Best long-distance 7mm or 30 cal rebarrel for Tikka T3x with .473" boltface?

[BringBackThe80s]

I have a Tikka T3x originally chambered in .308 Winchester, but that barrel has been very finicky in comparison to all my other rifles. I've already spun on a 6.5CM barrel that has shot almost everything lights-out without any load tuning whatsoever, so I trust the action, barrel, and optics.

So now I want to get a barrel I can spin on and off chambered for a cartridge better suited than the Creedmoor for large game at long ranges. Un-finicky accuracy is paramount, followed by max distance with velocity above 1800-2000 fps and energy above 1000/1500 fpe while minimizing wind drift. That is highly dependent on bullet choice, of course, which will need to stay within 3.34 C.O.A.L.

The choice would be easy if Weatherby's RPM line included a 7mm or 30 cal option. In their absence, the highest performing options I have identified for this action length and .473" boltface are:
- 280 Ackley Improved;
- 280 Sherman;
- 300 Sherman; and
- 30-06 Springfield.

Any other options I overlooked? Any recommendations about the options listed?

 

[Brucebarker024]

I’d have a hard time not doing a 284 Winchester or 7 saw

 

[43.6N]

So standard bolt face f class build?

284 Shehane (284win improved)

 

[One300wsm]

I have a Tikka T3x originally chambered in .308 Winchester, but that barrel has been very finicky in comparison to all my other rifles. I've already spun on a 6.5CM barrel that has shot almost everything lights-out without any load tuning whatsoever, so I trust the action, barrel, and optics.

So now I want to get a barrel I can spin on and off chambered for a cartridge better suited than the Creedmoor for large game at long ranges. Un-finicky accuracy is paramount, followed by max distance with velocity above 1800-2000 fps and energy above 1000/1500 fpe while minimizing wind drift. That is highly dependent on bullet choice, of course, which will need to stay within 3.34 C.O.A.L.

The choice would be easy if Weatherby's RPM line included a 7mm or 30 cal option. In their absence, the highest performing options I have identified for this action length and .473" boltface are:
- 280 Ackley Improved;
- 280 Sherman;
- 300 Sherman; and
- 30-06 Springfield.

Any other options I overlooked? Any recommendations about the options listed?

Me and my wife have taken Elk and Muledeer with the 280AI with 140 Accubonds but not at ranges over 350 yards. Honestly I had a little trouble resizing the cases from time to time shoulder clasping. Other than that no issues. You could do a 25 WBY RPM, 6.5 Wby RPM or a 338 WBY RPM. I have a 6.5 and 338 WBY RPM. Both shoot great no more recoil than a 280AI maybe touch more for the 338. The .338 bullet selection is pretty good160 - 300. Mine is Shooting a 185 TTSX over 3100 in a 20” barrel. 6.5 22” barrel 156 Berger Elite 2950 the 280AI can’t do that with a 160.

 

[BringBackThe80s]

I’d have a hard time not doing a 284 Winchester or 7 saw

I had not really comsidered either of those. I don't really need a short action cartridge, though, and those run about 200 fps slower than even the 280 A.I. Are there other advantages I am missing for long range hunting?

 

[43.6N]

I had not really comsidered either of those. I don't really need a short action cartridge, though, and those run about 200 fps slower than even the 280 A.I. Are there other advantages I am missing for long range hunting?

A couple of thoughts:
Another option, since pressure=Velocity might be to consider the 7 backcountry. But no personal expertise with this bullet.

I recommended the 284/284 shehane due to the historical un-finickyness that shooters reported back when this was a more popular chambering (2008ish?). It certainly is not as popular now as it used to be, broadly speaking because the efficient 6.5 cartridges gave the same ballistics with less recoil.

My experience has been that chasing absolute speed basically means being tied into inconsistent cartridge families. AND that a lot of the inconsistency can be tied to inconsistent powders.
Magnum volume cases need magnum type powders to get their speed potentials without overpressuring the system.

A lot of the consistency of the Creedmoor (and bench rest cartridges) can be tied to the types of powders they do well with.

In your list of cartridges you wanted the same easy load development as a Creedmoor, while getting more long range ballistic performance. So why not try to mimic the chamber design, bore-volume ratio, and high efficiency powder choices of the Creedmoor, but in a 7mm (or 30 cal)?

If we were to consider what a Creedmoor would look like if scaled up to 7mm/308:
The 7 creed functionally would be the 7 saw/284 win.
The 30 creed functionally would be the 300wsm.
Both can be loaded for long actions to take advantage of the longer high efficiency bullets. You would just need to make sure your barrel has an appropriate throat spec.

 

[coyotekilla]

You could always rechamber your 6.5 cm into a 6.5-06ai

 

[One300wsm]

A couple of thoughts:
Another option, since pressure=Velocity might be to consider the 7 backcountry. But no personal expertise with this bullet.

