Rebarreling .257Wby Mark V

[CoolHandCass]

I currently have a .257wby with a standard contour barrel (#2) in a Belle and Carlson aftermarket stock. Will I be able to change the barrel to a 7mm rem mag or 300 win mag? I am thinking of ordering a Shilen barrel #3 contour and having it installed by my local smith. Will I run into issues by doing this? Comments/Thoughts? Thanks.

 

[MudRunner2005]

I currently have a .257wby with a standard contour barrel (#2) in a Belle and Carlson aftermarket stock. Will I be able to change the barrel to a 7mm rem mag or 300 win mag? I am thinking of ordering a Shilen barrel #3 contour and having it installed by my local smith. Will I run into issues by doing this? Comments/Thoughts? Thanks.

You most certainly can. You shouldn't have any issues. I think you would enjoy the 7mm RemMag caliber. It should fit in the .257 Wby mag box better than the .300 WinMag. I used to own an Accumark in .257 Wby. Recently traded it off for another gun. After owning my .257 Wby, I noticed that Weatherby puts different length magazine boxes and followers in their rifles chambered for different calibers... And the .257, .270, and 7mm Wby calibers all use the same ones. The .300 Wby, .300 WinMag, and others of that length use the longer one. And the big .378 Wby based calibers use a different one, as well.

Which is why I was saying that I'd lean more towards the 7mm RemMag for that particular rifle, over the longer case of the .300 Win Mag or .300 Wby Mag.

 

[CoolHandCass]

Thanks MudRunner, any opinions on shilen barrels? Most reviews I've read have been positive. Will I have any issues fitting the #3 contour barrel? I know the channel will need to be widened.. I'm new to the game when it comes to customizing.

 

[MudRunner2005]

I would go #3 26" 1:9 twist 7mm RemMag, if it were mine. Yes, opening up the barrel channel will be needed. I would look into a cut-rifled barrel, like a Krieger 5R or Bartlein 5R. I would also have them true up the action and bolt face while you have the barrel off. And have the action and lug bedded for proper stock fitment.

If you reload and have all of your old .257 Wby brass, you can open the necks, trim the end, then fire-form them into 7mm RemMag. Or you could go the simplest route, and simply open up the necks on your .257 Wby brass to 7mm Wby and then reuse all your old brass, and chamber your new barrel for 7mm Wby.

 

[CoolHandCass]

Forgive my ignorance, but can you explain truing the action and bolt face? I currently have the action bedded but may need to make some adjustments after installing a new barrel. Is there a real advantage to cut-rifled barrel over button rifled barrel? My apologies for all the questions, I'm just learning.
Cass

 

[MudRunner2005]

Truing the action and bolt face means to square them up with the invisible centerline of the action to ensure the barrel is fitted on the action flush, and to ensure everything is as straight as it can possibly be, including the bore of the barrel to the very center of the bolt face and action face.

Button rifling is not as precise as cut-rifling a barrel. Cut-rifled barrels are the highest quality barrels available to us.

 

[CoolHandCass]

Thanks for the advice!

 

[Trickymissfit]

Before truing the action, I'd have a good look at it. JE posted awhile back saying that these were some of the straightest actions he'd ever encountered. I've never checked one, so I cannot say for sure. Caliber wise, I'd go with the 7mm WBY mag. Not much faster than the Remington, but a much better case design.

Myself, I'd send the rifle to Pacnor for a no free bore 7mm mag. Won't be much faster than the Remington, but will take a giant step with 175 grain+ bullets. Always felt a 30 caliber off this case would be a killer.
gary

 

[Deleted member 46119]

I have many Mark Vs and more on the way.

You can make the rifle any caliber you want.

If you choose a chambering with a COAL longer than the 257 Weatherby you will need to do or have your smith do 3 things. Remove the spacer in the mag box. Replace the follower with a long mag follower. Extend the bolt stop groove, this requires a mill.

There is no need to true it but if you are worried, have your smith check it.

As suggested, you could send it to Pac-Nor. I have 3 Pac-Nor barrels and will get more.

A #3 Weatherby profile will require a little fitting to your stock but not bad.

With the bolt stop extended you will be able to have a COAL upto 3.86 with mag feed.

Mud is correct, you can reuse your 257 brass for a couple different chamberings.

For me Mark V builds are exciting because you can do almost anything.

If you want a 7mm chambering:
7mm Remington Magnum
7mm Weatherby Magnum
7mm/300 Winchester Magnum
7mm/300 Weatherby Magnum
7mm STW
28 Nosler
7mm Remington Ultra Magnum

OMG sooooo coooool.

 

[CoolHandCass]

Thanks for the comments, I will most likely go with the 7mm Rem Mag. Since I have not yet delved into reloading yet. The price for Rem Mag is much less that the WBY ammo. I'm a newbie when it comes to upgrading rifles and some of the terminology. Seems like I came to the right place for info though. I will be checking out the different barrel manufacturers mentioned.

 

[Deleted member 46119]

Thanks for the comments, I will most likely go with the 7mm Rem Mag. Since I have not yet delved into reloading yet. The price for Rem Mag is much less that the WBY ammo. I'm a newbie when it comes to upgrading rifles and some of the terminology. Seems like I came to the right place for info though. I will be checking out the different barrel manufacturers mentioned.

A fine choice.

 

[MudRunner2005]

Before truing the action, I'd have a good look at it. JE posted awhile back saying that these were some of the straightest actions he'd ever encountered. I've never checked one, so I cannot say for sure. Caliber wise, I'd go with the 7mm WBY mag. Not much faster than the Remington, but a much better case design.

Myself, I'd send the rifle to Pacnor for a no free bore 7mm mag. Won't be much faster than the Remington, but will take a giant step with 175 grain+ bullets. Always felt a 30 caliber off this case would be a killer.
gary

When it comes to factory ammo, the Wby is loaded to about 13,000 PSI higher pressures. Which is where people get that 200 fps deviation that they love to preach about how the Weatherby is somehow better than the RemMag... But when you factor handloads into the equation, and load the 7RM up to the same pressures as the Wby, then that velocity deviation starts to go out the window (100 fps, usually less, difference), and it really just comes down to preference.

The 7mm Wby vs. 7mm RemMag ballistics are so close, it mainly comes down to 1 thing... Would you rather buy $1.00 a piece brass (Rem Mag), or $2 a piece brass (Weatherby).

 

[Deleted member 46119]

...
The 7mm Wby vs. 7mm RemMag ballistics are so close, it mainly comes down to 1 thing... Would you rather buy $1.00 a piece brass (Rem Mag), or $2 a piece brass (Weatherby).

Yes these are QuickLoad numbers but after so much work I have confidence that it is representative of the real world relationship between the 2 chamberings.

Same seating depth, not the same COAL

7mm Rem Mag 26" Sierra 175 #1940 66.2 of 7828 60221psi 2982fps
7mm Wby Mag 26" Sierra 175 #1940 69.0 of 7828 60241psi 3006fps

So indeed, they are very very close at as close to the same pressure as I can predict.

I could build a 7mag do some testing, rechamber it to 7wby and retest but I ain't gonna.

 

[MudRunner2005]

Thanks for crunching those numbers Fred. That's about as honest and fair as I can imagine a test being, because with barrels, some are slower and some are faster, so you can't really use "real-world testing" to get guaranteed results. No 2 barrels are the same. And QL is about as close as you can get to reality.

But it sure is good to solidify that this dumb ole' country boy from Alabama actually got 1 thing right...