MAG-20 300 BO

[xtratoy]

Can you use a mini 14 300 BO magazine to run 5.56. I am wondering if it has a block in it to account for the shorter 300 BO cartridge. Saw one for sale online for a decent price, but have never seen one in person to compare.

 

[rugerjunkie]

I thought the longer bullet in the blackout made them pretty much the same length. I don’t have one but comparison pics next to a 5.56 show it. If the mag is cheap enough I’d give it a try.

 

[xtratoy]

I didn't even think about the 300 being loaded with a 200 grain bullet. That makes sense.

 

[rugerjunkie]

Yeah. Some comparison pics even show the 300 having a greater oal than the 5.56 does.

 

[Mobuck]

I don't know about the Mini-14 mags but on the AR mags, the bullet ogive on a 300 round appears to be about where the case shoulder is on a .223 round. This helps hold the cases against the rear of the mag and helps prevent bullet nose damage.
We run AR MagPul .223 mags for the 300 w/o any issues at all regardless of bullet length. Primary hunting ammo is Gorilla sub-sonic HP and Fiocchi 125 grain tipped super-sonic.

 

[wanderson]

I have a Ruger Mini-14 in .300bo and run Ruger factory .300bo 20s, std. Ruger factory 10round 5.56 and Original Equipment brand 20s & 10s.
No difference whatsoever.
Some .300bo AR mags are SLIGHTLY different internally to help run loads with short stubby projectiles but I’ve never had trouble running 5.56 thru them. And both have the same internal OAL, no spacer. That includes Lancer and D&H mags.