My gunsmith told me not to shoot copper bullets (Barnes X, GS Custom) in my new Shillen barrel, said it is bad for it and should only shoot normal bullets

Is it true

Well, seeing as how "normal" bullets are copper jacketed, and that's all that's going to touch the bore regardless of bullet brand, I can't see how they'd be "bad" for your barrel. May not be the most accurate, but I can't see any harm being done.

I'd be a little sceptical about that statement as quoted. I have heard people say not to use Barnes until the barrel is broken in well, but that's just due to the sometimes terrible fouling from the Barnes. Makes it a pain in the a$$ to clean. You will not have any problems using the GS Custom bullets with driving bands (FN, HV).

I usually try to break in a barrel with cheaper bullets like the Sierra MatchKings.

Don

I believe that X bullets and maybe GS bullets are copper. I think I read they are ETP copper.

I believe that the jackets on most other bullets are guilding metal which I think is 95/5 or 95% copper and 5% zinc. Some bullet jackets are also made of steel. There have been cupro nickel bullets also and of course pure lead and it's alloys.

Another aspect of the X bullet and maybe not the GS is it's relative non compressability as it's solid copper where the GS has bands that will yield on design. Also of course the regular jacketed bullets have softer lead in them. How military bullets with guilding metal jackets and harder metal cores fall into this mix I am not sure.

I suppose that the X and GS bullets are made from copper for expansion purposes only. As you add zinc to copper it's gets harder.

I've heard about this copper fouling business with Barnes X, but have never had it happen to me. Fouling is normal. Cleaning about like other bullets. I just traded a 300 win mag that had 5000 round through it and 99.99% of them were Barnes X 180 grain. Accuracy did start to fall off last year, but that's expected with that many round through it. And besides, the gunshop had this Winchester Super Grade with the one piece floor plate that jumped off the rack and into my arms and just would not let me go.

What could I do?