Is faster better?

[xsn10s]

Keep in mind that BC is an average and varies with speed, higher speeds = higher BC, so the stated BC is calculated at "normal" velocities so at 4,000 fps it will be higher. As an example Sierra gives their BC's at different velocities. This is for the .308 230 grain SMK; .800 @1880 fps and above .780 between 1600 and 1880 fps .740 @ 1600 and below

I plugged in the 160 @4200 with the same variables as the 300 Hybrid. The Hybrid still had more energy and less wind drift at 800 yards. The 160 did shoot flatter. All this still needs to be confirmed by shooting.

 

[jebel]

Yes it is but if you don't know what your velocity would be for any said bullet you're still just making a guess. I've had good luck with JBS once I have a load developed for making drop charts. My question is whether there's a way to get and or make an educated guess BEFORE you invest in new bullets and whatnot only to find out it's no better than what you already had running.

Once I have a load worked up, I use the following formula to estimate what the velocity would be using a different weight bullet. The implied assumption is that both would be fired with the same force (same pressure).

 

[scope-eye]

All I was trying to convay was to dispell the myth that light bullets at high velocities are useless at long distances and fall flat which I have shown they don't.

Dean

 

[Hugnot]

Take a look at pages 164-170 of the Berger 1st edition load manual - Form Factors. Page 167 - some bullets may have equal BC's but different form factors (different drag profiles) & higher velocities may be realized with the lighter bullet. One of my favorite bullets is the 6mm 95 Berger VLD & I can get this going real fast from my 6mm-06, 8 twist. Another bullet is the 6mm 87 V-Max® and this does amazingly well despite its modest BC (G1 at about .42) at extended ranges when launched at over 3550 fps.

I learned the ® business from this forum.

Page 165 Berger manual, BC (G7) = SD/Form Factor or Form Factor = SD/BC(G7) look for long pointy bullets that have BC's higher than SD's

Low form factors are nicer than hi form factors.

BC's being G7 & SD = sectional density

 

[74honker]

Once I have a load worked up, I use the following formula to estimate what the velocity would be using a different weight bullet. The implied assumption is that both would be fired with the same force (same pressure).
View attachment 281181

Thank you. I will give this a try.

 

[TK50]

I will take a high BC bullet fairly heavy for caliber and shoot it at a velocity that gives me the maximum accuracy I can get from my best load. I will give up some velocity to attain the most accuracy. You can adjust for wind drift and add extra elevation to get you on target if necessary. You can't make up for inaccuracy. If you can't hit what you are shooting at no amount of speed will make up for that!!

 

[dogz]

Curious here and this might be a poor way to ask this question but do any of you guys utilize the actual speed and actual drops to calculate the BC's you're actually getting?

I think that made sense...?

 

[Idaho Lefty]

Curious here and this might be a poor way to ask this question but do any of you guys utilize the actual speed and actual drops to calculate the BC's you're actually getting?

I think that made sense...?

Yes, i did it ONCE with, the 140 AccuBonds going, 3,145 FPS in my .270 WSM 24", SS, Tikka t-3.
Nosler "said",.. the BC was .496,.. the actual BC turned out to be about, .480 -.482 as "Tested" for actual "Drops" using, a 200 yd. Zero, then, 400, 500 and 650 yards. Others said, that's about the, BC, they were getting, too ( I tested this in, 2017 ).
And a "Tape" was made for, my Scope to, "Dial" for Ranges every 25 yds, the Tape was, "Bang on" out to,.. 700 yards.
I'm now using, Berger 140 gr. Classic Hunters at, .528 BC ( Litz tested ) and have found them, to be a Truer BC and with, awesome, accuracy ( Sub 1/2 MOA,.. usually ) EXCEPT when, my .338 Magnum "Flinch",.. shows up to, the "Party" !
Personally, I would "Test" every other Bullet on the Planet for "Drops" and BC as most, BC's, are NOT, quite, "right ",..
Except,.. Berger's and some, Sierra's.

