Anyone own a 7mm 300 Win Mag?

[MudRunner2005]

No doubt the Remington wins the bang for the buck contest. Not that it means much, but in my usual haunting of gunshops I compared cost & velocity of the cheapest factory ammo I could spot from both locally.
1. Factory fresh Federal 7 RM 150 gr SP. 21.99$ @ Wally world. 3110fps.
2. Been sitting on the shelf so long the box's are falling apart Norma 7 WB 154 gr SP. 51.99$ @ a small obscure gun shop. 3258 fps.

Any thoughts on the Weatherby double radius shoulder? It definatley gets the job done with a minimum expenditure of length as in a steep shoulder. My thoughts are the smooth curves might possibly feed better than a steep conventional shoulder?

Not a fan of the Venturi shoulder. I prefer a 40º rectangular shoulder. There is zero advantage over a rectangular shoulder. A steep conventional shoulder has given me zero feeding issues, so I would say they are equal in feeding based on my experiences with both of them.

 

[M9Powell]

Or just putting more Powder to it. From what I am seeing 89 grains retumbo is nowhere near it's max potential. Other cartridges matching performance per say are maxed out which leads to throat erosion poor barrel life etc. I am gonna work up my retumbo loads just to see what it can actually do and see what happens to accuracy. I also have some rl33 I may try for ***** and giggles. I am already exceeding a hot 7mag load by close to 100fps with 90 grains retumbo. Ya it is using quite a bit more Powder but shoots real good.

My Hornady 9th edition doesn't list anything heavier than 175s nor any loads with Retumbo for the RUM, it does show the 7 mm Weatherby matching it with 18 grs less powder. Both 26" barrels, both book max, both 175 Hornady.

7 mm WBY 70.1 grs H4831 = 3100 fps. Several other powders also give 3100 fps.
7 mm RUM 88.6 grs RL25 = 3100fps. All the other listed powders max out @ 3000 fps.


Have you tried the Berger 195s in it? I know you supposedly need a 1 in 8" twist, but I think it'd be worth a shot. You might get them fast enough to stabilise in a 9" twist.

 

[Lrt307]

Ya there is very little Data available worth a darn on the 7rum. One must load up carefully and find where she works best. I actually did try the 195's and was bummed out. It wouldn't stabilize em. I tried mostly retumbo and rl33. Speeds were 3000-3020 loaded up on a factory tube. I am currently building a 7rum with 30" tube and 1:8 twist to shoot the 195. This according to Bob Beck is flat nasty. Berger claims above 3000fps an average bc of .814.

 

[M9Powell]

Ya there is very little Data available worth a darn on the 7rum. One must load up carefully and find where she works best. I actually did try the 195's and was bummed out. It wouldn't stabilize em. I tried mostly retumbo and rl33. Speeds were 3000-3020 loaded up on a factory tube. I am currently building a 7rum with 30" tube and 1:8 twist to shoot the 195. This according to Bob Beck is flat nasty. Berger claims above 3000fps an average bc of .814.

Yea, I suspect with the heavier bullet & longer tube the RUM might start kicking some butt.

 

[M9Powell]

Not a fan of the Venturi shoulder. I prefer a 40º rectangular shoulder. There is zero advantage over a rectangular shoulder.

Any particular reason, other than cost & don't like Weatherby? You have better luck than me @ getting 40 degree shoulders too feed. I don't like the cost either. But I can form them from cheaper brass.

 

[Lrt307]

Yea, I suspect with the heavier bullet & longer tube the RUM might start kicking some butt.

I guess I shouldn't over react. I am going to be building the Custom 7rum soon. Currently is bad wording. I have 2@ the smith right now and the next 2 will be 7rum and 6.5saum.

 

[M9Powell]

I also suspect the RUM would be ideal for forward ignition experiments. You lose some of the internal volume due too the ignition tube. The RUM can spare losing 4 or 5 grs of volume. Some 20 mm loads use this. Elmer Keith used to do it with duplex powder loads in the 338-378. Supposedly gives a slight velocity improvement, better barrel life, reduced ES through getting more complete combustion in the case.

 

[MudRunner2005]

Any particular reason, other than cost & don't like Weatherby? You have better luck than me @ getting 40 degree shoulders too feed. I don't like the cost either. But I can form them from cheaper brass.

I don't dislike Weatherby cartridges, just their rifles. However, I do dislike the fact that they charge double compared to other standard SAAMI cartridges that do the same thing, just because they think there's still something "special" about them. I just think the modern premise for his cartridge designs are outdated. Back when Roy designed and developed his cartridges, powders and bullets were VERY limited, unlike today where we have hundreds of options. Back then, the only way to get more velocity was to stuff a lot more powder behind the bullet (two examples: compare .25-06 AI to .257 Wby, and .280 AI to 7mm RemMag). Now days we know this practice can be extremely minimized thanks to modern advancements in powders and brass alloys. His shoulder design is also antiquated. While it has been proven the sharper shoulders have their merit, the rounded part of the shoulder equation has no real basis for any advantage other than purely aesthetics.

That's why.

