It's been mooted on 3 occaisions durng my lifetime, I don't know the detail of the first one but on the second attempt it attracted vitriolic letters in the NRA Rifleman from their old guard.
The project to assess the feasibility of a merger was funded by UK Sport via British Shooting, research was carried out and group sessions were held. The creation of a single body comprising the NRA nad NSRA seemed possible but the CPSA did present some issues. In any event the matter stalled because the CPSA pulled out of the process without giving any reason. As funding was only available to facilitate the creation of a single shooting organisation the withdrawl of the CPSA stopped it in its tracks.There was an attempt to merge them and the CPSA ~2008 but it collapsed. NRA pulled out, CPSA is a Ltd not a Charity (and technically an England-level body, not GB).
I think the field sports contingent are pretty well served by BASC, but as usual not all are members and the majority of those that are are only there for the insurance. BSSC has no funding and lacks coordination but does at least give the impression of some sort of unity. As Hemmers notes, the NRA of America is certainly not the be all and end all, a good many US sport shooters loathe it. It is (nowadays) a political organisation that is focussed on constitutional rights pertaining to gun ownership, the Right to Keep and Bear Arms (RKBA). That's US domestic politics so I won't go there.There's certainly room for consolidation but I suspect the target shooters and hunters are respectively best served by dedicated organisations who can then collaborate though the BSSC umbrella on shooting-wide matters along with the industry groups like the GTA.
This is pretty common on the continent - France has separate Tir and Chasseur Federations and even in the USA their NRA is not the be-all-and-end-all, being accompanied by USAShooting, the CMP, National Shooting Sports Federation and UKPSA amongst others.
A merger or whatever of the NSRA\NRA would appear to be the best way ahead for UK sport shooting, but that is not about to happen. A read through the minutes of the NRA Council Meetings and those of the NSRA show that there are a good many points of contention between the associations. Even if some accomodation was reached, I firmly believe that something similar to what the NSRA are currently proposing would sooner or later be taken up by the NRA; probably sooner.
To summarise, mergers have been mooted before but to the best of my knowledge it has never been the NSRA that scuppered them. Shooting is too cheap and we shall have to accept that we need to pay more; £35/year is less than a £1/week and its introduction would bring us into line with other sports. A lot of the perceived under performance of the NSRA is down to a lack of resource, i.e. they just can't afford it because the punters aren't used to paying.
The NSRA is far from perfect but unless you are prepared to build a new body then it's all we've got and to make it any better we all need to start paying more.Unless anyone fancies investing the blood, sweat and tears starting a new body from scratch then the NSRA is what we have.
Rutty