I reload my .300 WBY ammo with IMR 4350 and IMR 4831
In the past I have purchased Weatherby brand factory ammo and just wonder if anyone knows which powder brand they use?
Their ammo is good, but at $3.00 to $3.50 a round, no thank you.

Just curious.

Mauser K98

Norma at one time manufactured Wthby`s ammo and I think still does some of it. I`d take a SWAG and say they used their own powder to do it, but can`t swear to it

I had heard that IMR7828 was designed for Weatherby ammo. I use it in some of mine but always had better accuracy with RL22 or 25.

Questions like this come up all the time. Even if you knew the powder that is used in factory ammo, it would do you no good. Handloaders are sold powders lots which meet very tight performance criteria, while factories use bulk powder lots which do not meet the same performance criteria. The factories will vary the charge to get the velocity they need, but it will most likely be different than what you'd need to match that velocity - even with a powder of the same "name".


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I would bet it was Vihtavuori

Others will have their favorites I'm sure but I have to agree with 'Ol Joe & TX above plus Ted.

Factory will use a proprietary mix that meets their criteria for pressure & accuracy.

Ted's probably not too far off with the VV powder either; simply from source.

With lots of chrony time the best powders for my 300 Weatherby Magnum with 165 & 180 bullets has been VV-N-165 & H4831SC.

Your barrel may have it's own favorite, too.

You can be sure that since Norma loads the ammunition for Weatherby that they use their own powders.

It may not be a canister powder that you and I can buy, but it is a Norma supplied powder, I would have to bet.

IMR 7828 was not originaly developed for any of the Weatherby calibers, it was originaly used in factory 7mm Rem Mag loads. (Long before it became available to the shooting public.)

quote:

Originally posted by TX Nimrod:
Questions like this come up all the time. Even if you knew the powder that is used in factory ammo, it would do you no good. Handloaders are sold powders lots which meet very tight performance criteria, while factories use bulk powder lots which do not meet the same performance criteria. The factories will vary the charge to get the velocity they need, but it will most likely be different than what you'd need to match that velocity - even with a powder of the same "name".


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Well said. Regardless of what powder may be used by the factory, your "mileage" will likely differ.

BTW, if Norma still manufactures the proprietary Weatherby ammunition (which they have done for decades), then it is highly unlikely that the powder is other than Norma. Norma powders, while excellent, have always had a reputation for greater-than-average lot to lot variations. I'm not sure why some are guessing Vhitavouri, since that powder is from Finland, not Sweden where Norma is located, but maybe they know something I don't.

Norma MRP. Have never had a problem with equal barrel length matching factory fps with it using data published by Norma in the 300..

quote:

Originally posted by j stoviak:
Norma MRP. Have never had a problem with equal barrel length matching factory fps with it using data published by Norma in the 300..

roger that

I would tend to agree with the learned posters guessing at Norma powders.

What one should remember, though, is that Norma does not actually manufacture their own powder, they brand powder manufactured by Bofors.

- mike

Bofors/Norma

Tighter tolerances than the R/L product

MRP and MRP2

Closest R/L products = R/L 22 and R/L 25

Lawndart: It's been along time since I used Norma-branded powder, but its lot-to-lot variation tended to be just as great as the same powders in the RL line. I always advise anyone who is considering using either of the excellent Norma or Reloader powders to buy as much of one lot as they project they will need for the forseeable future for a given load since changing lots of either powder may very likely require adjusting the load for the new lot.