New Build: 6.5-300 Weatherby

[LongestShot]

LongestShot - I built one on a well traveled 300 WBY Mag MK V custom. Used a Bartlein 5R heavy sporter contour barrel at 26" finished length with a radial muzzle break, very easy on the shoulders. Got it dialed in with 130 Berger VLD hunting bullets, I can send you the powder and related data if it will help you.

Shoots very very well. I have my own reamer, has chambered 2 rifles so far- PTG finish reamer, standard/stock WBY chamber. I am/was not concerrned with barrel life as I my only intended purpose was to hunt with it so 400/800/1200 rounds was not important in my rifle and should last a very long time.
Shot about 20 to 30 rounds to get to my accurate load. With respect to other calibers mentioned, I am a fanatic on the 6.5 calibers, so that was it, plus plenty (if expensive) ammo available for my stock chamber. This rifle went to my nephew in the attached pic, View attachment 507278and have since purchased an Accumark MK V in the same caliber. A 7mm option was mentioned, there is a 7mm WBY MAG. I had MK V in a 7mm STW, big fan of the STW's. Awesome Beanfield Calibers. You have a fantastic donor rifle, Good luck with your build.

Thanks for the response; I would appreciate any and all info regarding powder and related data, thanks.

 

[Dragoon300]

Thanks for the response; I would appreciate any and all info regarding powder and related data, thanks.

I my opinion Vihtavouri N570, N568 , N565 or Reloader 33 are the best choice. I have had the best results with N570 in both my 6.5 PRC and 338 Lapua. It fills the cases of both quite perfectly and gives great velocity with low extreme spread. I highly recommend this powder. I also recommend the Berger 156 and 153.5 grain projectiles, they are very high BC and are very accurate in my 6.5 PRC. I was very seriously considering the 6.5-300 Wby. But decided to go with the PRC and not deal with a belted cartridge. That's not to say anything bad about them, I didn't want another one. In your case I think it's a great idea and choice! Some one mentioned the 7mm-300 Wby. again a great cartridge if you were wanting a 7mm. Do the 6.5-300 Wby. it is the top of the lineup of production 6.5's!
I mentioned earlier Bartlien barrels, my personal favorite! I know they take a while to get, but they offer the things I want and do an excellent job for me. Find a barrel and start shooting! Have a lot of fun! And most importantly do what you want to do!

 

[yobuck]

If you actually read my post, you'd realize that I already purchased the stock, dies and brass. The fact that I'm using the action from the 300 Weatherby should let you appreciate that I no longer have any interest in shooting the 300. Your assumption that the 7x300 is a better option is simply an opinion, not a fact. I asked for different opinions regarding a recommendation for a barrel; I didn't ask for opinions regarding my choice to opt for the 6.5-300 Weatherby.

Well as for the brass, standard 300 Wetherby brass is a one step process to run thru a standard 7x 300 Wetherby die.
So even your old fired brass could be reused.
You would need a step down die for the 6.5 however.
As for velocity, a 7x300 with a 162 gr bullet will equal or exceed the velocity of a 140 gr in the 6.5x300,
And thats a fact not an opinion.
Another fact is that if you had been around 50 years ago as i was, you would also have known that the 6.5x300 Wetherby users of which there were many at that time, (all) switched over to 7 mm when it was time for a new barrel.
And the reason was, better all round performance.
As for what (you ) do, that of coarse is entirely your choice.
Just be aware that you arent making the best one for that which you are contemplating doing.

 

[Longtooth32]

If you are just looking for a barrel...look at the Pac-nor "super-match" barrels. https://pac-nor.com/barrels/

You may have to supply them with a 6.5/300 Wby reamer...

 

[Mike D Texas]

Well as for the brass, standard 300 Wetherby brass is a one step process to run thru a standard 7x 300 Wetherby die.
So even your old fired brass could be reused.
You would need a step down die for the 6.5 however.
As for velocity, a 7x300 with a 162 gr bullet will equal or exceed the velocity of a 140 gr in the 6.5x300,
And thats a fact not an opinion.
Another fact is that if you had been around 50 years ago as i was, you would also have known that the 6.5x300 Wetherby users of which there were many at that time, (all) switched over to 7 mm when it was time for a new barrel.
And the reason was, better all round performance.
As for what (you ) do, that of coarse is entirely your choice.
Just be aware that you arent making the best one for that which you are contemplating doing.

OK, you're going to have to explain this one to me. You have the same parent case, same powder capacity....how is a heavier bullet going to match or exceed the lighter bullet?

