All should be 1 degree taper per side to form the leade.... Note that the taper for the leade ends up smaller than the pilot for chip clearance and to make sure you get a fine edge on the front of the leade.... I use 0.002” under the land diameter for the pilot (just to make sure it doesn’t drag or sieze) and 0.001” over the groove diameter for the chamber, but that means you may have to actually cut the reamer 0.001” smaller than drawn, depending on how it cuts.... Sorry I can’t be more precise.... You can zoom in on the drawing on the .pdf file, one of the reasons I like to use them....
For TJ’s .25 ACP barrel.... Pilot 0.241”, Chamber 0.251”(0.243” land 0.250” groove)
For LW .25 barrel.... Pilot 0.246”, Chamber 0.255” (0.248” land, 0.254” groove) – This may also be correct for Green Mountain (MRod), I am not sure
For TJ’s .257 barrel.... Pilot 0.248”, Chamber 0.258” (0.250” land, 0.257” groove)
For TJ’s .300 barrel.... Pilot 0.292”, Chamber 0.301” (0.294” land, 0.300” groove)
For TJ’s .308 barrel.... Pilot 0.298”, Chamber 0.309” (0.300” land, 0.308” groove)
I use O1 Drill Rod (oil hardening), and then after hardening and polishing I temper to dark straw (IIRC ~ 500*F for 30 minutes).... If the reamer doesn’t cut fast enough for you, you can take the corner off the trailing edge of the vertical (following) side, but go easy, it doesn’t take much to make it bite harder.... Having the cutting edge 0.020” below the C/L makes it cut reasonably well, the lower you drop the cutting edge the faster it cuts, but rougher.... if you raise it up to the C/L it cuts extremely slowly but a very fine finish.... Position the “V” at the top to form a reservoir for your cutting oil.... and clean FREQUENTLY you don’t want any chips getting jammed.... GO SLOW AND EASY !!!....
For TJ’s .25 ACP barrel.... Pilot 0.241”, Chamber 0.251”(0.243” land 0.250” groove)
For LW .25 barrel.... Pilot 0.246”, Chamber 0.255” (0.248” land, 0.254” groove) – This may also be correct for Green Mountain (MRod), I am not sure
For TJ’s .257 barrel.... Pilot 0.248”, Chamber 0.258” (0.250” land, 0.257” groove)
For TJ’s .300 barrel.... Pilot 0.292”, Chamber 0.301” (0.294” land, 0.300” groove)
For TJ’s .308 barrel.... Pilot 0.298”, Chamber 0.309” (0.300” land, 0.308” groove)
I use O1 Drill Rod (oil hardening), and then after hardening and polishing I temper to dark straw (IIRC ~ 500*F for 30 minutes).... If the reamer doesn’t cut fast enough for you, you can take the corner off the trailing edge of the vertical (following) side, but go easy, it doesn’t take much to make it bite harder.... Having the cutting edge 0.020” below the C/L makes it cut reasonably well, the lower you drop the cutting edge the faster it cuts, but rougher.... if you raise it up to the C/L it cuts extremely slowly but a very fine finish.... Position the “V” at the top to form a reservoir for your cutting oil.... and clean FREQUENTLY you don’t want any chips getting jammed.... GO SLOW AND EASY !!!....
| 357_chamber_reamer.pdf |
