11/16 - Powder & Cartridge Calculations

Something been on your mind that you have always wanted to ask and google is no help. Ask it here!
Post Reply
User avatar
Okie44
Posts: 51
Joined: 12 Feb 2016 17:02
My Press Choice: Turret
Location: NW Louisiana
Has thanked: 2 times
Been thanked: 17 times

11/16 - Powder & Cartridge Calculations

Post by Okie44 »

One of my favorite plinking loads for the 357 Mag with a 158 gr bullet uses 5 gr Titegroup. How many rounds will I be able to load with 1 lb. of powder?
Image
“Good judgement is the result of experience and experience the result of bad judgement.”
― Mark Twain
62chevy
Founding Member
Founding Member
Posts: 1617
Joined: 17 Oct 2013 18:09
My Press Choice: Turret
Location: West Virginia
Has thanked: 1017 times
Been thanked: 323 times

Re: 11/16 - Powder & Cartridge Calculations

Post by 62chevy »

Simple divide 5 into 7000 or 1400 loads.

7000 is the number of grains in a pound.

you can do the same with lead 7000 divided by 158 is 44.303797468 bullets per pound.

+guns +guns +guns
Je suis Charlie
User avatar
Ranch Dog
Site Admin
Site Admin
Posts: 6456
Joined: 22 Jun 2013 17:16
My Press Choice: Progressive
Location: Inez, TX
Has thanked: 1616 times
Been thanked: 2850 times

Re: 11/16 - Powder & Cartridge Calculations

Post by Ranch Dog »

Okay that was pretty quick. How about this? With the bullet seated, how much space (%) does 5-grains of Titegroup occupy of the useful case capacity?

We would need okie44 to give us the overall length of the bullet along with the diameter it is sized to plus the cartridge OAL he is using. I think we could go with the 357 Mag's standard H2O capacity of 25.60 grains and length of 1.290" and the Titegroup's VMD spec of .0848.

Heck, might as well figure out the space 5-grains occupies of the entire case capacity as well so we can see if that charge will overflow if doubled helping us to prevent a KABOOM.

I'll be back in 6 days ;)
Michael
Image
62chevy
Founding Member
Founding Member
Posts: 1617
Joined: 17 Oct 2013 18:09
My Press Choice: Turret
Location: West Virginia
Has thanked: 1017 times
Been thanked: 323 times

Re: 11/16 - Powder & Cartridge Calculations

Post by 62chevy »

Ops that just got out of control :mrgreen: But would like to know how to figure that all out.
Je suis Charlie
Ohio3Wheels
Supporter
Supporter
Posts: 888
Joined: 06 Mar 2016 16:09
My Press Choice: Hand Press
Location: SW Ohio
Has thanked: 156 times
Been thanked: 240 times

Re: 11/16 - Powder & Cartridge Calculations

Post by Ohio3Wheels »

As an aside what bullet is that? For no gas check I like the looks of it, as you said for plinking. Nice lube groove.

Make smoke,
Curt.......makin' smoke and raising my carbon foot print one cartridge at a time +guns +guns
User avatar
Okie44
Posts: 51
Joined: 12 Feb 2016 17:02
My Press Choice: Turret
Location: NW Louisiana
Has thanked: 2 times
Been thanked: 17 times

Re: 11/16 - Powder & Cartridge Calculations

Post by Okie44 »

Bullet length.664" Loaded to 1.58" sized .359

The bullet is a Lyman 358665. Lee has a similar mold 358-158 although the Lee appears to have a more pronounced bevel base than the Lyman. I've been thinking of getting a six cavity Lee to speed up production.
“Good judgement is the result of experience and experience the result of bad judgement.”
― Mark Twain
User avatar
Ranch Dog
Site Admin
Site Admin
Posts: 6456
Joined: 22 Jun 2013 17:16
My Press Choice: Progressive
Location: Inez, TX
Has thanked: 1616 times
Been thanked: 2850 times

Re: 11/16 - Powder & Cartridge Calculations

Post by Ranch Dog »

Okay... until we get to the specifics of the bullet and cartridge overall length, let's look at an empty case vs. the powder charge.

All it takes is the volume of powder (in cubic centimeters) divided by the volume available in the empty case.

1 cc of water weighs 15.432 grains, that is the average of typical tap water but if you really want to get into this, specific waters have specific weights. Anyway...

With the given capacity of H2O being 25.6 grains, the math is:
25.6/15.432= 1.66 cc
A 357 Mag case filled with tap water, flat across the rim, would hold 1.66 cc of water by volume.

Lee has made the powder stuff pretty simple by defining VMD that math is:
VMD times the charge in grains = cc
.0848x5= .42 cc

The rest is easy math:
charge divided by full case capacity = filled (%)
.42/1.66= .25
The case is filled only 25%[hr][hr]The rest is going to be easy if we treat the bullet as a cylinder and determine the volume of the cylinder occupying case space in cc. We take that away from the 1.66 cc available in the case. With that solved we divide the charge cc (.42) buy this result to see the powder density of the load.
Michael
Image
User avatar
Ranch Dog
Site Admin
Site Admin
Posts: 6456
Joined: 22 Jun 2013 17:16
My Press Choice: Progressive
Location: Inez, TX
Has thanked: 1616 times
Been thanked: 2850 times

Re: 11/16 - Powder & Cartridge Calculations

Post by Ranch Dog »

The math of figuring out cc volume occupied by the bullet inside the case (the cylinder) is:

(diameter divided by 2) times ((diameter divided by 2) times the length seated (inches) times 3.14159 times 16.387064 = volume in cc.
Michael
Image
User avatar
GasGuzzler
Moderator & Supporter
Moderator & Supporter
Posts: 2035
Joined: 26 Jan 2016 22:39
My Press Choice: Turret
Location: Cooke County, TX
Has thanked: 330 times
Been thanked: 500 times

Re: 11/16 - Powder & Cartridge Calculations

Post by GasGuzzler »

I have a Lee 358158 in two holes (I think).

I like the math. I like using pi to that many digits. (As an aside I had a kid in one of my big time math classes that had pi memorized to over 100 digits because it was on a banner around the classroom and he paid little attention to lessons).

I've been helped by Okie more than just about anyone but come on dude. Use 2400 and you can't overcharge one enough to blow anything up. Haha. Sort of. Then again, 2400 requires a lot more of a powder very tough to find.

Okie, do you have to muzzle up shake your guns before you shoot 'em? :)
__________________________________________________________________________________________
I've always been crazy but it's kept me from goin' insane.
User avatar
Okie44
Posts: 51
Joined: 12 Feb 2016 17:02
My Press Choice: Turret
Location: NW Louisiana
Has thanked: 2 times
Been thanked: 17 times

Re: 11/16 - Powder & Cartridge Calculations

Post by Okie44 »

GasGuzzler wrote:


Okie, do you have to muzzle up shake your guns before you shoot 'em? :)


I don't do anything special. Titegroup is not real finicky about position. It will attack the plastic tube on the powder hopper!
“Good judgement is the result of experience and experience the result of bad judgement.”
― Mark Twain
Post Reply

Return to “Question Of The Month”