7.65 Argentine Ballistics


#1

Does anyone have a period ballistics chart for the 150gr spitzer load of the 7.65 Argentine? Information on other loadings is also appreciated, but not exactly what I’m looking for.

Thanks,

-Tau


#2

I found a drawing of the Turkish 10g spitzer, if anyone else wants it.


#3

There exists a Hirtenberger factory firing table for the heavy 12.0 g boattailed bullet of the 7.65 mm.
But I must warn you that it suspiciously well fits the Mayevski-Sabudski drag law (a.k.a Ingalls’ tables) as well as G1 drag law. It therefore is a purely computed table and we do not know to which extent it is based on real measurements at long ranges.
Are you still interested?

After having seen modern radar data (which is the most reliable data available today) for several rifle cartridges, my recommendation is: never trust an official firing table. They tend to be overly optimistic and below about Mach 1.2 are very unreliable due to the difficulty of exact measurements at these velocities.

The typical spitzer bullets like U.S. M1906/M2, German S, or Soviet L (M1908) behave very similarly and are well described by the U.S. drag law for the M2 bullet, the German S bullet or the British 1940. G1 is a total failure for these bullets, unless you are an ammunition manufacturer. G1 yields higher velocities on paper than in reality, especially if you use a ballistic coefficient determined close to the muzzle.

The question is: are you looking for historic data (as used by the military at the time) or do you want -as far is possible- realistic data to do comparisons with other cartridges?


#4

JPeelen, it can’t hurt. If you would send it my way, I’d be much obliged.

I am looking, mostly, for period data on muzzle velocity or chronographed velocity at a stated distance. I am trying to get as many sources as I can for a muzzle velocity measurement from as early a date as possible.

I have already got several good ballistic models for S/M2 type bullets that I can compare to each other. Adjusting these for similar bullets (like the Argentine’s) is pretty easy, so I’m not too worried about bad computed ballistics table as I always make my own with better drag models to determine if the table makes sense (as you say, they are rarely very accurate).


#5

I will dig it out.


#6

Tau, this is the ballistic chart of the Argentine Model 1909 cartridge with 10 g S profile bullet fired in the Argentine Model 1891 rifle reformed for this loading.


#7

Magnificent! Thank you, Fede!

That is with a 780mm barrel? Do you know if any charts are available for the 590mm or 447mm barrel lengths?


#8

If this was fired with a rifle having the standard barrel it would be 740 m/m (29.15 in.). Jack


#9

Tau, barrel length is 740 mm, as mentioned by Jack. This ballistic chart also applies to the Model 1909 rifle, which has the same barrel length. In fact, this is actually a Model 1909 rifle chart that was copied in the reformed Model 1891’s manual.

Regarding the barrel lengths you mention, which carbines are those? If you are interested, I can post charts of the Argentine Model 1909 cavalry and engineer carbines, both having a 556 mm barrel length.

Regards,

Fede


#10

The Hirtenberger firing table for the 12 g (9 degree boattail) bullet, as printed by Josef Mötz in Vol. 2 of his book on Austrian Military Cartridges is:


Colums are:
Horizontal range
Angle of departure
Angle of fall
Time of flight
Terminal velocity
Maximum ordinate
50 percent dispersion (length, width, height)
Drift correction

According to Hirtenberger, the muzzle velocity from a Colt machine gun is 745 m/s and 757.5 m/s from the rifle.

Edit: Sorry for the somewhat oversized image. This was my first attempt at showing one.


#11

I think that barrel length was a typo. I know relatively little about the different Mauser variations. Didn’t the Mexicans buy 23" (590mm) barreled 7.65mm rifles? They are mentioned in an FN catalog.


#12

The German-made Mauser 98 short rifles (K98a, K98k, Standard-Modell) were all fitted with a barrel of 600 m/m length, but for a reason not known to me when FN in Belgium and CZ in Czechoslovakia began to offer a similar type of short rifle in the 1920s the barrel was of 590 m/m length. I’d wonder if Mexico would have bought rifles in 7.65 m/m, however, because their standard caliber was 7 m/m. Jack


#13

In anticipation of an article that never got written, years ago I did a lot of research on metallic cartridges made in México for their use, made in México for other countries, and made in other countries for México. It was primarily on headstamps and their meaning. I found so many more Mexican headstamps than I thought existed, that after drawing all of them, I gave up on an article as being far to long for the ICCA (now IAA) bulletins contemorary to my research.

A review of my card file (each headstamp was drawn on a separate 3 x 5 card) reminded me of some surprises at that time, well known now, such as 7.52 x 54R and 8 mm Mauser made in México. I found none in 7.65 Belgian (Argentine) Mauser caliber. The point is, if México had adopted a 7.65 mm Mauser, I would think that Fábrica Nacional de México would have made ammo for that caliber, since they had the capability to produce small or large lots of most any metallic rifle cartridge that they needed. That doesn’t mean that no 7.65 mm Mausers ever made it to México. Prior to modern times, with firearms ownership now dramatically curtailed in that country, it was truly a gun-owner’s nation, with just about anyone with the desire to do so owned guns.
Most anything ever used in North, Central of South America up until those days could be found there, along with weapons from Europe and even Asia.