.30-06 rechamber to .300 Win Mag.

oldiron

oldiron

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This is something I need to do, not because it's the smart thing to do.
I'm waiting for the mail, getting a Browning 78 single shot, in 30-06. And changing up to .300 Win. Mag. A rather easy job according to the smith.
But apparently Browning .30-06 twist rate is 1 in 12. Most .300 Wins 1 in 10, a few 1 in 11, only Husqvarna uses 1 in 12 that I can see. (and some long range target guys).
The Browning 78 has a 26 inch barrel I think.

What would be the expected out-come of this project?? Thanks, Bill..
 
hoytcanon said:
A loss of about $500.
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And a gain of about 400fps

oldiron said:
This is something I need to do, not because it's the smart thing to do.
I'm waiting for the mail, getting a Browning 78 single shot, in 30-06. And changing up to .300 Win. Mag. A rather easy job according to the smith.
But apparently Browning .30-06 twist rate is 1 in 12. Most .300 Wins 1 in 10, a few 1 in 11, only Husqvarna uses 1 in 12 that I can see. (and some long range target guys).
The Browning 78 has a 26 inch barrel I think.

What would be the expected out-come of this project??

Thanks, Bill..
Click to expand...

The tough part is this also requires extractor/ejector modification, and if its not done right, you can have issues with the case sticking in the chamber if the ejector slips over the rim.
 
Well my 1-12" twist .308 Norma Magnum shoots 180gr just fine .........never tried any heavier nor need to.
 
Less than great accuracy (~3" groups at 100 meters off the bench) with 180gr Nosler Accubonds in my 1:12 twist .308. It's a long bullet, nearly as long as the 240gr Woodleigh. OK accuracy in my 1:11 twist .300 WM.

37663470185_b300d2caf0_b.jpg


38495033566_8d02d7b840_b.jpg
 
Your 1-12" twist will stabilize all flat based spitzer bullets up to and including 200 grains at 300 Win Mag Velocities.
It should also stabilize the 200 Accubond, the 200 Sierra Game King, and some other boattail bullets of similar length.
Some of the longer match bullets in 200+ weights may not stabilize, though.

I have several 308 Norma Magnum rifles. 3 are 1-10", 2 are 1-12". Believe it or not, one of the 12" twist rifles shoots
the 200 Partition or the 200 Accubond into really fine groups, preferring the 200's to the 180's. That is at right around
2960 fps, which is about what your 300 will deliver. EE
 
remington jim said:
Now your TALKING ! Still the Real KING of the 30 Cal ! jmo RJ
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:agree:
300 Weatherby Magnum:
Ballistic performance
Bullet mass/type Velocity Energy
150 gr (10 g) SP 3,540 ft/s (1,080 m/s) 4,173 ft·lbf (5,658 J)
165 gr (11 g) SP 3,390 ft/s (1,030 m/s) 4,210 ft·lbf (5,710 J)
180 gr (12 g) BST 3,250 ft/s (990 m/s) 4,223 ft·lbf (5,726 J)
200 gr (13 g) Partition 3,060 ft/s (930 m/s) 4,158 ft·lbf (5,637 J)
220 gr (14 g) Rn-Ex 2,845 ft/s (867 m/s) 3,954 ft·lbf (5,361 J)

180 gr @ 3250 fps for 4223 ft-lbs of ME ... a real azz-kicker !
 
SuperCub said:
Why not just go buy a 300WM instead and leave the poor Browning alone?
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Now that's just being sensible. But I already have a .300 WM. Old people just do weird stuff sometimes.
But now, the Weatherby round has me wondering. I Would be staying between 150 gr. to 200 gr.
Thanks for all replies. I need all the help I can get. Bill..
 
Slamfire said:
If you don't go for it will you ever get it out of your mind? Often times it's the things we don't do - rather than what we did - that we regret the most in life. ;)
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Lol!! , I'm old enough now to have realised both sides of that equation can have it's ups and downs. There is always something we all regret never doing. As to the OP's question it's entirely up to you, my own guideline is if I do more than think about it a few times I would go for it, but just be aware of costs and the amount of work needed to complete the project to your satisfaction before you go feet first.
 
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