Unfortunately, when you use commercially cast bullets they can leave lead in your barrel that is hard to remove. A solution of 50 hydrogen peroxide and 50 white vinegar reacts with lead and eats any lead in your barrel within2-3 minutes. . The remaining solution that comes out of the barrel does contain lead and is poisonous. Cast bullets can save you a lot of money. A rubber cork that can be bought at almost any hardware store could also be used. Patch out the excess solvent and you are done. The solution used in this process can cause damage to your barrel if it is exposed for long periods of time; it can also damage blueing on chrome moly barrels. Follow this by a dry patch through the barrel followed by a brush with solvent. If you shoot a lot of pistol ammunition there is a good chance you will shoot cast lead bullets out of your gun at one time or another. A Solution of 50 Hydrogen Peroxide and 50 Vinegar can be used to remove lead from barrels very quickly. The syringe also makes it easy to put the solution in the barrel. Only let it set in the barrel for 2-3 minutes and then dump it out and flush the barrel out with water. This case had a split in it so it needed to be discarded anyway. The bubbles are the solution reacting with the lead. You can repeat the process if there are stubborn deposits that wont come out on the first try. Here you can see the solution in the barrel. This is a procedure to remove lead out of barrels that works very well. To plug off the barrel I use a case that has been fired out of the gun. Here is the first patch after flushing the barrel with water. I use a large syringe to measure the proper amounts of vinegar and hydrogen peroxide into.