+p 300 weatherby mag

[undecided]

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?

 

[Mainmechanic]

Welcome to the forum. Slightly confusing statement and question. Have you already done some load development to determine the barrel needs replaced ? Please explain your +P question a little more for us.

 

[ButterBean]

Welcome to the forum. Slightly confusing statement and question. Have you already done some load development to determine the barrel needs replaced ? Please explain your +P question a little more for us.

I'm with you on this one ...........

 

[Capt RB]

Weatherby already has more freebore than you can reach so +p would be from someone with a custom reamer for a particular bullet. That may also make factory ammo over pressure. Before you explore a new barrel try bedding and playing with the pressure point. Very few weatherbys will not shoot better after some basic tuning

 

[undecided]

Sorry I should have explained more. Yes I am currently in load development. My goal is for a 1k yard plus hunting/ target rifle. I am exploring a barrel change due to mainly the heat generated and the fact it's a ported barrel and we all know that the recoil is brutal thus the idea for adding a break. I'm just asking about the +p because I essentially sure if it would really be that beneficial the add to or not. I can't recall ever seeing or hearing anyone doing it to a weatherby before.

 

[ButterBean]

I've never heard the plus pressure term used in a rifle cartridge before so I am at a loss

 

[Capt RB]

Sorry I should have explained more. Yes I am currently in load development. My goal is for a 1k yard plus hunting/ target rifle. I am exploring a barrel change due to mainly the heat generated and the fact it's a ported barrel and we all know that the recoil is brutal thus the idea for adding a break. I'm just asking about the +p because I essentially sure if it would really be that beneficial the add to or not. I can't recall ever seeing or hearing anyone doing it to a weatherby before.

The +p is a form of lengthening the freebore by cuting half of the rifling so that the bullet is still aligned with the bore. The weatherby chamber freebore is further than you can keep a bullet in the case in all but the longest 30 cal bullets which will not fit in the standard 300wby box magazine.
So in a nutshell the +p treatment would only be beneficial if you had a reamer made for a specific bullet. The sammi spec already has long freebore at the throat to gain velocity/reduce pressure

 

[undecided]

Ok that's what I was trying to figure out if it was bennifical of not with the amount of freebore thank you

 

[ButterBean]

The +p is a form of lengthening the freebore by cuting half of the rifling so that the bullet is still aligned with the bore. The weatherby chamber freebore is further than you can keep a bullet in the case in all but the longest 30 cal bullets which will not fit in the standard 300wby box magazine.
So in a nutshell the +p treatment would only be beneficial if you had a reamer made for a specific bullet. The sammi spec already has long freebore at the throat to gain velocity/reduce pressure

So its basically a Bore Rider reamed chamber ?

 

[25WSM]

The bore rider throat is sometimes called a +p. I'm a big fan of 257wbys and have 2 different reamers for it. One has the original wby freebore and one is custom. The custom one is not a plus p just a regular 1°30 at . 200 long. The speed difference is not even measurable. Would totally depend on if a particular barrel was faster that another. I see some gains in my plus p chambers but it's not huge. 50 to 100fps. I would take the plus p throat over the wby throat anyday. I like wby cartridges but don't care for all that freebore. Accuracy trump's speed to me. I will give up 100fps to have my rifle shoot . 25 moa.
Shep

 

[undecided]

Thank you I'm just trying to figure out what I need to do to get it to shoot where I want it to and I am not real Familiar with why a weatherby needs or takes at this point.

 

[25WSM]

Part of why wbys are faster is the really long freebore lowers pressure so you can increase the powder charge. Does it need that really long freebore? Not really but factory ammo might be a bit stiff without it will a wby shoot more accurate with out the long freebore? I say yes. I think your reamer with the plus p will shoot good.
Shep

 

[Skinem]

I'm a huge fan! 300 weatherby man. I've had a really good run killing darn near everything with it. It gave up at 1342 rounds. I'll factory rem 700 400. Bedded a brown precision thumbhole and had really served me well.

 

[Mike D Texas]

The bore rider throat is sometimes called a +p. I'm a big fan of 257wbys and have 2 different reamers for it. One has the original wby freebore and one is custom. The custom one is not a plus p just a regular 1°30 at . 200 long. The speed difference is not even measurable. Would totally depend on if a particular barrel was faster that another. I see some gains in my plus p chambers but it's not huge. 50 to 100fps. I would take the plus p throat over the wby throat anyday. I like wby cartridges but don't care for all that freebore. Accuracy trump's speed to me. I will give up 100fps to have my rifle shoot . 25 moa.
Shep

I'm told I have a unicorn. My 257 Wby shoots 115 Bergers at 3600fps with no signs other than a slight ejector mark.
Also shoots in the .2s most days. To my knowledge this is with a traditional Weatherby chamber.
That being said I'm also running well above any published data I've been able to find to achieve the velocity.

To the OP, these are the published freebies lengths I have been able to find on Weatherby cartridges.