 

[Buster***]

the .257 100 grain bullet will have amazing speed and the deer are DOA.

 

[yobuck]

Actually the 300 grain bullet overtakes the 250 grain bullet drastically around 1000 yards. At 1500 yards there's 100 more inches drop with the lighter bullet. The heavier bullet is 220 fps faster with 450 more ft lbs kinetic energy. If you can handle shooting the heavier bullet then why wouldn't you shoot it?? I've killed deer with a 22, not gonna see me with one at deer camp. LOL

Well youve got lots of nice hills in WV, i suggest you go sit on one and check out your stats with live ammo.

 

[yobuck]

I have two thing. Accuracy and Velocity and, If I don't get both, I look at different bullets, powder, primers and cases. How they preform down range. Longer than 500 to 600 yards, take more thinking and possible some changing. The 500 to 600 yards have been my limits, but I am running velocities @ 3200fps or greater in my rifles, and nothing over 200gr. Most of my bullets are Nosler Accubond now do to there changes. All are boat tails bullets. I have gotten great performance from those bullets over the year. If my groups aren't under or about 1/2" @ 100 yard I change something to achieve it. I don't have the twist in my rifle barrel to use all copper bullets. I am getting a rifle that will do that and I am looking that Hammer bullets. I like what I see in the Hammer bullets and feel they will more than hold up at the velocities I am looking at. I use the velocity for less drop and wind problems.

Well if your going to insist on shooting groups, at least do it at a longer distance, like say 400 yds.
The only thing small 100 yd groups accomplish imop is to make the shooter feel good about the shooter.
I personally feel group shooting is a waste of time and ammo anyway.
Id sooner pick out a small rock on a hillside at a longer distance and send the ammo at that.
If the gun repeats by sending them all into a kill zone area im happy.
And if it dosent, is the problem our load? Or could it be the way we go about shooting?
You dont necessarily have to have a tack driving gun in order to be very successful at killing a deer at long range.
Its only necessary to hit the deer regardless as to what it does or where it goes.
Having good close range groups wont guarantee that.
Which is why actuall shooting at the distances you plan on hunting is a requirement.

 

[FatOldMIHunter]

For a given bullet and a given barrel, there is an optimum velocity. If you exceed that optimum velocity, something will suffer. You don't want that to be the game you hunt. Usually, non-optimal velocity it will decrease accuracy, which translates to poor bullet placement on (or off) the target. It could also be affect bullet performance on the target (too much or too little expansion). For hunting, bullet selection is about more than BC. Get the right velocity for the barrel and bullet at the ranges you will be shooting at. Get the right bullet for the barrel and velocity at the ranges you will be shooting at. At some point, you will be limited by the barrel and your ability to aim it.

 

[scope-eye]

I knew about bullets having a certain BC at a specific velocity or at least a small window plus or minus. And I know BC increases with velocity so I wonder how much does thet BC increase at 500FPS or even 1000FPS over the velocity the bullet maker tested it at. I am sure every bullet different but there must be a rule of thumb to calculate it. That would sure explain the success I have been having thorugh out the years I have been doing this.

Dean

PS: I am sure when Barnes came out with there 160gr TTSX in 338cal and there .425 BC they never factored in they would some day be launched at 4200FPS.

 

[yobuck]

For a given bullet and a given barrel, there is an optimum velocity. If you exceed that optimum velocity, something will suffer. You don't want that to be the game you hunt. Usually, non-optimal velocity it will decrease accuracy, which translates to poor bullet placement on (or off) the target. It could also be affect bullet performance on the target (too much or too little expansion). For hunting, bullet selection is about more than BC. Get the right velocity for the barrel and bullet at the ranges you will be shooting at. Get the right bullet for the barrel and velocity at the ranges you will be shooting at. At some point, you will be limited by the barrel and your ability to aim it.

But the only way to prove that or any theory is to go shoot something.
Untill then it is what it is, opinion and theory.