I lost IT!

Someplace I had a copy of an interview with Mr. Ecoles in a very early "Rifle Shooter" magazine in which he stated the formula that the Mauser Company used to figure out the dimensions for their various mag boxes....

It was something like: measure the cartridge head diameter, and the shoulder diameter, and multiply by the cosine of X degrees, and those are your widths at these points.

The interview was about Mauser commericla sporters and military rifles. In it he stated that Mauser made each mag box for the particular cartridge they were contracting to build an order of rifles for. I.e. 8x57, Siamese Mauser, 7x57, etc.

This is golden info for an advanced tinkerer like me. Help!

I think this is what you might be looking for.

http://www.mausercentral.com/f...e+dimensions#p119064

November 1997 issue of Rifle Magazine.

I think what I wanted was on Mauser Central. I don't think that I have the Nov. 97 "Rifle." I had a hole in my subscription for aa while.

Thanks guys.

It was in an article of Rifle (hmmm, November of 1997). Wayne Van Zwoll interviewed D'Arcy Echols and Tom Burgess.

Diameter + (Diameter x Cosine of 30 degrees).

Tom told me a couple times that an extra 0.010" to 0.015" did not hurt, either.

Mike uses a grease pencil to mark the steel, so it is a moot point, anyway.

quote:

There is a formula to determine the proper width of a magazine box:

Multiply the cosine of 30 degrees (.866) by the case head (or belt) diameter, then add the head diameter to that product. For example a .375 H&H is .532 across the belt. So .866x..532 = .460 (+.532) = .992. This width should taper with the cartridge. Use the same formula for the width at the mouth. (This formula came from a RifleShooter magazine March/April 04 and is attributed to D'Archy Echols)

To lengthen the box, cut the back wall off, and weld in a filler strip, to increase the bolt throw, you need to modify the bolt stop and ejector.

When working the rails, start with 4 in the mag, and work on the left rail. Than with 3 in the mag, work the right rail. Only after the left and right rails are releasing properly do you tune the follower, with only 1 cartridge in the mag.

Mag box width first, left rail second, right rail third, follower fourth and extractor last.

Howzat Michael?

I believe Wiebe's method will get you to the same point with less math.....

quote:

Originally posted by Duane Wiebe:
Near as I can determine, this should be the proper box width at the cartridge base.

A quote attributed to Tom Burgess:

quote:

Take the diameter at about .200" forward of the base, or at the belt, Multiply this times 1.866025 ( sine of 60 plus one) and write it down, next slide an adjustable parallel at that point in the magazine box and measure the mag box width inside. Worst case scenario measure with a mike outside and subtract the wall thickness of the box times 2. The formula resultant is the theoretical yellow line down the middle of the pavement, so you subtract the interior from the theoretical. Next you measure at the point of the shoulder on the case and run the formula on that number. Here there is a caveat. If you use reloads use the dia. on one that has been full length resized. You subtract whatever the ammount less than theoretical came out of the base end calculation from this number and that is what the dimension should be at the shoulder. The closer a straight cylinder your case measures the more critical the dimensions are for proper feeding. Ie. if the shoulder end was .020 less than ideal then the shoulder end must be less that same ammount also.

Thanks for both of those quotes.

quote:

Originally posted by JBrown:
I believe Wiebe's method will get you to the same point with less math.....

quote:

Originally posted by Duane Wiebe:
Near as I can determine, this should be the proper box width at the cartridge base.

Brilliant! So often the simple approach is best...

The 1.86603 multiplier for the cartridge diameter inside the magazine comes from this trigonometry:
The cartridges pack into an equilateral triangle in cross section.

Some ideal box widths at the rear according to CIP maximums:

.375 H&H rim diameter of .5318" and belt diameter of .5339" maximum: box width at rear = 1.86603 x 0.5339" = 0.99627"
This is more than enough, since manufactured brass is always smaller than the CIP max.

404 Jeffery head diameter of .5429" maximum: box width at rear = 1.86603 x 0.5429" = 1.01307"

.416 Rigby rim diameter of .5902" maximum: box width at rear = 1.1013309"

500 Jeffery head diameter (rebated rim abomination, rim diameter 0.5751968") head diameter of .6188976" maximun:
box width at rear: 1.86603 x .6188976 = 1.1548814".

The CZ 550 Magnum box width at the rear is 1.052" (inside width).
This is greater than needed for the .404 Jeffery, however, my specimen,
uses the same box width at rear, but ribbed box as used for the .375 H&H thus decreasing the effective width to perfection for the 404 Jeffery,
and allowing 5 down in the box.
It is too large for the .375 H&H, and too small for the .416 Rigby, 500 Jeffery, and .505 Gibbs,
even when used without the ribs.
CZ uses the same box rear width for all of these cartridges,
on specimens I have measured.

.505 Gibbs rim diameter of .6401574" maximum: box width at rear = 1.1945529"

Forget about adding slop unless using the "rubber band method" to measure.

Using the max spec brass diameter will build in enough slop since the manufactured brass diameters are smaller than max spec anyway.

Boys: you even scare me. I even understand the math. The willingness to share the knowledge overwhelms me....

I am trying to figure out whether I want to make a 45-70 bolt gun on a Siamese Mauser, or a P-14 Enfield. I do my own work - its aproject gun.

I don't have the reamer yet. So it might just be easier to rework a standard large ring 98 to the 450 Marlin. I will have to see if I can gin up three cobled up cases from some 7mm Rem Mag cases from and load up dummies with my 45-70 dies. The belt will be too short, but we are only talking fit and feed issues.

I always think of the 450 Marlin as an long-belt 458x2.1 without all of the work of case shortening and neck reaming. I think Charlie Sisk was offering conversions on Ruger 77's and Model 70's in the "Rifle Magazine."

No matter what I do: I'll add some throat with a throating reamer to use up more of the mag box than the slightly less than 2.6 inches from SAAMI. I'll go for nothing less than 2.8 inches, and less than 400 grain cast bullets.

Let's us hear your thoughts on my project.

I do know where I can buy a slightly used 45-70 reamer, but that is a small part of the project.

Messing with a rimmed cartridge in a staggered magazine bolt action would quickly turn me away from the .45-70 Govt.
Why, I would rather have even a 450 Marlin, or better yet, the .458 American 2" in a bolt action.

On the flip side, I would much rather have the rimmed 45-70 in a lever action or single shot, whether falling block or break open.
And I can load that 45-70 as hot as any 450 Marlin load, in said LA or SS rifle.