Bore Lapping a Oberndorf .308 Mauser Barrel
Rifles need to be cleaned after every round of shooting. In fact, I clean after every ten shot strings (5 shots each) when I am shooting for 8mm cast bullet accuracy. Last night was different. Last night I started with the Oberndorf .308 Mauser. The gunsmith and I inspected the barrel with his bore scope and found the usual (60 year old) pitting. There was also some copper and lead fouling. He set me up with some lapping paste and away I went.
The procedure for restoring this old Mauser barrel is my own. So if you know of a better one let me know. First I removed the bolt and plugged the Mauser barrel with an old ear plug. Then I inserted a bore guide and filled the barrel with “Shooters Choice” bore cleaning solvent. While waiting for the solvent to work I cleaned the bolt and shot the breeze with a neighbor.
After 15 minutes I dumped the bore solvent and what a mess came out – mud, and lots of it! Let’s say the first 1/3 of shooters choice was clear and the rest was mud – good. I removed the plug from the muzzle end and covered it with a balloon to catch the patches. I scrubbed with some 30 strokes with a .32 caliber bronze bore brush. Then, after 10 patches, I pulled the balloon and ran a patch – still a bit dirty, not bad, but in close to rifling there were issues. So I put the balloon on and grabbed a 30 caliber mop.
After a liberal application of lapping paste I started. Now I have to say here that my neighbor owns no guns and so he was all questions and rather intrigued at what I was doing. He is, however, a mechanic, and so he warned me not to be too aggressive with the lapping compound – point well taken. Bore lapping, well-done that is, can enhance a barrels performance. Bore lapping that is overdone can ruin a bore. I have heard many grits and number of strokes mentioned as a “Rule of thumb” I do it by feel.
After 25-30 strokes the paste has already done its job removing the remaining fouling, copper (although the patches that came out did not show copper present after the shooters choice was used) and lead. I already know that the bore is pitted, I cannot help that, but this Mauser barrel has strong rifling and I begin to feel the process “smooth out” so to speak. The strokes are easier and less abrasive to feel. So i Stop, patch out the Mauser barrel with a couple more patches soaked with shooters choice, until we have no more residue.
Now I must say here that you can feel the difference with those last two dry patches – smooth, even, strokes that feel as though they are lubricated but are not.
After this I check the bore with a light and wow! What a difference….and here is the kicker, I took no pictures !@#$%$#@&* ! I must remember to take pictures to show you. I will too as I am about to do the same process on a Lee Enfield MK IV that I just picked up. I have never shot, much less owned a Enfield and am eager to try it out, so give me a week or so to get the job done and posted here. You can subscribe and get an instant notice when I do post AND I DO NOT SELL, GIVE OUT OR OTHERWISE ABUSE ANOTHER PERSONS E-MAIL.
Anyway, have a good day, and take your wife and kids out shooting with ya’