300 RUM back country rifle.

alinwa said:
Energy equals mass in grains times velocity squared divided by the constant 450400

Therefore the 270WSM with 130's @3250 has 3049 ftlb energy whereas the 140 @3150 has 3084

A 300gr bullet at 2000= 2664 ftlb

A 40gr bullet at 5000= 2220 ftlb
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Exactamundo.

alinwa said:
My point is that felt recoil is a factor when using a light rifle......... a huge factor, and since felt recoil is a factor of acceleration over time you can push a light bullet faster and maintain acceptable energy levels while reducing felt recoil.

Big bullets kick.

Hard.
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Which to you think will kick harder, a 270 WSM loaded to the nuts with a 130 grain bullet, or a 7mm 08 loaded with 140's?


alinwa said:
It's changed me from a "338 is minimal" guy to a "with these bullets you can use velocity to make your energy" guy.

al
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That's true to a point. But if you use too stout of a bullet for the intended quarry(and I believe the TTSX is too much for sheep), you can have it zip right through and expend most of it's energy on the hillside behind it. As I said before, sheep are not that tough, especially the desert and Dall variety, so a bullet that is more frangible has been better in my experiences.
 
Al, as long as you're playing with numbers -- and I think it one of the smartest things people can do -- which is harder in mountain-goat hunting, judging the distance, or judging the wind?

As a rule of thumb, if distance hard to figure, stay with a flat-shooting round, usually a lighter bullet moving fast. If wind is the bigger issue, a heavy bullet may have a more rainbow trajectory, but (if the BC's high) it won't move as much in the wind. We're not talking a couple inches here -- run the numbers. No, you can't have it both ways.

Why I shoot a .338 in competition. Distance is known.

BTW, if you're going to get rid of all your .338 stuff, you got any Type I Berger 300 Hybrids you want to sell at half price?

BTW2, while it's a PITA to carry, a high-mounted scope is a bit "flatter" shooting than a low-mounted scope.

For an over-the-top example: I have a 1K rifle in .300 Ackley where the scope is 6.75 inches above the bore. With a 400 yard zero, bullet's maximum rise is 5.7 inches high at 250 yards. With the only change being to lower the scope to 1.75 inches above the bore, it's 7.8 inches at 225 yards.

That's "two inches flatter shooting." Maybe for a varmint rifle you don't have to carry?

Everything's a Compromise.

--Dave Tooley
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Dave Tooley said:
Charles

Really??

Last time I check scope heigth had no affect on the laws of phyics.

Dave
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Nope. No influence at all. However, for the distances we care about, it can have a practical effect. Run the numbers on the JBM site

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

...or maybe I've made a mistake somewhere. But I doubt it (this time). Took Joel's old gun, put a new scope on it, ran the numbers on the JBM site, clicked to what it indicated, and was in the blue, first shot. Another one: dropped the speed 150 fps on the .338, ran the numbers, changed the sight, and again, was in the blue first shot.

Edit:

In other words, the trajectory is the same. but how you "tilt" that curve has an effect. The thing I left out earlier is you pay for the "flatter shooting" between 0 and 400 after 400 yards -- the "tilt" of the curve. Another compromise...
 
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Trajectory is the same but it shoots flatter. I don't think so but how the trajectory relates to the line of sight that's something else. Flatter has nothing to do with it.

Dave
 
Whatever the right word is. Here's the phenomena:

With the scope 1.75 inches above the bore, sight in at 400 yards. At 225 yards, you're 7.8 inches high. (187-grain bullet, B.C. 540, muzzle velocity 3200 fps.)

Change nothing but the height of the scope above the bore -- i.e., new, tall rings. Re-sight in at 400. Now, you're only 5.6 inches high at 250.

Don't know the correct term, and not to be too argumentative, but the effect is you've saved two inches in bullet rise between 15 and 400 yards. You pay for it a little bit after 400 yards.

So, what's the right ballistic term?
 
