Measuring and lapping

[Halftime]

Hi Veral,

  I've been measuring handguns for the past few days with the push-thru slugs and it's been a revelation at least once for each gun.

  The Dan Wesson has .359 cylinders and a groove diameter of about .3575. The slug engraved at the muzzle fell straight through the cylinder. The push-thru jerked to a stop twice going down the bore.

  My Ruger Security Six, which has the best feel of any gun I have, had cylinders just under .358 and a groove diameter of .358 - and I was thinking that it was just finicky about what bullets it liked (also occurred to me that I'm not that great a shooter!) . . . These throats were opened up this weekend. The bore was better than the DW but still need lapping which it will get next weekend. It was a little tricky measuring the bore though because it has 5 grooves. The land and grooves were also equal width, or very close to equal.

  The REAL surprise was my 4" Llama Martial 38 Special (5 screw S&W knockoff) that I got for a song at a gun shop probably because of the brand name. The blue was very good, the cylinder locked up with almost no play, the bore looked good with a penlight shined down the muzzle and the chambers seemed to line up without a shadow. The throats were .358 and the groove diameter .357 so far about as perfect as I could have hoped for. I slugged each cylinder throat and they seemed to be the roundest of all these guns. The slug thru the bore shows it hangs up a couple times too.

  Anyhow, all this was very productive and I feel like I have some notion of what I'm doing when the lapping starts. The push-thru slugs are simple and ingenious.

Thanks!
James P.

[Veral]

Thanks for the detailed report.  It is normal.

  I must comment on statement you made, "it occurred to me that I'm not that great of a shooter".

  This is a faithful promise.  When you are done lapping and fit each gun with an LBT mold, which can very well be one mold for all three guns since caliber is the same,  the guns will become an amazing teacher in my version of gun control.  Accuracy will be so good that you'll quickly notice the bullets are printing exactly where the sights were when the hammer dropped, and you will subconsciously begin noticing and correcting your errors in hold and controlling your squeeze.          Actually the same way one corrects how he points the nozzle on a garden hose, but with more finesse.  I was never able to hit well with a handgun till I made the handguns hit well, by lapping, LBT bullets, etc.  Exactly what this whole forum, and LBT is about.