7mmSTW vs 7mm remington ultra mag

yobuck

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If cartridge performance is the issue, line them all up on the same day and send a few rounds from each at a rock on the sidehill across the valley at say 1200 or so while you watch thru a good set of tripod mounted glasses.
Save the biggest one till last, one shot will probably make the decision for you.
I know l/r hunters who have moved up as for case capacity, but i dont know any who did the opposite.
While your at it, do the same with the 30 cals, and especially be sure to do it with the 338s, but of coarse at longer distance with those.
 

LRNut

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If cartridge performance is the issue, line them all up on the same day and send a few rounds from each at a rock on the sidehill across the valley at say 1200 or so while you watch thru a good set of tripod mounted glasses.
Save the biggest one till last, one shot will probably make the decision for you.
I know l/r hunters who have moved up as for case capacity, but i dont know any who did the opposite.
While your at it, do the same with the 30 cals, and especially be sure to do it with the 338s, but of coarse at longer distance with those.
LR is all about the wind. If you disagree, you need to shoot more. In your example, the big round would win simply because you have seen the effects of the wind on the previous rounds. Anyone can correct a missed wind call after the first shot.

I have a 7 STW, but it doesn't have a fast twist and consequently doesn't shoot heavy (high BC) bullets. My 28 Nolsers kick its butt. There isn't much difference between a 7mm 195 at 3000, a .308 225 ELD at 3000, or a 300 Berger at 2850 when it comes to the wind - they are all about the same.

I also notice there isn't much comment about accuracy vs allowable wind error; everyone talks about allowable wind error as if every bullet they shoot follows exactly the same path - but they don't.
 

yobuck

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LR is all about the wind. If you disagree, you need to shoot more. In your example, the big round would win simply because you have seen the effects of the wind on the previous rounds. Anyone can correct a missed wind call after the first shot.

I have a 7 STW, but it doesn't have a fast twist and consequently doesn't shoot heavy (high BC) bullets. My 28 Nolsers kick its butt. There isn't much difference between a 7mm 195 at 3000, a .308 225 ELD at 3000, or a 300 Berger at 2850 when it comes to the wind - they are all about the same.

I also notice there isn't much comment about accuracy vs allowable wind error; everyone talks about allowable wind error as if every bullet they shoot follows exactly the same path - but they don't.
Well mind you im not arguing your point.
But your basicly comparing apples with your example.
Im not talking about wind.
Im talking about velocity.
If you think a 300 gr @ say 3250 is no different than one @ 2850 at say about a mile, its only because youve never watched them. Ditto with all the others.
(You), and everybody else, will shoot the faster one better, especially in the wind.
 

ButterBean

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Well mind you im not arguing your point.
But your basicly comparing apples with your example.
Im not talking about wind.
Im talking about velocity.
If you think a 300 gr @ say 3250 is no different than one @ 2850 at say about a mile, its only because youve never watched them. Ditto with all the others.
(You), and everybody else, will shoot the faster one better, especially in the wind.
Yep
 

LRNut

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Well mind you im not arguing your point.
But your basicly comparing apples with your example.
Im not talking about wind.
Im talking about velocity.
If you think a 300 gr @ say 3250 is no different than one @ 2850 at say about a mile, its only because youve never watched them. Ditto with all the others.
(You), and everybody else, will shoot the faster one better, especially in the wind.
Yes, everything equal, the faster the better - no doubt. But I will take accuracy any time over velocity. Take your example above. A 300 Berger @2850 drifts .94 MOA for every mile of wind at 1760 yards (over twice the drift it has at 1000). The same bullet at 3250 drifts .75 MOA for every mile of wind (JBM, no spin drift). If we are trying to hit a 1MOA plate (17.6 inches) and each rifle shoots 1/2 MOA groups (meaning a max horizontal dispersion of 1/4 MOA from center), you have these allowable wind errors to guarantee a 100% probability of a hit:

2850: (.5-.5/2)/.94= .26mph
3250: (.5-.5/2)/.75= .33 mph

Speed doesn't matter that much; if you don't guess the wind perfectly, you risk missing at some point, because eventually there will be one bullet that hits 1/4 MOA away from center in the direction the wind is blowing (and the wind error blows you another 1/4 MOA). Of course, there is an equal chance that bullet hit in the direction opposite the wind, in which case you get a dead center hit and call yourself a wind savant, post the pic on LHR, etc.

