Firearm & Gun Forum - FireArmsTalk.com

Firearm & Gun Forum - FireArmsTalk.com (http://www.firearmstalk.com/forums/)
-   General Rifle Discussion (http://www.firearmstalk.com/forums/f18/)
-   -   odd question for the long range shooter (http://www.firearmstalk.com/forums/f18/odd-question-long-range-shooter-89302/)

Nathantc 04-22-2013 02:18 AM

odd question for the long range shooter
 
ok here goes

heavier bullets hold there velocity better right

so two bullets of major weight differences traveling at the same speed at the muzzle should have very similar trajectories when zeroed at 100 yards and then shot at 50 and 150 yards

basicly lets take a 9mm carbine and a .22lr rifle

they both start out right at about 1200fps
the 9mm is 124g
the .22lr is 36g

from what i have been reading that would tell me that the heavy 9mm would have a flatter trajectory then the .22lr if shooting out to 200 yards max

or is there something im missing

Salvo 04-22-2013 02:53 AM

The shape of the bullet.

The information you are thinking of assumes that rifle bullets of similar shape are being compared.

Nathantc 04-22-2013 03:26 AM

Quote:

Originally Posted by Salvo (Post 1222723)
The shape of the bullet.

The information you are thinking of assumes that rifle bullets of similar shape are being compared.

that correct,, like .22lr and 9mm are both shaped similar

lets say if you pushed a .270 110g at the same speed as a 30,06 180g

same speed now,, same shape, big difference in weight wouldnt the 180g be flatter out to 200 with a 100 yard zero

i know there is much much more to take in to effect at greater distances

c3shooter 04-22-2013 12:16 PM

Search the term "ballistic coefficent". That is a measure of how well a bullet moves thru air. It is a function of the oversall shape of the bullet, and the diameter of the bullet. A round ball has about the WORST, a long boat tailed spitzer the best.

Round that have a poor BC will slow down sooner than a round with a good BC. That is, two rounds may START at the same speed, one will slow down before the other. Traveling slower, it will drop more in the time it takes to cross a given distance.

If we were shooting in a vacuum, it would not matter. This is why so many of the LONG range shooters use 6mm, or 6.6. They have a GREAT BC. For hunting- 25-06 or .270- about as good as it gets.


http://en.wikipedia.org/wiki/Ballistic_coefficient

trip286 04-22-2013 01:09 PM

The effect of gravity is the same for every object. 32 feet per second per second or something like that. Meaning, everything falls to the ground at the same rate of speed (assuming a vacuum).

Now, where you get differing rates of bullet drop is this... How long the bullet is in the air before hitting its target. That's where BC and velocity come into play. High velocity and low BC will shoot flatter every time, regardless of bullet weight. If a bullet starts out at a higher speed, and loses its velocity more slowly, it will travel to its target quicker, not allowing gravity to affect it as much.

Now, there may be some that are more susceptible to wind drift, because wind CAN push around lighter bullets easier.

Salvo 04-22-2013 04:04 PM

Take a look at a 9mm bullet, and a bullet pulled from a .22lr...

In any pursuit of truth or fact, the ability and willingness to discriminate is job #1.

( Their shapes are quite different. )

Nathantc 04-22-2013 06:03 PM

ok so then it would be safe to assume that if i go out and get a 9mm carbine it would shoot flatter out to 100 and 200 yards than my .22

the reason i am looking in to this is im trying to keep my ammo cost as low as i can while sill being able to rid my property of feral dogs and coyotes

the .22 works but not well,, and my .270win works great but at almost $2 per round and a major problem with over penetration

some keep telling me to get a .22mag or .17hmr but both will have the same issue i am having with the .22lr,,, just not enough kill power to be blunt

any way short question,, the 9mm should in theory shoot flatter

trip286 04-22-2013 06:14 PM

If it leaves at a higher velocity and has a lower BC, then yes. I personally don't know if it meets either condition.

I'm trying to dig it up for you, but I can only find ballistics info on 9mm for handguns, not carbines. :(

Nathantc 04-22-2013 06:57 PM

Quote:

Originally Posted by trip286 (Post 1223299)
If it leaves at a higher velocity and has a lower BC, then yes. I personally don't know if it meets either condition.

I'm trying to dig it up for you, but I can only find ballistics info on 9mm for handguns, not carbines. :(

no ideal what the BC is for the 9mm but i personally chronographed the cheap PMC JHP 124g 9mm from my last hipoint 995ts (16" barrel) right under 1400fps,, cant remember the exact numbers and i know the 22lr is rated at 1250fps,,, i know these numbers wont be exact but there damn close (within 100fps for sure)

trip286 04-22-2013 08:06 PM

Then I would consider it sufficient.


All times are GMT. The time now is 06:00 AM.

Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.