Copper in TRG barrel question

[dropd57]

A buddy of mine who has a few TRG's, with the one in question, a 338 Lapua is having fouling issues. He loads for the gun with great results normally, however, during a recent range trip we noticed the groups open up quite a bit and chrono numbers rise considerably. Well my friend went back to the loading bench and broke down the remaining ammo to see if he screwed up his powder charge or overall length, etc. Everything checked out fine, but when he looked down the barrel he found severe copper fouling. Well, he cleaned and removed the copper from the barrel and went back to the range with the remaining ammo. The result was normal chrono numbers and his groups were back to one hole.

What is up? Is it a bad barrel or the Sierra bullet heads or something else? Anyone else have this happen?

 

[Trigger Monkey]

Re: Copper in TRG barrel question

Everything sounds normal, of course without knowing how many rounds went down the tube before the accuracy began to dive off not much more can be said. Barrels collect copper, how much and how soon depends on several things but when it gets to the point that it influences accuracy then it's generally a good time to clean the barrel, which your friend did and things went back to normal. I would say your friend should note how many rounds were fired and use that as a guide for when to clean.

 

[dropd57]

Re: Copper in TRG barrel question

Fine, but should pressures rise due to copper fouling?

 

[Unknown]

Re: Copper in TRG barrel question

It would make sense that the additional copper in the bore adds resistance to the bullet's passage through the bore, thereby increasing pressure. The hard chrome in the TRG barrel has much less resistance to the bullet's passage than copper.

The amount of fouling can vary depending on which bullets you are using. Really soft copper jackets tend to foul a bore faster than jackets that are a little harder.

 

[Spuhr]

Re: Copper in TRG barrel question

I have the same problem and I have my own little solution that seems to work ok.
I gauge the barrel, and the gauge is for my barrel 8,38mm/.3299"
When the resitance use to rise for pushing the gauge through the barrel I clean it with JB. There is normally no resistance at all.

After shooting sessions I clean the barrel with shooters choise and bronce bruch just to get out the powder fouling.
I usally have to clean with JB to get away with the copper after 400-500 rounds.

Håkan