I recommended the 284/284 shehane due to the historical un-finickyness that shooters reported back when this was a more popular chambering (2008ish?). It certainly is not as popular now as it used to be, broadly speaking because the efficient 6.5 cartridges gave the same ballistics with less recoil.

My experience has been that chasing absolute speed basically means being tied into inconsistent cartridge families. AND that a lot of the inconsistency can be tied to inconsistent powders.
Magnum volume cases need magnum type powders to get their speed potentials without overpressuring the system.

A lot of the consistency of the Creedmoor (and bench rest cartridges) can be tied to the types of powders they do well with.

In your list of cartridges you wanted the same easy load development as a Creedmoor, while getting more long range ballistic performance. So why not try to mimic the chamber design, bore-volume ratio, and high efficiency powder choices of the Creedmoor, but in a 7mm (or 30 cal)?

The 7 creed functionally is the 7 saw/284 win.
The 30 creed functionally is the 300wsm.
Both can be loaded for long actions to take advantage of the longer high efficiency bullets. You would just need to make sure your barrel has an appropriate throat spec.

I agree up to the point where 30 cm functionally is the 300 wsm lol it’s not even close. My 300 wsm 20” barrel is running a 208 ELD-M 2850 fps a 168 ELD-M 3150 fps about 250 fps faster than the 30 CM. He just as well stick with a 308 win that would be more of a comparison.

 

[wpeach1912]

I think something from the 284 Winchester case is going to be your best bet. If you want truly consistent long range performance, you want lapua brass. I wouldn’t trust the weatherby brass. I think a 280ai with 180+ bullets will be too long for your action. Likely same with 6.5-06. 7BC really is the winner here if it lives up to its claims, but again with the consistency caveat

 

[43.6N]

I agree up to the point where 30 cm functionally is the 300 wsm lol it’s not even close. My 300 wsm 20” barrel is running a 208 ELD-M 2850 fps a 168 ELD-M 3150 fps about 250 fps faster than the 30 CM. He just as well stick with a 308 win that would be more of a comparison.

No argument from me on what you listed.

I was speaking more in terms of how the WSM builds pressure. H4350 (and similar) is a great powder for the WSM. I will edit my post for clarity.

And if you’re not familiar (but given your username, you might be) check out the f-open 300wsm chamber spec variant. Basically loading 220-240 Bergers at creedmoor speeds.

 

[Tanner]

Anything /06 based is going to fit like crap in a Tikka mag.

284 Win with 180s would be a pretty sure bet in a .473” Tikka.

 

[One300wsm]

Guess someone should have ask I my self was just assuming. Bringbackthe80s do you hand load ?

 

[Mag_7s]

Another cool cartridge to add to the list would be the 6.5-284.

 

[One300wsm]

Anything /06 based is going to fit like crap in a Tikka mag.

284 Win with 180s would be a pretty sure bet in a .473” Tikka.

I thought tikka used the same receiver for short and long action just change bolt stop and mag ?

 

[One300wsm]

Another cool cartridge to add to the list would be the 6.5-284.

looks like he’s wanting something in .284 or .308 cal.

 

[Rockpicker]

7X57

 

[Mag_7s]

looks like he’s wanting something in .284 or .308 cal.

Totally understandable, I myself have a cult following of the 7s, but man my hunting partner does some work at extented range with his 6.5-284.

 

[jd270win]

I have a T3X in 284 Win w/ a 24” 1:8 #3 Muellerworks barrel. It has a long throat (.250 FB) - which is a bit excessive for the bullets I would prefer. I’ll likely order a reamer w/ around .188-.200 FB for the next barrel.

It likes most bullets - it is a consistent 1 MOA gun. Peterson makes good brass, and it is available.

I’ve worked up four loads that I like/am comfortable hunting w/ here in AK:

168 ABLR @ 2755
160 LRX @ 2865
180 HVLD @ 2725
141 Hammer HBC @ 2970

The ballistics work for me, but I’m not competent enough to shoot at animals more than 600 yds away.

 

[z987k]

The choice would be easy if Weatherby's RPM line included a 7mm or 30 cal option.

Nothing would be easier than running a .284 mandrel through a 6.5rpm case. Get bushing dies for 6.5rpm and put an appropriate 7mm bushing in it. People have already done that and there's a reamer.... like this one.

7mm-6.5 Weatherby RPM - 4D Reamer Rentals

7mm x 6.5 WBY RPM Sretched out 284 Winchester case made by Weatherby. Chamber Reamer rental

4drentals.com

Looking around online it comes in at 78.9gr case capacity. About 5gr more than 280ai, 3ish less than 7rm. So In between those, closer to 7RM. If you ran it in a chassis with the mdt magazine, you can seat those bullets a bit longer.