When I work up new loads for my rifles, I shot either 3 shot string or 5 shot string with a fouling shot. Depending on what caliber I am shooting. My question, is it necessary to clean the barrel between each string? I have been doing this process ever since I have been reloading and trying new loads. Keep on doing this or forget about?
It's not normal, or desired, to clean between groups during load development.
You want each group you're evaluating to be of apples to apples.
Having said that, I once had a gun that copper fouled out by shot #8.
It was an H&R handy rifle so the barrel could only be changed by the factory.
I managed to get 25 shots between cleanings after Tubb's firelapping and tungsten bullet coatings.
But alas the gun wasn't worth that much effort. I separated it into several dumpsters one day.
Now, when/if you go to cold clean bore load development, then you'd clean between every shot.
I guess the main reason I clean between strings is that the barrel is going to get fouled. When that does happen the groups should/are going to open up. It might take 5 shots or 25 or more to find that out. My thought is, cleaning between shots, the different loads will tell me if it's the loads that are opening up and not a fouled barrel.
Please tell me if I'm thinking wrong. I won't judge you on your advice. Just like learning new things.
P.S. Thank you for the info that has allready been given.
The better quality barrel's bore and groove dimensions and finish one has, the fewet shots need be fired to foul it. With Winchester, FN and Remington factory barrels, it's took from 3 to 9 shots to foul them to where they settle down. On the other hand, top grade barrels such as Obermeyer, Hart and Kreiger, they shoot to within 1/4 to 1/3 MOA of point of aim from the first to a few dozen shots later. I think they'll all change some as bores with no fouling (bullet or powder) in them shoot bullets out at a different speed with the first shot than subsequent ones because the resistance is different from clean to fouling.
I recently put together a remington sps heavy barreled 308, and before I ever put a bullet down the barrel, I ran about 50 patches, with multiple strokes, of JB non embeded polishing compound from brownell's through the barrel. Now after I shoot 70-80 rounds it only takes 5 or 6 six patches to clean, and that includes copper and powder fouling. Might be worth a try to save some bewteen load cleaning.
What I usually do is run a powder fouler through when I switch from double base to single, or stick to ball. If it is a dis-similar powder, it CAN have some effect on accuracy(usually 1st shot of group flyer). I learned this from service rifle shooters back in Oregon nearly 20 years ago. I have forgotten a few times to allow an extra shot to do this, and when I look at any groups with a flyer, it's usually 1st shot, and a fouler would have stopped it. The fouling is different, so the bullets ride it differently.