BC & Bullet Selection with ML’ing

Over time the option of bullet selection for ML’ing has really expanded given the shooter many more choices to choose from. Regardless of your choice whether for targets, different size animals or velocity range you want to work in, a key factor for some may be the bullet’s BC. Knowing a bullets true BC and the actual velocity you are producing there are computer programs that can tell you the bullets velocity at a given range, remaining ft-lbs of energy and the trajectory (bullet drop) over a given range. To some who do extended range shooting this is useful information.

In most cases if you are shooting less than 100yds a bullet’s BC is not a strong determining factor as much as ft-lbs of energy for delivering an accurate lethal hit. But as we increase our range we find knowing a bullets flight reaction determined by its actual BC is more important to us for making a good shot.
The easiest way to understand BC is a numerical value that represents the ease at which a bullet moves through air. Yes there are factors that alter a bullet’s assigned BC such as altitude for example where the air is less or more dense.

For a hunters purpose we just need to know the value of the BC for our given hunting condition so we can accurately allow or calculate for bullet drop at a given distance.
I for one found published BC’s for given bullets are not as accurate as I need/expect them to be. Only actual testing at different ranges and using the produced flight trajectory can the actual BC for my shooting condition be determined. This also goes the same for most CF rifle loads.

I’m no shooting expert or perfectionist by any means but I can reduce the error for accuracy by knowing the real BC of a bullet. One piece of equipment that helps in this area is a chronograph to verify velocities. IMO this is one of the best choices for equipment to invest in if you’re are a serious shooter or hunter.
Yeah I know many will say that it is a pain in the butt to setup, not accurate under certain weather conditions and awkward for range setup when other shooters are around. Then there is the initial cost investment that some feel isn’t worth it. For me having a chronograph for load data and possible diagnostic for some problems that you may encounter is a priceless piece of equipment.

This post is not meant to direct anyone to change their way of shooting but add some awareness that may prove helpful to someone else.


Ed

Coincidentally when I was reading something earlier in the week a came across a paragraph that fits in with this discussion....

Randy Wakeman points out;

Quote:

---

The ballistic coefficient changes with both distance and velocity. Few bullet makers acknowledge this, but Sierra Bullets is the rare exception. Here is an example: one of Sierra's .458 diameter, 300 grain bullets has a BC of .120 @ 2400 fps and above, .145 between 2400 and 1900 fps, .185 between 1900 and 1400 fps, and .210 between 1400 and 1150 fps. It is dynamic, not static, and muzzleloading rifles use a wider range of ballistic coefficients than many projectiles, as we can load the example bullet to a .145 or a .185 BC at the muzzle, and may well be using the .210 BC prior to taking our animal.

---

Makes you wonder how with varying distances to targets, in a hunt scenario, you could compensate for such swings in the formula quick enough.

Sure explains why they use computerized ballistic calculators for snipers now...:)

MikePal

For most hunter applications for ranges out to 300yds I look for an average mean (BC) that I can run through a ballistic calculator that matches my measured bullet drop. This is why I feel it’s important to initially shoot/test each specific load at multiple ranges for conformation.

Even though we have calculators to assist us with longer range shooting they are only as accurate as the info provided to them. Old school of proof testing your loads still rules as #1 in my book. ;)


Ed

Quote:

---

Originally Posted by ET1

For most hunter applications for ranges out to 300yds I look for an average mean (BC) that I can run through a ballistic calculator that matches my measured bullet drop.

---

I always like Cecil's take on BC in regards to Muzzle loaders....

Quote:

---

A bullet traveling at 1850 fps sighted in at 100 yards with a BC of .2 will drop 1.2" more at 200 yards than a bullet with a BC of .25 and will drop 1.9" more than a bullet with a BC of .3. Bottom line is BC makes great conversation over the fire at hunting camp but for the vast majority of muzzleloader hunting circumstances, BC is a non issue.

---

I have to agree, as I know that shooting a 425gr Keith Nose bullet, it's ballistically equivalent to making a rock fly. It hits the ground at 250 yds..LOL...

I remember, some 30 yrs ago now, teaching this stuff in regards to the ballistic computer calculations for on the Leopard CI Tank with a 105 mm APFSDS (Armour-piercing fin-stabilized discarding-sabot) rounds with a muzzle velocity of 1,740 m/s (5,700 ft/s) out to 2,200 yds. It's important to have that 1st round hit in a tank battle :)

Mike Pal

I definitely agree that in a tank battle I want to do the tagging and not get tagged.
It sounds like you’ve had an interesting exposure to Exterior Ballistics in your life.

For my application with muzzle loading Ballistic Calculators have a limited function.
Under certain conditions without a doubt I can make a good shot to 200yds and limit my shooting range to this point for healthy deer. Having proof tested the load I also know how much farther I could possible carry the shot and remaining energy. If a cripple should appear say at 250yds and having known info previously mentioned and worked through a ballistic calculator I wouldn’t hesitate to try and take that crippled deer down at that range without solely depending on a Hail Mary shot.

Cecil’s response to BC may have been better applied years ago considering achievable velocities today and bullets now available. For the average hunter who uses a muzzle-loader and BP his definition does still hold a fair amount of truth.
For me BC is a working numerical value that can be helpful for trajectory calculations and not a non-issue as Cecil sees it. If he would have stated non-critical then I would agree.
I guess we all have different opinions of viewpoints.


Ed

I have a question about Precision Rifle's bullets. When I sighted in my Savage ML, I figured it would take plenty of rounds, various bullet and load combinations. I started with Hornady XTP 250 gr. and 4759 powder. With the accuracy I achieved, I never tried the other bullets. I am very familiar with the knock down power of the xtp, and more than happy with the way they perform. I have many PR bullets sitting on the shelf. Can someone tell me how the PR bullets perform on game? I have read great things about their accuracy on paper, but have read quite a few negative stories when using them on game(not expanding properly). What is your thoughts? John.

Quote:

---

Originally Posted by Final Flight

Can someone tell me how the PR bullets perform on game? I have read great things about their accuracy on paper, but have read quite a few negative stories when using them on game(not expanding properly). What is your thoughts? John.

---

Don't think I ever read a bad review of a PR bullet....best lead bullets on the market..proven !! :)

This is a 300gr QT bullet I recovered from a deer I shot at less than 50yds...the bullet was in the armpit on the far side.

Looks exactly like a lead bullet is suppose to perform !!



http://i125.photobucket.com/albums/p...ePal06/QT1.jpg

http://i125.photobucket.com/albums/p...ePal06/QT2.jpg

This is the damage caused by a 360 gr Keith Nose shot at about 20 yds....A clear neck shot that totally disintegrated two vertebrae, tore out the wind pipe and severed the jugular vein. Can't kill a deer more humanly than that...and that should be the goal of any bullet.


http://i125.photobucket.com/albums/p...06/unicorn.jpg

the lead bullets are great for most muzzleloader applications, not so good when pushed at faster speeds

Quote:

---

Originally Posted by smokeeter

the lead bullets are great for most muzzleloader applications, not so good when pushed at faster speeds

---

Thanks, this is exactly what I'm concerned about. John.

Not sure what velocities you guys are talking about....but these PR bullets have been crono'd out 500 yrds.

Take a look at the PR bullet ballistics tables at link;

https://www.prbullet.com/bal.htm