First day at the range with a trapdoor

[107ch]

Hi,
I went to the range today to shoot a trapdoor cutdown carbine I got a while back. Starline brass, 65 gr. of goex ffg, and 530 gr Postels from cheycast and spg lube. I fired about 30 rounds, I was planning on 40. OUCH!! That military buttplate hurts!. I had one very good group of five shots at 50 yds, all touching. But after 15 or so the group opened up considerably. I don't know if the lube was giving out or what. I was not using a blow tube. Should I ?? I have one , but I thought with that short carbine length barrel I would not need it. Any insight on shooting these old firearms would be appreciated. It sure was fun!
Dennis

[Charles Vail]

Yes you should use the blowtube. The throat area of your rifle needs to have the powder residue keep moist . After this many shots the fouling was probably distorting your bullets causing inaccuracy. A couple of breaths should help after each shot, however, a damp patch after maybe a ten shot string wouldn't hurt either. With some experimenting you'll find out when the accuracy of your particular rifle starts to deteriorate requireing either the blowtube or a barrel swabbing! For hunting use you shouldn't need a blowtube if only firing  2-3 shots depending on your lube, barrel length and  ambient temperatures.  Hope this helps!