and 5.56 is cheaper to train with.

so buy two uppers, one in 5.56 and one in 300 blk

same pistol lower.

swap and pick.

I'd rather avoid having both. 300BLK will load into a 5.56 and then very bad things happen

its the other way around.

5.56 will load into 300 blk, but not vice versa.

300 blk into a 5.56 upper would cause you to have a jam because its necked differently.

but the case is shorter, so the bolt closes on the 300 and then your gun explodes

but 300 blk is a 5.56 cartridge so it will accept a 5.56 no problem.

I mean, clearly mixing ammos isn't nice.

so.... just dont?

5.56 with Frangible rounds are good for home defence. Get a pistol AR or a 16in with a 15in rail is a good idea for CQB.

my problem with 300 blk is that virtually no one actually has it.

300blk will not fit into a 5.56 bartel5

Barrell

Well order the rounds from Graf and Sons

Or lucky gunner

if I can't buy it at walmart, I don't want to expect to have it any time.

i wouldn't rely on it for home defense.

True

you might not be able to buy it and that would suck.

https://www.thefirearmblog.com/blog/2015/01/13/psa-always-known-caliber-300-blk-5-56-kaboom/

mistake 1: polymer lower.

mistake 2: being a moron.

300BLK doesn't exactly "chamber" in a 5.56 rifle, but there's enough room for the bolt to close

ahhh

that makes sense.

Yeah its going to feed but cause an explosion on the chamber as it

I'm guessing that its tight enough to force a round to push back into the brass

True

Has a failure to lock

I'd like to think I'm not a moron, but the possibility of such a failure is something I'd want to avoid altogether

Yep.

proper procedure is key

but I get the feel. If I had to pick only one, 5.56 all day

300 blk is a meme round.

And not screwing up your ammo

If you check this google document you'll find a link to a youtube video and a translated transcript of a meeting between the leaders of NRK, the Norwegian version of BBC, where they said that they were gonna make Trump look bad for the previous election.
They always film their meetings, and this video was leaked by someone within NRK.
Keep in mind, this is Norwegian MSM, and even here they try to make Trump look bad.

https://docs.google.com/document/d/1MZx5N6Bey40cHNvGKPszI2Fht_kVxZtu8k4r6f1lDfo/edit?usp=sharing

just buy a 7.62 AR or an AK

I'd definitely go 300BLK if they ever deregulate suppressors, but it sounds like 5.56 is the way to go