So the other day I had a conversation with someone who mentioned that on some bullets having a faster MV was slower at 1k. He said certain bullets can slow down much faster in the front part of the shot vs a slower bullet not having to work as Hard. After watching some videos of well respected shooters and gunsmiths saying a load will tune at 600 and not shot well at 1k makes me wonder is this is true.
Faster bullets at MV slower at distance
- Thread starter wywindsor
- Start date
XTR
F-TR obssessed shooting junkie
Look up ballistic coefficients. Get a copy of Brian Litz “External Ballistics “
The short answer is that a bullet with a higher ballistic coefficient loses less velocity at a given range than one with a lower BC. Unless you’re talking about the big bores it usually doesn’t make much difference at the ranges most people shoot (inside 600 yards)
A 155 gr 308 launched at 3000 FPS will get to 1000 yards with a lower velocity than a 200 launched at 2700 fps.
Go play around with JBM Ballistics
The short answer is that a bullet with a higher ballistic coefficient loses less velocity at a given range than one with a lower BC. Unless you’re talking about the big bores it usually doesn’t make much difference at the ranges most people shoot (inside 600 yards)
A 155 gr 308 launched at 3000 FPS will get to 1000 yards with a lower velocity than a 200 launched at 2700 fps.
Go play around with JBM Ballistics
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Fast14riot
Gold $$ Contributor
Speed decay is typically described mathematically as a ratio of aerodynamic efficiency against a known standard. This factor is labeled BC for ballistic coefficient.
In practical terms, think of throwing a feather as hard as you can vs throwing a dart. A feather will slow down really fast because it has a lot of drag and low weight. A dart has less drag and more weight.
As for accuracy/precision and "tune" both can be good, but the lighter bullet will lose energy the faster the farther it has to go.
In practical terms, think of throwing a feather as hard as you can vs throwing a dart. A feather will slow down really fast because it has a lot of drag and low weight. A dart has less drag and more weight.
As for accuracy/precision and "tune" both can be good, but the lighter bullet will lose energy the faster the farther it has to go.
Yes, it is possible to choose bullets that would make this statement true.
jelenko
Gold $$ Contributor
It wouldn't be true for the same bullet.
Without considering anything else, why would the bullet that has a higher muzzle velocity slow down faster after it reached the same velocity as the one that started slower - i.e., it wouldn't => the one that started faster will always be traveling faster.
By the time the one with the faster muzzle velocity reaches the velocity of the bullet that started slower, it has to be farther down range [simply because it started faster].
At the same time, the one that started faster will loose more velocity than the one that started slower.
As example, a SMK 69 with a muzzle velocity of 3100 fps, is going 1000 fps at 1000 yards but is going 965 fps if launched at 2900 fps.
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RegionRat
Gold $$ Contributor
To be helpful, muzzle velocity is one parameter and BC is another.
Your friend is likely discussing two very different bullets, and even then the specific BC and muzzle speed matter or you get a different outcome.
If only one bullet is being discussed in both the high muzzle speed and low muzzle speed, then the friend's opinion is wrong since deceleration is yet another value and not the same as velocity.
Yes, the same bullet leaving a muzzle at a higher velocity also starts with a higher deceleration, but that doesn't mean that same bullet leaving slower will ever "catch up" or have a higher velocity at any given distance.
Your friend is likely discussing two very different bullets, and even then the specific BC and muzzle speed matter or you get a different outcome.
If only one bullet is being discussed in both the high muzzle speed and low muzzle speed, then the friend's opinion is wrong since deceleration is yet another value and not the same as velocity.
Yes, the same bullet leaving a muzzle at a higher velocity also starts with a higher deceleration, but that doesn't mean that same bullet leaving slower will ever "catch up" or have a higher velocity at any given distance.
XTR
F-TR obssessed shooting junkie
@wywindsor , please be aware that the people posting here are referring to bullets not cartridges. In my case above the referenced bullets would be from a 308Win, jelenko’s example would be in a 223Rem.
@alf , come on man, the 6Creed is better than everything, except maybe ice cream.
@alf , come on man, the 6Creed is better than everything, except maybe ice cream.
The 3000 bullet is 1616 @ 1000 loss of 1384
2750 has 1451 loss of 1299
So, the faster bullet has lost more velocity than the slower bullet.
I believe the op’s conversation was alluding to this .
Same bullet shot at 1000 fps , 774 fps @ 1000 loss of 226 fps.
