Ballistically speaking . . . what's more accurate?

tpcollins · January 25, 2013, 01:08 PM

If we take for instance .45 caliber 200 grain bullets, with jacketed lead being the shortest due to density, versus an all copper bullet being a bit longer, and an all brass bullet being the longest - which of the 3 would shoot the best 100 yard accuracy? Thanks.

Jimro · January 25, 2013, 01:56 PM

I can't answer that question in reality because there are too many variables.

I can answer hypothetically if we make some assumptions. Assumption 1: that all bullets of the same type are mathematically identical in shape and density. Assumption 2: that all bullets have perfect balance. Assumption 3: that bullet length alone determines ballistic coefficient in this case.

With these assumptions (that cannot be replicated in reality) then the longest bullet with the highest BC will be the "most accurate."

This is only because the effects of wind will be smaller due to more retained velocity.

In reality, there is no such thing as a perfectly balanced bullet in a perfectly uniform lot so your best bet is to buy 100 of each and see how they perform in your firearm.

Jimro

Old Grump · January 25, 2013, 04:58 PM

Assuming all match grade quality I would give the nod to the longer brass bullet but for all practical purposes at close range like 100 yards you will be hard put to find any of them inaccurate. It would be more telling if you tried them at 200 yards or more.

wncchester · January 25, 2013, 07:33 PM

"Ballistically speaking . . . what's more accurate? "

The ones that go into the tightest cluster. Other than that, none of us can tell you what your rig and loading skills can produce with anything.

black mamba · January 25, 2013, 07:50 PM

The first thing I thought of was which would have the best twist rate for it's length.

tpcollins · January 26, 2013, 09:46 AM

Thanks for the replies. Here is a pic comparing Hormady XTP versus the all copper Barnes TAC-XP. On each end is a jacketed lead 155gr XTP. left to right in the middle are the 125gr, 140gr, & 155gr Barnes TAC-XP. I have some Barnes samples in the 140gr and 155gr on the way - we'll see what groups the best.

When I plug my data into the Miller stability chart, the 155gr Barnes seems the best bet for my application.

**Unclenick** · January 26, 2013, 10:07 AM

Wncchester had the best reply. If you want to get technical, the longer a bullet is, the greater the length of the lever arm by which aerodynamic forces try to turn the direction of the bullet off its trajectory and make it tumble. In general, length is the most critical factor. Sectional density of the bullet is the second most critical factor, as putting more mass into the spin and more inertia into plowing into the atmosphere makes the bullet harder to turn. However, mass does not trump length. A bullet that's twice as heavy and long and has twice the sectional density, will be harder to stabilize than its half-length lighter counterpart because length trumps weight in importance to stability.

That said, .45 handguns have more twist than is required for long range stability. So the chances are your whole selection will shoot. That's why it comes back to what Wncchester said.

There is a free stability estimator if you scroll down to the bottom of this page. It requires bullet weight, length, rate of rifling twist in your barrel, muzzle velocity, and atmospheric conditions to figure air density from. However, it will likely just give you very high stability factor numbers for all the bullets you have, so you once again get back to having to try them to see what seems to work best from your gun.

tpcollins · January 26, 2013, 11:36 AM

Thanks again for the advise. Actually - I'm wanting to use these bullets in plastic sabots to shoot in a youth sized .50 caliber muzzleloader for my very young grandson. My goal is to find something that will shoot good at 50 yards with a light recoil as to not frighten the youngster.

I do have some really short 135gr XTP 10mm but they look more like a patched ball.

**Unclenick** · January 26, 2013, 06:23 PM

Follow the link to that calculator. You will need to know your twist rate. You then have to assume the bullet spins up at that rate and that it doesn't slip inside the sabot. I don't know how you can be certain of that without trying, though.

January 25, 2013, 01:08 PM	#1
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Ballistically speaking . . . what's more accurate? If we take for instance .45 caliber 200 grain bullets, with jacketed lead being the shortest due to density, versus an all copper bullet being a bit longer, and an all brass bullet being the longest - which of the 3 would shoot the best 100 yard accuracy? Thanks. __________________ What direction did that last shot at Kennedy come from?

