levellinebrad Posted July 3, 2014 Share Posted July 3, 2014 Powder charge should have no impact on feeding. Link to comment Share on other sites More sharing options...
G19 Posted July 3, 2014 Author Share Posted July 3, 2014 Powder charge should have no impact on feeding. It does - at 2.9gr, none of the rounds fed. As I gradually increased the charge, an increasing proportion of the rounds fed properly. I assume this has to do with full retraction of the slide. Of course it could be that at 3.3gr, the slide is fully retracting and no additional feeding benefit would be gained by an increase over 3.3gr. Link to comment Share on other sites More sharing options...
tires2burn Posted July 3, 2014 Share Posted July 3, 2014 Where is the 3.3 coming in on your loading data? High. middle, low. Maybe you can step it up a little to give the slide more snap. Link to comment Share on other sites More sharing options...
levellinebrad Posted July 4, 2014 Share Posted July 4, 2014 Powder charge should have no impact on feeding.It does - at 2.9gr, none of the rounds fed. As I gradually increased the charge, an increasing proportion of the rounds fed properly. I assume this has to do with full retraction of the slide. Of course it could be that at 3.3gr, the slide is fully retracting and no additional feeding benefit would be gained by an increase over 3.3gr.I see what you are saying. That is still not a feeding issue. That is a function issue. Do you by chance have access to a chronograph? it would be nice to know what velocity each round was producing. Link to comment Share on other sites More sharing options...
LikesToShoot Posted July 4, 2014 Share Posted July 4, 2014 I use the split case method of determining COL for whatever bullet I'm using. For my M&P's I go around 1.135 or less, depending on bullet and barrel being used. This isn't bench rest shooting so loading "X" off the lands won't matter much. It's an M&P, not a bull's-eye gun. If you use a U-die that'll get rid of most of the brass concerns, then load them short enough to run 100%. If you switch to a tight chamber aftermarket barrel, SL or whoever, then you'll have to chamber check the rounds or have the tight chamber modified. Link to comment Share on other sites More sharing options...
G19 Posted July 4, 2014 Author Share Posted July 4, 2014 Where is the 3.3 coming in on your loading data? High. middle, low. Maybe you can step it up a little to give the slide more snap. In Lee's Modern Reloading, the only listing I see for SR 7625 in 9mm 147gr bullets is for 147gr XTP, with start and "never exceed" charges of 2.8gr and 3.3gr (1.100 OAL), so at 3.3gr, I'm already at the listed max. That said, lots of people are using more than 3.3gr without any issues. So I could step up the charge a little bit. I'm also wondering whether moving in either direction from a 1.145 OAL would help with more reliable feeding. Link to comment Share on other sites More sharing options...
G19 Posted July 4, 2014 Author Share Posted July 4, 2014 Powder charge should have no impact on feeding.It does - at 2.9gr, none of the rounds fed. As I gradually increased the charge, an increasing proportion of the rounds fed properly. I assume this has to do with full retraction of the slide. Of course it could be that at 3.3gr, the slide is fully retracting and no additional feeding benefit would be gained by an increase over 3.3gr.I see what you are saying. That is still not a feeding issue. That is a function issue. Do you by chance have access to a chronograph? it would be nice to know what velocity each round was producing. At 3.3gr and 147gr lead, I'm getting ~820 fps. Pretty slow, huh? Link to comment Share on other sites More sharing options...
levellinebrad Posted July 4, 2014 Share Posted July 4, 2014 Powder charge should have no impact on feeding.It does - at 2.9gr, none of the rounds fed. As I gradually increased the charge, an increasing proportion of the rounds fed properly. I assume this has to do with full retraction of the slide. Of course it could be that at 3.3gr, the slide is fully retracting and no additional feeding benefit would be gained by an increase over 3.3gr.I see what you are saying. That is still not a feeding issue. That is a function issue. Do you by chance have access to a chronograph? it would be nice to know what velocity each round was producing. At 3.3gr and 147gr lead, I'm getting ~820 fps. Pretty slow, huh? That is pretty slow. I would bump the powder charge to 3.5 or 3.6. I would try to get to 900fps. Link to comment Share on other sites More sharing options...
tac_driver Posted July 6, 2014 Share Posted July 6, 2014 check your crimp at the mouth of the case should be .276 - .278 also when doing the plunk test the round should be able to turn freely inside the chamber I had a KKM barrel that i had to seat to 1.055 to pass the plunk test with Missouri 124gr bullets Link to comment Share on other sites More sharing options...
rhyrlik Posted July 6, 2014 Share Posted July 6, 2014 They don't have to pass the plunk test. Cast bullets are going to fit tighter in the chamber because they are sized larger and are covered with lube. Some will have splotches of lube on the nose that will interfere with plunking. The force of the slide slamming into battery will overcome these minor fit issues. As was suggested, determine max OAL with dummy rounds and work up a load. Link to comment Share on other sites More sharing options...
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