So it turns out that you can use 2 normal AND an XL spacer on the 38mm CTI. This means that you could just buy a 3 grain and 6XL to cover all the 38mm reloads, awesome!
I never noticed that the 6xl was a spacer + XL longer than the 6 grain. I always assumed it was just the XL spacer longer so that's where my misunderstanding is from. So you can use 3 spacers (2 normal and 1 xl) but it only goes down to 5 grain, makes sense.
Responded quicker than I could edit my response. Yeah I get it now, XL is longer than I thought.
My understanding is it is not absolutely necessary for the motor case to fit within the MMT length, it can extend past. You need to have enough airframe left to pack you recovery system (chute and protection). If you don't, then you need the shorter casing.
That's what I meant ... room within the booster to fit the motor casing. I am simply trying to prevent people from thinking that if they buy the minimum amount of casings to fly every reload, it doesn't magically make their rocket capable of fitting all those casings.
That's why I am building all of my HPR nose cones with a dual bulkhead and forged eye bolt to add weight for bigger motors. Planning ahead provides flexibility down the road. Then again, you could always just build another (bigger) rocket...
