Calculation for cartridge specific magazine platform

28 February 2018, 05:03

Folks,

I am aware of the calculation required for magazine dimensions for specific cartridges and have my Mauser feeding well but I have been thinking of going one step further and building a cartridge specific magazine platform.

Does anyone know of such a formula ???

28 February 2018, 21:08

Phil Brousseau

i'm not sure i understand your question. are you aware of mauser's formula for individual cartridges?

28 February 2018, 21:29

bluefish

quote:
mauser's formula for individual cartridges

Phil

Can you provide that formula or a link to it please?

Thanks.

28 February 2018, 22:09

adamhunter

I think it it rim dia. x .866 + rim. dia. For a 30/06 it would be:

(.473 x .866) + .473 = .883

Same for shoulder.

28 February 2018, 22:19

Phil Brousseau

adamhunter is probably right. google: mauser cartridge specific magazine dimensions. second on list. bolt action rifles pg. 13 and forth on list: deer rifles and cartridges D'Arcy Echols explains. i hope this helps.

28 February 2018, 22:34

Phil Brousseau

good write up on african hunting.com. proper magazine layout.

01 March 2018, 05:02

twobobbwana

Adamhunter,

I think you've got it right.

In it's fullest form it's:

The magazine width corresponding to the shoulder of the case is shoulder diameter x cosine 30 degrees (.866") + shoulder diameter and;

The magazine width corresponding to the belt/head/rim of the case is belt/head/rim diameter x cosine 30 degrees (.866") + belt/head/rim diameter.

I am wondering what the significance of the 30 degrees is. Is it the optimum relationship of the cartridges in the mag ???

Does the 30 degrees correspond with the angle of the "cartridge partition" (for the lack of a better description) on the magazine platform ???

I believe that Darcy Echols and David Miller go to the trouble of making cartridge specific magazine platforms and it can only be for better feeding.

I'm sure that there are others out there that do the same.

What say you custom gun metalsmiths ????

01 March 2018, 05:30

Bitterroot

By "platform" I believe you mean follower in our terms. Yes, the follower can be made for specific cartridge dimensions also.

01 March 2018, 18:27

adamhunter

quote:
mauser cartridge specific magazine dimensions

I have the book that Phil was referencing - Bolt Action Rifles by Wayne Van Zwoll. That's the only reason I knew the formula. I'm not a metal smith but did use the formula when trying to make my son's .260 Remington feed better. It worked!

02 March 2018, 04:49

twobobbwana

Bitterroot,

Yes it's the magazine follower that I'm talking about.

adamhunter,

Yes it certainly does work. I converted a military 8mm Mauser (FN98) to .300 Wby Mag and it'll hold four down plus one up.

It feeds 100% ............ but I was musing on building a cartridge specific magazine follower in order to see if it would make the feeding even smoother.

Spose I just haven't got enough projects !!!!?????

02 March 2018, 05:08

Bobster

I suspect the three thirty degree angles combined equal 90 degrees which is straight up. What you want to feed rounds straight up from the mag. Then compute the mag width to accomodate and the follower angle as well.

quote:
Originally posted by twobobbwana:
Adamhunter,

I think you've got it right.

In it's fullest form it's:

The magazine width corresponding to the shoulder of the case is shoulder diameter x cosine 30 degrees (.866") + shoulder diameter and;

The magazine width corresponding to the belt/head/rim of the case is belt/head/rim diameter x cosine 30 degrees (.866") + belt/head/rim diameter.

I am wondering what the significance of the 30 degrees is. Is it the optimum relationship of the cartridges in the mag ???

Does the 30 degrees correspond with the angle of the "cartridge partition" (for the lack of a better description) on the magazine platform ???

I believe that Darcy Echols and David Miller go to the trouble of making cartridge specific magazine platforms and it can only be for better feeding.

I'm sure that there are others out there that do the same.

What say you custom gun metalsmiths ????

02 March 2018, 08:33

adamhunter

quote:
Originally posted by Bobster:
I suspect the three thirty degree angles combined equal 90 degrees which is straight up. What you want to feed rounds straight up from the mag. Then compute the mag width to accomodate and the follower angle as well.
quote:
Originally posted by twobobbwana:
Adamhunter,

I think you've got it right.

In it's fullest form it's:

The magazine width corresponding to the shoulder of the case is shoulder diameter x cosine 30 degrees (.866") + shoulder diameter and;

The magazine width corresponding to the belt/head/rim of the case is belt/head/rim diameter x cosine 30 degrees (.866") + belt/head/rim diameter.

I am wondering what the significance of the 30 degrees is. Is it the optimum relationship of the cartridges in the mag ???

Does the 30 degrees correspond with the angle of the "cartridge partition" (for the lack of a better description) on the magazine platform ???

I believe that Darcy Echols and David Miller go to the trouble of making cartridge specific magazine platforms and it can only be for better feeding.

I'm sure that there are others out there that do the same.

What say you custom gun metalsmiths ????

My trig classes are too far in the past and can’t do the math in my head anymore but I speculate it has something to do with the triangle that 3 cartridges would form, each taking 30%.
I may be way off though.