My understanding is that John Henry Walsh (Stonehenge) wrote his Manual of British Rural Sports in 1855 (as recounted by him in a later preface), and the Wikipedia entry for Walsh states that "In November 1855, his comprehensive and illustrated Manual of British Rural Sports was published and was enthusiastically received. This was the first of many editions. In April 1856 the second edition was published which corrected minor errors. In the same year he joined the staff of The Field, and became its editor at the close of 1857."

I don't have a copy of the first edition, but the copies I have seen all have a publication date of 1856, the same year the second edition was published (which I do have). I do not know how different the two editions are, but I suspect the changes were minimal. The preface of the 2nd edition is dated October 1855. The book does illustrate Lang's gun, which interestingly enough appears to show the classic Lefaucheux-type double-bite action, and not the single-bite action (with rising stud) usually associated with Lang's guns of the 1850s. I cannot say how accurate the illustration is, whether Lang was building both types, or whether Lang was obtaining partially finished guns from the Continent. More room for research, I think.

The book does give a description of Lang's breech-loading gun (paragraph number 61, starting on page 20), and there is no mention of the Needham needle-fire or the Lancaster gun (as there is in Walsh's The Shotgun and Sporting Rifle, 1st edition in 1859).

Here is the illustration from the Manual of British Rural Sports (2nd ed.):


[Linked Image from i.imgur.com]

Walsh was certainly familiar with the pin-fire when he wrote his book, though it does not appear that he had much influence over The Field and its thoughts about the pin-fire before he took on the mantle of shooting editor.

The 4th edition was published in 1859; the 5th in 1861; the 6th in 1865; the 7th in 1867; and the 14th in 1879.