Caliber choice help

[mfk]

I currently have a Remington 700 long action that's currently running as a 257 wby mag. I'm trying to decide what to build it into. I've considered 6.5 prc, 6.5x284, 264 wm, but am open to others. If I stay with a 6.5 I'd like to run Berger 140's 3200 or faster, but plan on eventually running the Berger 155's if they ever come out (which I was told would be towards the end of 2019). Also I want this gun to be kid friendly as both my kids will be going thru hunters ed this spring. Also I'm currently having a 300 rum built so I'll have the 30 caliber covered. Thanks

It is like Christmas picking out a new caliber.

I did the ocw test and found a "node" at 44.6 grains of h4350 gave me mv of 2688...the barrel length on the rifle is 22 inches...
I know the mv seems low but if you compare the 162 eldx to the 140 grn nosler accubond, the eldx outruns it at three hundred yards and just maintains out to well past a thousand yards...

I did the ocw test and found a "node" at 44.6 grains of h4350 gave me mv of 2688...the barrel length on the rifle is 22 inches...
I know the mv seems low but if you compare the 162 eldx to the 140 grn nosler accubond, the eldx outruns it at three hundred yards and just maintains out to well past a thousand yards...

I agree. I am a fan of heavy for caliber projectiles.

 

[jkwright]

There are a lot of great 7mm bullets as well. Something to consider. A 180 eldm with its ridiculous BC out of a 7mm rem mag at 2850-3000 fps is tough to beat ballistics wise. Youd have the option of running lighter bullets for kids if need be. 7mm rem mag is super easy to find brass for and easy to find ammo for if you needed it some for some reason. With a good break recoil should be fairly mild. Another option anyhow.

 

[snox801]

Why not keep it a .257? Very flat shooting with 115's. You are ok with a new barrel so just get a faster twist 7-8 and shoot the new blackjack? I really wish I had done a 8 twist on my .257 not a ten.

 

[Alibiiv]

I currently have a Remington 700 long action that's currently running as a 257 wby mag. I'm trying to decide what to build it into. I've considered 6.5 prc, 6.5x284, 264 wm, but am open to others. If I stay with a 6.5 I'd like to run Berger 140's 3200 or faster, but plan on eventually running the Berger 155's if they ever come out (which I was told would be towards the end of 2019). Also I want this gun to be kid friendly as both my kids will be going thru hunters ed this spring. Also I'm currently having a 300 rum built so I'll have the 30 caliber covered. Thanks

Let's steer things up a bit here. Haaaaa...... I am thinking that perhaps there's a lot being asked here out of a belted magnum base. If I were looking for something that was kid friendly, maybe what you already have is not too bad of a choice. My daughter started hunting when she turned 15. I bought her a Ruger 77, featherweight in .243 Winchester. It had a really nice piece of wood on it, "until" while hunting she slipped in the snow, the rifle ended up, muzzle down in a brook, buried just past the forend!! At that time is was about two weeks pay to buy it; not a happy father, but.......stuff happens. Just something to think about for a young hunter's first rifle.

 

[Gamesniper19]

I currently have a Remington 700 long action that's currently running as a 257 wby mag. I'm trying to decide what to build it into. I've considered 6.5 prc, 6.5x284, 264 wm, but am open to others. If I stay with a 6.5 I'd like to run Berger 140's 3200 or faster, but plan on eventually running the Berger 155's if they ever come out (which I was told would be towards the end of 2019). Also I want this gun to be kid friendly as both my kids will be going thru hunters ed this spring. Also I'm currently having a 300 rum built so I'll have the 30 caliber covered. Thanks

Based on your ask and parameters, there are 2 calibers that I have experience with that would meet your demands to run 140 grain bullet at the speed and still be as "kid friendly" as one can be. The following opinion is based on an 8 twist 24" barrel:
6.5 PRC - might get to about 3120 or 3150 with a 140. Touching 3200 would be is possible and may cause pressure issues.
6.5 GAP - will get you to over 3200 and my personal load with that very bullet does. I run a 24" PROOF CF 24" barrel with 8 twist and 63.1 grains of H1000. I see magneto speed confirmed fps of 3220 and a SD of 9. 21.6 foot lbs of recoil energy. For kids under 12 I prefer to stay under 20lbs of recoil which is right about at the 308 level.

Both of these caliber are optimized for short or medium actions and I have no experience with them in a long action.


Now if you want to move into a Long Case you can easily achieve 3200+ fps and you will absolutely need a brake to keep it kid friendly. Anytime you move into a rifle with 70 grains of powder, it lands you in the 25 lbs of recoil energy range which is around 30-06.

 

[snox801]

Yep the .257 Roy with the blackjack is still in the bullet weight range he wants and none of the 6.5 mentioned will be hanging with that. It will be a fast .25 cal and has a very good bc that will make it very good past 500 yards.

 

[Eagle eyes 17]

I currently have a Remington 700 long action that's currently running as a 257 wby mag. I'm trying to decide what to build it into. I've considered 6.5 prc, 6.5x284, 264 wm, but am open to others. If I stay with a 6.5 I'd like to run Berger 140's 3200 or faster, but plan on eventually running the Berger 155's if they ever come out (which I was told would be towards the end of 2019). Also I want this gun to be kid friendly as both my kids will be going thru hunters ed this spring. Also I'm currently having a 300 rum built so I'll have the 30 caliber covered. Thanks

I took a Remington 700 in a 308/7.62 and dropped it in a Magpul stock ... Great for 150gr 30 cal. but if you want a great long action I would do the same with a 7mm , you can get a good deal on one with a 26" barrel.
I also have the Remington 700 Long Range in a 300 RUM , it's my favorite rifle for 30 cal loads.