Since the time I started bullet casting in 1974, numerous folks have proclaimed that before one could shoot cast bullets with the best accuracy, all traces of copper fouling must be removed from the barrel. Since I have shot mostly cast bullets in my rifles for the past 28 years, most of my rifles havent seen a jacketed bullet in that time.
That changed when I purchased a .30 W.C.F. (.30-30) Winchester 1894-1994 Centennial rifle a few years ago and wanted to replicate some discontinued factory loads that were available circa 1922-1950 with a 110 gr. H.P. bullet at 2,720 f.p.s. I soon found out that after shooting 20 rounds or so, a fair amount of bore scrub a dub was required to remove the copper fouling. Then, one day, I was at Ridgway Rifle Clubs NRA High Power silhouette range having a ball shooting down the steel javelina @ 327 yards with a .30-30 110 gr. H.P. replication handload using a fast stepping 110 gr. Sierra H.P. bullet. After shooting about 30 rounds, a glance at the end of the bore indicated that, sure enough, copper wash was present.
I was pressed for time and had some 200 gr. cast bullet .30-30 loads I wanted to try on the steel rams @ 500 meters, so I decided to shoot them without cleaning the barrel. When I got home, I was in the process getting set up to clean the bore when I noticed the copper wash was gone! Thinking that possibly the powder fouling was covering it up, I wet a patch with Hoppes and ran it through the bore. To my surprise and delight, the copper fouling was indeed gone.
Since that day I have repeated the scenario several times with the same results and just recently a cast bullet cleanup also worked in my Marlin 336A after a range session with some jacketed bullets. In both cases, the cast bullets were .001-.002 over groove diameter and about 10 cast bullet rounds were fired. It appears that the lead alloy bonds with the copper wash much the same as the old 50/50 solder did with copper pipe and carries it out of the barrel.
One learns something new every day.
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