16.5” .243 or 6.5CM?

[CBB1]

I got a gift card for a new rifle and will be buying a tikka and cutting it to 16.5” for my suppressor. Application is for whitetail out to 500 yards. I’m trying to to decide between a 8” twist 243 or a 6.5CM. I handload so I can get the benefit out of the fast twist 243. Trying to decide in the next day or two to take advantage of the rebate.

I pretty set on the tikka in these calibers and already have a .223 RSS.


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[hereinaz]

100% the .243 for me.

 

[CBB1]

Thank you. Do you mind explaining why?


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[hereinaz]

Thank you. Do you mind explaining why?


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With a fast twist, I can hand load the high BC bullets from 95 to 108s in the 243 and will have better exterior ballistics and the same terminal ballistics as the 6.5 cm. The .243 with fast twist is pretty much the same as a 6 creed, except availability of factory match ammo. But, even with factory ammo in .243 with light bullets, inside 500 yards, velocity matters more than BC.

If you have the .223 RSS, I assume you know that bullet choice/terminal velocity are all that matters for killing, and that precision matters most cause you gotta deliver any bullet to the vitals.

 

[CBB1]

That makes sense, thank you.


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[SuperDUECE22]

243 for the same reasons @hereinaz stated

 

[CBB1]

I’m not sure about the AI process, but is it worth talking to my gunsmith about having it Improved while he has the barrel off to thread?


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[hereinaz]

I’m not sure about the AI process, but is it worth talking to my gunsmith about having it Improved while he has the barrel off to thread?


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The AI process changes the chamber/brass shape to be more like a Creedmoor. The AI brass has less body taper and sharper shoulder angle. You get some added benefits, additional velocity with more powder capacity, less brass growth, etc.

The drawback is you have to "fireform" brass. But, you can just shoot factory .243 ammo and out pops a .243 AI. From there, its a load and shoot like normal.

I don't know that I would worry about paying to have it AI unless you want to squeeze everything out of it and will replace it with another AI barrel when you burn it out.

If I were going to change anything about the chamber on a new factory rifle, I would just sell the .243 and install a prefit in 6 creedmoor. Then, when you burn the first barrel, you just buy another 6 creed and keep going. I'd rather invest in the 6 Creed once for lots of other reasons.

If you plan on rebarreling, check out whether you want to get a 6.5 Creedmoor barrel for the better resale value.

 

[CBB1]

Having a 223 trainer, I highly doubt I will shoot the barrel out on this one anytime soon. Good point on leaving it 243, I have other 243s and it will be nice not having to separate out the brass. If handloading, what benefits do the 6cm give over the fast twist 243 with the same projectile?


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[hereinaz]

Having a 223 trainer, I highly doubt I will shoot the barrel out on this one anytime soon. Good point on leaving it 243, I have other 243s and it will be nice not having to separate out the brass. If handloading, what benefits do the 6cm give over the fast twist 243 with the same projectile?


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A little velocity and easier to find a load for. Not worth setting up for a new caliber if you already have .243 and are going to get the Tikka.

 

[CBB1]

Probably going to get one of these two tomorrow. Any additional last minute input?


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[bhylton]

Probably going to get one of these two tomorrow. Any additional last minute input?


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What did you decide on and have you had the gunsmith work done/shot it?

 

[CBB1]

I actually ended up getting the 1:8” .243 and the 6.5CM. Right now I am working on the .243 I have loaded the 108eldm to mag length with H1000 and it is showing a lot of promise. I only have a couple dozen rounds down the barrel right now but want to get a base line for MV with the load I am shooting before I decide where I will cut it to. I hope to get it to the gunsmith next week.


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[sveltri]

I actually ended up getting the 1:8” .243 and the 6.5CM. Right now I am working on the .243 I have loaded the 108eldm to mag length with H1000 and it is showing a lot of promise. I only have a couple dozen rounds down the barrel right now but want to get a base line for MV with the load I am shooting before I decide where I will cut it to. I hope to get it to the gunsmith next week.


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I'm getting ready to start load dev with my 243AI 108's and H1000, what kind of velocity are you getting?

 

[ddowning]

I'm getting ready to start load dev with my 243AI 108's and H1000, what kind of velocity are you getting?

Not a tikka factory barrel, but generally get 3150-3225 out of 26" handlapped barrels, both cut and button rifled. I have not shot anything lighter than 115s in my 28" barrels, but I get about an extra 100 fps there over the same load in a 26" barrel. I would assume there would be a pretty good velocity penalty for going short with H1000.

 

[CBB1]

I have not run it through the chrono yet. Will do that in the next couple days. Honestly just been playing with it seeing how it shoots. I started with 46gr of H1000 and saw no pressure signs. It shot 15 to around 1.3 MOA.


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[TxLite]

I have not run it through the chrono yet. Will do that in the next couple days. Honestly just been playing with it seeing how it shoots. I started with 46gr of H1000 and saw no pressure signs. It shot 15 to around 1.3 MOA.

How did things turn out?

 

[CBB1]

How did things turn out?

To be honest my suppressor blew up shooting my 300wm not long after that post and I just received it back. That kinda but a damper on things.


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[199p]

To be honest my suppressor blew up shooting my 300wm not long after that post and I just received it back. That kinda but a damper on things.


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Bro thats average

I run a 16" 6.5cm with a can and it shoots 143eldx factory ammo at 2530fps shoots steel to 700y and have taken red deer to 380y with it.

 

[SloppyJ]

Interested in the velocities when you get them figured out. I'm trying to decide on an 18" or 16.5" proof right now.