Post by gcf on Sept 4, 2024 13:51:29 GMT -5
Guys, the following is old hat to some of you, I'm quite sure.
That said - for the benefit of others - attached below is a picture of the Beartooth technical guide, that among other things, provides clear cut directions for effective fire lapping. Veral of LBT also wrote a similar book, that may still be available. Both of these guys know what they are doing - with regards to shooting cast bullets. If at all possible, I'd recommend laying hands on either - before diving in to the fire lapping process.
The recommendation outlined in the BT tech manual, is 320 grit compound (I believe the BT compound is 320 grit Clover re-labeled) embedded in SOFT lead bullets, and smeared into the bullet lube groove, & then fired at low (600fps) velocity. Followed up with a compound bore polishing session. A lot of (non-random) thought went into this process. The idea being to remove constrictions, irregularities, and provide a fine polished finish - without expanding the bore ID to the point that it will function with a larger caliber.
Not to say that a bit of thoughtful process variation can't be employed though. Fermin's interesting process outlined, is a variation that adheres to the original. I myself, thoroughly clean the bore, & lube with CLP after every cylinder full of lapping loads - and am convinced that it produces a more nicely polished bore, & generally enhances the process.
Now, hopefully without stepping on any toes, and understanding that everyone's mileage varies, I'll say that JUDICIOUSLY following the basics ( 320 grit compound embedded in soft lead bullets, and / or smeared into the bullet lube groove, then fired at low velocity) while checking progress frequently, is the safest route to follow - for anyone who values their firearms. As someone smarter than me once opined, it's a heck of a lot easier to remove metal from a bore, than it is to replace it.
Again, JMHO...
That said - for the benefit of others - attached below is a picture of the Beartooth technical guide, that among other things, provides clear cut directions for effective fire lapping. Veral of LBT also wrote a similar book, that may still be available. Both of these guys know what they are doing - with regards to shooting cast bullets. If at all possible, I'd recommend laying hands on either - before diving in to the fire lapping process.
The recommendation outlined in the BT tech manual, is 320 grit compound (I believe the BT compound is 320 grit Clover re-labeled) embedded in SOFT lead bullets, and smeared into the bullet lube groove, & then fired at low (600fps) velocity. Followed up with a compound bore polishing session. A lot of (non-random) thought went into this process. The idea being to remove constrictions, irregularities, and provide a fine polished finish - without expanding the bore ID to the point that it will function with a larger caliber.
Not to say that a bit of thoughtful process variation can't be employed though. Fermin's interesting process outlined, is a variation that adheres to the original. I myself, thoroughly clean the bore, & lube with CLP after every cylinder full of lapping loads - and am convinced that it produces a more nicely polished bore, & generally enhances the process.
Now, hopefully without stepping on any toes, and understanding that everyone's mileage varies, I'll say that JUDICIOUSLY following the basics ( 320 grit compound embedded in soft lead bullets, and / or smeared into the bullet lube groove, then fired at low velocity) while checking progress frequently, is the safest route to follow - for anyone who values their firearms. As someone smarter than me once opined, it's a heck of a lot easier to remove metal from a bore, than it is to replace it.
Again, JMHO...