braddsn Posted November 6, 2014 Posted November 6, 2014 Hey guys.. ill make this short and to the point. I launched a few 4 inch shells this eve. Last week i used 10 percent of shell weight and the lift seemed powerful and ground shaking.. but altitude was very low. So tonight i went 20 percent.. with little to no improvement. Mortar tube clearance is not the issue.. the shells fit nicely in tube. My bp is very good. So far i have only used 2FA.. but i am making some 4fa as we speak. Perhaps the 4fa will solve the problem? The shells break hard and loud with no flash booster.. but it was raining stars on my head because of low altitude lift. thanks for any advice on this. Should i go on up to 30 percent of shell weight?
Jakenbake Posted November 6, 2014 Posted November 6, 2014 Do you have a 3" tube? If so I would try launching a baseball with 5 grams of your BP. If the BP is good it should throw the ball almost out of sight.
Sparx88 Posted November 6, 2014 Posted November 6, 2014 Can't really go by what it sounds like because even slow BP will thump nice lifting. If clearance is good, tube length is good, and you tried doubling the amount of lift with no improvment would steer me towards BP performance.
enanthate Posted November 6, 2014 Posted November 6, 2014 (edited) Bigger grains might help, but sounds like the problem is elsewhere in my oppinion.I gotta ask; how much gap between the shell and mortar?A video of your BP would also be very helpful, just to eliminate that.And of course you dont have 1sec timefuse? Edited November 6, 2014 by enanthate
Shadowcat1969 Posted November 6, 2014 Posted November 6, 2014 Are the shells going off at apogee (their highest point of flight)? If they are still climbing when going off, your time fuse needs to be longer. Otherwise, on a small shell, smaller grains of BP can be better. I usually use -10+20 mesh (about 3fa or 4fa) for my 3" and 4" shells.
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