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I just got the results from Tom Armbrust. They are as follows.

Cheddite Hull
Cheddite 209 Primer
16.8 Gr's of Solo 1250
Gualandi Wad with a 70mm card under the shot
7/8 ozs. #8 shot

The five shells produced
#1 6400 psi. and 1109 fps
#2 72oo psi. and 1136 fps
#3 7000 psi. and 1131 fps
#4 6400 psi. and 1116 fps
#5 6400 psi. and 1114 fps

The average psi is 6680 psi. and 1121 fps.

The Federal Hulls were loaded with the same components
#1 8300 psi. and 1142 fps
#2 7200 psi. and 1137 fps
#3 7400 psi. and 1127 fps
#4 8500 psi. and 1171 fps
#5 8800 psi. and 1168 fps.

The average psi is 8040 psi. and 1149 fps

I also sent some once used RST Cheddite hulls with the same components loaded

#1 8200 psi. and 1150 fps
#2 8100 psi. and 1154 fps
#3 7800 psi. and 1139 fps
#4 7500 psi. and 1142 fps
#5 8500 psi. and 1161 fps

The average psi. is 8020 psi. and 1149 fps.

Tom sent along a note saying that the Green Cheddite hulls I sent were new and the pressure can be 1000 to 1500 lower than a hull that has beef fired before as the new hull is smoother on the inside causing less friction.

I also sent some of the same hulls with 15.9 Gr's of Green Dot

Cheddite hull
#1 8300 psi. and 1163 fps
#2 9800 psi. and 1202 fps
#3 9600 psi. and 1200 fps
#4 9800 psi. and 1199 fps
#5 9300 psi. and 1184 fps

Average is 9360 psi and 1189 fps

Federal hull
#1 10100 psi. and 1203 fps
#2 10000 psi. and 1200 fps
#3 10800 psi. and 1221 fps
#4 9200 psi. and 1174 fps
#5 9800 psi. and 1202 fps

Average for the Federal is 9980 psi. and 1200 fps

RST hull
#1 10200 psi. and 1219 fps
#2 10400 psi. and 1215 fps
#3 9800 psi. and 1196 fps
#4 10300 psi. and 1203 fps
#5 9900 psi. and 1203 fps

Average for the RST is 10120 psi. and 1207 fps

The RST hulls are Cheddite and this would explain the difference between a never fired hull and one fired before.

I am going to load 100 of the green hulls and shoot tehm and have some of them retested.

Regards, Gordon

Guest

Gordon those are all excellent loads and Tom's explanation of the higher pressure from the once fired hulls make good sense. Thanks for taking the time to develop and have these loads tested plus footing the bill. It will be interesting to see if the Australian made Winchester Super X are comparable with the once fired Cheddite (RST) results. Not to be nit picky but did you mean 7MM vs 70MM card wad?

Guest

Hi Gordon,

The following is just my opinion, but...

Save your money on those green Cheddites, the pressure difference isn't a very big deal. I would trust Mr. Armbrust's statement. If you were closer to max, maybe but the difference between 6,600 PSI and 8,000 PSI is basically meaningless. Maximum average is 11,500 PSI.

Folks put way too much emphasis on the pressure figure, and not enough where it should be, which is the consistent performance of the loads.

With the exception of the first Federal load, they all look like winners. Nice job!!

Twice Barrel

Yes the card that I put under the shot is a 1/16th or 1.77mm. I use a 32 ga. that I got from Circle Fly Wads.

Thank you for the oversight.

Regards, Gordon