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John,
Lots of good thoughts here.
Thanks for taking the time.
Yes Indeed!! DakotaDeer,
There's even an approximate formula for the same case but different calibers: Divide the cross-sectional area of one cartridge's bullet by the area of the other cartridge's bullet, then divide the difference by 4.
Here it would be .0633 (7mm) divided by .0547 (6.5mm):
.0633 divided by .0547 = 1.157
.157 divided by 4 = .0392
Then subtract .0392 from 1, and multiply the result times the velocity of the larger-bored cartridge:
1-.0392 = .9608
.9608 x 3175 (velocity of 140 in 7mm SAUM) = 3050 fps
This would be the approximate potential velocity of a 140 in the 6.5mm SAUM at the same pressure as a 140 from a 7mm SAUM, at around 62,000-63,000 psi.
I've never messed with the 6.5 SAUM but I've enjoyed this thread immensely. The above formula (equation) is a prime example. Very interesting and beneficial. THANKS from me too!!
jwall- *** 3100 guy***
A Flat Trajectory is Never a Handicap
Speed is Trajectory's Friend !!
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![[Linked Image]](http://i423.photobucket.com/albums/pp311/patrickgsinclair/Xrifle001-1.jpg) I will continue to keeping shooting it, until the barrel pukes. One of the things I've found very interesting, is I haven't "chased lands" with this load, or any other load for that matter. I've used the same BTO for almost everything I've tried. Testament to an excellent and precise job of cutting the chamber, very good barrel, and good reamer. I have 250 140gr JLK's arriving soon that I'm excited to try next. Swampworks claims a .700 G1....we'll see.
Luck....is the residue of design... ![[Linked Image]](http://i423.photobucket.com/albums/pp311/patrickgsinclair/96zvyt.gif)
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Campfire 'Bwana
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Campfire 'Bwana
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Pat, just curious, has the distance to the lands increased? Not that it matters when it's shooting like that.
A wise man is frequently humbled.
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Pat, just curious, has the distance to the lands increased? Not that it matters when it's shooting like that. I haven't checked it, but I will. FWIW, I haven't cleaned the barrel in 233 shots.
Luck....is the residue of design...
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Campfire 'Bwana
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I wouldn't clean it either. Might get it bronzed though, LOL.
A wise man is frequently humbled.
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Campfire Outfitter
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Well, I guess if you can be satisfied with that large a group....  (Personally, I'd be ecstatic.)
"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing."
Robert E. Howard
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Pat, just curious, has the distance to the lands increased? Not that it matters when it's shooting like that. I haven't checked it, but I will. FWIW, I haven't cleaned the barrel in 233 shots. When the barrel was new it was 2.215", base to lands. The throat has grown .0040" to 2.255". I'm jumping those 139's .0070".
Luck....is the residue of design...
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Campfire 'Bwana
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A wise man is frequently humbled.
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Pat, where do you get your targets?
Thanks
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http://precisionplustargets.com/index.htmI've used them for years....for my eyes, blue really works.
Luck....is the residue of design...
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Lookin' good, Pat! Glad to see that rifle is still hammering!
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Pat
Great shooting like always. Just curious since you measured the lands are you gonna change your 139 load to chase the lands? I see no need but just curious.
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"Are you going to pull those pistols or whistle Dixie?"
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That's it. I'm buying one...
I enjoy handguns and I really like shotguns,...but I love rifles!
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That's it. I'm buying one... Toldyaso... grin
“There are some who can live without wild things and some who cannot.”
ALDO LEOPOLD
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Randy
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I never could figure out why the 7mm SAUM wasn't more popular, because it's basically a short .280 Ackley, and allows enough room in a .28" magazine box for really long bullets. It's also very accurate and kills stuff! John, My two favorite cartridges for medium to big game ever since you starting touting the 7SAUM have been the 7SAUM and 300SAUM. I think Remington did such a poor job of marketing the cartridges in comparison to the WSM's and other recent "magnum" offerings and the fact that they quit chambering most of their rifles for them before the public had a chance to really get used to them led to that lack of popularity. My 300SAUM and 7SAUM rifles are scary accurate and light and handy as a 308 carbine. By the way.... I use Varget exclusively in both of mine and the performance and velocity is so outstanding that I simply have never looked further. Long live the SAUM cartridges and I'm certainly glad I stocked up on brass when it was readily available and cheap... $bob$
Many who have freedom have no idea where they got it....
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