 

[Lrt307]

I also suspect the RUM would be ideal for forward ignition experiments. You lose some of the internal volume due too the ignition tube. The RUM can spare losing 4 or 5 grs of volume. Some 20 mm loads use this. Elmer Keith used to do it with duplex powder loads in the 338-378. Supposedly gives a slight velocity improvement, better barrel life, reduced ES through getting more complete combustion in the case.

The crazy thing with the 89 grain load is single digit es. It's not Super fast but if somebody wants to shoot a Berger 180 @ 3125 with great accuracy and single digit as it's worth a try. Also appears to be way nice on brass.

 

[M9Powell]

I don't dislike Weatherby cartridges, just their rifles. However, I do dislike the fact that they charge double compared to other standard SAAMI cartridges that do the same thing, just because they think there's still something "special" about them. I just think the modern premise for his cartridge designs are outdated. Back when Roy designed and developed his cartridges, powders and bullets were VERY limited, unlike today where we have hundreds of options. Back then, the only way to get more velocity was to stuff a lot more powder behind the bullet (two examples: compare .25-06 AI to .257 Wby, and .280 AI to 7mm RemMag). Now days we know this practice can be extremely minimized thanks to modern advancements in powders and brass alloys. His shoulder design is also antiquated. While it has been proven the sharper shoulders have their merit, the rounded part of the shoulder equation has no real basis for any advantage other than purely aesthetics.

That's why.

A sharp 40 degree shoulder limits brass flow & cartridge elongation, it wastes very little of a cartridges longitudinal length. These r things mostly used by benchrest shooters. I don't think anyone is going to claim they help reliable feed which is irrelevant to a benchrest shooter. Almost all true development of brass cases occurred within a few years of developing smokeless powder. I see all this talk of modern & antiquated as silly. Anything you want to try has already been done years ago. Weatherby didn't devolop anything revolutionary, all he did was basically shorten the Holland & Holland magnums to fit in 30-06 length actions. I haven't seen any great modernisation of brass cases or powders in my lifetime. I'm 58. As far as powder for magnum cartridges go when I was a kid we used surplus 50 & 20 mm powders which were sold commercially as H870. I don't see anything much better today. I'm no Weatherby supporter, but if I can use something, I'm not going too turn it down because it says Weatherby, Remington or whatever on it. The Swiss 7.5X55 came out in the 1890s, in the 1950s the U.S. Army wasted untold millions of $$$ developing the 308 starting with the 300 Savage, which is basically a inferior 7.5X55. They'd have been better off to have just adopted the Swiss ctg. Pull the bullet on one & you'll see where the idea for "modern" VLDs comes from.

 

[M9Powell]

The crazy thing with the 89 grain load is single digit es. It's not Super fast but if somebody wants to shoot a Berger 180 @ 3125 with great accuracy and single digit as it's worth a try. Also appears to be way nice on brass.

Sounds like a good load.

 

[MudRunner2005]

A sharp 40 degree shoulder limits brass flow & cartridge elongation, it wastes very little of a cartridges longitudinal length. These r things mostly used by benchrest shooters. I don't think anyone is going to claim they help reliable feed which is irrelevant to a benchrest shooter. Almost all true development of brass cases occurred within a few years of developing smokeless powder. I see all this talk of modern & antiquated as silly. Anything you want to try has already been done years ago. Weatherby didn't devolop anything revolutionary, all he did was basically shorten the Holland & Holland magnums to fit in 30-06 length actions. I haven't seen any great modernisation of brass cases or powders in my lifetime. I'm 58. As far as powder for magnum cartridges go when I was a kid we used surplus 50 & 20 mm powders which were sold commercially as H870. I don't see anything much better today. I'm no Weatherby supporter, but if I can use something, I'm not going too turn it down because it says Weatherby, Remington or whatever on it. The Swiss 7.5X55 came out in the 1890s, in the 1950s the U.S. Army wasted untold millions of $$$ developing the 308 starting with the 300 Savage, which is basically a inferior 7.5X55. They'd have been better off to have just adopted the Swiss ctg. Pull the bullet on one & you'll see where the idea for "modern" VLDs comes from.

I get it, and I love a good debate, but this is a stalemate. We might as well agree to disagree and part as friends.

I will say one thing, not everything has already been done. I've drawn-up hundreds of wildcats (only kept about 100 or so, since most of them were too similar to current wildcats), some of which you would't even imagine based on the parent cartridges. I guess I'm a bit of a "mad scientist" when it comes to ammo and cartridge design, but yes, their radius shoulder is purely for looks and holds no actual advantage over a rectangular shoulder design.

 

[dwm]

"their radius shoulder is purely for looks and holds no actual advantage over a rectangular shoulder design"

Consider reading up on radius shoulders vs sharp square shoulders in a fluid dynamics book, that design is not for looks...

Also, who cares if commercially loaded ammo cost twice as much, we all reload our own anyway....

smile please...

 

[MudRunner2005]

"their radius shoulder is purely for looks and holds no actual advantage over a rectangular shoulder design"

Consider reading up on radius shoulders vs sharp square shoulders in a fluid dynamics book, that design is not for looks...

Also, who cares if commercially loaded ammo cost twice as much, we all reload our own anyway....

smile please...

Fluid dynamics and hydrodynamics are not the same as burn and pressure dynamics.

Smile please...