M61A1 no markings at all


#1

I got this drillcase with inert (blue) tip more than 30 years ago. The story tells it’s a M61A1 round from a Belgian F16 which seems possible considering the dimensions but I have already learned to be cautious… But why nothing on it: no headstamp, no marks…nothing at all. Or should I consider the detail on picture 3 (in the middle of the case) as some mark? And if so, what does it mean?


#2

Without any markings a positive ID is difficult but the projectile is not the standard 20x102 type as per it’s visible construction.

The OAL of the cartrigde may help in finding out if the projectile belongs to this case.

The round mark on the side of the case is from a closed gas port of a test barrel with a pressure gauge port. Means the case was fired in some sort of test environment in a factory and not in a regular gun chambered for this caliber.


#3

The story that your round is Belgian is quite possible, seen the strange visible construction as EOD says.
FN did make such odd constructed TP rounds in the '80s and they were designated FN 140


#4

Is a list of these FN designations known?


#5

I don’t know if there is a complete list of the FN designations, but i have a copy of an FN catalog (12,7mm to 30mm) that uses them.

The 20mm rounds have following numbers:

20x102: FN140:TP ; FN141:TP-T ; FN142:HEI-T/SD ; FN143:HEI ; FN144:API

20x110 : FN80:HEI ; FN82:HEI-T ; FN83A1:TP-T ; FN85A2:TP ; FN92:HEI-T/SD ; FN94:API-T

20x110RB: FN60:HEI ; FN62:HEI-T ; FN63A2:TP-T ; FN65A2:TP ; FN71:HEI-T/SD ; FN72A1:AP-T


#6

Thanks a lot for this information.

No 20x120 in the catalog? FN made projectiles with FN75 designation in the mid 1980s.


#7

Defender,

There’s no FN75 in the pages i have, but i’m not sure if i have copies of all pages from the original document…


#8

The OAL? My measure is too small… Case length is approximately 101,80, bullet lenght, seated in the case 65,87 and bullet diameter 19,54. Millimeters, please. After seeing the pictures of Orpheus on his site, it seems my cartridge is belonging to the same “familiy”. A German round? The person who gave it to me served at that time (1981) at least in Germany within the Belgian Army.


#9

duqjans,

I’m 99,9% sure yours is a Belgian FN140 20x102 round (but i guess you have a repainted projectile as even the copper driveband is painted…).


#10

orpheus,

Can it be a German case and a Belgian bullet?


#11

As the round is not crimped, it sure is possible that your case and your projectile are no matching set, but what makes you think the case is German?


#12

When the ink markings on the case are gone it is basically impossible to tell where it was made.


#13

[quote=“Defender”]Thanks a lot for this information.

No 20x120 in the catalog? FN made projectiles with FN75 designation in the mid 1980s.[/quote]

I guess it was pointless to have a way outdated caliber in the official catalog as the 1986 order of 20x120 from SEA was merely a big exception.


#14

Well, I remember 20x120 cases in a modern Lapua catalog. So I was just curious.
Sorry for this deviation. Now back to topic.


#15

Well, I remember 20x120 cases in a modern Lapua catalog. So I was just curious.
Sorry for this deviation. Now back to topic.[/quote]

That catalog is also 20+ years if I remember correctly. Also more than odd.


#16

To orpheus78:

Looking at you pictures, it seems that only the projectile of your Belgian FN140 is identical to mine, except for colouring. Then the case. Without any crimp. Two types in your collection: the German DM58 and/or the (American) M55A2. I know, this is only observation… Wish it was that simple…
But at least, it gives some new vision and insight in this kind of materials.


#17

As your case was fired in a test environment it may well be that there never was a crimp as it was not factory loaded and the case maybe served only as a separate propelling charge for any test vehicle that had to be acelerated to a certain speed.