I was saying that after some lead rounds, like one box, you can shoot a few jacketed rounds.
Some years back a guy blew up his pistol doing exactly that. He put 50 lead rounds down the bore and the pistol blew on the first jacketed round.
Why is it that so-called experts and so-called "leaders" are so quick to resort to absolute prohibitions...
Because of incidents like the one I just recounted.
And because it's difficult or impossible to quantify when it might be safe and when it might damage the gun. How could one possibly make a general, across the board statement about how many lead rounds can be shot before a jacketed round might cause damage? Bores lead at different rates, barrels have different levels of strength, rifling types vary, different calibers operate at different pressures, within a caliber different loadings will lead the bore differently and will result in different chamber pressures, ambient temperature can increase pressure significantly, etc., etc., etc..
There's simply no way to come up with a good
practical method that will always work for any gun in any caliber with any ammunition combination that will allow one to accurately determine when it might be safe and when it's going to blow the barrel.
In response, I would say, why is it that people always think that everything is very simple? Why can't they realize that sometimes things are complicated--sometimes variables differ so much from one situation to the next that there's no way to boil things down to a simple rule of thumb?
Ok, if you want to know how to determine when it's safe and when it's not, here's how you do it.
Get a chamber discharge pressure measuring system for your pistol and perform the following procedure.
Clean the bore thoroughly so that there is no lead in the bore at all.
Fire a single lead round.
Fire a jacketed round and note the chamber pressure.
Clean the bore thoroughly so that there is no lead in the bore at all.
Fire 2 lead rounds
Fire a jacketed round and note the chamber pressure.
Clean the bore thoroughly so that there is no lead in the bore at all.
Fire 3 lead rounds
Fire a jacketed round and note the chamber pressure.
Clean the bore thoroughly so that there is no lead in the bore at all.
Fire 4 lead rounds
Fire a jacketed round and note the chamber pressure.
...
Repeat these 3 steps increasing the lead round count by 1 each time until you note that the chamber pressure when firing the jacketed round reaches SAAMI maximum for that caliber. At that point, back off the number of lead rounds fired by 10% and consider that the safe amount that you can fire with THAT ammo through THAT gun without cleaning before firing a jacketed round through the bore.
This procedure will have to be repeated for each gun you own since different firearms (even different examples of the same model) can lead their bores at VERY different rates. Also, if you change the ammunition you're using (either the lead or the jacketed) you'll need to repeat the procedure to establish a new baseline.
The bottom line is that you want to shoot jacketed rounds down your leaded bore then go ahead. You've been warned, if you're willing to take the risk then go for it. It's your gun and it will be your hand holding it. Just don't do it next to anyone on the range because even if it's a risk you're willing to take, the person next to you probably won't be all that excited about the possibility of dodging flying parts of your firearm.
For really stubborn lead removal try a 50/50 mix of Hydrogen Peroxide (the common drug store variety) and white vinegar. Plug the bore, fill it up using a dropper or syringe and let it stand for 5-10 minutes. (Do not let it stand for too long.)
Be careful with the gunk that comes out of the barrel. It contains lead acetate which is toxic and which has the unusual property that it can be absorbed through the skin.