Over the last 10 years, I've gone from "clean them every 500-1000 rounds" to the "clean them after every range session" practice. This is a result of observing lots of tiny pits in my competition pistol bores due to leaving spent combustion products in the bore long enough for corrosion to take place. Over the last 3 years, I've changed from bullseye match shooting to much more casual and less frequent 100 and 200 yard precision shooting, so my standards for accuracy have increased much faster than improvements in skill level. I also acquired a good Teslong borescope so that I could see changes to the pistol bores.
The problem has always been how to evaluate the borescope results and what plan of action to take based on that evaluation. The following is based on my very limited experience and on the use of just a few of my own firearms. Also note that target results are dependent on much more than bore condition and the hardest thing for me to do is to correctly identify cause and effect. I try to keep as many variables constant as I can but even my own medical issues and temperament affect group size when shooting a pistol at 100 yards.
I have had some slightly worse than average results over the past two months with the P-10F and P-10S pistols. I've had exceptionally good results with the 97B"E" and with my old P-09 as of yesterday. In short, the pistols I have shot the most seem to have fallen off yet I am able to shoot the least used pistols as good as ever. After the good result with the P-09 on Thursday, I decided maybe I could see some differences in the bores if I borescoped the P-10 barrels at the same time as the P-09 barrel. The video below is the result.
https://youtu.be/dpTMxZE45y0It is possible that just a little too much carbon buildup in the P-10F and P-10S barrels is resulting in a little more spread at 100 yards. The P-09 barrel still has carbon in the grooves, but the deposit appears very thin and smooth, rather than rough and chunky like in the P-10 barrels. If I can remove the carbon, perhaps the P-10 pistols will return to their normal outstanding accuracy, which has been equal to the P-09 in the past. I'll know middle of next week, after I deep clean the barrels over the weekend.
Note that I am nit-picking here. I expect to see 6" groups out of all three pistols at 100 yards, with an occasional 3-4" group. The group sizes for the P-10 guns currently seem to be maybe 2" larger than that, not bad, but not as good as they should be shooting. After shooting two sub 3" groups recently, and knowing that the best day average I've ever had at 100 yards was with the little P-10S, I know something is up and I want to correct the problem and get back to shooting small groups with the striker fired pistols. More next week.
Joe