August 29, 2022, 07:17 AM
BeancookerA Question for mbinky
Ammo temp makes a difference?
Guessing that the temp changes the distance the round travels?
August 29, 2022, 08:16 AM
MikeinNC^temps affect the distance the round travels by affecting velocity. We used to take temps daily in all magazines. The big gun had an input for temps so that the firing computer could get first round hits on target
September 03, 2022, 09:31 PM
mbinkyquote:
Originally posted by MikeinNC:
What’s the difference in the TM1 & TS1 ammo?
TPMP-T M1002
https://www.gd-ots.com/munitio...unition/120mm-m1002/TPCSDS-T M865
https://www.gd-ots.com/munitio...munition/120mm-m865/Training ammo. HEAT and SABOT.
The HEAT round is pretty much gone from inventory. Units still train with it as the fire control still has the ballistic calculations and it runs like an MPAT.
Last time over in Trashcanistan we carried MPAT and MPHE, which was just the German DM11 round. Had to modify the breech of the M256 but it was the preferred round in country. Worked like a champ.
https://rheinmetall-defence.co...metall_IDEX_DM11.pdfThe DM11 is a programable round; you can set it to point, delay, or airburst. Very handy.
Say you are shooting at a hardened target? Want an old school HEAT round type of effect. Set it to point. Big boom.
Say you are shooting at at mud hut and you want to get the shit pumps inside. Set it to delay. It will punch through the mud hut wall and go off a split second later. Bad day for the ones inside.
Say you are engaging a mortar team behind a berm at 1500 meters (first confirmed kill with the round, BTW). You load MPHE, gunner selects AIR from the gunners station, you lase the target, round gets the info, fire, and the big boom goes off right above the assholes.
It worked pretty good.

September 03, 2022, 10:11 PM
mbinkyquote:
Originally posted by Beancooker:
Ammo temp makes a difference?
Guessing that the temp changes the distance the round travels?
As mentioned, yes it does. Biggest factor is the burn rate of the propellant. We may not notice it when shooting 9mm WWB, but when you are trying to hit a target at 2000M while you are moving in the opposite direction at 20 KPH, small factors come into play.
Again, as mentioned, velocity plays a big role when you are launching big projectiles. A change of 100 M/S due to burn rate can mean the difference between a hit or a miss way out there.
The number of factors that go into a ballistic solution in an Abrams is amazing. And it happens in a split second. There are two types: automatic and manual. Ammo temp is a manual input. Crosswind is an automatic input (for example). If there is a failure of the ammo temperature gage the crew is trained to input a "standard" number to get the solution; if they are on a gunnery range they can ask the tower for the ambient and go from there. Since the rounds they are carrying are not a real combat load and will not spend a great amount of time in the ammo compartment the ambient will most likely be close enough.
The basic fire control of the M1 series of tanks was developed in the late 60's, early 70's.
We still use the same principals they put into the programming today.
Those slide rule, skinny tie, white starched shirt guys knew what they were doing.
Hat tip to the nerds. Tank gunnery is awesome.
September 04, 2022, 10:12 AM
MikeinNCThanks mbinky, our 76mm ammo was very similar. Three fuse settings for different targets
IR- for aircraft/missiles- the fuse emits and detect when it’s near an object and explodes to creat flak thus downing the plane or missile
PD-point detonate for ships
Delay- strikes and penetrates then explodes for ship
The projectile is 14pounds and velocity is 3000fps
This wiki page talks about it and some newer fuses
https://en.wikipedia.org/wiki/...ara_76_mm#Ammunition