 

[Phil Rizzo]

I recomend and prefer Bartlien barrels. Go with 5R Lefthand rotation (for Northern hemisphere) gain twist starting @ 1:8.35 to 1:7.35 @ muzzle. I recommend N570 powder for it too. I have a 31" 6.5 PRC running 156 Bergers @ 3350 fps with 64 grains of Vihtavouri N570, you would be able to go faster with the 6.5-300 Wby. In a 31" barrel, not sure how fast it will go with a 26". This combination works great in my Desert Tech SRS-A1.

ever consider a 6.5 PRC/SI?
I only know of one guys results with one but he's thorough.

 

[yobuck]

OK, you're going to have to explain this one to me. You have the same parent case, same powder capacity....how is a heavier bullet going to match or exceed the lighter bullet?

Actually with the modern day powders, there have been improvements in velocity numbers with most cartridges.
Back in the days of 50 years or more ago most hunters using the wildcat cartridges like the 6.5x300 Wetherby or later the 7x300 were using powder like H870 because it was available.
4831 was a bit too fast and caused pressure before suitable velocity was obtained.
H570 was a bit better, but also very hard to find.
What really made the 7x300 come to its full potential was when 7828 powder was introduced.
With that powder, velocities of 34 to 3500 FPS are possible using the 162 gr bullet in 28" barrels.
Im personally using 78 gr with the 162 for a velocity of 3350 plus in both 26" and 29" barreled guns.
Now that said, i can get the same velocity from my Mark five actioned 300 Norma using 190 gr bullets.
Which is why i recommended to the OP to just stick with the 300 Wby.
Spend the money on a really good pair of binnoculars instead.

 

[comfisherman]

I'm fairly barrel brand indiscriminate, when my peer group all got outta school we started rebarreling and building customs. Fairly quickly we all developed fairly entrenched brand loyalty to various companies and methods of manufacture. Truth be told it boiled down to whatever premium we first had success with. Overtime the realization that a lot of folks do the barrel game pretty doggone good.

If it were me I'd be finding the smith willing to do a rebarrel on a Weatherby, who has a reamer and go with whatever brand they partner with or prefer to use.

One thought on the barrel in general. If your not shooting for a light weight rig, and don't mind carrying a 26 inch barrel plus break. Consider just adding a few inches to the barrel and omit the break. If your using a sendero type contour at 29 inches the rifle is going to be plenty heavy to manage even the heavy 6.5 pills. Those extra inches give non trivial fps gains, allowing you to hit higher fps without running the upper pressure nodes. Everything seems to last just a scosh longer when you back it down to the mid level loads.

This was kinda the prevailing thought 15 yeas ago, and having done it with a similarly overbore cartridge it worked for me. Well at least up until moving back to the island and crawling through alders... then everything long got chopped, especially the 29 inch barrels.

 

[TxPhred]

Thanks for the response; I would appreciate any and all info regarding powder and related data, thanks.

Here are my loads.
Berger 130 VLD Hunting, 3.589 COAL, Retumbo, I started at 80.5 grs. All Weatherby Brass, New.
Two best loads were:
80.5 - 3396fps
81.8 - 3441 avg fps / 10.0 SD
Current - 82.0 - 3439 fps
I did not see any signs of pressure in my rifle at 82.0
I had 72.5/3140fps as start and 81.5/3293fps from Berger Data.

Barnes TTSX 120GR - 3.600 COAL Retumbo
Best load 82.3 grs - 3557fps avg. / 13.0 SD.

Hope this helps. Good luck and you know the disclaimer stuff.

 

[Chris F]

OK, you're going to have to explain this one to me. You have the same parent case, same powder capacity....how is a heavier bullet going to match or exceed the lighter bullet?

Bigger piston. One of the peculiarities of internal ballistics….with bullets of same weight, the bigger diameter bullet achieves higher velocities all other things being equal (same powder capacity, same pressure etc).

 

[Dragoon300]

ever consider a 6.5 PRC/SI?
I only know of one guys results with one but he's thorough.

When I did mine that wasn't an option. It probably works well though.

 

[comfisherman]

The bore efficiency advantage is significant, even more so as the overbore increases.

I.e. the wsm family has bore size efficiency gains but the rum has even more pronounced gains.

 

[Lee7588]

My 26 NOSLER out preforms my 6.5-300 by a long way and barrel life is about the same I also have a 6.5 STW which is close to the 26 NOS.

I curious on what ways your 26 is out performing the 6.5-300?

 

[Lee7588]

Bigger piston. One of the peculiarities of internal ballistics….with bullets of same weight, the bigger diameter bullet achieves higher velocities all other things being equal (same powder capacity, same pressure etc).

His claim is about 2 different weight bullets not the same weight, bigger piston burns more fuel