Author Topic: Bullet shape & alloy effecting velocity  (Read 291 times)

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Offline ought6

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Bullet shape & alloy effecting velocity
« on: May 07, 2005, 09:11:02 AM »
Is there anyone out there with an Oehler system that measures not only velocity, but pressure?  I have a great experiment.  Using common 30 caliber bullets (because they are the most popular)of the same weight, using the same primer(same lot #), powder and weight(same lot #), same cases, same firearm, and obviously - the same caliber (30-06, 308, etc.), see which bullets gave the highest velocity vs pressure.  Jacketed bullets of the same weight and style (i.e. spitzer), but different manufacturers have not only different bearing surfaces thus, differing drag, but they also have different alloys, thus, differing drag.

If we wanted to use a common (brand) bullet that, by either reduced bearing surface, or the use of jacket alloy that produced the best velocity vs pressure, which would it be?

Boy, it'd be nice if Rick Jamison was on this forum.  I know he's got all the bells and whistles.

Can anyone give this a scientific shot?  It would be very appreciated. :D
Psalms 18:34-35 He trains my hands for battle, So that my arms can bend a bow of bronze. (35) You have also given me the shield of Your salvation, And Your right hand upholds me; And Your gentleness makes me great.

ought6

Offline ought6

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Bullet shape & alloy effecting velocity
« Reply #1 on: May 10, 2005, 01:19:09 PM »
Well,
No takers, huh?  I've waited a while.

I'm glad I found 24 hour campfire forum.  I received many responses there!!

I thought some of you knowledgeable folk would have chimed in on this one.

 :cry:
Psalms 18:34-35 He trains my hands for battle, So that my arms can bend a bow of bronze. (35) You have also given me the shield of Your salvation, And Your right hand upholds me; And Your gentleness makes me great.

ought6

Offline RugerNo3

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Bullet shape & alloy effecting velocity
« Reply #2 on: May 12, 2005, 12:04:09 AM »
The big variable is bullets have to be of the same lot number and you would have to have an anticipated lifetime supply of them for this info to be of any use. Other then that,?????
Then throat erosion of the subject rifle is a big variable which leads to more questions and all info generated would only apply to this firearm. Looks like a never ending story for personal satisfaction. All of this leads to where? This is a pragmatic answer, I know, but may be the reason you didn't get any answers from all these intelligent posters. Not trying to be funny, but in truth you are on a very slippery slope with all this data you would be collecting. I see no place for it to be useful to anyone other then self satisfaction, so run your tests for no other reason. Having fun is what it's all about.
"Use a big enough gun!"

Offline ought6

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Bullet shape & alloy effecting velocity
« Reply #3 on: May 11, 2005, 07:01:43 PM »
Thanks, Ruger, for responding.  I agree that it would be fun if I had the equipment.  Alas, I'm stimied by only a chronograph.  Anyway, I know that some bullets, because of their alloy or shape take more pressure to engrave onto the rifling.  Others simply slide on in and are able to achieve the same velocities with lower pressures.  That is all I'm after.  Disregarding the coated bullets (yuck!!), from talking to the fine folks at Sierra bullets, even their bullets are quite different.  Now, I'm concentrating on 180 grainers.  However, at one time, I was mostly loading 165 grainers.  I found in the Sierra manual with the particular cartridge I was loading (300WSM at the time), that they were able to use the exact same grains of R19 powder with the 180's as the 165's.  The techs explained that it was because of the bearing surface of the 180 grainers being less than the 165's and slide down the bore easier.  
See where I'm coming from? :D

Hey, how did this reply get above your's?????
Psalms 18:34-35 He trains my hands for battle, So that my arms can bend a bow of bronze. (35) You have also given me the shield of Your salvation, And Your right hand upholds me; And Your gentleness makes me great.

ought6