Difference between "Multi-cal lower" and 223/556 lower

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srqsteve
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Difference between "Multi-cal lower" and 223/556 lower

Post by srqsteve »

What is the difference between a lower designated as "Multi-cal" to one that is for 223/556?
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Odessaman
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Post by Odessaman »

Not a darn thing but the inscription. Manufacturers didn't want to lose potential sales from customers who want to build a .300 Blackout or some other rifle that uses the standard 223/556 lower, but didn't want their custom job inscribed with 223/556.

Now, if you have a lower marked "Multi-cal" and you apply for a tax stamp for an SBR, ATF wants you to put the intended caliber in the application, not Multi-cal. So if you plan to slap a 10" upper in 5.56 on a Multi-cal lower, you need to put 5.56 on the Form 1.
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srqsteve
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Post by srqsteve »

Thanks; that's what I thought but wasn't sure.
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flcracker
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Post by flcracker »

Odessaman wrote: Wed Dec 18, 2019 5:58 pm ... if you plan to slap a 10" upper in 5.56 on a Multi-cal lower, you need to put 5.56 on the Form 1.
Am I correct in my understanding that as long as you retain possession of the upper that matches the information on the approved Form 1 and it can be readily re-installed on the lower, then you can swap out any other upper you wish?
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Odessaman
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Post by Odessaman »

flcracker wrote: Thu Dec 19, 2019 10:33 am
Odessaman wrote: Wed Dec 18, 2019 5:58 pm ... if you plan to slap a 10" upper in 5.56 on a Multi-cal lower, you need to put 5.56 on the Form 1.
Am I correct in my understanding that as long as you retain possession of the upper that matches the information on the approved Form 1 and it can be readily re-installed on the lower, then you can swap out any other upper you wish?
Yes, that's correct - once you get the stamp and get the lower properly engraved, you can swap back and forth among other compatible uppers.
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imnotryan
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Post by imnotryan »

Yeah most if not all new lowers sold no longer include any caliber indication on them.

It was never anything more than a "the upper assembly on this is supposed to be..."
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