flintlocke,
I doubt the budget of the NRA magazines declined enough to eliminate the research articles. Instead, like many other magazines they were almost forced to run more articles about products made by their advertisers.
This trend started in the 1980s, when one smaller magazine company in New York City decided the way to sell more ads (and hence make more money) was to promise advertisers feature articles praising their products. This proved pretty effective, at least in the short run, and started to spread throughout the industry--to the point where many advertisers EXPECTED positive feature articles about their products. If the magazine publisher wouldn't comply, they'd spend their ad dollars elsewhere.
I started writing for American Hunter in the late 80s and American Rifleman in the late 90s, the first because the then-editor asked me to, having noticed my hunting stories in other magazines. About a decade later, the overall publisher of the NRA magazines asked me write for the Rifleman as well, because he'd seen my technical articles in other magazines. At the time the Rifleman still ran some research-type articles in every issue, so that's what I wrote--which is why I didn't really notice when AR articles started to change after that publisher retired.
Eventually I wrote a review of a new riflescope (naturally from an advertiser) with lots of technical info--and was rebuked by one of the junior editors for not being "enthusiastic" enough about the scope. Until then I thought describing my test-results would allow readers to decide about the quality of the scope.
Not long after that I noticed that new "reviews" written by other writers (especially some of the sub-editors) often weren't really reviews, but mostly enthusiasm. Eventually I was primarily given assignments about new and exciting products from advertisers, and while I tried to include some technical stuff, my enthusiasm kept waning. Eventually I put my efforts into other markets that still wanted more actual information.
One interesting result of this trend occurred several years ago: The publishing company that started running "enthusiasm" articles about advertised products went belly-up, largely because their magazines essentially became collections of thinly-disguised press releases.
