way. If it did, you would need a special bolt head for many different cartridges. Example, Tikka magnum bolt can shoot 300wm, 300saum, 300wsm. Different rim diameters and body diameters.

I'm confused. Are you saying the bolt face doesn't need to match the cartridge? That you could use a typical short action with a .473 bolt face and rebarrel to say a 223? I'm sure you know that's incorrect but I'm not getting your point.

The bolt face does not support any part of the cartridge, it only provides a rear face for the chamber the same way the rear breach of a single shot rifle does. The issue using a larger bolt face with a smaller cartridge rim is that while it would feed in and fire properly, extraction would be your primary issue. No way to pull the spent brass out without changing the extractor system.

Jay

 

[TheM1DoesMyTalking]

I see. No it doesn't support the case in that way. If it did, you would need a special bolt head for many different cartridges. Example, Tikka magnum bolt can shoot 300wm, 300saum, 300wsm. Different rim diameters and body diameters.

The bolt face does not support any part of the cartridge, it only provides a rear face for the chamber the same way the rear breach of a single shot rifle does. The issue using a larger bolt face with a smaller cartridge rim is that while it would feed in and fire properly, extraction would be your primary issue. No way to pull the spent brass out without changing the extractor system.

Jay

Good clarification! Thanks for setting the record straight, @HighUintas and @The Guide

I did a little reading on it and found this:

Bolt Face Clearance
The bolt face always needs to be larger in diameter than the case rim maximum. You can have a larger bolt face, but it’s important to be aware of extraction claw engagement. The bolt face doesn’t contribute to supporting the case like the chamber wall does. This is because the web and rim of the case are so strong that this part of the case doesn’t need to be squeezed in from it’s circumference. Clearance affects both extraction and ejection. Smaller rounds are not a problem, but you may find it difficult to extract them.

Common Bolt Faces Demystified (Bolt Action Centerfire) – Ultimate Reloader

ultimatereloader.com

 

[HighUintas]

I'm confused. Are you saying the bolt face doesn't need to match the cartridge? That you could use a typical short action with a .473 bolt face and rebarrel to say a 223? I'm sure you know that's incorrect but I'm not getting your point.

For tikkas, the only thing you have to worry about is feeding and extraction. If you put a 223 barrel on a 473 bolt Tikka, it probably wouldn't extract reliably of at all because the extractor is not the appropriate distance from the cartridge rim. As far as feeding, I'm not sure if the extra clearance around the cartridge rim would cause any issues or not.

 

[khuber84]

I wish more folks would just make factory ammo for 6 br.. That is more attractive to me.

This is where I am at, I've got 2 extra 473 faced tikkas sitting in the safe waiting for jobs.

@Formidilosus 6arc has 34gr capacy with short neck, the 6br is 38gr with very long neck. Ran at same pressure, do you think the 6br would have similar barrel life of the 308? I believe you've advocated that characteristic of the 6arc. I've never shot out a 6br, but did push a 6bra to 3k rounds before I pulled it 3 years ago, was still shooting well under sub moa, I just went 6gt with all my match rigs.

 

[HighUintas]

Who makes quality 6br brass and is it consistently available?

 

[wind gypsy]

Who makes quality 6br brass and is it consistently available?

Lapua, peterson, alpha.

It should last buku firings.

 

[BlueJay]

Weight loaded and ready to rock? You know someone was gonna ask.

Ha yeah...with the suppressor it's 9.5lbs. That's right about where I want my guns for shootability.

 

[Castle Rock]

I’ve seen where someone on here had it working with the m mags. But I was looking at it awhile back with 22&6arc in 223 mags they fit perfect coal wise but it rides a little low. I think you could easily sand or file the lips to widen them. The tikka mags are not easy to take apart, anyone have any pointers regarding mag disassembly?

Tikka mags are ridiculously easy to strip
Tape a couple of matches to the sides of the base and squeeze gently in a vice, the top just lifts off

 

[beretta_man11]

I'm a huge 6arc fan. We killed several deer with my daughters gun last year, put it in a different stock and shot a PRS match with it a few weeks later.
orgin action
proof CF
manners CS

 

[TX_Diver]

What powders are you guys loading the 6arc with 108/109 ELD-Ms? Would the 6 arc be suited to 112 matchburners or 115 DTACs also? Anyone using Staball Match?

I have a lot of 6.5cm components to use up still, but am interested in a 6 arc also... If I can get 2700-2750fps out of an 18-19" barrel, then on paper it matches my 6.5cm for terminal range (which is still currently further than I can shoot), but also gives me a bit better package as my kids start shooting and hunting.

