Would like velocity and trajectory comparison

montanajoe

between 150 gr .270 Win and 120 gr 6.5 creedmoor. Would really like side by side comparison. Thanks.

mark christian

This is one for moderator nononsense, who is the site's expert in ballistics.

Milliron

Guess you have good reason for this. Seems to me to be an apple/orange thing. Why not compare !40 grain in each. JMHO

MIKE WISKEY

bullet 'weight' has little to do with 'trajectory', the ballistic coefficient and velocity do. best is to compare bullets with the same b.c.

Milliron

And that makes sense. Guess I am "hard wired" to terminal effect. Let my prejudice keep me from "listening" to the question.

nononsense

There are a couple of stumbling blocks when we try to compare two different cartridges and two different bullets. But we can make some generalizations regarding the bullets flight based on internal ballistic calculations.

The above examples from Nosler are good general charts for internal powder performance which allow for a muzzle velocity comparison. From here we can take this MV information and use it to plot ballistic profiles or drop and drift charts.

My comparison is done from my notes and calculations using the same style bullet, the 150 gr. and the 120 gr. Ballistic Tips. Without getting into some interesting math I can generalize the following information:

.270 Win. + 150 gr. BT = 2987 fps. @ the muzzle, 2972 ft/lbs. of energy at the muzzle in a 24" barrel

Keeping 1000 ft/lbs. as the minimum energy at any distance this yields:

700 yards maximum with 109 inches of drop and 33 inches of drip in an average 10 MPH 90 degree wind.

________

6.5 Creedmoor + 120 gr. BT = 3100 fps. @ the muzzle, 2610 ft/lbs. of energy at the muzzle in a 24" barrel

Again, keeping 1,000 ft/lbs. as the minimum energy at any distance this yields:

600 yards maximum with 66 inches of drop and 24 inches of drift in an average 10 MPH 90 degree wind.

________

All of these numbers can be juggled to provide several different scenarios just as in any statistical report. The numbers I used above attempt to keep things in an 'apple to apple' comparison. Even the barrel length is the same. You can derive the information simply from the above. You can also doa much more complex version by juggling the bullet style and weight, often achieving some surprising results.

Best.

select-fire

Here is a start.. go to each link on the site at the top. It will show trajectory ..enter bullet type etc... This will keep you busy for awhile .. but real interesting on ballistic coefficient on long range energy.

http://www.shooterscalculator.com/bullet-kinetic-energy.php

montanajoe

Thanks, that answers what I was looking for and then some. I appreciate you taking the time to figure and post this.

Just trying to do a comparison of grandma's .270 with the round she uses -vs- granddaughter's 6.5 and the round she uses.

Select, thanks for the link, that could be cool to play with comparing rounds.

select-fire

Thank you for the thread. I got the 25/06 miracle bullet from nononsense's post on another thread

Mobuck

My hunting partner showed up with a .270 to zero for our upcoming elk hunt. After a few shots, the 270's recoil was getting to him so I offered to let him pop a couple through the suppressed 6.5Creedmoor. His comment "Nice little deer gun, too bad it's not got enough gitty up for elk". I produced the numbers indicating the 6.5C was only 6-7% below his mighty 270 at ethical hunting ranges. Then I told him the only thing preventing me from taking the 6.5C on our hunt was lack of suitable ammo.

We got his 270 zeroed but darned if the guy didn't spend half a day driving around Des Moines looking for some Accubond/Partition/ Barnes bullet 6.5C ammo. I'd bet he owns a 6.5C before we go west next year. The only reason I bought the rifle was due to it being suppressor ready in an economical package but it sure is fun to shoot and coffee cup accurate to 350 yards.

Bottom Gun

I've been using this one. It will allow comparison of two loads in graph and chart form.

http://gundata.org/ballistic-calculator/