nylon driving bands?

[Fred]

Hi folks
I bought a few of these off ebay a long time ago. They are approx 125mm diameter and have serrated inner surfaces. I assume that the seller has just found them on a test range and that they may be from an APDS projectile. What might they be off and how could they be detached from the projectile without splitting?


Fred

 

[leeski]

hi fred thay look like there from a 120mm tank round the base of the head unscrews and thay clip in then the base is refitted will post a pic for you later

regards leeski

 

[Chris 42 RQ]

Nylon Bands

Hin Fred very much as Leeski says, although generally the bands disintegrate into a few dozen pieces as the shell leaves the bore.

I think you may have a couple of early "trial" bands there as a lot were fired using very high pressure air as opposed to a burning propellant to provide the designers with some answers before putting them into proper cases and firing them with modern propellants.
You might like to have a look and see if there are any signs of "Powder Burns" on those bands especially at the rear ?

Most APDS/APFSDS rounds use a Nylon/Glass Fibre reinforced band for extra strength as early bands tended to "Strip" and therefore not spin the projectile at the required R.P.M. thus producing all sorts of other problems.

Rounds like the 155 mm Have a "Gas check" band mounted behind the projectiles driving band but these do not "Spin" the projectile merelyhelp prevent very hot gases passing the Driving band in the early "Shot start" before the projectile actually moves up the bore.

Chris :tinysmile_shy_t:

 

[Fred]

Thanks for the input guys
I cannot see any burn marks, which would be consistent with what Chris says. I have a couple more rings, not illustrated and its interesting that they are all different sizes. I was wondering if the 120mm BAT ever used nylon driving bands.
fred

 

[Chris 42 RQ]

B.A.T. 120 mm

Thanks for the input guys
I cannot see any burn marks, which would be consistent with what Chris says. I have a couple more rings, not illustrated and its interesting that they are all different sizes. I was wondering if the 120mm BAT ever used nylon driving bands.
fred

Sorry Fred never heard of the B.A.T. system using any Nylon bands even the few exotic models that were made had ordinary Copper/Guilding metal Driving Bands.

The use of Nylon bands is by no means restricted to the following which did utilise these bands-
120 MM TK APDS/APFSDS/PracDS.
20 Pounder APDS
155 MM rounds destined for the M109 (?) Self Propelled gun.
To name just a few !

I assume that your Bands are threaded inside which would tend to indicate that they were more likely to have come from an APDS round, but how come they have not disintegrated who knows ?

Chris :tinysmile_shy_t:

 

[leeski]

120 mm tank shell

hi fred heres some pics of my tank shell with the nylon driving band

 

[Chris 42 RQ]

120 mm TK Gallery Practice !

Lee could you please let me know what markings that projectile has on the body.

That is a most unusual projectile and I wonder if it is the equivalent of a "Gallery Practice" round ???

Thanks for sharing that with us.

Chris :tinysmile_shy_t:

 

[Fred]

Thanks for the pics Leeski. One of my other bands, which I didnt photograph is exactly like that, even down to the feathered edges where the rifling has deformed it. This particular one does have some possible burn marks in the grooves. Do you know which tank gun that your shell is from (nice shell by the way).

fred

 

[Fred]

heres the pic. Note the black scorch marks between the lands.


fred