I know this topic has been beaten to death.  

Is there a guide or a FAQ to show me the recommended bullet weights for this twist?  

I assume I won't be able to shoot 45gr. HP's through this.  

Does 1/7 properly stabilize 55gr?  Or is it similar to how a 1/9 stabilizes a 75gr.  Works most of the time, but not always?

Also, it seems like most 14.5" barrels are offered in 1/7 - what's the reason for this?

Thanks.

1/7 w/ 55gr all day long.

Alot of companies offer 1:7 because thats what the military is using now so that they can call it mil spec. My 1:7 will shoot 55 gr all day but I havent tried anything longer than that. I had a 1:9 that shot 75 gr hp reloads just fine. Its not the grain of the bullet that matters its the length.

My 1/7 shoots 55gr fine and that is the lightest bullet I ever shoot so it works fine for me

I shoot 2 carbines one 16 inch 1-7 A2 Colt and a 1-12 SPR Colt along with a Armalite M 15 SPR 20" w/ 1-9. My range bud shoots a 20" HBAR 1-9 frankengun and a 11.5 carbine in 1-7.. We have shot about 5000 rounds between us this year alone of 55 to 77gr ammo with no problems.

Granted the accuracy of the heavier bullets in the 1-7 / 1-9 are  better. Have yet to have any gun shoot really bad regardless of twist rate and bullet weight.

I have yet to get 55gr PMC or 55gr Federal to do anything other than group a little sloppy (2-3 MOA)  even at long range i.e 300 + yards.

Unless you are shooting for benchrest accuracy just buy the most reliable and affordable you can get on your budget. And yes this subject has been beaten to death : )

Also check out the ammo forum. More good info there.