CG of my new .357 bullet in simplest form!

[BT Sniper]

OK guys I got somthing hear for you to watch. Should be pretty clear even to the simplest of minds like mine.

Here is the original on left, improved with HP in center, and on right the improved version in FP
http://i636.photobucket.com/albums/uu87/BTSniper/357extreems001.jpg


video link
http://i636.photobucket.com/albums/uu87/BTSniper/th_CGofa357.jpg (http://s636.photobucket.com/albums/uu87/BTSniper/?action=view&current=CGofa357.mp4)

What we have here is a quick video of three .38 cal 158 grain bullets rolling down my computer desk to demonstrate the CG of these bullets. Notice these are all the same weight.

First one you will see is my improved .38 cal JHP from a cutomers modified CH die. Nothing fancy just rolls straight down table.

Same with the second bullet, this one the improved version in FP.

Now the last one you will see the obvious difference. It is made from the unaltered CH die before I fixed it up a bit. As you can see it is imposible for it to roll straight down the table.

Now I will leave the possible ballistic implications of this to the experts but in simplest terms the last bullet is nose heavy! It's CG (center of gravity) is at or in front of the most foward portion of the bearing surface causing it to turn obvioulsy. As such, any bullet that weighs less then 158 formed in the unaltered die will also be nose heavy as the shape of the nose does not change just the amount of bullet you have behind it.

So it seems that this modification I made to the die may potentially make a better ballenced and therefore potentially more accurate bullet? Of course we have a slightly larger nose now causing a bit more drag but .......... I'll leave the rest up to the experts, I like what I see!

Good shooting!

BT

[BT Sniper]

Some day I will figure out how to post the video so you don't have to go to my photpbucket account to view it. Sorry.

Enjoy the show!:popcorn:

[BwBrown]

Brian,

Is it possible that the third bullet is not a uniform diameter - slightly larger or smaller diameter at the middle vs. the end? If the base was a bit larger than the center, it would roll to the side.

Only the micrometer knows for sure.

Just a thought... the stock CH die might be slightly tapered.
Bob

[BT Sniper]

Thats a thought and I'll check but the bullets where made from same die. Which means the only change made was to the size of the nose, nothing changed in the body of the die as far as the taper may be concerned. When I roll the third teh base of the base of the bullet is off the table (not in contact with table) which would tell me it has to be ballance issue.

BT

[a.squibload]

Here's the link copied from the "direct link" window on the right side of the Photobucket page,
I just pasted it in the reply:

http://s636.photobucket.com/albums/uu87/BTSniper/?action=view&current=CGofa357.mp4

You can also use the "Insert link" button (under the smiley button)
in the "reply to thread" window, turns out looking the same:

http://s636.photobucket.com/albums/uu87/BTSniper/?action=view&current=CGofa357.mp4

I don't think you can post a video right in the thread?


PS: That boolit is nose-heavy all right, you can't use it, it will just crash into the ground!...:kidding:

[Daywalker]

I noticed at the bottom of the pages that 45nut has the HTML codes turned off. In order to embed vids, the HTML codes has to be on as the videos are formatted in HTML coding....

If he would allow HTML codes, then you could embed vids to play directly here without being directed away from the site..

[44magLeo]

How does the third bullet shoot? Is it accurate or all over?

[jixxerbill]

just for craps and giggles balance the bullet in a loop of fine twine , maybe a very small dab of super glue to hold in place.. then twirl like a david and goliath deal see if it flies nose first ???..im just wondering....bill

[Blammer]

just make sure you have pleanty of glass with in proximity, so when it cuts loose, you'll know where it landed... :)

[greywuuf]

so why are we thinking nose heavy is a bad thing ? nose light is the cause of most of the stabilization issue we have, the more tail heavy ( cg farther back) the more spin we have to impart to counter the natural tendancy of the heavy end to go first. thats why the heavy ( actually long) bullets have to have such fast twist barrels. a plain cylinder will be balanced... a point makes that end lighter than the flat end, the longer the point and the farther away from the flat end the more the heavy end is backwards, thus the practice with subsonic shooters to load bullets backwards

[LeadHound]

Good point Greywuuf

I load HBWC both ways and can tell you it works. While loading them heavy end first they are more accurate then I out to 25 yards+. When loaded backwards the accuracy is only good at short range upto 6-8 yards, I have not done hard test to see exact range. I do know that under 20 ft they hit POA and thats all I ask of this bassackerd bullet.

If you can make a front heavy pointed projectile congrats you done good.

[greywuuf]

well front heavy bullets require some odd filler materials in the base and some tungsten in the nose, but I have done it, they tend to "over stabilize though" and they are way spendy.

I guess I should have said the backwards bullets will sometimes stabilize and low speed when they bullet is "to heavy" for the twist. by moving the cg forward (loading backwards) you dont need as much RPM

Dan

[docone31]

What are those jackets made from?
Were they commercial jackets, or do you have a draw die?
I have several rolling mills, so I can roll out sheet stock, then anneal in my kilns.
When I start swaging, I want to form my own jackets also.

[BT Sniper]

Customer's personal jackets. I assume they where commercial.