I wasn't going to waste time posting this info until I read this thread looking for other loads to try.20X11 wrote:ROFL...yeah, they group 2 completely different 125 gr projectiles together. AND they think H110 will handle a heavier charge than Lil Gun...not only do I doubt Sierra’s published data, I refute it based on my own empirical evidence.
So...not so "official" in my book.
And...now that I take a second look, they have a OAL that is less than the co-designer of the 2121 projectile recommends...completely bogus data, obviously RUSHED out the door to satisfy demand. Too bad they didn't do it right.
I doubt their loads for the 125gr matchking with Lil Gun will even properly cycle the AR platform.
I loaded up 70 rounds of 125 and 110 grain and went out Sunday morning to try out the Sierra data and here are some of the results:
Daniel Defense DDM4V5 16" w/ carbine gas system
CCI 450 Primers (yes, I know they didn't use these, but they're all I have, and I thought I'd be fine with the lighter loads)
Remington 223 brass, no crimp
Lil Gun powder
5 shots unsuppressed, chrony at 10'
Sierra 125 ProHunter, COL 2.000
16.0gr.: 2133, 2153, 2164, 2017, 2123 - First shot didn't cycle, so I loaded single rounds, and bolt did not hold open on any.
16.5gr.: 2002, 2030, 2026, 2080, 2189 - All had bolt hold back
Sierra 125 Matchking, COL 2.210
16.0gr.: 2038, 2020, 2038, 2060, 2002 - First shot didn't cycle, so I loaded single rounds, and bolt did not hold open on any.
16.5gr.: 2029, 2044, 1949, 2014, 2076 - All had bolt hold back, and had the best accuracy out of all the loads with this (although it still wasn't impressive).
I had 10 rounds of these 4 loads and shot the other 5 of each load suppressed without cycling issues, including on the 16gr. loads.
I'm pretty damn meticulous when I reload, so I thought the chrony (ProChrono) numbers indicated the chrono was toast, that is until I sent a number of shots across it using my air rifle (Air Arms S410 PCP) at the range and got accurate readings on the shots. To be honest the numbers left me so confused I didn't record the suppressed shots with the 125gr bullets because I didn't think there was much of a point. I checked each cartridge after firing since I was using the magnum primers and folks have mentioned pressure spikes, and there were no signs of any issues.
At the end of the day I'm going back to the Hodgdon load data but try the Sierra COL's. After I got back from the range I bought an RCBS Chargemaster combo from Natchez so I can load faster and not have to dick with the manual scale, although I know my charges were consistent. I was trying to use up the last of the Lil Gun I bought, but now that I have 4 lb's of WIN296 I'm going to start using that instead.