If that 2850 fps bullet groups 1/4 MOA, your allowable wind error is:
(.5-.25/2)/.94 = .4, meaning you can misjudge the wind by .4 mph and hit the target every time, slightly better than the faster bullet. Of course, with bigger differences in accuracy (.75 vs .25) the allowable wind error is even larger for the more accurate rifle, even if the bullet is slower.

Something to think about the next time you want to whack an elk at a mile, especially considering the wind is going to change more than your allowable error during the TOF.

What about 1000 yards, same as above but trying to hit a 10" target?

2850 (1/2 MOA accuracy):
wind drift is .44 MOA per mile of wind; allowable wind estimation error:
(.5-.5/2)/.44=.57 mph allowable error

3250 (1/2 MOA accuracy):
wind drift is .35 MOA per mile of wind; allowable wind estimation error:
(.5-.5/2)/.35=.71 mph allowable error

3250 (3/4 MOA accuracy):
wind drift is .35 MOA per mile of wind; allowable wind estimation error:
(.5-.75/2)/.35=.36 mph allowable error

The math above shows:
1. A 400 fps MV difference only increases your allowable error wind estimation error by .14 mph (granted, percentage wise it is 24.5%,)
2. A rifle that shoots 1/4 MOA but 400 fps slower has more allowable wind estimation error.

Maybe too much math and too theoretical, but my experience at LR bears out: accuracy beats velocity when it comes to wind.
 
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jshepherd61

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Gotcha, I was wondering because the primer pockets go out first in my case. But I was just curious with other shooters.
That’s typical of most overbore cartridges! I still have some unused A-Square brass which is the benchmark for brass when they were still in operation. I bought 2K pieces of brass. Should last my lifetime! And NO, not selling any!
 

yobuck

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Yes, everything equal, the faster the better - no doubt. But I will take accuracy any time over velocity. Take your example above. A 300 Berger @2850 drifts .94 MOA for every mile of wind at 1760 yards (over twice the drift it has at 1000). The same bullet at 3250 drifts .75 MOA for every mile of wind (JBM, no spin drift). If we are trying to hit a 1MOA plate (17.6 inches) and each rifle shoots 1/2 MOA groups (meaning a max horizontal dispersion of 1/4 MOA from center), you have these allowable wind errors to guarantee a 100% probability of a hit:

2850: (.5-.5/2)/.94= .26mph
3250: (.5-.5/2)/.75= .33 mph

Speed doesn't matter that much; if you don't guess the wind perfectly, you risk missing at some point, because eventually there will be one bullet that hits 1/4 MOA away from center in the direction the wind is blowing (and the wind error blows you another 1/4 MOA). Of course, there is an equal chance that bullet hit in the direction opposite the wind, in which case you get a dead center hit and call yourself a wind savant, post the pic on LHR, etc.

If that 2850 fps bullet groups 1/4 MOA, your allowable wind error is:
(.5-.25/2)/.94 = .4, meaning you can misjudge the wind by .4 mph and hit the target every time, slightly better than the faster bullet. Of course, with bigger differences in accuracy (.75 vs .25) the allowable wind error is even larger for the more accurate rifle, even if the bullet is slower.

Something to think about the next time you want to whack an elk at a mile, especially considering the wind is going to change more than your allowable error during the TOF.

What about 1000 yards, same as above but trying to hit a 10" target?

2850 (1/2 MOA accuracy):
wind drift is .44 MOA per mile of wind; allowable wind estimation error:
(.5-.5/2)/.44=.57 mph allowable error

3250 (1/2 MOA accuracy):
wind drift is .35 MOA per mile of wind; allowable wind estimation error:
(.5-.5/2)/.35=.71 mph allowable error

3250 (3/4 MOA accuracy):
wind drift is .35 MOA per mile of wind; allowable wind estimation error:
(.5-.75/2)/.35=.36 mph allowable error

The math above shows:
1. A 400 fps MV difference only increases your allowable error wind estimation error by .14 mph (granted, percentage wise it is 24.5%,)
2. A rifle that shoots 1/4 MOA but 400 fps slower has more allowable wind estimation error.

