WW2 US 60mm M49A2 High explosive mortar shell

[pzgr40]

Cutaway model of a WW2 US 60mm M49A2 High explosive mortar shell as used in the 60mm M2 mortar.
The M2 mortar was a light mortar used for infantry support at company level, filling the gap between the thrown hand grenade and the heavier 81mm mortar.

The M49A2 shell consists of a cast steel body, machined on the outside at the top to form a forward bearing surface and a gas check. The shell body is filled with 0,34 pound of TNT.

The tail has a screw in primer cap in the base with a M5A1 cardboard 20 gauge cartridge filled with ballistite above it.
Four celluloid incremental charges are placed between the tailfins, secured with a clip. Depending upon the required range the mortar is fired with four charges for the maximum range (2000 yards), either without incremental charges for the shortest range (200 to 300 yards). With the max. range the Vo of the projectile is 520 mtrs/sec. Incremental charges can be removed for in-between ranges.

The fuze used is the PD M52B1 (PD stands for Point Detonating) (Pict 03 & 04)
The fuze consists of a lower fuze housing (01) containing the safety mechanisms, the out of line placed detonator, and a booster charge screwed into the base. The upper fuze housing (02) contains the spring loaded firing pin (09).
Functioning of the fuze:
Prior to firing, the safety wire (wire, see pict.04) that fixates the set back pin (03) is removed. Upon firing, the set back (03) pin moves backward against it’s spring (04), thereby releasing the spring loaded safety pin (05) that fixates the slider (06) as well as the primer/detonator (07) placed in the slider in the safe -out of line- position. As long as the mortar shell is in the barrel, the safety pin (05) cannot fall out of the fuze housing as it is stopped by the inner wall of the barrel, as soon as the shell has left the barrel, the safety pin (05) falls away.
In safe position the primer/detonator (07) is out of line with the firing pin (09) and the Tetryl lead (08). When armed the the slider spring (10) has moved the slider with the primer/detonator in line with the firing pin (09) and Tetryl lead (08). Upon impact the firing pin moves downward into the primer detonator, initialing the Tetryl lead, the booster charge and the main charge in the mortar shell.

The difference between the fuze PD M52 , the PD M52B1 and the PD M52B2 is as follows:
- the PD M52 fuze housing is fully aluminum made,
- the PD M52B1 fuze housing is fully Bakelite made,
- the PD M52B2 fuze has a Bakelite lower fuze housing, and an aluminum upper fuze housing.

Regards, DJH

 

[US-Subs]

DJ, don't forget the bakelite on aluminum version of the fuze, and the WP version (attached burster), among others.

 

[Peter OM]

Hello, just looking for some information on this M2 mortar shell marked, " 1954 60 mm M50A2 " on the body and " DUMMY SQ &D " on the fuse area. Is this an official dummy round?Thanks, Peter OM

 

[US-Subs]

No, on two counts. First is your terminology. The M50 is a US practice mortar, not a dummy. Second, the fuze that you have is a dummy, but it is for French mortars, not the US M50. I've only seen it on 120mm's. I suppose that export versions of the M50 could have been made by/for other countries that might have used that particular fuze, but not to my knowledge. The dummy fuze would not have been used with that mortar regardless, as the M50 had a spotting charge and needed a source of initiation which it would not get from a dummy fuze.