T
tricrown
Guest
I used some fire form barrels to ready new brass for next season. The 30BR, 30 Dasher, and 6BR imp all turned out fine. But the 22BR imp cases have been very hard to get near right. The process went:
6BR Lapua brass was run through a FL 22BR die.
All cases were loaded the same with an upside down bullet seated to a depth that provided .002” neck chamber clearance and then fired.
Fired cases were first turned to within .0005” of finished thickness. Then turned again at finished size and turned once more at same settings.
Cases were fired again with a full charge with no need to size.
All readings were taken at 3 points per case with a cheap tubing mic that was in a holder using one click on the ratchet nob. Turning was done by hand with a Sinclair NT1000 and 40 deg cutter held by aluminum shims that were clamped in an aluminum barrel vice. When I went to sort the 80 cases into 2 boxes of 40 the thickness measurements varied at first by as much as .008”. Half of the half or so that came in where they were suppose to still had a .001” or .002” high or low point.
Even though they were all treated the same the cases had blown out differently after both firings. 10 had extra headspace that caused hard bolt closing. On some when I went to even their neck thickness after the second firing I noticed that maybe a quarter were so tight that they went into the expander mandrel hard. Just as many went in with no handle pressure.
I've had trouble before making good even 22BR cases and was wondering if these are common problems when trying to reduce case necks “down” from their original size? Was also wondering if reaming them out right after the first fire-forming before turning would make for more even neck turning? Any tricks?
6BR Lapua brass was run through a FL 22BR die.
All cases were loaded the same with an upside down bullet seated to a depth that provided .002” neck chamber clearance and then fired.
Fired cases were first turned to within .0005” of finished thickness. Then turned again at finished size and turned once more at same settings.
Cases were fired again with a full charge with no need to size.
All readings were taken at 3 points per case with a cheap tubing mic that was in a holder using one click on the ratchet nob. Turning was done by hand with a Sinclair NT1000 and 40 deg cutter held by aluminum shims that were clamped in an aluminum barrel vice. When I went to sort the 80 cases into 2 boxes of 40 the thickness measurements varied at first by as much as .008”. Half of the half or so that came in where they were suppose to still had a .001” or .002” high or low point.
Even though they were all treated the same the cases had blown out differently after both firings. 10 had extra headspace that caused hard bolt closing. On some when I went to even their neck thickness after the second firing I noticed that maybe a quarter were so tight that they went into the expander mandrel hard. Just as many went in with no handle pressure.
I've had trouble before making good even 22BR cases and was wondering if these are common problems when trying to reduce case necks “down” from their original size? Was also wondering if reaming them out right after the first fire-forming before turning would make for more even neck turning? Any tricks?