Member
Joined: 02 Oct 2004
Posts: 425
Location: Maine
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Shot some ¾ oz. Promo loads today, and about ½ were slightly weak, and off-sounding. Load used a RGL hull, Promo, R16 wad, Noblesport 209 (subbed for Win 209), ¾ oz. #9 and a filler wad. Temp was in the mid-30's today. Ths load has always worked well in warmer temps.
I recalled a thread on shotgunworld where people were having cold weather issues in 12g with Promo, clays, and e3 with light payloads, mild primers, shallow crimps and cold temps.
http://www.shotgunworld.com/bbs/viewtopic.php?t=98128&highlight=double+burn+promo
Long story short, what was probably happening, was a double burn phenomenon, where the powder was not completely ignited, and a delayed, secondary burn pounded the base of the wad, cracking it, resulting in blowby, and an off sounding report. This was diagnosed with a pressure test barrel, where 2 pressure spikes were observed with these blooper loads.
I had 2 bloopers from station 7, which I was able to retrieve the wads, and lo and behold, the base of these wads were cracked. I don't have a pressure test barrel, so I can't prove that a double burn is taking place, but it would seem likely. Anecdotally, I have found clays to be a better cold weather performer than Promo, so I think I'll try it instead, by reducing this load to ¾ oz, (RGL hull, SP16, 13gr Clays, Win 209, 1oz lead) and staying with the Noblesport primer.
http://data.hodgdon.com/shotshell_load.asp |
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