Starting a new thread on this as this was getting off topic in another thread

There are 3 types of MK3 sliding butt groups all bear the same drawing number MG 3772,but have different vocab listing numbers.
The original MK3 butt slide is BH 0566
This was superceded by the MK3/1 butt slide C1/CA 0853
Then the the MK3/2 MG 3772

The 1959 L4A1 IPL only lists the MK3/2
The 1959 L4A2 IPL lists all 3 types but notes the MK3/2 is current and all other MK's are obsolecent.
The 1963 L4A4 IPL shows the same as the above L4A2 IPL.

The REME CENTRAL INSPECTORATE (Inspection Standards) for 303 MK's 1,2,2/1 &3 note - Slides butt MK 3/1 and 3/2 differ only from the MK3 in that they are of a strengthened pattern.

LoC's introduce (for what they are worth) the MK3/1 in 1948 (C 3564)
And the MK3/2 in 1949 (c 3815)
In 1952 the MK3/2 butt slide was given an extension for use in MKI,2 & 2/1 Brens (c 4830)

The last dated unissued Donington primary packed butt slide I have seen is NSN 961-7933 (Dec 1970) this is the 'strengthened pattern' and this does not have 'lightened' rails.

ATB Kevin
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