At the moment I am leaning against it.
I just bought an FN 98 in .257 Roberts. I have quest on for a factory take off stock, If I find one I have a rather rare and valuable rifle. But as the rifle is, its just a very nice hunting rifle.
I kind of like the Idea of an AI, with the 24 inch barrel, I have a good opertunity to maximize the potential but in my reserch of the various manuals it looks to me like if loaded to equal presures with 100 grain and up bullets , you don't gain much The barnes book has very good loads for the standard Roberts with standard X bullets reaching 3183 for a 100 gr bullet and 2975, for a 115. The AI
only boosts the 100 to 3226, and the 115 to 3042. Is that really worth the cost of the job and the dies ? at the moment I say no, but I am interested in your opinion. Thanks ...tj3006

Thomas

Sounds like you already made up your mind but, P.O. Ackley felt the 257 Ackley was one of the best of his improved cartridges and one that he hisself recommended. For a real improvement in the 257 Roberts, figure out a way to seat the bullets out to increase case capacity. In some rifles, such as the pre--64 Win M 70 this can be done by replacing the magazine with one made for 30-06 length cartridges. Not sure if your Mauser box is long enough or if the chamber throat will permit this, so that's two things you'll have to look at.

Ray

The 257roberts will have some of the greatest gains. That is mainly because the normal pressure for the Roberts is 54,000. Even the +p is only loaded to around 57,000 I believe.

To do it right you need to pull the barrel set it back one turn and rechamber. If it were mine I would leave it alone and simply load to 63-65,000. YOu will get the majority of the gain.

you need to be careful. i built a custom on a ruger #3 action in 250/3000 and loved it. then i got the ackley itch and punched it out. i can't tell you how much fun i've had with the 250AI. after about a year i started missing my 250/3000 so i built another rifle;this time a bolt gun. there is no way of knowing how much you will like the 257AI or miss the 257 Rob.so be careful!!!!!!!!

I Really have not made up my mind, but ramrod said basicly the same thing I said, The roberts is loaded to lower preasure. Acording to sammi apecs, but the AI version really has no preasure specs. I will think about AI ing some more. Sure as hell the day my smith calls me and says he is done with the project I will find the take off stock to make it origional, more or less.. The rifle magazine will I belive, hold an 06. But its at the smith and i didnr mess with it much yet As to the chamber I don't know.
I do know that my 20 inch ruger in the Roberts gets 3140 from the 100 grain TSX barnes. and with 4 more inches of barrel I should be able to beat that by at least 50 Feet and mabye 100.
I really hope I can get this FN to group with the 110 grain accubond. My Ruger nor my custom 25,06 will group that bullet very well...tj3006

Thomas: How much will you be shooting this rifle? If you shoot a lot you may benefit from the AI treatment. Most people look at the AI treatment in velocity gain terms only. But the reduction in case stretching and reduced need to trim cases may be a bigger factor than the velocity gains if you shoot a lot.

Depending on how well the work is done, accuracy can be inhanced. But it will seldom be better than the origional barrel was. You will get more efficient powder combustion with slower powders, and set up right, it should not be too far behind a 2506. The AI chamber should be 3 to 4 thousandths shorter in the shoulder than factory rounds to minimize headspace problems with fireforming loads.

If you don't shoot a lot or don't want to shoot more, stay with the standard Roberts. It won't require you to fireform to get the best performance. I doubt that any animal you are going to shoot with your Roberts will be able to tell whether it is improved or not...Rusty.