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I just got an SBR permit back about 2 weeks ago. It took 5 weeks from mailbox back to my mailbox. Sure beats the old Chicago days waiting 8 months or longer on Forms. I fired my 12" AR tonight for the first time without my chronograph since I was mainly testing function. It seemed to go super on loads that were sub in my 16" using AA#9. I tried 8.9 & 9.0 grain charges and both cracked. I will shoot some more loads across the chrony this weekend and share. BTW my 16" was a Shilen and the 12" is a Noveske and both 1:8's. It was also colder outside by 30 degrees compared to when I worked the other load up. Which could account for a slower speed of sound. Remember speed of sound = 49.06 times the square root of (T + 459). Temp is in good old Fahrenheit. Every powder lot and barrel is a little different. I used a titanium QSM suppressor too which is tighter than the Thundertrap so I suspect some more freebore boost too. I'm gonna hopefully find out this weekend.
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