Doesn’t fit with zev tech / mega arms ar15 upper/lower - Strike Industries Advanced Receiver Extension Buffer Tube

I installed this tube into my lower and the tube extended too far into the front of the lower receiver that the upper wouldn’t even fit (blocked by the tube threads). I did not screw it in too far, just enough to perfectly get stopped by the detent. So, I backed it out one revolution to fit the upper. Well now there is a gap, b/w my JP silent buffer spring system and the BCG. The only option if I want to keep it is to sand off the first few threads to avoid collision with the upper or not use the silent buffer system. Most people don’t have an issue because they use a regular buffer spring and wouldn’t have an issue backing out one turn as the spring would continue to stay in direct contact. Three stars because mil spec should be mil spec, period; and this is not, it’s off by about 1/32 inches.