Question about my 7mm

hbhobby · January 15, 2013, 08:45 AM

I have recently started reloading again for my 7 mm rem mag and i was looking at my reloading manual and noticed that the difference in carteridge size of 7mm rem mag and 7mm weth mag are almost exactly the same except for neck shape and neck length. My question is why are the powder loads so much different if the case is the same size and projectile is same size? The reason i even noticed is that my book had a powder i have listed for use in 7mm weth mag but not for 7mm rem mag. I am going to go get a new manual so the problem will be resolved but i still was wondering why such different loads when everything was so simular: case size, projectile, speeds and pressures?

Nathan · January 15, 2013, 09:19 AM

I think max press is different as well as throat dimensions.

7mm Rem Mag has greater accuracy potential...it is not all about velocity!

7mm WSM would be an even more ideal cartridge, but mag capacity suffers.

hooligan1 · January 15, 2013, 05:13 PM

You need to understand that bullet options, are what makes manuals useful,, in other words pick a bullet, then buy the manual that features said bullet, then work your loads up from there.
Usually bullet manufactures test and print load data, that you can try to duplicate,(if you so desire) or just try to get more accurate hunting or target shooting loads.
I have a 7mm Remington Magnum, and when the stars all align I want to go west and hunt elk, and other bigger critters, so I picked a bullet that would be perfect for elk, and etc., the 160 Accubond, well its a Nosler product and so I purchased the #6 manual that features this bullet.
And the various powders that they listed will be kinda daunting, I found with that bullet IMR 7828 works best in my rifle, recoil isn't harsh, and its very consistant usually less than 3/4 inch at 100 yds. (5 shot group). I tried IMR 4350, H1000, IMR 4831, H4831 sc (hard bolt lift with minimum load),H4350.
That's actually half the fun, going to the range and testing loads.

reynolds357 · January 15, 2013, 07:12 PM

Even though it should not be, IMR4350 is the most accurate and within 50 fps of the slower burning powders.

GeauxTide · January 15, 2013, 08:23 PM

The Weatherby line has a 3/4" freebore and long case necks. As mentioned, their SAAMI max is higher.

reynolds357 · January 15, 2013, 09:00 PM

Load Rem mag with WBY data and at the very least you will have a separation at the belt.

January 15, 2013, 08:45 AM	#1
hbhobby Senior Member Join Date: January 14, 2013 Location: Payson Az Posts: 169	Question about my 7mm I have recently started reloading again for my 7 mm rem mag and i was looking at my reloading manual and noticed that the difference in carteridge size of 7mm rem mag and 7mm weth mag are almost exactly the same except for neck shape and neck length. My question is why are the powder loads so much different if the case is the same size and projectile is same size? The reason i even noticed is that my book had a powder i have listed for use in 7mm weth mag but not for 7mm rem mag. I am going to go get a new manual so the problem will be resolved but i still was wondering why such different loads when everything was so simular: case size, projectile, speeds and pressures?

January 15, 2013, 05:13 PM	#3
hooligan1 Senior Member Join Date: July 18, 2010 Location: Independence Missouri Posts: 4,585	You need to understand that bullet options, are what makes manuals useful,, in other words pick a bullet, then buy the manual that features said bullet, then work your loads up from there. Usually bullet manufactures test and print load data, that you can try to duplicate,(if you so desire) or just try to get more accurate hunting or target shooting loads. I have a 7mm Remington Magnum, and when the stars all align I want to go west and hunt elk, and other bigger critters, so I picked a bullet that would be perfect for elk, and etc., the 160 Accubond, well its a Nosler product and so I purchased the #6 manual that features this bullet. And the various powders that they listed will be kinda daunting, I found with that bullet IMR 7828 works best in my rifle, recoil isn't harsh, and its very consistant usually less than 3/4 inch at 100 yds. (5 shot group). I tried IMR 4350, H1000, IMR 4831, H4831 sc (hard bolt lift with minimum load),H4350. That's actually half the fun, going to the range and testing loads. __________________ Keep your Axe sharp and your powder dry.

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January 15, 2013, 09:19 AM	#2
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,323	I think max press is different as well as throat dimensions. 7mm Rem Mag has greater accuracy potential...it is not all about velocity! 7mm WSM would be an even more ideal cartridge, but mag capacity suffers.

January 15, 2013, 07:12 PM	#4
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,164	Even though it should not be, IMR4350 is the most accurate and within 50 fps of the slower burning powders.

January 15, 2013, 08:23 PM	#5
GeauxTide Senior Member Join Date: April 20, 2009 Location: Helena, AL Posts: 4,423	The Weatherby line has a 3/4" freebore and long case necks. As mentioned, their SAAMI max is higher.

January 15, 2013, 09:00 PM	#6
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,164	Load Rem mag with WBY data and at the very least you will have a separation at the belt.