PDA

View Full Version : Carbon ring on shoulder



JonathanK
06-12-2011, 05:11 PM
I was doing some practicing yesterday and had a good tune going, I started to notice my bolt getting hard to close. I figured the brass had hardened a bit, so I set my die to push em back a little more(just enough so I close the bolt with a little resistance) all seemed well for a bit, then I my groups started opening up and I started getting flyers. I then noticed that the carbon ring had moved on to the shoulders of my brass. I chalked it up to the brass had work hardened and was not springing back to the chamber, so I fire formed some brass and the ring is in the middle of the neck now. The brass had been shot close to 15 times at 29.3-29.8 of 09 133, so Im thinking they need to be anealed for practice brass or discarded. I usually get bolt click with my brass and thats when I would discard them, this time was different no click just gas leaking around the shoulder. I think from now on when I notice the bolt getting hard close I will not shoot that brass any more in a match.


http://i799.photobucket.com/albums/yy274/jonathank15/C360_2011-06-1215-36-49.jpg

Octopus
06-12-2011, 08:31 PM
While this is not a direct answer for your questions you may find it of interest. Back in 2001 or so I took 20 new rounds of 6 PPC brass I had made up for my 0.262 6 PPC barrel. Neck wall was turned to 0.0085. I shot the brass 6 times and then annealed it. Next I shot it 10 times. The best accuracy was on cycle 2 to 5 after it was annealed. Precision fell off some with rounds 6 and 7 and then seem to hold about steady till cycle 10 after annealing. I keep shooting this same brass and annealing it. I found the best accuracy was on cycle 2 to 5 after it was annealed to be consistence. Lesson learned. Now days I anneal after cycle 5 the majority of the time with a Ken Light machine. By the way this same 20 rounds of brass has over 45 cycles and I still use it sometimes. I usually full length resize after I anneal and then trim OAL as needed.

I suspect your brass is work hardened and needs to be annealed more often.

Bob Kingsbury
06-12-2011, 09:31 PM
Are you using a FL die that does not use a bushing ? I have used 50 cases darned near for the life of a barrel without
annealing and have never had that. I have seen it where a fixed die was used and the shoulders were pushed a bit to
far.

JonathanK
06-12-2011, 11:58 PM
Are you using a FL die that does not use a bushing ? I have used 50 cases darned near for the life of a barrel without
annealing and have never had that. I have seen it where a fixed die was used and the shoulders were pushed a bit to
far.

I always FL size with a Harrels bushing die custom for my reamer, and i set it up with a piece of deprimed brass to where the bolt when dropped(gravity only) will stop at around 4-oclock an require just a little pressure to close all the way. Im starting to think maybe its the hot Texas sun combined with my semi-hot load spiking pressure and working hard on my brass, Im just used to getting bolt click before something catastrophic to an agg. like this happens

JonathanK
06-13-2011, 12:33 AM
One really important thing I should have realized and noted, this brass is out of a new box.....Maybe related to the issue Jackie reported, I will try to find an uncut piece of brass out of the old batch and see if they measure differently.