January 25, 2013, 01:56 PM	#2
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	I can't answer that question in reality because there are too many variables. I can answer hypothetically if we make some assumptions. Assumption 1: that all bullets of the same type are mathematically identical in shape and density. Assumption 2: that all bullets have perfect balance. Assumption 3: that bullet length alone determines ballistic coefficient in this case. With these assumptions (that cannot be replicated in reality) then the longest bullet with the highest BC will be the "most accurate." This is only because the effects of wind will be smaller due to more retained velocity. In reality, there is no such thing as a perfectly balanced bullet in a perfectly uniform lot so your best bet is to buy 100 of each and see how they perform in your firearm. Jimro __________________ Machine guns are awesome until you have to carry one.

January 25, 2013, 04:58 PM	#3
Old Grump Member in memoriam Join Date: April 9, 2009 Location: Blue River Wisconsin, in Posts: 3,144	Assuming all match grade quality I would give the nod to the longer brass bullet but for all practical purposes at close range like 100 yards you will be hard put to find any of them inaccurate. It would be more telling if you tried them at 200 yards or more. __________________ Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters. --Daniel Webster--

January 26, 2013, 09:46 AM	#6
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Thanks for the replies. Here is a pic comparing Hormady XTP versus the all copper Barnes TAC-XP. On each end is a jacketed lead 155gr XTP. left to right in the middle are the 125gr, 140gr, & 155gr Barnes TAC-XP. I have some Barnes samples in the 140gr and 155gr on the way - we'll see what groups the best. When I plug my data into the Miller stability chart, the 155gr Barnes seems the best bet for my application. __________________ What direction did that last shot at Kennedy come from? Last edited by tpcollins; January 26, 2013 at 09:51 AM.

January 26, 2013, 10:07 AM	#7
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Wncchester had the best reply. If you want to get technical, the longer a bullet is, the greater the length of the lever arm by which aerodynamic forces try to turn the direction of the bullet off its trajectory and make it tumble. In general, length is the most critical factor. Sectional density of the bullet is the second most critical factor, as putting more mass into the spin and more inertia into plowing into the atmosphere makes the bullet harder to turn. However, mass does not trump length. A bullet that's twice as heavy and long and has twice the sectional density, will be harder to stabilize than its half-length lighter counterpart because length trumps weight in importance to stability. That said, .45 handguns have more twist than is required for long range stability. So the chances are your whole selection will shoot. That's why it comes back to what Wncchester said. There is a free stability estimator if you scroll down to the bottom of this page. It requires bullet weight, length, rate of rifling twist in your barrel, muzzle velocity, and atmospheric conditions to figure air density from. However, it will likely just give you very high stability factor numbers for all the bullets you have, so you once again get back to having to try them to see what seems to work best from your gun. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

January 25, 2013, 07:33 PM	#4
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"Ballistically speaking . . . what's more accurate? " The ones that go into the tightest cluster. Other than that, none of us can tell you what your rig and loading skills can produce with anything.

January 25, 2013, 07:50 PM	#5
black mamba Senior Member Join Date: September 13, 2011 Location: SW Florida Posts: 890	The first thing I thought of was which would have the best twist rate for it's length.

January 26, 2013, 11:36 AM	#8
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Thanks again for the advise. Actually - I'm wanting to use these bullets in plastic sabots to shoot in a youth sized .50 caliber muzzleloader for my very young grandson. My goal is to find something that will shoot good at 50 yards with a light recoil as to not frighten the youngster. I do have some really short 135gr XTP 10mm but they look more like a patched ball. __________________ What direction did that last shot at Kennedy come from?

January 26, 2013, 06:23 PM	#9
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Follow the link to that calculator. You will need to know your twist rate. You then have to assume the bullet spins up at that rate and that it doesn't slip inside the sabot. I don't know how you can be certain of that without trying, though. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle