I'll try that load some time. Mine is 9'twist Brux bbl
is the 7wsm dead?
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Engineering101
Well-Known Member
Iron Worker,
The latest Hornady handbook, #9, lists the max load for the 139 grain SST and RL-19 in the 7mm WSM at 71.0 grains which produces 3,300 fps out of their 24 inch Model 70. You have two more inches of barrel which will add some velocity. If you take that into account along with the possiblity of a faster burn rate on your powder and the effect of your custom Brux barrel, I can see how you could get the velocities you mentioned. Of course the comments made about chronographs not reading correctly are also valid.
To give you another data point regarding Brux barrels, I have a 7mm WSM in a 28 inch Brux with a 1 in 9 twist. I had it custom throated for the Barnes 168 grain LRX. That bullet is actually longer than the 180 grain Berger so the COAL is 3.165". This gives me 10 more grains of powder capacity than if I left it per SAAMI. I'm getting 3,157 fps with that bullet using 76.6 grains of Magnum. The muzzle engergy of that load is 3,718 ft lbs. Pressure is probably around 63,000 psi so that is about all I can get out of it. That isn't very far behind a stock 7mm RUM which shows what you can do with a good barrel and a bit of custom gunsmithing.
The latest Hornady handbook, #9, lists the max load for the 139 grain SST and RL-19 in the 7mm WSM at 71.0 grains which produces 3,300 fps out of their 24 inch Model 70. You have two more inches of barrel which will add some velocity. If you take that into account along with the possiblity of a faster burn rate on your powder and the effect of your custom Brux barrel, I can see how you could get the velocities you mentioned. Of course the comments made about chronographs not reading correctly are also valid.
To give you another data point regarding Brux barrels, I have a 7mm WSM in a 28 inch Brux with a 1 in 9 twist. I had it custom throated for the Barnes 168 grain LRX. That bullet is actually longer than the 180 grain Berger so the COAL is 3.165". This gives me 10 more grains of powder capacity than if I left it per SAAMI. I'm getting 3,157 fps with that bullet using 76.6 grains of Magnum. The muzzle engergy of that load is 3,718 ft lbs. Pressure is probably around 63,000 psi so that is about all I can get out of it. That isn't very far behind a stock 7mm RUM which shows what you can do with a good barrel and a bit of custom gunsmithing.
Very interesting ! I also shoot a 162 gr Hornady A-Max behind 65.5 grs of Re#22 and that produces 3160 FPS . I love these 7 wsm and Brux bbls . Mine has a standard SAMI throat .
Engineering101
Well-Known Member
Iron Worker
I too shoot the 162 grain AMAX as my practice load as the Barnes LRXs are bit on the pricey side. I load it down to 2,948 fps to hit an accuracy node.
By the way, though I said I can see how you could get the velocity you mentioned on your 139 grain SST load, it is running around 65 fps FASTER than a 7mm RUM will do with equal barrel lengths using its best powder. Since there are no free lunches I'd be a bit concerned that your pressures are higher than you might like. I'd probably back it down until you get really good accuracy and use it there.
Another thought on your chrograph. Do you use a laser boresighter to align it? I hang see through plastic in mine that I've marked with a grid in both the front and back screens. Just put the boresight laser in the rifle bore when the rifle is pointed at your target, make the laser dot hit the pastic in the same spot on the grid for both screens and you get perfect alignment which leads to repeatable chrono readings.
I too shoot the 162 grain AMAX as my practice load as the Barnes LRXs are bit on the pricey side. I load it down to 2,948 fps to hit an accuracy node.
By the way, though I said I can see how you could get the velocity you mentioned on your 139 grain SST load, it is running around 65 fps FASTER than a 7mm RUM will do with equal barrel lengths using its best powder. Since there are no free lunches I'd be a bit concerned that your pressures are higher than you might like. I'd probably back it down until you get really good accuracy and use it there.
Another thought on your chrograph. Do you use a laser boresighter to align it? I hang see through plastic in mine that I've marked with a grid in both the front and back screens. Just put the boresight laser in the rifle bore when the rifle is pointed at your target, make the laser dot hit the pastic in the same spot on the grid for both screens and you get perfect alignment which leads to repeatable chrono readings.
I'll check that out .
Engineering101
Well-Known Member
I got caught up in the high performance Brux discussion but did want to get the point of this thread. I too noticed the lack of support in the marketplace for the 7mm WSM while the others in the family seem to be doing well. I see 300 WSM and 270 WSM brass and ammo literally everywhere but not a piece for the 7mm WSM.
Since I was going custom, I didn't really suffer from the lack of choices however I did wonder what was going on because I couldn't see any technical reasons why it should be so.
The other day I was talking to the owner of Stockade Stocks. I mentioned that I was looking to buy a stock for my 7mm WSM. In the ensuing discussion he mentioned that there were some legal and/or patent issues behind the less than stellar market support for that cartridge. I've been trying to find out to what he was referring ever since and found only one vague mention of this on the Internet but that is it.
Does anyone know of legal or patent issues regards the 7mm WSM?
Since I was going custom, I didn't really suffer from the lack of choices however I did wonder what was going on because I couldn't see any technical reasons why it should be so.
The other day I was talking to the owner of Stockade Stocks. I mentioned that I was looking to buy a stock for my 7mm WSM. In the ensuing discussion he mentioned that there were some legal and/or patent issues behind the less than stellar market support for that cartridge. I've been trying to find out to what he was referring ever since and found only one vague mention of this on the Internet but that is it.
Does anyone know of legal or patent issues regards the 7mm WSM?
I heard it was from some kind of Lawsuit from a gun writer in shooting times magazine. Some people called him a traitor ! Can't remember his name.
4bycamper
Well-Known Member
He is Rick Jameson.
Some years ago I was reading his reloading column in Shooting Times mag. He was at that time writing about cartridges (made from cut-down 404 Jeffries brass I think). This must have been around 2000.
Later in 2002 or 2003 both Winchester and Remmy came out with their own "short mags" and Jameson sued and won. As a result of the judgement, Winchester closed its' doors and both win and Remmy were eventually sold to other company s with deeper pockets.
The shooting community judged Jameson as greedy so he lost his ST writing column and also his brass company.
And this is the short version!
I think the point that the court missed is that rifle makers have been chambering each others' cartridges for 100 years. .308 Rem vs .243 Win. And the list continues...
Engineering101
Well-Known Member
Thanks for the info on Jamison. Searching on his name I was able to find a bunch of stuff out on the Internet including the blow by blow from the patent infringement trial.
However I did not find any legal distinction between any of the WSMs that would explain why the 7mm WSM is the poor stepchild. From what I can see any royalties paid would apply to them all. Thus the mystery remains.
Nevertheless, I'm glad somebody invented it as it seems to be a fine cartridge - especially when you set it up where big bullets don't steal case capacity. Also, I like that it headspaces on the shoulder and I can stick the barrel on a short action or long depending on what I'm doing with it.
However I did not find any legal distinction between any of the WSMs that would explain why the 7mm WSM is the poor stepchild. From what I can see any royalties paid would apply to them all. Thus the mystery remains.
Nevertheless, I'm glad somebody invented it as it seems to be a fine cartridge - especially when you set it up where big bullets don't steal case capacity. Also, I like that it headspaces on the shoulder and I can stick the barrel on a short action or long depending on what I'm doing with it.