Breaking the sound barrier carries penalties but cheats gravity better.
alf
Silver $$ Contributor
All true, but despite the bigger loss, the faster start still wins the race in drop & drift at any distance.
Nobody that I'm aware of picks a cartridge based on who loses the least velocity.
It's all about physics.......increase velocity increases drag which increases rate of deceleration.....physics.
This is the same projectile sent at different velocities......the faster projectile will lose velocity quicker.
This information is found in the back of most reloading manuals in the ballistics tables.
Good luck and stay safe.
No. Assuming the same design bullet. From any given velocity to the terminal point of travel the bullets will behave the same. The bullet traveling faster has no memory of what has been. THE ONLY DIFFERENCE between the two might be a slight difference in the rotational (spin) which would likely favor the bullet launched faster from the same twist barrel. The bullet with the higher velocity will have more velocity at the target.
Comparing identical bullets launched at two different muzzle velocities, 2700 and 2996.6 fps. The 2996.6 fps bullet will reach 2700 fps at 160 yds from the muzzle. If the target is 1000 yds downrange then the bullet will travel 840 yds from the 2700 fps point. In the case of the 2700 fps the bullet loss 1293.3 fps in the first 840 yds to a velocity of 1406.7 and a velocity at the target of 1206.9 fps. In the case of the 2996.6 fps bullet the velocity drop is 1293.3 fps from 160yds to the target with a final velocity of 1406.7 fps.
It is incorrect to compare the bullet drop over the velocity range of interest since the 2996.6 bullet will have a vertical velocity due to gravity at the 160yd point while the 2700 fps bullet will have ~zero vertical velocity due to gravity leaving the muzzle. In the case above the vertical drop of the 2700 fps bullet is -372.6 inches while the 2996.6 fps bullet is 287.1 inches the target.
A comment to clarify the drop and windage. The bullet drop is not a direct function of BC or distance but is actually the flight time from muzzle to target. In this case the flight times are 1.662 sec versus 1.462 sec. While it is not absolutely correct you can approximate the difference in vertical drop as the ratio of the
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dellet
Gold $$ Contributor
Never say never.
Don’t believe everything you read.
Context is critical.
A poor design doesn’t care about math.
Hornady bullets.
Sierra 168 SMK.
One of the stated reasons for Hornady introducing the ELD line of bullets and changing the polymer in the tips from what was used in the Amax, was that at high speeds and long distances, the tips melted.
In an extreme case a bullet pushed past its physical limits deforms in flight. Sometimes to a point that it self destructs. So a fast bullet that does not make it to the target because it blew up in flight or started tumbling, is useless compared to the same bullet with 200 fps less muzzle velocity that does.
That could explain the first part of the question. A statement out of context. A deformed bullet may not shed velocity faster initially, but it will certainly be traveling slower at the target at some distance, if it gets there at all.
The second part is absolutely true, but not necessarily related to the first. The Sierra 30 caliber 168 grain bullet is a very well documented case of a bullet that wins matches out to 600 yards and is basically useless at 1000.
In the right context, your friends statement could be true. But how it was presented here, at face value, is not correct.
The senecio you mention can be true. Consider three ranges 100yd, 600yd , and 1000yds and you will find that each has basic variables that are significant and different. At 100yds accuracy and precision are primarily driven by consistent release of the bullet on a consistent trajectory. Velocity and environmental factors are secondary. At 600yds the same requirement at 100yds is primary but now velocity consistency's moves into importance as well as wind and temperature. Take it to 1000yds and velocity consistency is extremely important as well as bullet design as many cartridges are now in the transonic region of velocity (<Mach 1.2).
Consider the time of flight for a typical 308 at 100yds the bullet is in the air for about .12 seconds during which wind and gravity have time to affect the bullet. At 600yds the bullet is in the air for about 0.83 seconds and at 1000yds the bullet is in the air for about 1.7 seconds.
ELR LVR
Silver $$ Contributor
Yes it is true
think of it more in the terms of
Percentage of velocity loss per every 100 yds
the bullets I use have approx 4.5% velocity loss for every 100 yds
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VS say a 7mm Mag that uses Heavier bullets, but have a velocity loss of 10% for every 100 yds
the 7 mag might start off having more knock down power up close.
but after 600 yds, I take over with a 6mm 115 gr, and win from 600 on out to 2200 yds
Take over in both Retained velocity and ft/lbs of Energy
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B.C. is the term to learn and understand
jelenko
Gold $$ Contributor
Remember, the OP followed up and said the statement was about the same bullet, not two different bullets.
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