Hey,
I have just bought a Sako 75 in 243 win. The barrel is 22,5 inches. I'm thinking og changing it to be a 243 AI. Is that reasonable? What advantages can I expect? Should the barrel have been longer to get optimum diffenrence?

Johannes

JTK ,
I have a .243 AI .
From a velocity viewpoint I wouldn't bother rechambering because you'll probably only get around 100 fps extra .In the field you would never notice the difference .
Feed is ok in my Remington 700 but I did lose one round of magazine capacity .
Case life and (maybe ?) throat life may improve a little but advantages are probably outweighed by the necessity to fireform .
Also will need to set your barrel back one thread before new chamber is cut . Not really a drama but then again not really desirable either .
My rifle was a .22/250 that I rebarrelled so no additional cost over going to a standard .243 . Wouldn't bother rechambering a factory barrel .

Just came from my reloading room where I was measuring the difference in capacity between the std .243 vs my 243 AI brass same box Lapua. I used Win 760 powder and the result was std held 54.5 grains and AI held 57.2 grains. The diffenerce in the field in not noticable and the speed difference is mostly in the mind. I shoot a Cooper Montana Varmint 24" barrel. Best loads are 70 BT's at 3550 47.2 grains of W 760. The reason I did this was because I have been dabbling with the idea of a 25 Souper and the difference between a 243 and a 257 AI is 10 grains! I was amazed... no wonder the 257 AI is so awesome.

If I were rebarreling anyway, then it might make sense but the perf. gain will be minimal. I went through this when I wanted a .260. Since I was rebarreling a M700 anyway, I went .260ai. I do like that the cases last well past 10 firings, only had to trim them once. It odes allow you to run max. .260 loads w/ alittle less pressure.

I have wrestled long and hard over this but just this morning went standard 243 in my soon to be Border Barreled Sako AII classic.

I don't use brass enough to care about stretch (it generaly get's lost in the undergrowth first) don't shoot over 300yards and quite frankly want one gun that I can admit to having without appearing a gun nut!

A 6mm 284 appeals more due to the lack of fire forming required.

I have a friend who traded for a Sako rechambered to .243 AI. It has become his favorite rifle -- but only because of its accuracy, and the quality of the gun. As far as performance, an honest 50 fps or so additional velocity at similar pressures is all you can reasonbly expect, and the rewards in a shorter barrel would be even less. I would agree that the original .243 should have been designed with a sharper shoulder, but there is so little gain in the Improved version as to give remodeling an existing .243 a very low cost-benefit ratio.

The longer and much more tapered 6mm Remington and .257 Roberts cases are another story, most especially if you ignore making an "improved" version and move the shoulder forward and shorten the neck as well.

1894mk2 im also interested in having my tikka 595 rebarreled by border barrels, do you mind me asking just how much it was for the job and which profile barrel you choose ?
thanks mark

Thanks for the answers and comments. I think I will stick to the 243 win.

Johannes

quote:

Originally posted by chapster1:
1894mk2 im also interested in having my tikka 595 rebarreled by border barrels, do you mind me asking just how much it was for the job and which profile barrel you choose ?
thanks mark

It's only just ordered but cost will be £564 or so unblued. Can't remember if that includes the profiling cost (£40) or not. Profile will be an exact copy of the existing barrel (plus 3" length) as it has a rare 'classic' stock that I do not want to change the barrel channel on or have to rebed.

It's a bit stupid as the existing barrel is deadly accurate but allthough it's pretty much my favourite rifle, every time I look at it I wonder why the barrel is missing 3".

Hey 1894,
du you have a picture of your SAKO AII?

Johannes

Yup but I can't post it on forums due to work software screen, if you pm me your e mail I'll some piccies.

1894mk2 cheers im not sure as to weather to have a border barrel or a kreiger ?

I very nearly went Kreiger last year but at the last moment had concerns over the copy being exactly copied and pulled the plug.

I can't comment on accuracy not having had either allthough I am convinced both will shoot better than we can. The main issue is who does the work.

If you have Border do it they will provide and fit the barrel - if there is an issue it will be all down to them. If you have a smith fit a Krieger it could be either the smith or the barrel. Add Border being from the UK and Dr Kolbe being a very helpful person and I decided Border with the bluing being done by the Webley-Venom custom shop

Who are you thinking of doing the work for you?

http://www.rifles.me.uk
steve kershaw for the kreiger

quote:

I'm thinking og changing it to be a 243 AI. Is that reasonable?

IMO your gains are so small that it's not worth the effort.