half a dozen在这里是什么意思

half a dozen在这里是什么意思He proved himself one of the greatest salesman,as,by sheer machandising ability,he promoted successfully a multi-barrel weapon inferior to half a dozen other guns available at the time.大意我知道是说他推销技术厉害,把自己这不如别人的多管枪成功推销出去.只是不太明白half a dozen是说其它的枪只有6管吗?还是half a dozen是说远不如,跟inferior to有关?