How much could I expect to pay a competent gunsmith to convert a M70 Featherweight in 30-06 to an AI chamber? Are there any disadvantages to rechambering to AI? How accurately will it shoot regular 30-06, in case AI ammo gets lost during a hunting trip?

Would like to hear some thoughts of those who've had the conversion done also. Thanks!

BearGuide

You can expect a good increase in performance with the 30-06 AI providing that you have a 24 inch barrel and you have the gunsmith throat the barrel a little longer than SAAMI specs for the 180 gr bullet seated out where the base is even with the shoulder neck junction.

There has been much debate about this particular conversion but it has been my conclusion that when shooters got only a small increase in velocity, it was because they did not throat the barrel for longer cartridge OL and or they were using a 22 inch barrel.

Normaly in this conversion the gun will shoot at least as accurately as it did before and from what I can determine it will get at least between 1 and 2 minutes of angle accuracy when you fire factory ammo in the improved chamber.

In order to do this conversion the barrel has to be set back one turn so it can be headspaced minus .004. Prices tend to vary but in my area it would cost approximately $95.00.

The only negative I can think of in doing this conversion is the cost of dies, they are a little steep. But if you like fooling with ideas like this, go for it. When you squeeze the trigger on that whitetail or mulie this fall and he goes down like he was struck by lightning you will love it.

Yes, I'll second that. The 30-06 AI is a good conversion if you pay attention to the details. I'm not sure about the cost, the last time I had a re-chamber job, it cost $125 Cdn. I believe that the Lymen dies for this are the least expensive. Hope this helps. - Dan

I did the exact thing you are thinking of; I rechambered a M70 FWT in 30'06 to the AI. I have always regretted doing it. The gain in the 22 inch bbl was neglible. With the powders available now ( I did mine about 10 yrs ago) one should be able to reach the same velocities as with the AI. A larger case requires more powder to attain the same velocities at the same pressures. It definately lowers the resale value of the gun. I probably would have kept it if I hadn't buggered it up.FWIW.

The accuracy of a properly chambered AI will be plenty good enough for hunting while shooting factory ammo, the loss is in velocity due to expanding the case to the imp chamber. The performance gain of AI cartridges is very widely debated. My experience is that you can expect a 2%-5% increase- when the velocity gain is more than 5% over the standard case loaded to maximum pressure, you are exceeding that pressure with the AI, you just don't see it on the brass-- When an AI case exhibits the "classic" signs of pressure the pressures are way above the SAFE level.

The rule-of-thumb is if you raise the case capactity by 10% you will get a 2.5% increase in velcoity...I had two friends who did it with 24" barrels and they realized 70-80 fps increase...hardly worth the effort....no change in accuracy.

I have a 30-06 AI that I built on a Mauser VZ-24 action a few years ago. It shoots 180 gr bullets into .5 inch groups all day long. It has a 26 inch shilen barrel and a short throat. I think it hit about 2890fps. Took it to Africa and shot about 10 animals with it out to 400 yrds ( hartebeest). I have been very imopressed with the 30-06 AI ever since. You can shoot factory 30-06 out of it and sometimes thats how I fireform the cases. Most of the people who are unhappy with the 30-06AI have too short a barrel.-Rob

Thanks for all the info! Since the Featherweight has a 22" bbl., the conversion seems to be a poor choice for this particular rifle. Maybe it's a good excuse to buy one in 300 WSM.

I like the AI version for a target rifle cartridge to use 190 to 200 grain bullets but really don't think I would bother in a hunting rifle. Given the choice though I would choose it over a WSM for hunting only because the magazine holds two more shots and the performance is comparable. Regards, Bill