Ruger doesn't have a Warranty, written, nor implied. They have a promise to customer satisfaction. It's spelled out as to why in your owner's manual. What happens, when you modify a Ruger firearm, is if you send something in which needs attention, they'll replace the modified parts with factory parts, and often charge you for them. I expect this paradigm will change, as they've thrown themselves into the AR-15, 1911, and precision rifle arenas, where consumer modification is the rule, not the exception.

Between the 62grn and 70grn, flip a coin. Both are going to kill deer efficiently. I would personally lean towards the 62, to keep the impact velocity higher, Barnes bullets just do NOT want to expand below 2000fps. Either should be well above that mark for stalking deer with a 223/5.56, but since either will do the job upon impact, I'd favor the greater impact velocity.

Personally, the 60grn Nosler Partition is the bullet I recommend highest for 5.56 on deer. It's a bit cheaper than the 62 TSX, loads about the same, and has a broader range of expansion velocity - BUT - with the same assurance the shank will penetrate deeply even if the tip is shed in a high velocity impact.