Maybe too much math and too theoretical, but my experience at LR bears out: accuracy beats velocity when it comes to wind.
Well realize that im simply a hunter who prefers doing it at longer distances.
And a not very well educated hunter as well, so visual information trumps factual information for me every time.
For some reason you think i dont understand whats needed to hit a target.
Fact is i do understand, but that is a totally separate issue from what im talking about.
Let me simplify the example so theres less confusion.
Lets just use 4 different 338s all using the same 300 gr bullet.
The muzzel velocity of the 4 different guns will vary from 2850 to 3250 fps but you are not told that beforehand.
You will be sitting about 10’ behind the shooter looking thru very good quality large binoculars on a tripod.
Weve picked out a target at say 1500 yds simply to use as an aiming point for all the guns.
Matters not if it even gets hit, what were watching is the journey, the trip to the target by the bullet from each gun.
Lets just shoot 1 shot from each gun, and your ready as each one is shot.
Its no different than watching a drag race, and we know who always wins those.
Assuming there is also some wind, which one do you think will be less affected?
But with regard to that, at least the smart l/r hunters will pick a different spot to hunt rather than deal with high wind, especially at the longer distances.
And the same thing applies when comparing other cartridges like the 7 Rem Mag and the 7mm ultramag.
To simplify it even further, take a 223 and a 22/250 on a prairie dog hunt. Use 55 gr bullets in both and take 200 rounds for each.
See which one you run out of ammo for first.
Next trip your apt to be taking 400 rounds and just the 22/250.
Remember now, you can kill a dog at 1000 yds easily with a 223. Yep you can. lol
 

gunaddict

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My 7 Rum that I sold to a friend.
92.5 gr H50BMG 180 VLDH bullet 3300fps 29 inch barrel
My brothers 7 Rum
VN570 190 Atip 3240 fps 27 1/2 inch barrel
My new 7 Rum , not happy with it so far.
 

Northkill

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Ive got the 1/9.5 twist 26" barrel so we went a hair lighter with the bullets and using the 168 vld bergers but still in development stage and changes to bullet make or powder are still doable just trying to figure out what is best for this rifle before i load up the 100 casings i have for it. As far as the rifle is concerned i just have left is to put some glass on it that will do it justice
Seriously consider monos. Good options that are easy to tune loads for and shoot good - not to mention outstanding terminal performance on game. Punching above their weight class. The slow twist limits to the lighter offerings, but believe me, they will be zingers that hit like lightning.

 

LRNut

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Well realize that im simply a hunter who prefers doing it at longer distances.
And a not very well educated hunter as well, so visual information trumps factual information for me every time.
For some reason you think i dont understand whats needed to hit a target.
Fact is i do understand, but that is a totally separate issue from what im talking about.
Let me simplify the example so theres less confusion.
Lets just use 4 different 338s all using the same 300 gr bullet.
The muzzel velocity of the 4 different guns will vary from 2850 to 3250 fps but you are not told that beforehand.
You will be sitting about 10’ behind the shooter looking thru very good quality large binoculars on a tripod.
Weve picked out a target at say 1500 yds simply to use as an aiming point for all the guns.
Matters not if it even gets hit, what were watching is the journey, the trip to the target by the bullet from each gun.
Lets just shoot 1 shot from each gun, and your ready as each one is shot.
Its no different than watching a drag race, and we know who always wins those.
Assuming there is also some wind, which one do you think will be less affected?
But with regard to that, at least the smart l/r hunters will pick a different spot to hunt rather than deal with high wind, especially at the longer distances.
And the same thing applies when comparing other cartridges like the 7 Rem Mag and the 7mm ultramag.
To simplify it even further, take a 223 and a 22/250 on a prairie dog hunt. Use 55 gr bullets in both and take 200 rounds for each.
See which one you run out of ammo for first.
Next trip your apt to be taking 400 rounds and just the 22/250.
Remember now, you can kill a dog at 1000 yds easily with a 223. Yep you can. lol
I am not disagreeing with anything you are saying...I am agreeing that all else equal, higher MV is better. But the advantages of higher MV will not make up a lack of accuracy, nor will it give you an appreciable increase in wind estimation error. So in the debate at hand, if I had a 7STW and a 7RUM, both with fast twists, I would pick the most accurate - an accurate 7STW will trump the 7RUM when it comes to wind.

As for shooting PDs, I much prefer the .223; if I know I am going to take long shots, I use my fast twist .220 Swift that shoots 80 gr Amax bullets that have half the wind drift of a 55 gr 22-250 bullet.
 
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