My 22-250 has a 1/14" twist barrel. What size bullets would best suit this barrel, 50 gr. 55 gr.?

http://www.riflebarrels.com/products/caliber_twist_rates.htm

According to that link with a 1:14 twist you want 50-52grs.

45-62 gr bullets should shoot reasonably well out of your gun. 1-14" is pretty much what you'll get from most factory rifles, the standard is pretty much the 55 gr.

It is length, not weight, that determines this. For example, my .222 with 1/14" twist did very well with 55-grain flatbased bullets, but poorly with 55 grain spitzer boattailed slugs.... 50 grainers should be OK though.

Greenhill formula: 180/length of bullet (in calibers) = required twist (in calibers).....
So if the bullet is 4 calibers (4X.224") long, the twist must be around 1 turn in 10". How many calibers long are your two different bullets?

This is very true the length of a barrel can and will play a very important factor. Especially on very fast burning powder and calibers!

However, the base plays more of an obstickle than realized in some cases!

And in my opinion it has to do with blow by(or seal), from the case?
Spitzer bullets seem to have a disadvantage as far as speed and accuracy because of inconsistancy of seating the bullet when fired? Again this is my 2 cents? But I have found that Spitzer type bullets seem to diffeaint for accurracy when pushed to the limit of speed on fast burning powder rates?