:):):)

The old "Point Blank Range Conundrum," I never expected to see it here LOL!!!

too funny.

Shucks.... you REALLY want your PBR maximized you set your scope 3.5" above the bore.....

Draw it on paper guys, it'll make more sense that way.

al
 
Charles E said:
Al, as long as you're playing with numbers -- and I think it one of the smartest things people can do -- which is harder in mountain-goat hunting, judging the distance, or judging the wind?

As a rule of thumb, if distance hard to figure, stay with a flat-shooting round, usually a lighter bullet moving fast. If wind is the bigger issue, a heavy bullet may have a more rainbow trajectory, but (if the BC's high) it won't move as much in the wind. We're not talking a couple inches here -- run the numbers. No, you can't have it both ways.

Why I shoot a .338 in competition. Distance is known.

BTW, if you're going to get rid of all your .338 stuff, you got any Type I Berger 300 Hybrids you want to sell at half price?
Click to expand...

OK, dude said 350yds, I took that as gospel. I'm saying that inside 350yds your choice of bullet is pretty much lost in the noise as far as ballistics goes. I can set up any of 50 hunting combinations that'll stay on a grapefruit at 350yds regardless what the wind or sun or rain or pestiferous aerial anteaters are doing. As long as the shooter holds over "just a little" like 6-8 inches, and doesn't go off the animal he'll easily stay in a kill zone inside 350. IF he's got his other mechanics right..... I myself can easily hit an apple 9 days out of 10 using 1 shot with rifles from 22cal up to 338....and I don't claim to be a shooter.

My goal is simply to maximize energy dump and bleedout on an animal that's quite likely hanging over a 300ft drop. SLAPP! that goat, spin it like a pancake and set it down. When you get there an hour later it's likely to still be there. BTW, about that 300ft......To all the rest of the world elevation is a concept, "what's the big deal over a hunnerd yards???" but to sheep/goat hunters it's as important as water.

Well almost. (actually flatlanders don't really know how important water is neither eh!)


And no Charles I ain't ever going to get away from 338's and I certainly ain't selling any generation of Bergers even though the BC on the new ones 70 points off the 1st ones LOL in fact I just picked up two long action mag bf guns because I'm running your 404 case against the 338 McCallum. I may just convert.....

al
 
Don't overlook the .260 Remington. It would be my choice in a lightweight rifle, pleasant to shoot and accurate.
 
They are magic, you will magically find yourself tracking stuff!!!
 
Back to the comments of the Barnes TSX and TTSX bullets.

I have had a few bullet failures. Just plain weird stuff. Never with a Barnes.

I have had a number of one shot kills on everything from antelope to buffalo using the Barnes TSX or TTSX.

Before using the Barnes I always used Partitions.

Comparing the two, the Barnes is a magic bullet from accuracy to terminal performance.

The secret to accuracy with the Barnes is seating depth .050 or more off just to start. My .243 requires 0.100 off for pin point accuracy.

Even though I am a big fan of the 7mm, if I were to shoot 130 - 140 grain class bullets the 260 would be a better choice over the 7-08.
 
I'm surprised that on a benchrest forum no one has endorsed the .308.

My .308 weighs about 7.5 pounds and with a 150 gr. Nosler partition is death to large bodied mule deer.
 
I'm surprised that on a benchrest forum no one has endorsed the .308.

My thoughts as well as it is the Miltary's choice for their 1000 meter Sniper rifles and one would think they are still using it for good reason.
J.Louis
 
Louis.J said:
I'm surprised that on a benchrest forum no one has endorsed the .308.

My thoughts as well as it is the Miltary's choice for their 1000 meter Sniper rifles and one would think they are still using it for good reason.
J.Louis
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If someone in the military (which branch, BTW?) is using it for 1,000 meter sniping, no, they don't have a good (performance) reason.
 
Nobody in the military is using 308 for 1000yd sniping. Urban SWAT teams still use it but long range guys start with the 300WM.

al
 
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