I have an SBR lower receiver, originally registered as 5.56, 9mm, 10mm, 6.5 Grendel, .22LR, 7.62x39, .40, and .300 Whisper. It was registered also as 2"-15" on barel length and some variable on OAL as well.
I also have 2 other AR lowers (not registered SBR).
I have 2 uppers - one is my 9mm (8.5" barrel) and the other is a 16" 5.56 upper.
So, currently my SBR lower has my 9mm upper on it. One of my reguar AR lowers has the 16" 5.56 upper on it.
That leaves me with one regular lower with no upper on it.
Well, let's say I would like to get another shorty upper - maybe a 7.62x25, or a 5.45x39, or even a 5.56
What would be my best bet?
1 - Getting one of my two existing regular lowers SBR-ed and put a ton of calibers and lengths on the paperwork?
2 - Just get the shorty upper and only place it on the registered SBR lower? If so, would I send in a letter to ATF adding the caliber (like the 5.45x39 or 7.62x25 that I don't have on the old paperwork?)
Anything else I need to consider?
I also have 2 other AR lowers (not registered SBR).
I have 2 uppers - one is my 9mm (8.5" barrel) and the other is a 16" 5.56 upper.
So, currently my SBR lower has my 9mm upper on it. One of my reguar AR lowers has the 16" 5.56 upper on it.
That leaves me with one regular lower with no upper on it.
Well, let's say I would like to get another shorty upper - maybe a 7.62x25, or a 5.45x39, or even a 5.56
What would be my best bet?
1 - Getting one of my two existing regular lowers SBR-ed and put a ton of calibers and lengths on the paperwork?
2 - Just get the shorty upper and only place it on the registered SBR lower? If so, would I send in a letter to ATF adding the caliber (like the 5.45x39 or 7.62x25 that I don't have on the old paperwork?)
Anything else I need to consider?