Thanks Roskoe. I originally was going to have a custom built in 338/06 b ut when I heard about 35 Whelan AI, i thought that it would be a great custom rifle.However you are correct about cartridge selection. Thanks. That's what I like about this forum, lots of knowledgeable, helpful folks.

I personally have shot a 35 whelen ai that belongs to a friend. I have tried to buy it many times I am so impressed. It impresses everyone that is around it. Very good on hogs.
I have a couple AI's 25-06 and 30-30. both are very good.
As far as a brush buster goes, no cartridge is any better than another.
Just a myth.
Shoot any caliber,any bullet into brush and it will be deflected from you point of aimby the first thing it hits.

The .250-3000 and the 257 Roberts AI are the most often stated examples of improvement.....I should add to this the 7MM Mauser.....as all of these when chambered in their original configuration in a modern bolt action rifle and fired at the pressures of modern cartridges show excellent performance differences.....the addition of AI dimensions after this do very little for them.....I actually had a guy tell me he was getting what amounted to be velocities in excess of .257 Weatherby velocities from his .257 Roberts AI.
One can (if he has the equipment to gauge the pressure accurately...and the usual reloading indicators don't do this for you) actually shoot to about 70,000 PSI with little to no serious pressure indicators. Unfortunately the shooter don't know this because he hasn't the equipment.
It's a commonly believed rule of thumb that for every increase of case volume of X %, that 1/4th of that is realized in velocity increase.....and this rule of thum has been born out many times...Example:...if one can blow out the case to increase it's inside volume 10% then he should realize 2 1/2 % increase in pressures.....any additional increase in pressures is due to actually firing the case above the saami pressures of factory loaded ammo.

Or in other words almost all the gains one gets from the AI cartridges could have been realized with the parent cartridge if loaded to the same pressures one loads his AI cartridge.
A cartridge with 10% increase of capacity if originally shooting 3,000'/sec will be expected to now shoot 3,075"/sec and very few can actually be increased 10% in volume. Among those that can are the .300 and .375 H&H and if one looks to the gains of the .300 and .375 Weatherby he sees that loaded to the same pressures as the .300 H&H there's actually very little gain.
When it comes to the fine old cartridges such as the .257 Roberts one needs to find loading data for it that makes it shine as it should.....but make no mistake about it in no way is it ever going to be a .25-06. It's a fine cartridge as is and the AI version actually don't gain 100'/sec in reality.
Probably no other group of cartridges have had so much money wasted on them as the Ackjley cartridges.....if it improves confidence then so be it....but to say that it actually makes a (noticible) difference is just not correct at all.

Vapodog - are your opinions about the Ackley Improved's based on actual first hand experience?

To me, being a former racer, AI's are just like hot rodding a car.
Some cars or cartridges respond well to hot rodding. Other are a waste of time.
Now days there are cartridges that can do the job you want without hot rodding,but wheres the fun in that.
The AI's I have or have been around are alot of fun to work with just don't go over 5% more powder,as stated in Ackleys book, than the parent cartridge and always be looking for pressure signs. My 25-06 AI is a real pain, didn't gain much at all. The 30-30 AI as a lot to gain, it can equal a 300 savage with ease but will never be a 308

You make a good point, Aunsaber. My personal .25-06 Ackley Improved really came alive when I set it back and rechambered it. I am able to get .257 Weatherby ballistics out of it without problems, and the accuracy is very good. But I have seen some .270's, particularly those with shorter barrels, that didn't really seem to "improve" much after being rechambered to A.I.

The best of the Ackley Improved cartridges, IMO, is the .22-250 40 degree. 55 grain bullets can be pushed at speeds approaching 4K. Never have to trim cases. I have one with a Hart barrel that will shoot 1/4" with some loads. And if you back off the charge to middle 3800 range, brass life is amazing. I have a batch of cases that have been fired 21 times - never trimmed - primer pockets are still tight - necks aren't split. How's that for prairie dog economics?

Just read an interesting artical in Rife Shooter mag. on Cartridge Efficiency,looks like the 35 Whelen AI is at the top.

The battle will continue forever.....no one ever asks what amount of improvement there is between the .270 winchestewr and the .270 Weatherby with the same length barrels.....and the .270 WBY has a far greater powder capacity!
The same can be said for the .280 Remington and the 7M mag as well as the .30-06 and the .300 H&H...these enormous increases in powder capacity yields a surprisingly small increase in velocity and yet we have people stating that (assuming safe pressures within the saami specs) their .257 AI Roberts shoots faster than a .257 Weatherby!!!!!
If one chooses to delude himself there's little that can be done about it. I take great pride in having never built one.....that I listened to a guy that knew this years ago....hey...it's your money.....spend it your way!!!

I've not only shot AI's and owned them. I also spend numerous hours sitting with Parker Ackley himself in his shop. In all that time, he never had a huge amount to say about his "improvement" of cartridges.

One thing he did tell me, was that he used test bbls. to check velocities with, many of them 26 to 30" long!!! That means he got MAX V gains for the powder burned!!!!

Nothing is for nothing!!! You just can't get huge V gains with out burning more powder, OR pushing the pressures up!!! You can kid your self into thinking you can, but in the "real" world it just doesn't happen!!!

As was already said, those cartridges like the 30-30 have huge gains because case capacity goes up quite a bit, and also because the 30-30 is "under loaded" to begin with!! Others like 25-06 doesn't gain a huge amount "if" you keep the pressures similar to the factory levels!!

Drilling Man