Here are some questions about cleaning rifle barrels after shooting LEAD bullets and some representative answers from shooters on the internet:
1. Do you clean DURING a match or range session?
2. How often, or when, do you clean the barrel?
3. Do you clean until brushing produces no more black stuff, until you get a clean patch?


"1. Yes I clean during matches or shooting sessions. I find in my two rifles accuracy degrades in one somewhere around 15 shots and the other around 25 shots. Accuracy degradation is defined as either the groups open up, or impact location migrates.
2. I clean between groups unless I can hold the total amount of shots (fouling and score) to less than 15 total.
3. I do not clean until the barrel is clean. I clean only to manage a certain level of fouling. I find barrels don't shoot good if they are squeaky clean, nor do they shoot good if really fouled. 
One must determine the level of fouling that shoots good in a particular rifle and shoot within those minimum shot/maximum shot parameters.
My .30BR hits it's stride after 2 fouling shots. My 1903 Springfield needs at least 5 fouling shots and also seems to need a certain level of "warmness" in the barrel. The .30BR will shoot good in a cold barrel if the fouling level is between the min/max levels.
I've also found out the fouling parameters vary based on barrel type and powder type. Some powders are very dirty and some are very clean. V135, if the barrel is squeaky clean, requires about 20-25 shots just to get the .30BR barrel shooting good again. Varget requires much less. ...."
Bill Warner on CBA

"I clean after every relay during a match or about every 15 rounds. I too find accuracy starts to suffer if I don't. My cleaning process involves pushing an undersize brush wrapped with a patch of one of the lead removal cloths sold under various names twice through the barrel followed by two patches of Ed's Red and finish up with a couple of dry patches. For the 30 cal. I use a 6.5 brush and for the 6.5 I use a 22 cal. brush.
I've examined the barrel after cleaning with a bore scope and it's nice and clean. I use HTWW in my match rifles and tend to get a little leading so the lead wipes really help. As far as getting a perfectly white patch at the end of cleaning, I've never been able to
do it but I don't think it's barrel material or I'd be shooting a smooth bore by now.

I've tried a bunch of cleaning methods and haven't found any that do as good a job with as little work as this one.
.... if you're going to make a habit of cleaning your rifle a decent bore guide is a necessary tool if you want the throat to last."
Pat Iffland  on CBA

 
"I clean when I arrive home after a range session.
I clean until I get a patch that is slightly discolored with some kind of gray material. I've never been able to get a patch thru any rifle barrel that wasn't discolored with that faintly gray stuff. No, it is not lead, and the bore is free of jacket metal too. I have begun to suspect that it is barrel metal itself. ....
.... I'm not the only one who gets a faint grey stuff on every patch, no matter HOW clean the bore has become."
John Bischoff on CBA

"I clean at the end of the day sometimes at the range sometimes at home. I use Bore Tech rimfire solvent. For 32 caliber rifles I wrap a patch around a .30 cal brush. I use a wet patch then a dry untill the black is gone and all I am getting is cooked lube. Lastly I run a patch with some lanolin cut with mineral sperits through the bore." 
40 Rod on ASSRA

"Before I started using Alberta Schuetzen lube I had to clean within 30 shots due to leading. With the improved lube I clean after the end of the day (usually 100 + shots) and only get fine lead dust on the first cleaning patch. For peace of mind I always clean prior to each competition event. 
A bore scope taught me that gun cleaning solvents don't handle the carbon build up. Yes there are very many good products that quickly remove lead and the powder fouling however you would be surprised how much carbon buildup takes place over time with even the most stringent cleaning practices. 
Then I discovered JBs cleaning compound. Works great at getting that  build up out of there. Also I lay down a film of Kroil oil before commencing the next round to prevent the start of lead fouling (before that first lubed bullet has a chance to lay down some lubricant). 
For rimfire I clean before a competition but make sure I fire at least 50 rounds to stabilize the groups before the competition. 
It is better to clean at the range as soon as possible after competition. 
If  the rifle sits a while then that fouling hardens up and is somewhat more difficult to completely remove. 
For chrome moly barrels leaving the fouling overnight after shooting on one of those cool days can result in condensation which reacts with the fouling to form acids that pit out the barrel. I have rebarreled numerous pitted barrels for guys who put their rifles away without cleaning after hunting on a cool humid fall day. "
Tommy on ASSRA