I recently bought a Robertson 20b with 2-1/2" chambers and am in process buying another 20b 2-1/2" Atkin SLE. I already load 2-1/2" 12b and 16b shells for my Atkin 12 and Harkom 16. I am preparing to begin loading for the short 20b guns.

I have some RST 20b 2-1/2" ammo and paper hulls, but almost all my 20 gauge hulls are WAA 20s - a couple bushels full. I'd like to work up suitable 3/4 and 7/8 oz. loads using the AAs. Measuring the length of fired hulls and comparing the '2-1/2" RSt and the 2-3/4" WAA20s I see that the fired RST paper hulls are 64.5mm long, while the WAA20s are just 67mm long, so difference of 2.5mm or 3/32" between the two hulls types. I COULD cut down the AA hulls but feel that the difference between the two hulls is very small and many "2-1/2 inch' Brit cartridges are loaded in hulls that are 67.5mm long. So I am tempted to simply load a lower pressure load in the standard WAA20 hull.

I am asking those who have some experience with loading for 2-1/2" 20b Brit guns what they do and have they used the slightly longer AA hulls without cutting off the hull by 3/32" ??

Thanks for your help.

C Man

C Man
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