12 ga wad question

[Steve Hodges]

I am looking at loading data using Perfect Pattern for 12 Gauge loads. I like the low pressures that you can get with this powder but am a bid confused with one of the wad recommendations. For a 7/8 oz load it is calling for a CB 0175-12 wad. Just wondering why a 3/4 oz wad is used in a 7/8 oz load?

[edgarspencer]

Perhaps it's intended as a 3/4oz load in a 2 1/2" (?)

[Steve Hodges]

Edgar this is from the Hodgdon Reloading Data Center. I entered 2 3/4 Win Aa hulls, 7/8 oz lead shot, perfect pattern powder. Received 48 loads and out of that this wad is recommended in 24 loads. It reads CB 0175-12 for the wad.

[Cold Spring]

Steve, the CB 1078-12 wad loaded with 7/8 ounce will sit a little low in Gun Club or STS hulls with lighter loads using Perfect Pattern powder because so little VOLUME is occupied by PP as compared with other familiar bur largely unavailable powders that require a much higher number powder bushing. PP is a modern high energy/low volume powder. I have many cases of 1078 wads on hand and use them ahead of PP powder though the crimp is a little low and dished. I've never used the 1075 wads (3/4 ounce) but I presume the column under the shot cup is a bit longer which will result in a flatter crimp when 1075's are loaded over PP powder and with 7/8 ounce of shot.

[Steve Hodges]

Thanks Frank that makes perfect sense. I do the same for 7/8 oz 20 ga loads in top gun hulls. I use a 3/4 oz wad and my crimp is perfect, where a 7/8 oz wad is dished out like you said.

[Double Lab]

What Frank said Steve. It has to do with the density of the powder. Actually wads have very little effect on the pressures in a load especially loads under 9k in 12ga. A good crimp is much more important in performance.