I need a 400 yard deer gun. Here’s my options......

[Stein]

30-06 all day and twice on Sunday.

.243 is fine, especially for someone recoil sensitive, but you will get much cleaner kills and less ruined meat with the good ol -06.  The 243 bullet is designed to come apart to kill to compensate for the lack of mass.  It does the job but leaves much more blown apart and bloodshot meat.

[fish vacuum]

I don't see anything saying you're going to practice a lot.
I don't see anything saying you've tried either of your rifles at 400.
I don't see anything saying you've ever shot at 400.
I do see a statement that you haven't rifle hunted in 10 years.
Missed opportunities because of distance are part of hunting.

He actually says he hasn’t done any of those things but will be in the future.

He says he'll be doing research.

[tgomez]

I shoot a 30-06 for all big game. I use I80 grain Remington Core-Lokt ammo. The heavier bullets weight is great for deer, bear and Elk especially past the 250 yard mark. The farthest I will take a shot under ideal conditions is 400 yards at big game animals. I do however shoot steel targets from I00 to 660 yards with my 06 for practice and familiarity of my rifle. You need to practice your tail off to feel fully confident in a shot at that range. I recommend you get a better scope, something in the 4-I2 or 4-I6 range. I also like to run a bipod on my rifle. I use a I4-26" model because I like to have a dead rest in the sitting position. As others have mentioned sight in your 06 at 225-250 yards to achieve your max POINT BLANT RANGE. You should be able to hold dead on the deer from 30 to 275 yards with no issues. The 300, 350, 400 is where you will really need to know your bullet drop. At I00 yards sight in for 2-2.5" high. Try different ammo to see what your rifle groups best. You can't go wrong with a 30-06 for any North American big game animal. Bullet placement is key and most rifles are more capable than the shooter.

[jasnt]

243 has plenty of energy for deer past 500 even with 95gr bullets.  Get some trigger time and a decent scope and it will do fine.   

[the1rod]

I don't see anything saying you're going to practice a lot.
I don't see anything saying you've tried either of your rifles at 400.
I don't see anything saying you've ever shot at 400.
I do see a statement that you haven't rifle hunted in 10 years.
Missed opportunities because of distance are part of hunting.

He actually says he hasn’t done any of those things but will be in the future.

He says he'll be doing research.

What did you want him to do? Lay out a step by step plan for you?  He's on here asking for suggestions and information,  that's the right first step to make. Lots of practice is what people are suggesting,  and that's a great next step,  after he decides what rifle to use,  which is what he was asking about. So what are you getting at here?  Do you want him to waste a bunch of time and money to find out the hard way and then ask questions??

[bobcat]

I would set up both rifles that you currently own for possible 400 yard shots and then practice with both, at 400 yards and further, so that you can determine each rifle's potential. The cartridge isn't the most important factor, accuracy is. If both turn out to be equally capable at 400 yards, I would choose the 30/06 most of the time. But there's nothing wrong with the 243 either, as long as you are shooting quality bullets.

[HarboritE]

Thank you all for the replies. I think my first step will be buying an assortment of good ammo and practice practice practice as suggested with both for awhile. The missed opportunities I was referring too were because of my comfort level. Both scopes are ok great condition, no issues with clarity. If I can’t be consistent with the old scopes I’ll buy a new one. Fish Vacuum, missed opportunities are a part of hunting !!?? Thanks for the valuable lesson. Given I haven’t put any real time in to this yet, all the input is much appreciated. Thanks guys !

[RockChuck]

I’d say either will do the job out to 400 take which ever you are more comfortable with and consistent with.

[300rum]

Here's the deal, you don't need to practice to shoot 400 yards, or at least practice much.  You need to have a good rest (Prone with your rifle laying across a pack is sufficient), you need to know where to hold (easy, I told you in my earlier post) and you need to be able to pull the trigger back without disrupting the sights.

Pulling the trigger back without disrupting the sights is the hardest part.  You can literally shoot in any conceivable position and make all your hits if you can do this.  Off hand, kneeling, tree branch, as long as you can pull the trigger without disrupting your sights, you are good.  Trigger work can literally be done without any ammunition and at first is best done without ammunition.  All you need to do is dryfire.  Pick a small target at any range and practice pulling the trigger without disturbing the sights.  Keep your eyes open through the entire process of pulling the trigger in dryfire, and watch the sight for any movement.  Your eyes will tell you where the bullet will hit at the very moment your shot breaks in dryfire.  This is called "calling the shot"

When you do get to live fire you need to learn to keep your eyes open through the break of the shot.  Even in live fire, you can literally know where the bullet will go before it leaves the barrel, your eyes will tell you if you can keep your eyes open.  To do this, video yourself or have someone stand to the side and watch your eyes to see if you are blinking.  After time you will be able to keep your eyes open through the break of the shot and you will become a better rifleman.

Lanny Bassham won an Olympic Gold Medal with very limited live fire practice.  Mostly it was dryfire.  He has a great book "With Winning in Mind".

The fact is that most people close their eyes right at the point of breaking the shot, they have no clue where the bullet went at ignition.  Watch MLB catchers for instance, it amazes me how many close their eyes just prior to catching a pitch.  Watch a catcher who muffs a pitch in the dirt, if you can see it, most of the time they have their eyes closed!         

Once you have a rifle that is sighted in with acceptable ammo and you have your holdovers down, it is all about the trigger and letting your eyes tell your finger what to do and when to do it.     

[Igor]

243 has plenty of energy for deer past 500 even with 95gr bullets.  Get some trigger time and a decent scope and it will do fine.

A 165 gr. .308 (.30-'06) has approximately 50% more kinetic energy at 400 yards than a .95 gr. .243, with a bullet like a Winchester silver tip.

[yorketransport]

243 has plenty of energy for deer past 500 even with 95gr bullets.  Get some trigger time and a decent scope and it will do fine.

A 165 gr. .308 (.30-'06) has approximately 50% more kinetic energy at 400 yards than a .95 gr. .243, with a bullet like a Winchester silver tip.

Kinetic energy doesn’t kill stuff.

[Tjv28]

What kind of groupings are you getting?  I think a tikka .270, with a leupold vx-3 might be exactly what you “need”

[trophyhunt]

Huskamaw optics, Dial and shoot

[Igor]

243 has plenty of energy for deer past 500 even with 95gr bullets.  Get some trigger time and a decent scope and it will do fine.

A 165 gr. .308 (.30-'06) has approximately 50% more kinetic energy at 400 yards than a .95 gr. .243, with a bullet like a Winchester silver tip.

Kinetic energy doesn’t kill stuff.

That's about as naive a statement as I've seen on here.  If a hunter is going to shoot an animal at 400 yards, he had better have adequate energy to compensate for less than perfect shot placement.  If the round he is shooting has minimal energy to do the job, then he had better be very selective in the shots he takes...............and most hunters are NOT.  And, the .243 falls into the category of minimal kinetic energy to kill a deer at 400 yards with perfect shot placement.

Read this:

Kinetic energy, the ability to do work (or in this case damage), is the most common measure of killing power for rifle bullets.

https://www.chuckhawks.com/rifle_bullet_killing_power.htm

[mountainman]

243 has plenty of energy for deer past 500 even with 95gr bullets.  Get some trigger time and a decent scope and it will do fine.

A 165 gr. .308 (.30-'06) has approximately 50% more kinetic energy at 400 yards than a .95 gr. .243, with a bullet like a Winchester silver tip.

Kinetic energy doesn’t kill stuff.

But it sure hedges success in your favor 😉