Friend's 06 bolt gave out aqnd he wants to borrow my 243 for West Texas Mule deer. He said shots out too 300 yds not uncommon. I'm not sure the 243 has enough "umph" for Mulies.

I guess it will be ok with premium loads, good shot placement and a good bullet. What do ya think?

With good bullets and a steady rest 300 yards is probably as far as you ought to go with it. Should be fine though so long shot placement is good.

It'll do, BUT I'd limit my shots using a 243Win. to no more than 200yds., using premium
ammo (Core-Lokt Ultras, Nosler Partitions, Trophy Bondeds, etc.), and take only broadside heart/lung shots. THE 243Win. IS MINIMAL!

As long as the bullet choice is good i would be more concerned about the shooter. 300 yds in my opinion is stretching it for a .243

I live out west. 300 yards is about the norm, 4-500 isn't unheard of. If your anykind of a hunter, you should be able to get closer. There are exeptions, of course, like when a coulee all of a sudden jumps in front of you, and your shooting accross a valley. If he's looking for a flat shooting replacment, suggest to him a .270. It has more whack, less recoil than his 06, and will retain more than enough enerfy to kill a deer at those ranges. by the way, I would never endorse shooting at the extended ranges. 300 is my max, givin all things being perfect.

If all things are perfect the 243 is sufficient with proper bullet choice. Such as, a 100 grain controlled expansion bullet. Perfect would mean broadside with no obstructions in the way and no wind to drift the bullet. Also, using a range finder to know the exact distance to the target. Then you must be able to execute the shot without making a mistake. Mule deer can and have been taken with the 243. I would opt for something larger if I have the opportunity.

I've used the 243 win and taken quite a few deer with it . This year I took a nice buck at 260 yards with it , got a complete pass thru ,broke the top of both shoulders ,shattered the spine and passed out the other side using a 85 gr barnes bullet . Premium bullets is the only way to go with this gun in my opinion .

Did his -06 break, or did he beak it? If the answer is "it broke" then the .243 with the right bullets is ok for mulies. If the answer is "he broke it" then "the .243 is too small acording to the guys on the internet and you should borrow Bob's .375 H&H for the trip"