J. Grainger & Son gunmakers?

Mornin', All, from a very hot and humid East Anglia UK. I'm doing a little research into sharpshooting rifles oF the American civil War, and I've come across a two-band Enfield rifle said to be in .45 cal [more probably .451 cal], described as a 'sergeants model' with the lock totally blank except for the name J. Grainger & Son in the top right-hand corner.

I've be very grateful if anybody here could throw some light on this maker or supplier, allegedly a London, England-based company known in later years for their Cape guns used in south Africa.

TIA.

"STOCKEL" gives a number of Graingers-- some outside the target period. Of course data culled from printed matter could have typos / errors from that period.

Grainger A, Port Elizabeth, South Africa 1883-4
Grainger H, Port Elizabeth, South Africa 1882
Grainger H & T Port Elizabeth, South Africa 1882
Grainger A, Port Elizabeth, South Africa 1883-4
Grainger J, Port Elizabeth, South Africa 1882 - 1900
Grainger James, Wolverhampton 1851-56
Grainger John, Toronto 1854-68
Grainger John, Birmingham 1859-64
Grainger W, Grahamstown, South Africa 1882-1900
Grainger & Son, Grahamstown, South Africa 1865-90

Nigel Brown "British Gunmakers" does not list a "Grainger" in Vol1 - London - but in Vol.2 he lists 3, only 2 from the period --
James Grainger, lockmaker, Wolverhampton 1851-56 (exhibited at the Great Exhibition)
John Grainger, Handsworth (now a suburb of Birmingham) 1862-64.
Bailey & Nie refer to these two
Mike Newland's excellent "Gun and Gun Part makers of Staffordshire" has 2 pages of "Graingers" -- referring to the Toronto one as possibly eventually moving to SA. If you want a scan, please let me know.

ATB

Jim