Tikka T3X in 6 ARC

[Hurley88]

Hi everyone,

I’m new to this forum and just wanted to share some info; I’ve been handed so much good info over the years on forums that it’s only right to contribute when I can. So here goes, in case this wasn’t known prior (and I’m not the first to do this by any means). 

I took a Tikka T3X chambered in 223 Remington. Removed the barrel, stripped the bolt. Sent bolt of to Kinport Peak Rifles to have the bolt face reamed to accept the 6ARC case head. Ordered a barrel from PBB. 
Just assembled the rifle a couple weeks ago. Tested the Tikka S, M & M+ magazines, had heard from all my research that the M was the most reliable but in a couple hundred feedings I couldn’t get any of them to cause issue. 

Ejection with SWFA 3-9x42 and Athlon Midas TAC 4-16x44 were non-issues, both in medium rings. No dings in case mouths, no marks on windage turrets. Did run into a snag when testing for CBTO (I use the Wheeler method), but that isn’t the fault of the barrel maker. Personally I disagree with that dimension from Hornady engineers, subsequent testing will determine if I’m right or wrong as the barrel has now been pulled off & sent to be throated. I’ll update that when I get it back & test it. 

Took it to the range prior to sending barrel off to be throated, because who can resist when they get a new gun? Everything functioned flawlessly, but it was a short trip just to get it out of my system; before throating load dev was a waste of time. 

Anyway there you have it; the Tikka T3X is a viable option, runs flawlessly…and I’ll report back regarding chamber dimensions in-depth along with accuracy results. If done right it isn’t expensive. Buy the gun, then the barrel can be covered by the sale of the 223 barrel in certain circles, bolt face is about $100-150…so not much more than the original cost of the rifle in the end.

[CZ527 Guy]

Hi everyone,

I’m new to this forum and just wanted to share some info; I’ve been handed so much good info over the years on forums that it’s only right to contribute when I can. So here goes, in case this wasn’t known prior (and I’m not the first to do this by any means). 

I took a Tikka T3X chambered in 223 Remington. Removed the barrel, stripped the bolt. Sent bolt of to Kinport Peak Rifles to have the bolt face reamed to accept the 6ARC case head. Ordered a barrel from PBB. 
Just assembled the rifle a couple weeks ago. Tested the Tikka S, M & M+ magazines, had heard from all my research that the M was the most reliable but in a couple hundred feedings I couldn’t get any of them to cause issue. 

Ejection with SWFA 3-9x42 and Athlon Midas TAC 4-16x44 were non-issues, both in medium rings. No dings in case mouths, no marks on windage turrets. Did run into a snag when testing for CBTO (I use the Wheeler method), but that isn’t the fault of the barrel maker. Personally I disagree with that dimension from Hornady engineers, subsequent testing will determine if I’m right or wrong as the barrel has now been pulled off & sent to be throated. I’ll update that when I get it back & test it. 

Took it to the range prior to sending barrel off to be throated, because who can resist when they get a new gun? Everything functioned flawlessly, but it was a short trip just to get it out of my system; before throating load dev was a waste of time. 

Anyway there you have it; the Tikka T3X is a viable option, runs flawlessly…and I’ll report back regarding chamber dimensions in-depth along with accuracy results. If done right it isn’t expensive. Buy the gun, then the barrel can be covered by the sale of the 223 barrel in certain circles, bolt face is about $100-150…so not much more than the original cost of the rifle in the end.

Sounds like you have setteled this one. Now to convince Tikka. Looking forward to Tikka offering the 6mm Arc as a factory chambering. Get her Done Tikka!

[Harronek]

I’m very interested in this .
Do you have a picture of the Bolt Head alteration ?
Also very happy to hear about the Magazine compatibility, because reliable feeding and operation is a “ must have “ for my Rifles.
Any photos of the bolt / loaded magazines etc would be greatly appreciated.

Ken

[Hurley88]

Just jotted down a note to send pics once I get back home this weekend. Out of town right now. But he basically reams out the bolt face to 0.445” IIRC.

As an update, still haven’t had any issue with any of the magazines. But it turns out that the barrel was chambered with a worn reamer & the manufacturer is refunding me. Throat was horrible, accuracy was unacceptable. Should’ve got the bore scope out as soon as I measured bullet jump, would’ve saved a couple hundred rounds of ammo. But, a busy life makes for half-brained progress. Sometimes you gotta circle back.

Will update once the new barrel arrives.

[Hurley88]

As far as feeding & reliability are concerned, yes they’re a must have. The reason I chose the Tikka action is because they just run. Sand/dirt/sleet, they just run. My biggest misgiving about this build was feed reliability, specifically whether the extractor would ride over the case rim properly since the extractor is in the same location as it would be for a 223 but the case head is now larger on the 6ARC. This thing has now fed over 600 rounds (200 while at the range, 400 testing at home with dummy rounds & different seating depths). I did hear the extractor ‘click’ over the case rim when closing the bolt slowly and that did give me some concern; until I did it with a 7Mag, 30-06, 6.5 Creed, 7-08, and 243. Heard the same noise. In several thousand rounds from those guns it has never had an issue. So, I’d say feed reliability isn’t a concern at this point.

[Hurley88]

These are pics of Tikka bolts & an action. As most of you are probably already aware, Tikka uses the same bolt body and action body for all cartridges. They just stop the bolt’s rearward travel sooner for a short action and later for a long action. They have standard, magnum, and small (223 Remington) bolt faces, which are just milled/reamed to different inner diameters with the extractor milled to be closer or further from center. 

In the pics below I lined up a magnum, standard, and my 6ARC bolt. Since Tikka just changes the diameter, then so can we. As mentioned above, the extractor location hasn’t had one issue thus far. 

   
   
   
   

[Hurley88]

These pics show some of the seating depths I tested for feeding, and how the cartridges fit in the different size magazines (all the ones in the magazines are factory Hornady 108 ELDM rounds, so they’re all the same seating depth). I took a close-up of the small magazine from a straight angle to show that the round fits just fine.

   
   
   

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Obviously you wouldn’t use the large magazine for the 6ARC. Heck, you’d need to swap the bolt stop to even get the bolt to travel that far rearward. But I wanted to include it for comparison’s sake. And no, I never tested the large mag for feed reliability lol.

You’ll notice the feed lips end in different places; I thought this would make a difference in feeding but they all work just fine. The Medium seems to be just a tiny bit smoother? More the way it sounds than anything I can feel. Since I was seating further than SAAMI max with my loads I had to use the Medium, but if I were seating within SAAMI spec I’d be using the Small for sure. I did bounce testing to see if I could get the rounds to slide forward in the Medium and it takes quite a bit. Running the bolt & stripping rounds moves them more. But again, never caused any issue with feeding.

Hope this was helpful! If anyone wants to see anything else, let me know.