Ideas Please: Loading for a pair of .300 Wby's(?)

[pertnear]

I have a good friend & his wife that are avid hunters. They can afford it & go on several big game hunts a year. They both shoot .300 Wby Mag in Weatherby mark V rifles. They shoot factory Wby ammo in 165 gr & 180 gr preferring Barnes TSX bullets. Now they are feeling very uncomfortable because they can't find ammo. So they have turned to me because I'm a handloader.

Now I have been reloading for a lifetime, but nothing bigger than a .264 WM. I'm pretty old fashion & my load development has always been "trial & error" working up an accurate load. I'm just now learning about OCW & ladders etc. So what they need is for someone (me-yikes?) to find loads that duplicate the factory ammo & works well in both of their rifles. The idea of shooting a lot of .300 Wby from the bench scares hell out of me! The slowest powder I've ever used is 4831 usually by the pound. Looks like a .300 would suck up a 1 lb pronto! Are there any data on what's in Wby factory ammo?

Any thoughts/ideas would be most appreciated....

 

[David Milisock]

Belted magnums have had no issues for me. Sizing for 2 rifles follows a similar process as below. Size for each rifle separately or size for the tightest chamber and use the sized cases for both rifles.

There (IMO) are two approaches in situations like this I prefer the latter. Following manufacturer loading data you can work near or maximum loads for each rifle in high temperature environments then they would need to keep the cartridges separate for each rifle.

I prefer to load a 85% to 90% load for the rifle the exhibits pressure signs first. Then the cartridges will be safe for both rifles.

The latter in my opinion would simulate factory ammunition which they are used to.

 

[Jager]

If it were casual, low-pressure plinking stuff it'd be one thing. But your friends sound like very serious people, who put a lot of time, effort, and money into their hunting pursuits (God bless 'em... we need more hunters like that).

If it were me I'd tell your friends that you're happy to help them develop a load for their rifles. And that you're happy to either help them get set up with their own handloading setup, or they can use yours. But that you don't really feel comfortable "replicating a factory load" for them.

Handloading is a beautiful part of shooting. Some of us enjoy it as much as pulling the trigger. But there are sixteen million ways it can go sideways. Because it has all those risks and elements attached to it, it's not something to do lightly, for others.

The good news is it sounds like your pals have the wherewithal to be very successful at loading their own ammo, if they choose to do so.

 

[yotehater]

Reloder 22 is in their factory rounds. Easy to duplicate.

 

[mike mccormick]

Weatherby factory ammo is loaded by Norma and uses Norma brass with Weatherby headstamp. The factory ammo is run at maximum loading. I would keep resizing to a minimum, and definitely anneal the necks, as they get splits fairly regularly if you don't. My understanding has always been that the factory ammo was loaded with Norma powder(MRP?).Hybrid 100V works great for me, as does H4350 with light bullets. Also, check for signs of case head seperation each time you prep brsss.

 

[Gary in MD]

I’d start with RL 22 and IMR 7828
Federal large rifle magnum primer if you have them. The Weatherby magnums usually operate better at the upper side of listed powder charges in the manuals.
Gary

 

[10XSHOOTER]

H-1000 will also work in the Weatherby's

 

[M-61]

I wonder if they'll ask you to sight in the rifles?
Many years ago I did it for a friend's 378 Weatherby.
Actually the accuracy and punishment were quite surprising.
I did use a bag of shot between the butt and my shoulder

 

[1lessdog]

I shoot IMR-7828 WITH 165gr Hornady Interlocks, Elk, Moose and Deer. I shoot them high in the shoulders and they drop right there. For me none of the shoot them behind the shoulder. With that big gun it will stretch the off shoulder hide but not push thru. And they drop right there.

Interlocks are my go to bullet for big animals.

 

[Kurz]

This link is for factory .300 Weatherby loads including 180 TSX:

https://shootersreference.com/reloadingdata/300-weatherby-magnum/

 

[pertnear]

I wonder if they'll ask you to sight in the rifles?
Many years ago I did it for a friend's 378 Weatherby.
Actually the accuracy and punishment were quite surprising.
I did use a bag of shot between the butt and my shoulder

I actually mounted the scopes for them on both of their rifles. I bore sighted them the old fashion way by looking thru the barrel & adjusting the crosshairs to the same spot a 100+ yd away. Luckily that got them within inches of zero & it took only a few shots to get them tuned in (with them shooting)!

 

[Coyotefurharvester]

Hopefully you have a couple factory rounds to reference for coal(if using same bullet). Shoulders same as always bump when needed for proper bolt closing. A chronograph would be useable for duplicating velocity of factory. Pull a round apart and get a weight for the powder, find a similar charge/velocity and work up to it. Hard part is access to components. I just finished a similar project for my neighbors 7mm mag using left over factory Hornady 154 sst, groups were way better at 300 yards with handloads than the factory using the same bullet and velocities close to the factory ammo. Used H4831sc because that's what I had.

 

[Radar]

Reloader 22 and 200gr Accubond has shot very well in several 300Wby for me.

 

[riflewoman]

My Weatherby loads were developed for my Rechambered pre-64 Model 70 300 H&H.

I had very good luck with 4831 and Nosler 180 Partitions. But today, I’d go with Barnes TTSX bullets either 165-180 grain. Certainly RL 22 and 23 as well as good ol’ 4831. If I could get some, I’d also try Norma MRP because that’s what was in the factory ammo. That MAY be the same as RL22, I don’t really know. I do know that a lot of 4831 was burnt in the big Weatherby cases in years past.

 

[Gb300wm]

Weatherby’s love IMR7828

 

[Coyotefurharvester]

If shooting sitting at a bench, you can reduce recoil by hanging a weight off the front edge of the bench tied to the front sling swivel. When I use this method, I adjust the string so the weight is a couple inches off the ground, a weight about the same as the rifle weighs really helps. A stand up bench also helps with hard recoil guns, we use it for slug guns and muzzleloader.

 

[pertnear]

If shooting sitting at a bench, you can reduce recoil by hanging a weight off the front edge of the bench tied to the front sling swivel. When I use this method, I adjust the string so the weight is a couple inches off the ground, a weight about the same as the rifle weighs really helps. A stand up bench also helps with hard recoil guns, we use it for slug guns and muzzleloader.

Interesting - never thought about or seen the use of a counter-weight to offset recoil. Hmmm......what about a hard-rubber bungee maybe?