Thread: Tiika t3 7mm08/284

Can you gents please tell me all about any problems that i need to watch out for doing this rechamber .I want to run 160 plus bullets in the standard barrel length and which brass is best . Thanks

Had a 284 tikka and done loads for a 708 tikka using 160+pills. 284 had a 19" bbl, 708 had an 18" but got 162eldms doing 2750~ with 54gr~ of 2209 in the 284 and 162 eldx doing 2680 with ALOT less 2206h in the 708. Hot load but wouldn't go to the trouble of a 284 again. That 708 was a hot load but standard barrel you should get that speed easily which means it is good on red sized animals out a long way.

Originally Posted by wayno

Can you gents please tell me all about any problems that i need to watch out for doing this rechamber .I want to run 160 plus bullets in the standard barrel length and which brass is best . Thanks

First problem will be finding a Smith willing to ream in the first place.

Arthur Cleland reamed my last chamber from a T3 7mm-08 to a .284

I’m not running 160’s but 140’s instead and loving them.

Other things to factor in is you’ll need a long bolt stop and also the larger magazine.

Other than that your good to go

I have done two - one for me and one for a hunting mate. I’m running 162 ELD-X with 2213sc at a mild 2740 fps but accurate. Both rifles reamed by Dave Ward in Dovedale. Mine has had the face of the action machined off to flatten it and a traditional tombstone lug added and all bedded into a factory stock. It’s my go to rifle of the four I own and I would take some convincing to ever sell it.

As Seventenths says, a long bolt stop (Dean Maisey supplied for $60 posted from memory) and long mag will be needed. Mine was originally a .25-06, so had those anyway. Bought my 7-08 barrel unfired on here.

Brass will be your biggest challenge. When I had mine some Winchester 284 brass popped up for sale so I stocked up. Failing that most people seem to get 6.5-284 lapua brass and neck it up to 284. If you want to run bigger 160gr pills you will want it reamed a little longer to accomodate this so you can get max performance. Great caliber.

Lapua are doing .284 win brass this year according to their website.

Would the 7x57 twist rate be better for the bigger projectile too or the normal 7mm08 one ok?

Lapua and Peterson do 284 brass, plenty of amiths ream tikka barrels still, 2750 pretty common speed people are finding accuracy at in 19" barrel, had mine to 2900 but was a hot load of re17.

Originally Posted by csmiffy

Would the 7x57 twist rate be better for the bigger projectile too or the normal 7mm08 one ok?

Depends of the rifle manufacture. Tikka's 7mm08 twist is 9.5" same as 7mm rem mag, Remington twist is 9.25" both are fine for the 162Gr projectile's.
So manufacture's (Savage comes to mind) only use a 10" twist which is not so good.

Originally Posted by wayno

Can you gents please tell me all about any problems that i need to watch out for doing this rechamber .I want to run 160 plus bullets in the standard barrel length and which brass is best . Thanks

Here's a thought that I have been pondering on for some time that someone with more knowledge than me could answer.
If you are going to the trouble of reaming to 284 and fitting a long bolt stop and mag, wouldn't it be just as easy to ream it to 280Rem or even 280AI?
The brass seems to be more readily available and the ballistics as good if not better.

I have often wondered why this is the case. In 6.5 the industry standard has become 8 twist, yet most manufacturers still produce slow twist 7mm rifles which are not suitable for stabilising some of the new, heavy and long projectiles.

My 7-08 based T3 spins 162 ELD-X just fine, but my custom 7 RM has an 8.7 twist barrel for the 180 ELD-M.

Too much twist can be a bad idea, but manufacturers need to catch up and produce rifles in the 8.5-9 twist range.

Originally Posted by winaa

Here's a thought that I have been pondering on for some time that someone with more knowledge than me could answer.
If you are going to the trouble of reaming to 284 and fitting a long bolt stop and mag, wouldn't it be just as easy to ream it to 280Rem or even 280AI?
The brass seems to be more readily available and the ballistics as good if not better.

Good point, and I considered it when doing my T3. The .284 Win case is much shorter, which allows projectiles to be seated out as long as you want whilst still fitting in the T3 magazine. In mine I have about 3mm of mag space remaining with the 162s seated longer than SAMMI spec. Tikka mags are short so this would be less of a problem in others.

You might just get a bit more velocity from a .280 if you load it hot but that comes at the price of shorter barrel life. The .280 AI really should be compared with the .284 Shehane if we are comparing apples to apples.

Originally Posted by winaa

Here's a thought that I have been pondering on for some time that someone with more knowledge than me could answer.
If you are going to the trouble of reaming to 284 and fitting a long bolt stop and mag, wouldn't it be just as easy to ream it to 280Rem or even 280AI?
The brass seems to be more readily available and the ballistics as good if not better.

Yep, been there and done that before I went to a .284

I found the .284 to be more efficient with shorter barrels where as with the .280 you need the full length barrel.

I was at the time tempted to go .280 AI but I would have had to fire form cases as there wasn’t any AI brass around then unlike now.

I’ve had a 16 inch barrel on my .284 and that went well but for down south I prefer a 20 inch barrel.

Personally I wouldn’t go any shorter than 18 inches

+1 for what @Seventenths has stated. 280ai will get you more speed - getting close to 7mmRM but you need to go with min 24in bbl. I get 2980 fps in my 280ai with the old 162AMAX. 284 will tolerate short bbl better, 20in for me is the sweet spot for 284 barrel length if you want an all rounder & with 160gn pills this will get you around 2830 -2850 fps. .