Good morning all. I have a 10.5 Jakl 5.56 upper that works flawlessly all the time. I recently got a 300 blackout upper and it will not cycle anything at all, basically works as a single shot with manually having to run the charging handle and hitting mag release to chamber next round. I have tried several different ammo manufacturers and weights with the same results. Upper is clean and oiled well. I have reached out to PSA customer service with no response in over a week. Any help with ideas would be fantastic. Also, the gas knob on my 300 works in reverse of the 5.56, is that normal?
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What mags are you using? Are you using a suppressor? What specific ammo are you using?
Using only Magpul 300 blackout specific mags.
AAC ammo 110, 125, 150, 220 grain ammo along with saber 125, 150 grain tipped ammo. Sig elite 125 grain all copper, Remington 150 grain, Winchester 150 grain. Have run it unsuppressed until I can get it to run correctly.
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All brand new ammo and mags as this is the first and only 300 blackout I own.
Until you use a can focus on one type super ammo. Sorry for all the questions just trying to rule things out…
Have you tried the gas block in all positions? Also, i would try a standard mag, just to rule that out.
Did you disassemble the upper? Have you checked to make sure everything with the piston is aligned?
Finally, can you post some pictures?
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Is the carrier and sled clean and well oiled? I didn’t take the sled (metal piece inside the upper that the charging handle inserts into) out of mine when I first got it. It got gunked after a while and after pulling the charging handle back to seat a round it got stuck in the rearward position. The spring wasn’t strong enough to send the bolt home. Took the bolt out and oiled and cleaned the sled really good and now it’s smooth like butter.
Not saying its the same issue, but I know mine wouldn’t have returned to battery had I been shooting it instead of just seating a round.
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Disassembled, cleaned, oiled upper when it was delivered, tried every gas block position and unit has not cycled ever.
Disassembled, cleaned, oiled upper when it was delivered. Has not cycled ever. Return spring is noticably weaker than the one I have in my 5.56.
I had one of the 5.56 uppers as well and the spring in the 300 is noticeably weaker so same experience there.
If you need to return it for repair, CALL CS. That has IMO been the best way. Also check your spam folder if you emailed them, as sometimes a return email will go there.
@KRoyal has the right idea about the sled as it has a good length of friction surface. Here are a couple pictures that show where I grease. It’s kind of hit and miss at first where the friction points are, so you’ll see grease all over on mine. Some unexpected places show up when you grease the whole thing and cycle it a few times.
There could be more places. I cycled mine hundreds of times over the winter when I couldn’t go out; it was pretty rough at first until finding most friction points. Finding them on the sled made a big difference (see red highlights on first picture).
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I would remove the gas block and make sure its not blocked and flows air. Check that the barrel was drilled
Hopefully you get through to CS soon. Personally, I would send it back for warranty work instead of tearing into it trying to figure it out. Let the pros handle it.
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I think it’s something amiss with the gas system, but def send it back.
Exact same issue I have currently. 3 different brands of mags. 5 different brands of ammo and would not cycle after anything. I did grind down a dime size hole in the front of each magazine and 4 of the 5 cycles somewhat consistently. But I shouldnt have to do this to get it to work at 50% of the time.
Welcome to the forums @mikegoff29 
And oddly enough, the correct 300 magpull Works the least. the other after market lancer and hex work better.
You did what to the magazines? Need some pics…
just a thought from somebody who does not own a jakl…
Is the sled on it heavier than a standard AR bcg?I asked because one poster said the spring appears to be quite a bit lighter on a 300 upper and wondering if that 300 spring is not strong enough to run the weight of the jackal sled?