The following information is from a November 1945 publication, which rounds up all the wartime 2" mortar varieties of bombs, cartridges and tails.
This remained extant until 1954, when two amendments were produced, before the publication was superseded and produced in the Loxonbar version, where much of the information was not included because it was no longer relevant to technical staff.
CARTRIDGES TAIL UNITS (NOTE. this is supposed to be CARTRIDGES and TAIL UNITS as a table but I cannot get it to work)
47 gr Ballistite Mk 1 24 hole aluminium tails. Without the extra holes the tails will fracture on firing.
47 gr Ballistite Mk 2 18 hole aluminium tails. No fracturing should occur on firing
47 gr. 81mm. Powder Mk 1 (smokeless, N.A production) Mazak or steel tails
55 gr Ballistite Mk 1 Mazak or steel tails. A small %tage of mazak tails may fracture on firing, but
drilling extra holes not required.
55 gr Ballistite Mk 2 Mazak or steel tails. No fracturing of mazak tails should occur on firing.
50 gr Ballistite (smokeless) Mk 1 Mazak or steel tails. NOTE Mazak was deleted by Amendment 1 in 1954.
52 gr. 81 mm. Powder Mk 1 (North American production) Mazak or steel tails.
In addition to the normal package markings of the time, here are some special markings.
'HC' has already been mentioned.
The words 'ALUMINIUM TAILS' on boxes indicates that the aluminium tails in the package are not suitable for conversion to long range firing.
The letters "LR" indicate the presence of 55 gr or 50 gr Ballistite cartridges for long range firing. In addition, the spring catches, hinges and handle hinges are painted blue and a daub or blue band is painted on each cylinder of the bomb carriers.
A large quantity of boxes produced in North America were painted service green instead of light green. To indicate the presence of smoke ammunition, while obviating the necessity of re-painting the boxes, 2 inch light green bands were painted around the ends and across the top and bottom of each end.
A 1 inch letter 'X' in a circle in red, with an EXMND date means that the bomb fuzes have been X rayed and are safe for use.
I have seen the windshield caps in service, but have never heard of it being used to differentiate fuzes for use with HE only. It is more likely to be a strengthening feature to allow you to fire in driving rain or through thin vegetation. The only other bomb to use fuzes in the 151/161 series is the Bomb 2" Mor Bomb Thrower Bursting Mk 3 filled White Phosphorous. These disappeared in the 1950s as Grenade No 80 WP, fired by Fuze Electric F 103 became the AFV screening smoke of choice. The Bomb Mor 2" Practice HE also has a removable cap, but with a big nut head in the middle.
QUOTE "It has been found that premature bursts of 2" mortar bombs fuzed No 151 have have been caused by the use of ammunition which had made an abnormally heavy landing when dropped from aircraft during exercise. Such a landing would occur from complete failure of the parachute to open or partial opening only of the canopy with the resultant failure to check appreciably the rate of descent of the attached container". This led to the modification of the Fuze 151 and the introduction of Fuze 161.
MARKINGS OF CARTRIDGES (From Amdt 1 of 1954 this applied to Mk 1 only).
Until around the end of 1944 the only markings on the cartridge case, were Makers monogram/initials and Mark.
Then this: CARTRIDGE COLOUR OF CASE PAPER COLOUR OF STENCILLING (this should be a three heading table).
47 gr Ballistite Buff Black
50 gr Ballistite Buff Red
55 gr Ballistite Buff Red
18 gr Ballistite or Hercules Green Black
17 gr Ballistite or Hercules Green Black
42 gr G20 Green Black
73 gr Ballistite Green Red (for use with SIGNAL SUCCESS to gain sufficient height for suitable signal and burn duration).
Since the end of 1944 full details of cartridges are printed along the length in ONE EIGHTH OF AN INCH LETTERS as follows:
The word SMOKELESS where applicable.
2 in ML MORTAR or 2 in BOMB THROWER as applicable (the latter obviously no longer applicable).
"SIGNAL SUCCESS" as applicable (no longer applicable)
The weight and nature of the charge.
Mark of cartridge.
Manufacturer's initials or trade mark.
In an earlier post I mentioned that mazak tails may suffer from what is known as 'mazak poisoning' and that it is possible to detect this because the tail appears to have surface lines like crazy paving. There may also be a whitish powder present. As I said before, such tails can be crushed in the hand leaving part of the central tube.
The cause of this may be contact with some adhesives, but the main cause is damp due to repeated temperature changes, accompanied by high humidity in tropical climates. I encountered this in an extinct ammunition sub depot in Africa in the early 1960s. We had to replace all stocks of mazak tails with steel tails.