09-25-2022, 02:00 AM
stonehog Wrote:Good advice, guys - thanks for all the inputs! I'm looking back over my load data, and my original testing with this load was in my PSA 20" upper getting about 2446 ave velocity. I noted perfect 4pm eject pattern with this load as well, so gassing seems good. Odin and PSA FWIW, as well as my 18" Faxon upper.
I did a COL test with this powder charge with a 123 gr Hornady BTHP in the 12" Odin I had the failure in. Interesting that in that bullet and test, I did have a few issues with Federal cases that were hard to extract. My notes:
"Note: all these (2.246 - 2.26) may be too long for throat length. In the 123 Hornady BTHP, I had bullets possibly stick in the lands and had click-no-bang, and then trouble extracting the unfired cartridge"
At the time, I theorized that it was a jam into lands issue, but this didn't exactly line up after I got the Hornady COL gauge which found jam length of 2.3050 for the HPBT and 2.310 for the ELD-M.
It is interesting that I've only noticed the ring on one other case out of the 40+ I've shot in that batch so far. Next step is actually measure the powder from a few rounds when I get my puller...
stonehog for your remaining ELD-M rounds from this batch, are you absolutely certain that they jam into the lands? Forget the COL gauge and how it compares to the HPBT. Test it with an actual round in the chamber.
With the bolt removed completely, I just drop a round into the chamber by hand and then I'll push on the primer end hard enough to "jam" it. If the round is jammed into the lands, it will not fall out of the barrel by gravity when you set the upper pointing straight up. And you'll have to use a cleaning rod to remove it. If it is not jammed, it falls out freely. I just did this to properly seat some 120gr ELD-Ms and it worked well. I found out they jam at 2.210" on my barrel so I set my COL to 2.190 which is much shorter than the Hornady book value.