An officer of the Regiment de Clare, 1767
About a year ago I started compiling links to articles that are now accessible for free on Jstor. The articles are taken from various historical journals and have been subdivided into four sections. I haven't had the chance to look at many of them yet but, just going from the titles, I suspect that 18th century wargamers will be bound to find something of interest. As more US, Irish and Scottish historical journals appear to be accessible, subjects related to those countries are more heavily respresented.
Although these articles are accessible for free, you will have to register with Jstor. You will also be restricted to viewing only three articles every two weeks, in the UK at least (or 'the countries formally known as the UK', depending on what happens in the next few hours). But that's a small price to pay to have otherwise free access to this resource.
Articles on Irish soldiers in foreign service, and the experience of Ireland during the Seven Years' War
I'll carry on digging around the internet for more, and will add them to the relevant pages as I find them.