Leatherstocking
CGN Regular
- Location
- BC Rockies
Like
E=M(V squared) ?
E=M(V squared) ?
effeciency in a case like 7 mag
- Thread starter WhelanLad
- Start date
Yupp. E=mV^2 is how you'd type it out properly, double the velocity gives you 4x the energy.
1x2^2=4
1x4^2=16
If you look at just about any popular long range competition round, it's going to run one of the heaviest bullets in the caliber range and use about 1/3 of the bullet weight in powder....
From that you can pretty much extract where the efficiency lies between accuracy, muzzle velocity and barrel life.
Figure how much bullet weight you need and divide by 3 to determine powder capacity target
Or take the powder weight times 3 to determine the ideal bullet weight range for the powder charge.
From that you can pretty much extract where the efficiency lies between accuracy, muzzle velocity and barrel life.
Figure how much bullet weight you need and divide by 3 to determine powder capacity target
Or take the powder weight times 3 to determine the ideal bullet weight range for the powder charge.
Leatherstocking
CGN Regular
- Location
- BC Rockies
Looks like typical Barnes expansion. But not Barnes, missing the grooves. Not that I’ve ever recovered a Barnes bullet from an animated; they always make an exit hole. Only shot whitetails with them, about 10.
I did shoot a few at milk jugs of water, though, and they all looked like the Barnes ads
I did shoot a few at milk jugs of water, though, and they all looked like the Barnes ads
Leatherstocking
CGN Regular
- Location
- BC Rockies
I love my 150 TTSX
There is a big difference between long range target and medium range hunting though, hunting bullets require a minimum velocity for expansion. Certain bullets are designed specifically for long range hunting and have more forgiving minimum velocities but those are the exception not the norm. Because of this, the heavy for caliber bullets can very well limit your range.
Last edited:
How about 139gr? Plucked from a 1/4 mile moose
I was referring to cup and core bullets, at close range. My experience was with 140 gr Sierra's behind a full case of compressed H870, on whitetail, within 100 yards. That bullet out of a 7-08, or perhaps at a whitetail several hundred yards further out, different story. My bad, should have been more specific.
Somewhat different rules with solid copper or gilding metal bullets, no experience there, I'll have to rely on your expertise on that.
Do you use the same bullet for Whitetail, or is that your one bullet for all big game in the 7mm Mag.
Last edited:
Leatherstocking
CGN Regular
- Location
- BC Rockies
Lighter bullets have higher MV, but at longer ranges the BC more than makes up for it
Sure. But at what range? 500+? 99% of hunters shouldn't be shooting that far...
I just checked federal premium, comparing the 175 fusion vs 150 fusion, and the 160 trophy bonded vs 140 trophy bonded, all factory 7mm rem mag offerings. In both comparisons the lighter bullet was still going faster at 500yds. The fusion is going almost 200fps faster, the trophy bonded only about 40fps. The initial velocity of the 175 fusion load is kinda wimpy (2760fps) but even if you bumped that up another 100fps to make it more in line with other factory 175gr offerings it'll still be 100fps behind the 150gr load.
Leatherstocking
CGN Regular
- Location
- BC Rockies
Good point, glad you noticed my error.
What about trajectory, though. I plugged in some data,perhaps a Sierra c
Online calculator, I think the heavier bullers had flatter trajectory. And more recoil.
What about trajectory, though. I plugged in some data,perhaps a Sierra c
Online calculator, I think the heavier bullers had flatter trajectory. And more recoil.
There is no possible way a bullet with slower velocity at all times would give you a flatter trajectory.
It could potentially get you less wind drift, but the differences won't be huge and really if there's much of any wind you shouldn't be shooting at the sort of ranges where such a thing really starts to matter. Checking the federal trophy bonded again, it's 16.9" vs 18.7" at 500yds for a 10km cross wind, with the 160 being the smaller one - so sure enough heavier does buck the wind better as expected. Of course, 500yds would be a long ass shot with no wind for most people, me included...
Leatherstocking
CGN Regular
- Location
- BC Rockies
Okay, you’re right again.
I just plugged the BC, MV and bullet weight for 150 vs 175 grn TSX into Hornady calculator. With min loads of IMR4831.
Trajectory-45.5 vs -51.5.
I’m. Surprised. A longstanding misunderstanding debunked.
Wind deflection is worse, too.
I just plugged the BC, MV and bullet weight for 150 vs 175 grn TSX into Hornady calculator. With min loads of IMR4831.
Trajectory-45.5 vs -51.5.
I’m. Surprised. A longstanding misunderstanding debunked.
Wind deflection is worse, too.
