keyhole & inaccurate
Quote from Reloader on June 30, 2010, 12:17 pmDue to availabilty of powder locally, I recently switched from AA#9 to Longshot for 10mm. After loading up and shooting several hundred rounds (with my SDB), I can not figure out what is going on. My loads have used a variety of brass, WLP, rainier 180 fn, oal 1.260". When I used AA#9 (12.5gr - 13.3gr), my rounds were very accurate and consistent. Since switching to Longshot (8.9gr & 9.5gr), my rounds have become inconsistent and very inaccurate. Other than powder measure, all press adjustments have remained the same. I have not had any failure to fires, but in addition to being very inaccurate, the bullets seem to be in the process of tumbling due to the horizonal holes in paper targets. These rounds have been shot through several Glocks and S&W pistols (with the S&W fairing only slightly better). Any ideas would be greatly appreciated.
Due to availabilty of powder locally, I recently switched from AA#9 to Longshot for 10mm. After loading up and shooting several hundred rounds (with my SDB), I can not figure out what is going on. My loads have used a variety of brass, WLP, rainier 180 fn, oal 1.260". When I used AA#9 (12.5gr - 13.3gr), my rounds were very accurate and consistent. Since switching to Longshot (8.9gr & 9.5gr), my rounds have become inconsistent and very inaccurate. Other than powder measure, all press adjustments have remained the same. I have not had any failure to fires, but in addition to being very inaccurate, the bullets seem to be in the process of tumbling due to the horizonal holes in paper targets. These rounds have been shot through several Glocks and S&W pistols (with the S&W fairing only slightly better). Any ideas would be greatly appreciated.
Quote from Reloader on July 2, 2010, 1:53 pmUnfortunately I do not have access to a chronograph. I am hoping that one of the local gun stores/ranges might have one that could be used. Thank you once again.
Unfortunately I do not have access to a chronograph. I am hoping that one of the local gun stores/ranges might have one that could be used. Thank you once again.
Quote from Reloader on November 4, 2010, 11:54 amYou have changed powders now you have to start from scratch. and try differant loads all over till you find the one that works
You have changed powders now you have to start from scratch. and try differant loads all over till you find the one that works
Quote from Reloader on November 4, 2010, 5:00 pmTry backing off the crimp die about 1/4 turn. Sometimes excessive crimp can cause this as well.
Try backing off the crimp die about 1/4 turn. Sometimes excessive crimp can cause this as well.
Quote from Reloader on December 7, 2010, 8:31 pmFirst of all, thank you to all who have shared their knowledge. Update: loaded up another batch (dropped charge to 8.6gr. of Longshot - Hodgdon manual starting load is 8.5gr.). Keyholing and lack of accuracy seems to have subsided (crimp remained the same, but I will keep an eye on this for the future), but I noticed that I now have some pitting on the breechface of both of the Glocks that these rounds have been fired through. Cases have been from several manufactures and have been reloaded 3-4 times. Have not seen any signs of excessive pressure with any of the loads. I am begining to wonder if I need to de-prime the cases prior to tumbling and then run a primer pocket brush through them prior to loading, or if I just need to break down and buy new brass. Once again, thank you.
First of all, thank you to all who have shared their knowledge. Update: loaded up another batch (dropped charge to 8.6gr. of Longshot - Hodgdon manual starting load is 8.5gr.). Keyholing and lack of accuracy seems to have subsided (crimp remained the same, but I will keep an eye on this for the future), but I noticed that I now have some pitting on the breechface of both of the Glocks that these rounds have been fired through. Cases have been from several manufactures and have been reloaded 3-4 times. Have not seen any signs of excessive pressure with any of the loads. I am begining to wonder if I need to de-prime the cases prior to tumbling and then run a primer pocket brush through them prior to loading, or if I just need to break down and buy new brass. Once again, thank you.
Quote from Reloader on December 8, 2010, 4:12 pmGlock claims the pitting on the breech face is caused by light loads. I doubt cleaning the primer pockets will make any improvement.
Glock claims the pitting on the breech face is caused by light loads. I doubt cleaning the primer pockets will make any improvement.
Quote from Reloader on December 17, 2010, 12:54 pmI have never heard of light loads causing breeachface pitting, however the loads that I referenced in my last post are on the "starting load" range of the data. I thought the pitting/erosion that I was experiencing was due to the primers not sealing completely in the primer pocket and thereby causing a leak of flame/hot gases which was acting like a blowtorch on the breechface. It looks like a perfect circle (exact size of the primer/primer pocket) of dots. Thank you once again for sharing.
I have never heard of light loads causing breeachface pitting, however the loads that I referenced in my last post are on the "starting load" range of the data. I thought the pitting/erosion that I was experiencing was due to the primers not sealing completely in the primer pocket and thereby causing a leak of flame/hot gases which was acting like a blowtorch on the breechface. It looks like a perfect circle (exact size of the primer/primer pocket) of dots. Thank you once again for sharing.
Quote from Reloader on April 19, 2012, 2:27 amI would watch and adjust to almost no crimp with plated bullets, especially in 10mm and 357SIG calibers. Just a touch too much crimp does cause tumbling in my experience. Best way to check is to pull the bullet with a bullet puller, if you see any ring or mark at the case mouth back off the crimp. Most plated bullets are quite soft and will not take the same taper crimp as their jacketed or hard cast counterparts.
Jim
I would watch and adjust to almost no crimp with plated bullets, especially in 10mm and 357SIG calibers. Just a touch too much crimp does cause tumbling in my experience. Best way to check is to pull the bullet with a bullet puller, if you see any ring or mark at the case mouth back off the crimp. Most plated bullets are quite soft and will not take the same taper crimp as their jacketed or hard cast counterparts.
Jim