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-   -   180 vs 150 ,30-06....velocity difference (https://www.huntingnet.com/forum/reloading/317317-180-vs-150-30-06-velocity-difference.html)

farmerbythelake 02-13-2010 08:08 PM

180 vs 150 ,30-06....velocity difference
 
With a 30-06 Marlin XL7C and a Hawke 3 x 12 SR6, I will try to get 180 grain and 150 to have the same velocity. Will that give them the same bullet drop? If the same velocity, the drop should be the same right? If the drop will become different at what point will the drop change.
The eight loads I will test are:
180 Nosler Partition with H4350 54g and 55g,
180 Nosler Partition with H4895 46g and 47g,
Hornady 150 spire point with H4350 55g and 56g ,
Hornady 150 sprie point with H4895 45g and 46g.
Anyone have any thoughts?
I will try to get a crony and get the loads as close as possible.:fighting0007:

Big Z 02-14-2010 05:48 AM

Short answer--no.

falcon 02-14-2010 07:11 AM


Short answer--no.

+1

i have worked up Remington Core-Lokt 150 grain and 180 grain loads for my .30-06 that shoot to the same POI at 200 yards. The muzzle velocities differ by about 200 fps: At 200 yards the difference in velocities is about 50 fps.

Teach Deer 02-14-2010 07:51 AM

If you can get your bullets launching at the same velocity, then they will have very similar ballistic paths...not necessarily identical though (because of bullet shape, ballistic coefficient, and a hundred other small details).

However, I worry about over-pressuring the 180 grain loads to match the velocity of the 150 grain bullets. There is normally about a 200-300 ft/s difference between the two.

Unless you are shooting at ranges in excess of 300 yards, the normal difference between the two is not really that significant.

farmerbythelake 02-14-2010 11:32 AM

Facon, and Teach Deer thanks for the information. The only load that looks a little hot is the 180 with H4895 47g. If I can get a crony linned up I'll report back to let you know how it works out.

bigbulls 02-14-2010 02:06 PM

If you launch both bullets at the same exact velocity (assuming the same style bullet) then the heavier bullet will shoot flatter and have less wind drift than the lighter weight bullet. Due to it being more resistant to friction it will retain velocity better and will arrive at the target before the lighter weight bullet will.

For example look at how 150 and 180 grain Hornady SST's will compare at 500 yards. Launched at 2800 fps, zeroed at 200 yards.

150 grain...
Time in flight - .666 seconds
Wind drift - 22.9 inches
Bullet drop -47.5 inches

180 grain...
Time in Flight - .645 seconds
Wind drift - 19.2 inches
Bullet drop - -44.6 inches

farmerbythelake 02-14-2010 04:54 PM

Big Bulls,
Thats great information, were did you get it?

bigbulls 02-14-2010 05:19 PM

There are several ballistics programs you can get. Some you can use for free on line.

http://biggameinfo.com/ has a pretty good free one.

farmerbythelake 02-14-2010 05:58 PM

Thanks, going to get to the range as soon as I get some loads worked up.FUN FUN

Prairie Wolf 02-19-2010 08:35 AM

Another thing, don't be surprised if 150's and 180's don't shoot to the same point of impact.

You seem like you are trying to get 150's and 180's to shoot identically for the same gun. You probably can get them close. Maybe bump the 150's up a little bit in velocity and they will match the 180's pretty close. You can play with ballistic coefficients and velocities and make them match.

But you will still have to sight in when switching from one to the other, and real world results may not match computer plots. Bullets companies have been known to fudge a little on ballistic coefficients.


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