Experimental Mills grenade 1917

[Andy A]

I was very lucky to acquire this Experimental Mills grenade last year, Its a NO 36 which was trialed for use in a Burns cup grenade discharger without the use of a gas check. Instead it has a thick band of metal around the second segments. It was found I gather at the Esher Experimental range with just a centre tube and no filler screw so I have kept it as found, It was completely empty with a brass base plug  made by Messrs Morum and co and dated I/1917, I suspect whoever was trialling it used whatever plug they had to hand and there are no visible makers marks on the body which was usual at this stage of the war.Sadly, the original plug was separated from the body of the grenade when sold so I have replaced it with an earlier one from the same maker.So far no information has been found on it  so its rather an unknown item and possibly the only one in existence making it  somewhat rare when you consider that they made over 75 million Mills Grenades in WW1. All i have done to it is stabilise the rust  inside and out as it was in poor condition when i got it and sealed it from any air to hopefully make it last a while longer.It was obviously not put into service for reasons unknown, either it did not work efficiently or was too costly to produce, we will never know.  As it was  in the ground for some time, I suspect the body will corrode in time. No idea if it was originally painted in any way, I suspect not. but its completely inert and has pride of place in my collection. If anyone has a brass Morum and co base plug dated 1.1917 they would be willing to  part with please let me know.

 

 

Andy

[JMB1943]

Andy,

I have recently become interested in the Mills No. 36 grenade and on trawling the threads came across your experimental one.

Very surprising that none of the grenade aficionados @Gunner Bailey @14276265 have picked up on this.

Possibly the reason that it never made into production was that the somewhat rough castings could not reliably seal the discharger cup consistently to give the range achievable using the gas-check disc.

Have you seen literature regarding this experimental shape?

Regards,

JMB

[Gunner Bailey]

JMB

A number of gas check body designs were considered. Some are documented some are not. The idea persisted thought to WW2 but never achieved production. 

GB

[14276265]

JMB,

This is a well-documented one. Range and accuracy trials were carried out, with several dozen shots fired. As you surmise, the castings were the reason for the device not progressing, not because they were too loose, but because they proved too tight* and the rifle used to fire them - which had previously successfully fired hundreds of No.36 grenade - suffered a structural mishap. (The average maximum range attained was significantly above that of the No.36 with gas check disc.) A new rifle was used and suffered a similar fate to the first and the trials were terminated.

The various findings from the trial resulted in no further action being taken.

 

*Many of the grenades made for the trial did not even fit into the discharger cup.

 

 

265

 

 

[JMB1943]

265,

Thanks for that information.

"avge. max range was significantly above that.....with the gas check disc" implies that there was considerable combustion gas loss around the circumference of the disc.

What do you reckon was the gap between the disc and the cup?

Regards,

JMB

[14276265]

JMB,

The inspection drawings for the No.1 MkI discharger cup give the internal diameter as H 2.52", L 2.515".

The drawings for the gas check disc give the diameter as H 2.51", L 2.505".

Therefore the tolerances imply a minimum gap of 5 thou, maximum 15 thou, with arguably an average of 10 thou.

 

 

265

[JMB1943]

265,

Thank you for posting that information.

Regards,

JMB