+p 300 weatherby mag

Sanford338

Well-Known Member
Joined
Mar 5, 2017
Messages
89
Location
San Antonio
I totally agree 👍 👍
Weatherby's have extra freebore in order to get more velocity, and if you lessen the freebore with a special reamer, you will not be able to fire factory Weatherby ammo in it, so if you make any changes in the amount of freebore, always add more freebore.

When I wildcat Weatherby's, I add more freebore for certain bullets to hold pressure to safe limits and increase velocity. If the smithing is done right, 1/2 MOA accuracy is common. To date my most accurate Weatherbys will shoot 1/4 MOA or better. With the best (I have been able to shoot) .092 5 shot group with a 30/378.

The question of +p loadings normally means loads that are faster than SAMMI max loads, but unless changes are made to the chamber specs. all that is normally all that is achieved is more pressure. But with proper dimensional changes to the chamber, more velocity can be achieved without increasing the pressure.

If I don't feel that I need or can increase velocity by 100 ft/sec + without excessive pressure or loss of accuracy, I decide not to change a perfectly good cartridge. There are many changes that need to be made to achieve more velocity without any disadvantages. So unless a person understands the effects of each change, Don't do it.

Just some advice from an old wildcatter.

J E CUSTOM
.092 ~ 5-shot group is just phenomenal!! Kudos Sir!! Love my MK5 30-378, but don’t have that kind of accuracy.. but work in process! Happy Thanksgiving to ALL!
 

J E Custom

Well-Known Member
Joined
Jul 29, 2004
Messages
10,726
Location
Texas
Here is the group.
1606408045411.png
1606408045411.png

Who said the big Weatherby's wouldn't shoot.

J E CUSTOM
 

yobuck

Well-Known Member
Joined
Aug 23, 2008
Messages
1,609
Location
east central fl. /n.c. pa.
Started working up a load for my 300 weatherby mk v deluxe. I am currently debating on what I want to do about a barrel. Currently leaning towards a 27in hart with a break. So my question is a +p really worth it with the free bore and all?
I see you are from Pa.
Certainly the 300 Wetherby is an excellent cartridge for long range hunting.
As you may know there are a number of excellent gunsmiths in Pa who specialize in long range rifles.
One of my grandsons (age 38), decided early this past summer it was time to rebarrel his older 40x Rem which was factory chambered in 300 Wby with their standard 27” barrel.
He already owned the new Krieger barrel, so he began calling gunsmiths in hopes of having the gun for this season.
Most told him no chance of getting it done for this fall, Except one, and that was surprisingly Mark King. Who happens to be the top choice gunsmith for many Williamsport shooters.
Now it is possible that some name association of people my grandson knows had some influence.
But the gun has been finished for more than a month, plenty of time for him to be very happy with the results.
And by the way, Mark left him know that the 300 Wby is one of his favorite cartridges for which he has multible reamers.
Dont ask me how he throated it, but however he did it works very well with the 210 Bergers he reccomended he use.
 

undecided

Member
Joined
Oct 13, 2020
Messages
21
Location
pennsylvania
I see you are from Pa.
Certainly the 300 Wetherby is an excellent cartridge for long range hunting.
As you may know there are a number of excellent gunsmiths in Pa who specialize in long range rifles.
One of my grandsons (age 38), decided early this past summer it was time to rebarrel his older 40x Rem which was factory chambered in 300 Wby with their standard 27” barrel.
He already owned the new Krieger barrel, so he began calling gunsmiths in hopes of having the gun for this season.
Most told him no chance of getting it done for this fall, Except one, and that was surprisingly Mark King. Who happens to be the top choice gunsmith for many Williamsport shooters.
Now it is possible that some name association of people my grandson knows had some influence.
But the gun has been finished for more than a month, plenty of time for him to be very happy with the results.
And by the way, Mark left him know that the 300 Wby is one of his favorite cartridges for which he has multible reamers.
Dont ask me how he throated it, but however he did it works very well with the 210 Bergers he reccomended he use.
I’ll have to check him out he’s only about an hour and half away. Thanks
 

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