General Rifles: July 2008 Archives
I saw some brass split at the base when I took the SMLE out last weekend. The firing sequence is as follows.
1. The firing pin shoves the case forward, rim against the breech.
2. The primer detonates. If it's not heavily crimped in place, it backs out, shoving the bolt and barrel as far apart as it can.
3. The thin, forward part of the case expands to fill and grip the chamber while the bullet moves out of the case and down the barrel.
4. The solid case head can't expand and grip the chamber, so it moves rearward, re-seating the primer, stretching the case walls just forward of the head, and stopping when it hits the bolt face. (In rear-locking actions like the Lee, the bolt and receiver also compress/stretch to add a little more movement. The higher the pressure, the more they move.)
5. If (and only if) the amount of head movement exceeds the elastic limits of the case, the cartridge separates into two pieces.
I was getting a lateral split, 180 degrees around the case, about an 1/8th inch from the base. There was also a slight angle to that 1/8th inch relative to the rest of the case...almost as if the ejector was trying to twist the base off. I've ordered go - no go gauges from Midway. Apparently there are 5 different bolt heads you can get to adjust headspace (update: the bolt heads are for the IV, not the III that I have)...or I had some bad brass. I was using factory Remington, so I wouldn't suspect the brass right off.
...and getting onto an Enfield forum gave me the answer.
And I am told the yellow paint was "tropical" camo and I shouldn't had taken it off. Tough, it was butt-ugly, covered the proof marks, and the rifle is certainly not a collector-grade piece anyway. I need to find a longer bolt-body. Something substantially longer that 5.493.
1. The firing pin shoves the case forward, rim against the breech.
2. The primer detonates. If it's not heavily crimped in place, it backs out, shoving the bolt and barrel as far apart as it can.
3. The thin, forward part of the case expands to fill and grip the chamber while the bullet moves out of the case and down the barrel.
4. The solid case head can't expand and grip the chamber, so it moves rearward, re-seating the primer, stretching the case walls just forward of the head, and stopping when it hits the bolt face. (In rear-locking actions like the Lee, the bolt and receiver also compress/stretch to add a little more movement. The higher the pressure, the more they move.)
5. If (and only if) the amount of head movement exceeds the elastic limits of the case, the cartridge separates into two pieces.
I was getting a lateral split, 180 degrees around the case, about an 1/8th inch from the base. There was also a slight angle to that 1/8th inch relative to the rest of the case...almost as if the ejector was trying to twist the base off. I've ordered go - no go gauges from Midway. Apparently there are 5 different bolt heads you can get to adjust headspace (update: the bolt heads are for the IV, not the III that I have)...or I had some bad brass. I was using factory Remington, so I wouldn't suspect the brass right off.
...and getting onto an Enfield forum gave me the answer.
And I am told the yellow paint was "tropical" camo and I shouldn't had taken it off. Tough, it was butt-ugly, covered the proof marks, and the rifle is certainly not a collector-grade piece anyway. I need to find a longer bolt-body. Something substantially longer that 5.493.
