20mm Drill rounds

[spotter]

ave just cut these two 20mm drill rounds ,dont know much about these so please feel free to add more
The fat one i believe is a 20mm Vulcan ?? drill round it is weighted with a resin insert..No stampings would this have been painted originally ??
The other i believe is a 20mm Hispano ?? This is of copper construction and plated ,with a threaded steel plug soldered in the base.Stamped Drill on the lower end of the body and headstamped 20mm

 

[TonyE]

20mm

Yes, they are an M61 Vulcan and a 20mm Hispano. The latter is a normal postwar British drill round.

Regards
TonyE

 

[leeski]

nice cutting spotter

regards lee

 

[spotter]

thanks for confirming what they are ,and the compliments.
Tip if anyones going to cut one of these drill vulcans buy plenty of high quality saw blades,i used 2 good quality ones on this one,theyre very hard steel

 

[Weasel]

Nice job...they look great.
Best Weasel.

 

[glevum]

What is the difference between 20x110 Oerlikon and 20x110 Hispano or are they the same round?

 

[hangarman]

20mm Vulcan

The fat one i believe is a 20mm Vulcan ?? drill round it is weighted with a resin insert..No stampings would this have been painted originally ??
[/quote]

They were originally cadmium plated. Always wondered what was inside.

 

[Chris 42 RQ]

Oez/Hisp

The cases are very different in shape as the Oerlikon has a rebated rim and a long tapered neck that gets blown out of shape during the firing sequence.
See the pictures below.
1-20 MM Oerlikon unfired
2-20 MM Oerlikon Fired case.
3-20 MM Hispano

 

[hangarman]

20mm

What is the difference between 20x110 Oerlikon and 20x110 Hispano or are they the same round?

The 20mm oerlikon is a rebated rimless round, the Hispano is rimless. The Oerlikon also has a longer neck .

20 x 110 Hispano rim .980" case 4.335" body .980" neck .811" bullet .783"

Hangarman

 

[glevum]

Thanks,

I didn't mean to hijack the thread.

 

[spotter]

dont apologise glevum,its all related to the original post
excellent information everyone thank you

 

[glevum]

I've been wondering for a long time how this case got like this.

Now I know.

 

[Tony Williams]

I've been wondering for a long time how this case got like this.

That is not what a fired Oerlikon case should look like (see the one in Chris's pic in post #8). Something seems to have gone wrong with yours...

 

[Chris 42 RQ]

Late pressure relief ?

I've been wondering for a long time how this case got like this.

Now I know.

Your case damage is almost certainly due to the gun it was fired from having been set up incorrectly.
after firing the pressure should be reducing before the case is fully extracted and it looks like that did not happen with your case!