Seth: I have no experience with A-2, it will be up to you to test your tangs.
I don't know the context to which Wayne suggested stainless steel, if I was going into combat my blade would be 52100.
I have never tested a tang that did not have a large rate of longitudinal reduction in its development so I can't comment on the strength of the grain structure of a tang that had the grain running perpendicular to the blade.
I have tested a number of Frank Richtig's blades and am told he made his blades with out regard to grain flow and I have never seen one of his blades broken at the handle. His heat treat was more sophisticated than most realize therefor I feel you could get around grain flow, but you are pretty much on your own and I sure hope you do some experimenting with your steel and methods and report your results back to the rest of the knife community. No matter what the theories dictate we still have a lot to learn.
This summer we tested the tang of one of our test blades, put about an inch of the tang into a vice and pounded it over to a sharp 90 degree bend, then put it on an anvil and flattened it back over the rest of the tang with a forging hammer it folded clean with no tears and took a lot of force to bend it. This was done cold, the steel had been annealed at 988 f. for two hours, three times in three days. When we hardened the blade the tang never got hot enough to allow it to harden. After three edge quenches (blade only heated to above critical) the blade including the tang had been tempered at 388 f. three times. I don't have a Rockwell tester but feel the tang was close to dead soft.
Any time you harden a piece of steel, the memory of that thermal cycle will remain in the steel. For this reason I never harden a tang. In my opinion, trying to temper a tang that has been hardened only provides a greater opportunity for failure. At one time we experimented hardening the entire blade (rather than just the lower 1/3) on the first two quenches, then only edge hardened on the third quench. The blade broke catastrophically into two pieces on the first 90 degree flex. Theoretically speaking one would figure the third quench where the spine was not heated to critical temp would have softened the spine adequately, but it did not.
Your choice of handle material has a lot to do with the strength of the tang in the handle. It is what I would call a complimentary issue. Strong handle material will allow you to get away with a tang of less mass (strength) than weaker handle material. For example (not trying to be self serving but it is what I use) our sheep horn is very strong, grain direction in sheep horn does not seem to be significant. I have never used a stronger or tougher handle material (metal handles excluded) and this is one of the reasons we use sheep horn. Once we acraglass a sheep horn handle onto a blade you can't beat it off with a hammer, the only way you can get it off is to either saw or grind it off. I have a knife that I used for about 8 years, I used it hard, chopped river ice at -20f and pounded on the spine of the blade with rocks and hammers, the handle is as solid today as it was the day I made it. I can drop that knife handle first onto a cement floor and it just bounces. I have done this demonstration numerous times at shows and in my shop without obvious damage to the horn.
Many years ago I made a bone handle for a knife for a friend, he dropped it while hunting, the butt of the handle hit a rock and chipped, he had to field dress and bone two elk with that knife, the palm of his had looked like it hand suffered greatly as the chip left very sharp edges on the butt of the handle. I put a sheep horn cap on the butt of the handle and he is still using it.
A good friend went into and still is making production knives with hidden tangs, one of the problems he had to solve was that the entire blade and tang were hardened, he had a threaded butt screw and recessed bushing with a nut in the back of the wood and stag handles, he was getting blades back broken at the tang. They started induction tempering the tangs up to the area of blade and that helped, but did not solve the problem. They tried torquing the screws tighter and that did not solve the problem.
Caps on more fragile handle materials such as bone, antler and some woods are a good idea, if they are put on right. Crown antler handles seem to hold up better than cut pieces at the butt.
The ability to pound on the butt of a handle to drive the tip of the blade into material is a very real need at times, I like smooth rounded handle butts as they are easier on my hands.
I feel lateral strength is a very real need in a knife. You may be making a knife for client who claims he will never "abuse" the knife. But you never know what circumstances are in his future, or in the future of the next person who owns the knife should he sell it or pass it down to another. For this reason I make every knife with the same considerations because my mark is on it.
Please never be bashful about asking me questions or questioning what I write, I have spent a life time seeking answers and continue to do so and appreciate the opportunity to share what I feel I have learned. Discussions such as this are of benefit to our community, at least that is my hope.
If I have not answered your question, please ask again. But I urge you to try these ideas with your steel, your designs and in your shop you will only know for sure through your own experience.
Don't do it Chris. Page will have you sucking your thumb in the corner of your kitchen, by the time he is done "relevently advicing" you.