Greg All Calibers
New member
My final summary on the GP-100 internals, after speaking with a few smithys on this topic.
Just FYI. Mine is working fine now but just wanted to share my notes with you..
There seems to be relevance of the various internal part stampings (the letters in the round circles), and how they best fit together (or even if they fit together at all!). There is probably some lookup table at Ruger that has a 'best fit' of which parts should be put into gun during final assy. These includes the cylinder, trigger, trigger housing, pawl, transfer bar, hammer strut, etc (the exact names are in the parts schematic).
Ruger seems to change/update internal parts often, probably as running changes or when there is a part vendor change. The stamping are the only way to keep track of the many versions of each part they use.
Anyway, I have concluded that during final assembly they probably start with a look-up chart (which probably matches the letters), and then check the the gun function. If it's still not 'acceptable', then they 'hand-fit' the parts ensure the gun is working well 'within spec' before boxing it up as a new gun.
In the case of the pawl, I have run across many types of slightly different shapes and designs - that make a BIG difference! For example, the ones stamped with a "B", is not only shaped somewhat different than others of another letter, but it also has a small 'bowl' indentation where the pawl spring plunger fits in. This keeps the pawl better seated when installed. The other letters do not have it, not that I have seen (interesting).
In in effort to fine-tune my gun, I tried many different parts and found a letter "B" pawl and letter "E" trigger do not work well together. The pawl overshoots the extractor ring slightly and causes the trigger to hold back. Perhaps the lookup table shows an "E" trigger is supposed to have a "E" pawl. To get my "B" pawl to work with my "E" trigger I had to work the pawl over carefully to get an exact match that functions well.
I also tried a "D" pawl- it does not even fit into the gun without hitting crane latch (the metal that is part of the crane latch button), and if you can wiggle it in, it's totally non-functional. But you put the "D" pawl up to the others, and there is very, very slight difference. It would go unnoticed by most people unless you actually tried it.
My stampings of some internal parts on my Ruger S/N 174-02xxx
Cylinder - "S"
Transfer Bar - "D"
Pawl - "B"
Trigger - "E"
Trigger Guard/Housing - both "K" and "G" stampings
Hammer - both "K" and "2" stampings
Hammer Strut - no stamping
Gun Frame - "K", "Z", and "P" stampings
Just FYI. Mine is working fine now but just wanted to share my notes with you..
There seems to be relevance of the various internal part stampings (the letters in the round circles), and how they best fit together (or even if they fit together at all!). There is probably some lookup table at Ruger that has a 'best fit' of which parts should be put into gun during final assy. These includes the cylinder, trigger, trigger housing, pawl, transfer bar, hammer strut, etc (the exact names are in the parts schematic).
Ruger seems to change/update internal parts often, probably as running changes or when there is a part vendor change. The stamping are the only way to keep track of the many versions of each part they use.
Anyway, I have concluded that during final assembly they probably start with a look-up chart (which probably matches the letters), and then check the the gun function. If it's still not 'acceptable', then they 'hand-fit' the parts ensure the gun is working well 'within spec' before boxing it up as a new gun.
In the case of the pawl, I have run across many types of slightly different shapes and designs - that make a BIG difference! For example, the ones stamped with a "B", is not only shaped somewhat different than others of another letter, but it also has a small 'bowl' indentation where the pawl spring plunger fits in. This keeps the pawl better seated when installed. The other letters do not have it, not that I have seen (interesting).
In in effort to fine-tune my gun, I tried many different parts and found a letter "B" pawl and letter "E" trigger do not work well together. The pawl overshoots the extractor ring slightly and causes the trigger to hold back. Perhaps the lookup table shows an "E" trigger is supposed to have a "E" pawl. To get my "B" pawl to work with my "E" trigger I had to work the pawl over carefully to get an exact match that functions well.
I also tried a "D" pawl- it does not even fit into the gun without hitting crane latch (the metal that is part of the crane latch button), and if you can wiggle it in, it's totally non-functional. But you put the "D" pawl up to the others, and there is very, very slight difference. It would go unnoticed by most people unless you actually tried it.
My stampings of some internal parts on my Ruger S/N 174-02xxx
Cylinder - "S"
Transfer Bar - "D"
Pawl - "B"
Trigger - "E"
Trigger Guard/Housing - both "K" and "G" stampings
Hammer - both "K" and "2" stampings
Hammer Strut - no stamping
Gun Frame - "K", "Z", and "P" stampings