https://palmettostatearmory.com/psa-16-chf-a2-mid-length-5-56-nato-1-7-13-5-lightweight-m-lok-moe-ept-rifle-kit-5165448203.html
Could someone just verify my logic is correct please. All I would need to do is change the barrel to run 300 blackout correct?
Yes, to shoot 300blk you would need a barrel change only. But 300blk can be finicky, especially without a suppressor. My opinion is that it is also best to just build a new upper and include an adjustable gas block, and to make it a different color (FDE for example). Then make sure your mags match color wise as you don’t want to shoot a .300blk down a 5.56 barrel…
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yes I just watched a video where the guy had one round of 300 blackout in his 5.56 clip and it chambered and he pulled the trigger but the bullet didn’t fire. He got really lucky. I already got a Odin works adjustable buffer and am looking into a adjustable gas block for the kit mentioned above. Yes I would get some kind of mag colored bands I’ve seen or some other way to tell the difference in the barrel and mags. Thank you for the safety concern and thanks for the confirmation.
I thought mid-length gas on 300blk was not so good? I usually see them set up with pistol length gas even if it’s a longer barrel?
You are correct. Op would need s new gas block and tube.
I built two 5.56 AR-15s on PSA kits (so far). Have been thinking about an AR pistol for the house, and thinking of 300 blk subsonic. I think I’ll use color coded 80% lower receivers with colored Magpul mags (to avoid the 300/5.56 mess up.
Why is 300 blk “finicky”? How is that helped by the addition of a supressor? (I really don’t want to go the route of tax stamp and government permission for stuff - so I don’t want to get a supressor)
My 300 BO (some abbreviations have more than one meaning ?) works great, using the gas to cycle the bolt.
To get a feeling for what the gas does, I use about 2.1 grams of powder in a 308. It won’t cycle the bolt correctly.
Subsonic may not run without a suppressor. 300blk was meant for 8.5" barrels and a can. Without the back pressure of a can, you can have major issues with cycling the bolt.
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Is that along the lines of a car idling badly because of a leak in the exhaust manifold then?
No, more along the lines of having a semi auto rifle that acts like a bolt action.
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Saw that issue on a video - had to charge each round. I don’t think I want that.
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I think every time we match an upper to a lower, we are doing a bit of serious gun-smithing. Most of the time it’s plug and play, and sometimes not.
It took me 2 years to get my 6.5 Creedmoor from Aero Precision to run correctly. I had to learn to feed it true magnum powders like 4831, with lots of Gas to drive the bolt.
Even though Hodgdon reloading says it can, I could not get it to work with even IMR 4320 & 4064.
My 300 blackout with 16 inch barrel came from Hardened Arms. They were a good supplier for a while, sorry to see them close.
It always cycled normally, I think using a PSA Lower.
So all the 300 kits psa sells may need a suppressor to run good? Thinking about it more, most likely if I was to get a 300 BO I would get a complete upper.
If you shoot supers, no issue. If you shoot subs, then yes, your best bet is to get a can.
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Gotcha thanks
having cycling problems comes with not having the adjustable gas block set right for the ammo choice. my 300 would not cycle 260gr bullets but works flawlessly with 220 & 200gr. i built mine strictly for subsonic rounds (home defense). however it will still reach out to 300yds as is. i have not tried supersonic rounds but don’t think i will have any issues with them.
Adjustable gas blocks help, but they were not even a thing when 300blk was developed. My 300 sbr doesn’t have one, and although I only use a can with it, it will cycle subs just fine without a can. How you set it up is key. But these days with AGB that fine tuning doesn’t exist like it did (gas port size, buffer, spring, and bcg).
Thanks for that clarification. I won’t get a suppresor as long as it involves big brother, but had thought about subsonic rounds for home defense. The only rifle I’ve ever shot is the one I built this year (5.56 least expensive kit I could find from PSA + 80% polymer lower) If I build a 300, it will be after I have found and bought ammo for it, in subsonic - AND learned more about how to build it to avoid cycling problems. Might make it in a different color with matching mags for 300 (to never mix with the 5.56)
It depends on the type of ammo (really the type of gun powder) you use. Generally speaking 300 BLK works best with pistol length gas in all barrel lengths. Sometimes there will be cycling issues due lack of back pressure with carbine and mid length gas systems.
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