Fancy some longer legs!! -6.5x55AI or 6.5x284

[maltbuck]

Currently use a 6.5x55 and have enjoyed it. But fancy something with sl longer legs (a nice thought!).

 

So I am considering rechambering my Sako 75 in either AI format or even 6.5x284. My question - is it worth the hassle of fireforming the AI, or do I simply go for the 6.5x284.

 

Many thanks

 

MB

[Ronin]

Whilst I love the 6.5x284, I think that 260 or 260 AI would need considering on your list.

 

I personally wouldnt bother with the "55", but dont let me put you off, its a good round, but requires specific bolt face..

[Andrew]

How much extra speed are you planning on needing? I can feel the hate coming on but, frankly, I've never found Ackley-Improving to be worth the effort. Every gunsmith I've met that Ackley's a cartridge will invariably talk the customer into a l-o-n-g barrel to add some speed and few proponents of Ackley chambers have ever actually pressure tested their loads to see what pressure the added velocity costs. You can increase case capacity as much as you want but the working pressures remain the same as the case is the weak link in the loading chain. A bullet of X weight requires Y amount of pressure to get it to Z speeds. You can't fool physics. One of the most radical Ackley-type chambers you can see is the 300 Weatherby Magnum. It is a 300 H&H with the shoulders blown out square. The case capacity went up 13% but the velocity only 3.7%! Weatherby built his rifles with gobs of free bore and very long barrels to try to improve on this.

 

If you enjoy the 6.5x55, why don't you load it to modern spec and see how you like it? The 6.5x55 has a larger case capacity than the 260 Remington but, unfortunately, was designed for a weak action. If you have modern brass and a modern weapon you should be able to work up to 260 load-levels (57 - 58K) safely.

 

Normally I would never advise someone to load past recommended load levels for a specific cartridge but the 6.5, like so many other cartridges that have followed shooters across a century of firearms development, is a good candidate for expanding performance. JMHO, of course.~Andrew

[jon]

There's a short article on the 'Guns n Ammo' site about the new Speer Manual 14 where they split the '55 loads between older and newer actions. Seems they can really move, "Unfortunately" mine shoots better with loads at mid speeds - so not hot-rodding here!

jon