 

[eLightfoot]

I just wish anybody would make an aftermarket action sized appropriate for this class of cartridges. Mags and bolts for 223, ARC, BR. wssm would be cool too but there’s no brass left.

 

[wind gypsy]

What powders are you guys loading the 6arc with 108/109 ELD-Ms? Would the 6 arc be suited to 112 matchburners or 115 DTACs also? Anyone using Staball Match?

I have a lot of 6.5cm components to use up still, but am interested in a 6 arc also... If I can get 2700-2750fps out of an 18-19" barrel, then on paper it matches my 6.5cm for terminal range (which is still currently further than I can shoot), but also gives me a bit better package as my kids start shooting and hunting.

That’d be asking an lot of the little case unless using a hot charge of lever.

This is with 24” barrel:

 

[The Guide]

That’d be asking an lot of the little case unless using a hot charge of lever.

This is with 24” barrel:
View attachment 774249

I think the 109 ELDM would be ultimate "big" bullet for the 6 ARC with a good jump in BC without a big jump in weight.

Jay

 

[TX_Diver]

I think the 109 ELDM would be ultimate "big" bullet for the 6 ARC with a good jump in BC without a big jump in weight.

Jay

Any idea on realistic velocities from an 18” or 20” barrel?

At $1.30ish per round it is tempting to get 2-3 cases of factory hornady ammo and then just reload that brass with some 109s afterwards.

Biggest hang up is that I don’t have any of the powders people seem to like for the arc. And if there was a more temp stable option it’d be nice. It is HOT here in summer and not hot where I hunt or in winter.

I have H4350 and varget which seems to lean 6cm or 6gt if I want to get creative…

 

[TX_Diver]

Except for the whole factory ammo in most sporting good stores, just like the 6BR. Woulda/coulda/shoulda- the ARC is what we’ve got for a viable factory option.


Getting a Tikka 308 bolt bushed to use the grendal/ARC case isn’t hard, you are already getting a barrel spun on. There will be a couple for S2H rental rifles.

I’d called UM the other day about a 6arc tikka and they made it sound like you had to get a .223 bolt opened up rather than bushing a .308 bolt?

The suggestion was a 6 dasher or 6gt from whoever I talked to.

Any idea who else to call or who to chat with at UM to figure that out?

 

[Formidilosus]

I’d called UM the other day about a 6arc tikka and they made it sound like you had to get a .223 bolt opened up rather than bushing a .308 bolt?

The suggestion was a 6 dasher or 6gt from whoever I talked to.

Any idea who else to call or who to chat with at UM to figure that out?

Kampfeld Custom - Custom Rifles, Custom Gunsmithing

 

[khuber84]

Any idea on realistic velocities from an 18” or 20” barrel?

At $1.30ish per round it is tempting to get 2-3 cases of factory hornady ammo and then just reload that brass with some 109s afterwards.

Biggest hang up is that I don’t have any of the powders people seem to like for the arc. And if there was a more temp stable option it’d be nice. It is HOT here in summer and not hot where I hunt or in winter.

I have H4350 and varget which seems to lean 6cm or 6gt if I want to get creative…

Temp stable powders don't get great velocity in the arc. They run lever and cfe223. High energy temp senative ball powders that give good speed. That's the problem with the arc. I honestly see the 6br or 6bra as a comparable option that runs Varget, N140, N150, 4166 at ARC or better velocity with 3000+ barrel life.

 

[SloppyJ]

The first match i shot there was a guy with a 6arc in my squad. I was very interested in his setup and learned a bit about it. I was running 108s in my 6 creed and he was too.

He was stepping on it with lever and getting mid 2800s. So close to me he was only a tenth or so off from me.

I don't know the specifics of his build but he was around a 26 or 28" barrel.

However, as mentioned earlier, all of the powders that get velocity in the 6arc aren't very temp stable. I'm content with my 6 creed but longer barrel life and less recoil are very intriguing. Even in a match setting here in the south, the temp swings could really mess with you. That's not to mention hunting conditions.

 

[BLJ]

Is it signs of pressure or a difference in velocity that comes from the non temp stable powders?

 

[Juan_ID]

Any idea on realistic velocities from an 18” or 20” barrel?

At $1.30ish per round it is tempting to get 2-3 cases of factory hornady ammo and then just reload that brass with some 109s afterwards.

Biggest hang up is that I don’t have any of the powders people seem to like for the arc. And if there was a more temp stable option it’d be nice. It is HOT here in summer and not hot where I hunt or in winter.

I have H4350 and varget which seems to lean 6cm or 6gt if I want to get creative…

I was getting 2700 fps from a 20” barrel with a max charge of varget and a 108 eldm. Shot small groups on paper too.