Recommend second caliber barrel?

[jjrothWA]

An upcoming gunshow may have a dealer with uppers fro about $90, I want to get a second caliber, thinking the .450 Bushmaster or the 7.62X39.
Present thinking is the .450 for being allowed in MI southern deer zone and its 300 yard range.

7.62X39 due to more availability, using SAMMI chamber or Mil-spec???

What are decent manufacturers to consider?

thanks.

[emmagee1917]

I went with several extra calibers in several uppers. Went with .300 Blackout in a SBR and a carbine and a .458 Socom in a carbine to start . I have suppressors coming in both calibers . I also went with a .50BMG upper and a " can cannon " upper . I'm now working on lowers for them all . It's hard to stop .
Chris

[Litt'le Lee]

I have 3 AR's in 7.62X39--one made with a 308 bore allowing more bullet choice--McGowen barrels--the other 2 a 16 in and a 20in stainless--all shoot great

[holdover]

built one in 6.5 Grendel, like the dime size groups at 300 yds.

[Former Cav]

built one in 6.5 Grendel, like the dime size groups at 300 yds.

what loads are you using?
what barrel /upper do you have?
see my write up about the 6.5 Grendel "progress" above.
Thanks

[Former Cav]

built one in 6.5 Grendel, like the dime size groups at 300 yds.

what load are you using for that? I have only one load out of 30 that will get me down to 13/16 inch (5 round group). And that is Varget which is not recommended as you can not get enough in the case to go faster then 2350 with a 123 SST bullet.

[GA-Dave]

I second the grendel. I am very impressed with the cartridge.

[Dan in NH]

for the AR platform go with the 6.5 grendel

[Art]

7.62 x 39 is a good cartridge and inexpensive but can have feeding issues in some AR rifles. The .300 Blackout provides similar ballistics without the feed issues and has the bonus of using standard AR magazines. Unfortunately it also costs a bunch more.

[Litt'le Lee]

the 300 blackout--very expense--I'ts a pistol round !!--most 7.62x39 ar's are usually prone to BAD MAGS--i'VE NEVER HAD A PROBLEM--ASC 20 rounders