7mm Rem. Mag. vs. 7mm Weatherby

[ForneyRider]

I was looking on a 7mm Weatherby vs. 7mm Rem Mag comparison and came across this post. I looked up the cartridges in Lee reloading book and they show to have about the same internal capacity, ~5.24cc.

The load book up to 200fps difference and 5-9gr difference in similar powder/bullet combinations.

 

[WYcoyote]

I have hunted with my 7 RM side by side with a friend that packs a 7 WM for 35+ years. We both handload with chronographs and trade notes. I give his the edge but only by the previously mentioned 100 fps or even less. They are very close to being ballistic twins, for all practical purposes.

 

[mrbigtexan]

I realize that i'm digging up an old thread but was wondering why weatherby went with a 1-10'' twist? Was it to gain velocity while slightly reducing pressure? Has anyone had a 7mm Rem mag with a 10 twist barrel? I notice that some 280's also go with a 10'' twist while I havent ever heard of the rem mag with a 10 twist.

 

[ForneyRider]

1:9.5 vs 1:10 is not much of a difference for common 7mm loads. 7mm-08 uses 1:10. Slightly more velocity overcomes slightly less twist.
My Shilen replacement barrel for 7mm Rem Mag is 1:9.

 

[Trickymissfit]

I just looked thru two loading manuals out of curiosity. Two show a 7mm mag max loads with 160 grain bullets at a very slight tick under 3100fps (around 3080fps). Then I look at the 7mm WBY mag at just slightly over 3200fps. Pressure wise Hogdon shows their chamber pressure CUP's and Accurate shows their in pounds per square inch (they do not relate to each other numerically). Now Hornaday shows that 200fps difference, but Hogdon doesn't. Now looking at the STW specs, I see close to a 100fps advantage, but also using well over ten grains more powder. Kind of tells me that the WBY is pretty much the max powder capacity in the .284 bore, and that's mostly with heavier bullets. In 150 grain and lighter bullets, the Remington is about perfect. The 7mm STW is overbore, but still nothing like some of the others are. One uses over 15 grains more powder (over the STW) to gain about 150fps over the Remington and Weatherby (at best). I think I'd be looking at the 175 grain bullets to gain the most out of the STW, WBY, and Remington mag.
gary

 

[Jumpalot]

Since I started this thread, I figured I'd give an update. I ended up with the 7mm RM. Load the 168 Bergers to 3030 fps. Killed a few antelope and mule deer and a whitetail with it. Farthest kill was 917 yds. It has served it's purpose perfectly as a light pack rifle with some reach. Can't complain at all. But, since Berger came out with the 215 gr. bullet, I find myself grabbing my 300 Win. Mag more often. I personally wouldn't go with less then a 1 in 9" barrel on a magnum because I wouldn't plan on shooting anything lighter then a 168 Berger. Now, I'm trying to decide if I want to rebarrel to something else.

 

[MudRunner2005]

I just looked thru two loading manuals out of curiosity. Two show a 7mm mag max loads with 160 grain bullets at a very slight tick under 3100fps (around 3080fps). Then I look at the 7mm WBY mag at just slightly over 3200fps. Pressure wise Hogdon shows their chamber pressure CUP's and Accurate shows their in pounds per square inch (they do not relate to each other numerically). Now Hornaday shows that 200fps difference, but Hogdon doesn't. Now looking at the STW specs, I see close to a 100fps advantage, but also using well over ten grains more powder. Kind of tells me that the WBY is pretty much the max powder capacity in the .284 bore, and that's mostly with heavier bullets. In 150 grain and lighter bullets, the Remington is about perfect. The 7mm STW is overbore, but still nothing like some of the others are. One uses over 15 grains more powder (over the STW) to gain about 150fps over the Remington and Weatherby (at best). I think I'd be looking at the 175 grain bullets to gain the most out of the STW, WBY, and Remington mag.
gary

The STW shines with the 180 Bergers and VERY slow burning powders. The STW about tops out the 7mm calibers as far as not quite crossng the threshold of diminishing returns. The 7RUM is definitely over the threshold and to me, is useless when you have an STW. I'll make up for the missing 100 fps and hold about twice the barrel life with the STW, compared to the RUM.

 

[Trickymissfit]

The STW shines with the 180 Bergers and VERY slow burning powders. The STW about tops out the 7mm calibers as far as not quite crossng the threshold of diminishing returns. The 7RUM is definitely over the threshold and to me, is useless when you have an STW. I'll make up for the missing 100 fps and hold about twice the barrel life with the STW, compared to the RUM.

just looking in manual I see about 3000fps with a 175 grain bullet in the 7mm Rem mag. I see 3100fps with the same bullet in the Weatherby. I see 3100fps in the Hodgdon manual (H1000 & 5010) while the Hornaday manual shows 3000fps, but also using about 10% more powder. Kind of tells us that the Weatherby is about all the case volume that the .284 bore can handle. Compare this with the 7mm WSM and we see the velocity down about 100fps (maybe 130fps), but using 10% less powder than the WBY mag (compared to the STW velocities). To add further insult, compare the 7mmx57AI to the mags, and we see another story. 2700fps with the same bullet using less than 53 grains of powder. Or even more with the .280AI, and still less than 60 grains of powder.
gary

 

[MudRunner2005]

just looking in manual I see about 3000fps with a 175 grain bullet in the 7mm Rem mag. I see 3100fps with the same bullet in the Weatherby. I see 3100fps in the Hodgdon manual (H1000 & 5010) while the Hornaday manual shows 3000fps, but also using about 10% more powder. Kind of tells us that the Weatherby is about all the case volume that the .284 bore can handle. Compare this with the 7mm WSM and we see the velocity down about 100fps (maybe 130fps), but using 10% less powder than the WBY mag (compared to the STW velocities). To add further insult, compare the 7mmx57AI to the mags, and we see another story. 2700fps with the same bullet using less than 53 grains of powder. Or even more with the .280AI, and still less than 60 grains of powder.
gary

Do you just hate the STW for some reason? I mean, you're always griping and moaning about about how the STW is junk and overrated, and way overbore, etc...

I love my 7mm RMs....Have 3 of them. I'd like to have a 7mm Wby. But the STW is more than respectable in it's own right.