Tikka .243 AI

eric1115

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Who has rechambered their 8 twist Tikka .243?

Do you run LA mags and bolt stop? I mocked up a .243 case with 108 ELDM and got 2.94ish with boat tail junction at neck/shoulder junction. Seems like this is potentially the peak of the convenience/velocity curve?

Considered a 6x55 or 6-284 or 6PRC, but brass seems like a much bigger hassle on either of the first two and the PRC would not be a simple rechamber due to bolt face. It would be my first cartridge outside of regular mainstream cartridges. I currently reload a half dozen different cartridges and would plan to handload everything for this no matter what chambering.

Lapua brass available, I've got a bunch of H1000, and already run 108 eldm's in a 6mm ARC so buying more in bulk is no biggie. What kind of velocity can I get out of an 18" barrel? Most of what I found was 24-26" barrel data with guys seeing 3100-3200 fps. If I could get 2900-3k I would be super happy. It seems like this would also have enough horsepower to run a 115+ ELDM or TMK well if that ever becomes a reality.

Anyone played with this?
 

clperry

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It’s like you’ve been reading my mind…. I’m in for folks that have experience.


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Ice-kub

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Watching this for sure... Have a SA 700 thats going to get a 243ai rebarrel.
 
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eric1115

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Let's add that I'd be sending it to get cut and threaded for a can either way, so it's headed off to a smith regardless of whether it gets rechambered or not.

True short action a 6CM probably makes more sense, but if it's on a Tikka there's less benefit if I'm planning to hand load everything anyway.
 
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If you want to dabble in a “wildcat” then I say go for it. I have a 257AI I built on a Ruger M77 Long action. Runs flawlessly and I can run the bullets as close or as far from the lands as I need.
 

pods8 (Rugged Stitching)

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Let's add that I'd be sending it to get cut and threaded for a can either way, so it's headed off to a smith regardless of whether it gets rechambered or not.

True short action a 6CM probably makes more sense, but if it's on a Tikka there's less benefit if I'm planning to hand load everything anyway.
Food for thought. If you're paying to cut & thread it (~$200) AND paying to have it rechambered (dunno cost on that off hand but sure ain't gonne be free to set back the barrel and ream it out, $200?) you're pretty deep into the cost of a prefit barrel and your 1:8 factory take off barrel would be desirable on the used market as well.
 
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eric1115

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Food for thought. If you're paying to cut & thread it (~$200) AND paying to have it rechambered (dunno cost on that off hand but sure ain't gonne be free to set back the barrel and ream it out, $200?) you're pretty deep into the cost of a prefit barrel and your 1:8 factory take off barrel would be desirable on the used market as well.
I've been trying to suppress those thoughts 😂.

Those thoughts lead me to intrusive thoughts of .25-284 and other things that my practical side thinks sound like an expensive, bad idea.
 

pods8 (Rugged Stitching)

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I've been trying to suppress those thoughts 😂.

Those thoughts lead me to intrusive thoughts of .25-284 and other things that my practical side thinks sound like an expensive, bad idea.
Those thoughts are why I have a 19" 284win prefit on order when I was first contemplating chopping a 7-08. :p

PS, ping me if that barrel does go on the market ;) , sooner or later the 1:10 in the "kids" 243win will be shot out and a 1:8 twist would have me consider sticking with that caliber for a while since its such an easy shooter. Current temptation is 6.5x284 for the future of that action.
 
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eric1115

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Those thoughts are why I have a 19" 284win prefit on order when I was first contemplating chopping a 7-08. :p

PS, ping me if that barrel does go on the market ;) , sooner or later the 1:10 in the "kids" 243win will be shot out and a 1:8 twist would have me consider sticking with that caliber for a while since its such an easy shooter. Current temptation is 6.5x284 for the future of that action.
Haha, you get it!

My kids used to watch a show called "if you give a mouse a cookie" that I felt personally targeted by at times.
 

clperry

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It’s a great cartridge and you’ll get that easy. An 18” barrel probably around 3,000-3,050fps for the 108gr.

That info is going to cost me money. I started on a 243…. The efficiency of the 243ai combined with the nostalgia will be too much to resist. I hand load for relaxation anyways, so no real draw back other than fire forming for me. Thanks for the info.


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Ice-kub

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That info is going to cost me money. I started on a 243…. The efficiency of the 243ai combined with the nostalgia will be too much to resist. I hand load for relaxation anyways, so no real draw back other than fire forming for me. Thanks for the info.


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So for the fire forming, could you load up some lower charge varmint rounds and then load your hunting rounds in the fire formed stuff?
 

clperry

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It’s my understanding that you want full loads to fire form so that the brass reaches all surfaces of the chamber thoroughly. If I am wrong, someone please correct.


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Axlrod

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We did a couple Rem varmints rechambered to 243AI. Berger 105's with R22 hit 3380 fps w/26" and 3120 fps w/20". The best shooting load was H4831sc at 3060 fps and the Berg. 105 in the 26". The 20" has about 1200 rounds on it and is ready to be replaced. The 26" has 700+ rounds and still shoots really well.

Using Lapua brass I use 243 Win. data, and pick a load a couple grains under max. They shoot as well as the A.I. loads, just a bit slower.
 
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eric1115

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Hhnnnng, this is not helping me to restrain myself. The fiscally responsible part of my brain was kind of hoping to get some feedback on why it's not a good idea.

Maybe I just need to remind that part of my brain about the cost difference between 180 Bergers and 65 grains of H1000 vs 108's and 20 grains less per shot?
 

CBB1

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I’ve been kicking this around in my head as well. What is the likely velocity gained from having it Improved?


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eric1115

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Rifle is going next week to Karl at Kampfeld for the rechamber and cut/thread for the can. RokStok and RS1.2 getting ordered after I get a few more things sold. SM rings and M+ mag on the way.

I have 500 106 TAP, a few hundred 108 ELDM and 150 already FF'd Lapua brass, and I'm beyond stoked.
 
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