Underwood 165 GDHP mini-smile :-)

[RMM]

Forgot to ask;  RMM, would you say the case was retracted a full eighth of an inch when it smilied?

I will get my calipers out tonight when I get back home and see if I can get a ballpark measurement. 

I might have to try and cut this casing apart to see what it looks like on the inside.  I will have to see what I can do with my little rotary tool.

This is an interesting puzzle to me.  I am in law school now, but I studied the applied sciences as an undergraduate.  I spent many hours in physics and chemistry labs.  Although all of the calculations I've seen from knowledgeable people say that either (1) too much force would be required to extract the cartridge while under that much pressure (so much that the extractor would rip off the case rim), or (2) the extremely high chamber pressure (enough to smiley the brass) occurs too quickly for the brass to smiley as it's being extracted. 

Obviously I've just made some very generalized statements here, but what we're seeing does not jive with either theory.  When your calculations and actual results do not correlate, then you're missing something. 

[REDLINE]

Forgot to ask;  RMM, would you say the case was retracted a full eighth of an inch when it smilied?

I will get my calipers out tonight when I get back home and see if I can get a ballpark measurement. 

I might have to try and cut this casing apart to see what it looks like on the inside.  I will have to see what I can do with my little rotary tool.

Cool.  Precise measurements would be great, especially so that other's of us with the same experience can then compare with different barrels (even different Glock barrels).

[RMM]

I just wanted to make a quick post and thank all of you for your kind reception.  I really appreciate all of the advice you've given me, both directly and indirectly.

Richard

[REDLINE]

You bet!  I think I can speak for most everyone here that we're happy you're here!  Lots of great info on this site, and you're doing a great job adding to it.  Glad you found us. 

[RMM]

I took some measurements.  This number is not 100% accurate, but I think that it is pretty close +- 0.005".

The smiley occurred when the case was 0.085" from being fully inserted into the barrel.

[REDLINE]

The smiley occurred when the case was 0.085" from being fully inserted into the barrel.

Okay, so not quite 3/32", but definitely over 1/16".  Thanks for taking the time.  It helps put things in perspective instead of purely trying to judge from the pics.

[The_Shadow]

Yes, thanks for the details and pictures...Now to determine why the case is being push, pulled or not being fully chambered to have less case support and the smile occur.   Barrel and slide need to lock together and fully slide forward as a unit to engage the locking block to hold the lockup. 

Some have reported where a shot was higher on target, than the point of aim, this may indicate the barrel may have started to tilt, to indicate early unlock condition.