Powder work-ups
#11
I am not anyones idea of a "expert" but I have been at this awhile, and I shot NRA High Power when I was younger, (pre-bifocals, I'm wearing trifocals these days).
I have been going through this process myself this year, using Varget, LVR and CFE.  Bullets I've worked with include Lapua 105 Scenars, The Berger 105 and 109s, 107 and 110 SMKs.  The Lapua Scenars, Berger 105s and 107 SMKs are all tangent ogive, while the Berger 109s and 110 SMKs are secant ogive, and seem much fussier to get tuned in to me.  I'm shooting an AR with a 22" Craddock RTR barrel, The local match I compete in is 440 yards off the bench. While LVR and CFE give better velocities, the Varget is giving me better accuracy, and better consistency across the seasonal temp variations, (May to October in northern Maine; 40F to 90F).    My mags will allow me to load out to 2.290, and I've tried single loading the 110 SMKs out to 2.33, but my most consistent results have been with 107 SMKs at 2.260 which puts them about .015 off the lands.  I may do some more work with the 110 SMKs to see if I can find an OAL inside of 2.290 that will work, but for now the 107's are staying under 1/2 MOA at 200 and keep up with the 6.5s and .308s in the wind so I'm happy with them so far.
It took me a while to come to the realization that 100 fps does not make much difference at a 1/4 mile, and is certainly not worth giving up any precision.  The local match is 5 spotters followed by three ten round strings from the bench, using the NRA 100 yard military target, (3-1/4" 10 ring, 1-1/4" X ring) primarily because the club has a big pile of them. They are scored after each string allowing for sight corrections. I managed to win for the first time  this year last Saturday with a 289-6X.  I had won a couple times last year using an AR in .223, but on the windier days the bigger bores would beat me every time, so I built this 6 ARC.  My work up process is: powder charge ladder in 2 grain increments at .010 to .020 of the lands. Then, using the best result, COAL variation ladder at .002 increments from .02 under the starting COAL to touching the lands, (depending on how close to max charge I am). Follow by a barrel tuning ladder, (if that rifle has a tunable brake).  I generally have a usable load at that point, which I may, or may not mess with further depending on the precision I've gotten.  I shoot all my ladders at 200 yards using 5 shot groups. If  I wind up with a couple that are very close, I'll do a "Shoot off" using 10 shot groups at 400 yards on a dead calm day, (pretty rare day around here).  At this point the rifle is capable of more precision than I am, so I'm more interested in additional barrel time than I am in additional load tuning. However, I think I may spend a little time this winter sorting brass and bullets by weight.
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Messages In This Thread
Powder work-ups - by KMW1954 - 10-19-2024, 12:31 PM
RE: Powder work-ups - by Rickhem - 10-19-2024, 02:16 PM
RE: Powder work-ups - by KMW1954 - 10-19-2024, 08:30 PM
RE: Powder work-ups - by grayfox - 10-19-2024, 11:39 PM
RE: Powder work-ups - by KMW1954 - 10-20-2024, 12:12 AM
RE: Powder work-ups - by grayfox - 10-20-2024, 08:34 AM
RE: Powder work-ups - by KMW1954 - 10-20-2024, 02:32 PM
RE: Powder work-ups - by grayfox - 10-20-2024, 03:02 PM
RE: Powder work-ups - by KMW1954 - 10-20-2024, 08:00 PM
RE: Powder work-ups - by grayfox - 10-20-2024, 09:52 PM
RE: Powder work-ups - by BD1 - 10-22-2024, 02:26 PM
RE: Powder work-ups - by KMW1954 - 10-26-2024, 04:27 AM

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