Unusual 8mm rounds.

[Willi Z.]

Hi Greg,

Tropical rounds are identified by the box and by the painted lacquer seal between the bullet and the casing. At first most just simply thought that tropical ammo just meant that it was weather sealed from the elemements. But, a 1942 Luftwaffe manual said otherwise;

"The atmospheric conditions in the tropics have an especially unfavorable effect on ammunition. Variations in temperatures and humidity alter the gas pressure on the propellant charges as well as the muzzle velocity, and thereby increase the dipersion. High temperatures and low atmospheric humidity lead to exceptionally hiugh gas pressures of the powder and if the occasion arises, to the bursting of barrels and distrubances in functioning; or they decompose or later the explosive and incendiary loads of other bullet charges. For those types of ammunition which are esepcially influenced by these effects, "Tropical Ammunition" has been devloped."

This is from Dan Kent's book on 8mm ammo. The Germans were anal about these kinds of things. They even had different markings on sniper scopes and other optics to designate whether they should be used in continential, artic or tropical regions. On the matter of small arms ammo, it does make a difference. I remember while shooting matches on the competitive IPSC circuit, that we had to test our loads (by chrono) to see how are powder charges were effected by the climate out in Arizonia and New Mexico. So, since most of the above posted trop rounds are for aircraft use, it was most crucial to know how the round would shoot, rather than for a MG34/42 on the ground.

Regards,

Willi

[John Hodgin]

Hi Willi,

Optics designed for certain climates is very interesting. This makes excellent sense. When you were collecting sniper did you find scopes marked for tropics or extreme cold? If so, please do a thread and post some photos of them.

An 8mm round would travel very differently in dry artic air compared to hot humid air. So much so, that at sniper ranges, it would mean the difference between a fatal hit and a wound or even a miss.

Since you were a sniper collector first, how about a thread on Fj snipers. How did they function within their larger units, command etc.? Even in the Crete photos (perhaps the staged post battle photos) there is a para with a scoped 98K.

Best,
John

[Brian M]

John,
there were scopes treated for different climates. the adjustments on the drums for windage and elevation were the same. there was no change in adjustment for the conditions, however, the scopes were treated for the differing conditions. i.e. charged with nitrogen or sealed with heavy grease for the arctic usage, sealed with a thin rubber gasket and special grease for the tropics, etc. to prevent fogging of the internals. the small "triangle" or "+" marks on the scope or optical piece bodies is filled with a color coded paint. blue paint designated winter or Arctic climates, Green was for Tropical climates, and White was general purpose. sometimes this can be hard to discern today as the scope may have been cleaned, or lost most or all of the paint.

to continue the marking paint discussion, other than on the scopes to designate climactic treatment, and on some pistols to mark the safety or "s,f" position, this was the only legitimate paint on weapons items that I am aware of. it served a definite purpose to mark these specific areas.