Huge Changes
The body of a conventional energy rifle was made out of metallic alloys for obvious reasons. The most suitable materials had to be able to contain or endure a lot of heat, electromagnetic forces and external attacks.
While there were plenty of innovators who sought to reinvent the concept of an energy rifle by utilizing alternative materials, their applications always turned out to be limited.
The alternative materials either turned out to be weaker, more expensive, more difficult to fabricate or more troublesome to repair. As long as one or more of these flaws held true, it simply made too little sense to adopt these alternative products on a larger scale.
In fact, even if a brilliant Master invented a weapon made out of alternative materials that was just as powerful and efficient as their conventional counterparts, it still wouldn't be a success!