3" Mortar information

[Ed Storey]

Interesting wooden box but I doubt it is for 3-In mortar bombs as the bombs were delivered in cardboard tubes, strapped together so that they could be carried in groups of three. These tubes were then shipping in either wooden or metal boxes; two sets of three - 6 bombs to a box.

[welbike]

Well Ed, I don't know, that's why I posted it here! the cubicles are slightly over 3" square (80mm) and a total of about 14" (360mm) deep.

Here a better picture of the lable;



Date is 1976, were they still used by then??

Cheers,

Lex

[Ed Storey]

The M.L. 3-In Mortar was replaced in the mid-1950s by the 81mm Mortar. Is there a marking on the bottom of the box, perhaps something like as an example B.103?

[Godwin Hampton]

Darrin, the 1951 Infantry Training pamphlet for the 3" Mortar shows a barrel with a removable breech piece, describing it as the Mk 5 barrel. The square baseplate with large holes and a chain handle at the rear of the top plate is called the No. 6 baseplate, and finally the bipod having stamped plates ( rather than forged ) joining the 2 legs to the elevating screw tube is described as the Mk 5 bipod.

Now these different versions of these 3 items could probably all be used together interchangably! So you could have a mortar having a Mk 3 barrel, a No 4 baseplate and a Mk 1 bipod!

The Small Arms Training pamphlets for 1939 and 1943 show the one-piece tube, the tapered corner baseplate and the bipod with forged horizontals joining the legs, without giving any marks or numbers.

The 1937 Handbook ( reprinted by The Naval and Military Press and very informative! ) probably issued when the mortar was accepted for service starts with the Mk 1 barrel, but gives no marks or numbers for the baseplate and bipod shown.

There were, thankfully, only 2 marks of sight which have a different mounting system so this also entails differences in the bipod sight supporting bracket.

So to simplify I divide the 3 inch ( actually 81mm ) mortar versions broadly into two types, the early with the one-piece tube, tapered baseplate and forged bipod and the later type with removable breech piece, square baseplate and stamped bipod.

[Mike Cecil]

Darrin,

I have some information on the 3 inch mortar base plates pertaining to Australia:

(1) pre-war and early war base plate Mk.1: as per the image in the Mortar Carrier handbook. Same as the Brit mortar plate.
(2) circa May 1943 introduction of the No.4 Mk1 base plate: essentially the same shape as the Mk.1, but with increased ribs and strengthening pieces to cope with higher incremental charges, as the Mk.1 was found to bend when firing higher charges. Most obvious differences were underneath, where there was substantial increased ribbing (and greater weight!). This appears to be the one illustrated in the book page image posted by Rob Love (above).
(3) In early 1945, certainly before June 1945: introduction of the base plate No.6 Mk.1(Aust), which is the square one with the two rope handles, as seen with mortars issued post-war. The plate was introduced to cope with the increased recoil of higher incremental charges and to be several pounds lighter in weight than the No4 Mk1. This remained the service base plate post-war until the withdrawal from service of the 3 inch mortar.

I'd suggest that finding either a Mk.1 or No.4 Mk1 base plate in Australia will be very difficult. You perhaps might find one overseas.... then you have to get it to Oz .... and past customs.

Regards

Mike

[David Perrott]

Hi all i have a pair of NOS storage tubes ie 2 lots of 3 in there original crate for sale if anyone is interested they are 42 and 43 dated.

cheers dave

[welbike]

Originally Posted by Ed Storey

The M.L. 3-In Mortar was replaced in the mid-1950s by the 81mm Mortar. Is there a marking on the bottom of the box, perhaps something like as an example B.103?

Ed, cannot find anything on the one box, will check the others though.

On the Subject of sights, have some sights f/s. too, marked 4.2" but believe they are same as 3"

Cheers,

Lex

[Darrin Wright]

Thanks all, now I have an understanding of what & when with the various mortar items.
I think it would be quite hard to find the correct early baseplate, then the cost would possibly make me cry.

Reading the trg pams, I think there are 2 aiming posts with each mortar.

Posting some pics of sights that I have found on Ebay for interest.

[Darrin Wright]

a couple of pics from Ebay of a bi-pod.

What Mk is this?

[Darrin Wright]

another pic showing the aiming posts and tube cleaning rod.
This is Colin's Mortar Carrier that appeared at Corowa some years ago.

What colour are the aiming posts painted?

Do others have pics out there to add to the variety of equipment used with the mortar? nationality does not matter, but would be good to highlight the differences.