The No. 27 Nose Pistol was declared obsolescent in November 1940.
This is really surprizing. Apparently a decision that remained "on the paper" due to the events, as the Pistol No.27 was the usual standard pistol of British GP bombs during the first half of ww2, and, in fact,
it appears in the various wartime British and allied ordnances as a standard equipment till at least 1944.
The No. 27 pistol was used on the GP 250lb MkI-III & MkIV, 500lb MkI-III & MkIV, GP 1000lb MkI &II, GP 1900lb, GP 4000lb, and was even used on late war HC bombs. It could also equip MC bombs (except the MC 500lb MkX) but was less frequent on these bombs than on the GPs.
The No27 nose pistol was still an official standard equiment in 1943, at least for the RAAF:
More over it was used extensively by them in the Western desert as a basis for the rod extended bombs dropped by Wellingons and Kittyhawks.
The following lines appear in the proceedings of the seminar of conventional weapons of Royal Air Force Historical Society, Oct 22nd, 2008:
"RAAF 3rd Sq. Curtiss Kittyhawk I during the Battle for El Alamein were reported to be equipped with bombs having "nose rods". Similarly, RAF 108 sq. Wellingtons in Action over Fayid in 1942 used to drop a mix of 500lb. tail fused H.E., 250lb. nose fused H.E., and one 250lb. "extension red" - the "extension red" designating an extended nose rod attached to the nose fuze, aimed at producing a (slight) air-burst effect. (BTW, on British bombs, delay pistols were often painted red, but were generally Tail fuzes)
The rod was screwed onto the male thread on the pressure plate of the No 27 or No 42 Nose Pistol; the No 42 certainly had one when it was installed in the 60 lb Infantry Training Bomb. Both the No 27 and No 42 were used in a number of GP and MC bombs."
And in the Britrish National Archives you may find this, dated 1943:
AVIA 16/87
Description:
Fragmentation effect on water of G.P. bombs fitted with No. 44 Mk. I and No. 44 sensitive pistols and No. 27 pistol with rod extension: trials
Date:
1943
Held by: The National Archives, Kew
Former reference in its original department TDU/13/43
and this from 1942
AVIA 6/12091
Description:
Pistol No.27 with mechanical arming delay
Date:
1942
Held by: The National Archives, Kew
Former reference in its original department: TN Arm. 83
The No.27 appears also as standard RAF/RAAF equipment in the TM-9-1984 Disposal of American and Allied Bombs and Fuzes from
1942

Furthermore the US Bombs and Fuzes from 1944 writes:
"(3) the No.42 is
now replacing the No.27"
More dfinitively, the British AIR PUBLICATION 1661B ("Prep ared by direction of the Minister of Aircraft Production, Promulgated by order of the Air Council") incluydes the "appendix issued with A .L . No. 66
August, 1943" where the Pistol No27 figures as standard for GP bombs


The same document includes an "Relevant amendments up to A .L . 72 incorporated in this reprint
January, 1944" where the Postol No.27 appears as standard for MC bombs:

