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Juggernaut WTF!

jay-elz

Member
Messages
30
So took my new upper out on my Juggernaut JT-15 & it was a 💩 show. This is the almost completely upper for JT that I swapped in my BCG & Charging handle from Juggernaut..

2 double feed
Multiple failure to feeds
Charging handle locking up after popping in a new mag
But the wild one was the forward assist just shooting itself out..

Any ideas on wtf 🤦🏽‍♂️
 

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So took my new upper out on my Juggernaut JT-15 & it was a 💩 show. This is the almost completely upper for JT that I swapped in my BCG & Charging handle from Juggernaut..

2 double feed
Multiple failure to feeds
Charging handle locking up after popping in a new mag
But the wild one was the forward assist just shooting itself out..

Any ideas on wtf 🤦🏽‍♂️
In regards to the double feeds and failure to feed, did you diassemble and clean the firearm of all the factory preservatives? When firing it, did you run the bcg wet? Did you use factory full power 5.56 loads?

On the firing line, I noticed some shooters who had these issues with juggernaut rifles and/or pistols were mainly due to not cleaning of preservatives and/or also running the bcg dry or bare minimum of oil. After I applied a generous amount of oil or grease/oil hybrid to their bcg and charging handle; they were able to get it to function just fine.

From what I remember about juggernaut factory set ups is that they tend to be tight tolerance; working their bcg even sounds tight. For something like this I would fire with 5.56 loads for the break in; and then go back to .223 Remington after the break in if .223 is preferred.

For the forward assist popping off; that’s an easy fix. Just need to get a new roll pin and install it. But that’s not a good look for JT.
 
In regards to the double feeds and failure to feed, did you diassemble and clean the firearm of all the factory preservatives? When firing it, did you run the bcg wet? Did you use factory full power 5.56 loads?

On the firing line, I noticed some shooters who had these issues with juggernaut rifles and/or pistols were mainly due to not cleaning of preservatives and/or also running the bcg dry or bare minimum of oil. After I applied oil or grease/oil hybrid to their bcg and charging handle; they were able to get it function just fine.

From what I remember about juggernaut factory set ups is that they tend to be tight tolerance; working the bcg even sounds tight. For something like this I would fire with 5.56 loads for the break in; and then go back to .223 Remington after the break in if .223 is preferred.

For the forward assist popping off; that’s an easy fix. Just need to get a new roll pin and install it. But that’s not a good look for JT.
As far as the BCG goes I did not & when I talked to JT, besides lubing, they said it was good to go out out of the box. When I had the Single shot upper all I did was lube and it ran fine, minus a double feed, thru about a 100 rounds or so. I oiled the hell out of the bcg & charging handle prior to and during todays range run.

I ran all 5.56 today, factory full power brass and green tip but no .223’s at all.

That 💩 flying off just has me leery as hell tbh. Only issue I had with original upper was a single incident of double feed but that was due to lack of lubrication on my part.
 
As far as the BCG goes I did not & when I talked to JT, besides lubing, they said it was good to go out out of the box. When I had the Single shot upper all I did was lube and it ran fine, minus a double feed, thru about a 100 rounds or so. I oiled the hell out of the bcg & charging handle prior to and during todays range run.

I ran all 5.56 today, factory full power brass and green tip but no .223’s at all.

That 💩 flying off just has me leery as hell tbh. Only issue I had with original upper was a single incident of double feed but that was due to lack of lubrication on my part.

I would give that upper and bcg a good cleaning and scrub that chamber with a AR-15 chamber brush.

Is that upper brand new? How many rounds did you put through this upper? You mentioned you put 100 rounds through the single shot upper; but what about the semi one that is having issues?

Maybe it’ll run good for your next run after the first shoot, cleaning, scrubbing, and then oiling wet.

Also what oil are you using? Is it high temp resistant?

How was the gassing? What direction was the brass ejecting?
 
So took my new upper out on my Juggernaut JT-15 & it was a 💩 show. This is the almost completely upper for JT that I swapped in my BCG & Charging handle from Juggernaut..

2 double feed
Multiple failure to feeds
Charging handle locking up after popping in a new mag
But the wild one was the forward assist just shooting itself out..

Any ideas on wtf 🤦🏽‍♂️
wild

Cleaning and lube you did?
 
I would give that upper and bcg a good cleaning and scrub that chamber with a AR-15 chamber brush.

Is that upper brand new? How many rounds did you put through this upper? You mentioned you put 100 rounds through the single shot upper; but what about the semi one that is having issues?

Maybe it’ll run good for your next run after the first shoot, cleaning, scrubbing, and then oiling wet.

Also what oil are you using? Is it high temp resistant?

How was the gassing? What direction was the brass ejecting?
Im stripping it down as soon as I get back home & will give a solid cleaning & oil job.

Yea the Upper is brand new, First time running it. 210 rounds through the brand new semi upper. Hopefully so cuz this is my first time running into so many issues back to back.

Im using lucas amd as far as I know yes it is. Gassing was and adjustment but not too bad and brass was shooting out around 3 to 4 oclock
 
Im stripping it down as soon as I get back home & will give a solid cleaning & oil job.

Yea the Upper is brand new, First time running it. 210 rounds through the brand new semi upper. Hopefully so cuz this is my first time running into so many issues back to back.

Im using lucas amd as far as I know yes it is. Gassing was and adjustment but not too bad and brass was shooting out around 3 to 4 oclock
I just noticed in that picture there isn’t a hole in the top for the forward assist to drive a roll pin through? Is it a set screw system like a aero m4e1 upper? Where is the access for either a roll pin or a set screw to hold the forward assist in place? Is the access from the bottom?
 
it's almost definitely not cleaning that's the problem because the new upper won't have like preservative grease. You did lube it so that's also not likely it. ARs do like to be run wet but you lubed it. There has to be another issue, the problem is there are so many things it could be. What magazines are you using, did you try other magazines? I would definitely suggest only use gen 3 pmags. how far was it ejecting and what direction? does it go to slide lock on an empty mag? If its undergassed and short stroking it would do what you are saying and would not go to slide lock. What buffer weight do you have in it? a lighter buffer would remedy if it's undergassed. Does the bolt move freely by hand all the way into the buffer tube? Gassing issues can be gas port, gas block, gas tube, gas block alignment or the BCG. I would honestly just bring it to juggernaut if you are local. Don't waste ammo without diagnosing an issue first, an AR doesn't really need a break in, if it does it's out of spec and that's it's own problem.
 
See that rear takedown pin hole? Loss of material from repeated inserting of kingpin like I have stated in another thread. Billet 6061, weakest material next to polymer used for lowers.
 
I just noticed in that picture there isn’t a hole in the top for the forward assist to drive a roll pin through? Is it a set screw system like a aero m4e1 upper? Where is the access for either a roll pin or a set screw to hold the forward assist in place? Is the access from the bottom?
Ive got to exam it today
it's almost definitely not cleaning that's the problem because the new upper won't have like preservative grease. You did lube it so that's also not likely it. ARs do like to be run wet but you lubed it. There has to be another issue, the problem is there are so many things it could be. What magazines are you using, did you try other magazines? I would definitely suggest only use gen 3 pmags. how far was it ejecting and what direction? does it go to slide lock on an empty mag? If its undergassed and short stroking it would do what you are saying and would not go to slide lock. What buffer weight do you have in it? a lighter buffer would remedy if it's undergassed. Does the bolt move freely by hand all the way into the buffer tube? Gassing issues can be gas port, gas block, gas tube, gas block alignment or the BCG. I would honestly just bring it to juggernaut if you are local. Don't waste ammo without diagnosing an issue first, an AR doesn't really need a break in, if it does it's out of spec and that's it's own problem.
im running all Pmag Gen 3 10/30’s
Ejection is 3-4p and its not violent at all.

Buffer & spring are milspec most likely H1 since its the stock spring and weight that came with the original buffer system from JT. I swapped out tube and installed milspec tube and SBA3 brace last week, prior to range day yesterday.

Im up in Northern CA so JT is out of the option. I emailed them and just waiting for a response. May take it to a local gunsmith to have then break it all the way down and see whats going on.
 
See that rear takedown pin hole? Loss of material from repeated inserting of kingpin like I have stated in another thread. Billet 6061, weakest material next to polymer used for lowers.
Yea that happened when I was changing over to the Hellfighter PAL system which btw doesnt work on Hogue Mag lock pin systems 😒
 
Ive got to exam it today

im running all Pmag Gen 3 10/30’s
Ejection is 3-4p and its not violent at all.

Buffer & spring are milspec most likely H1 since its the stock spring and weight that came with the original buffer system from JT. I swapped out tube and installed milspec tube and SBA3 brace last week, prior to range day yesterday.

Im up in Northern CA so JT is out of the option. I emailed them and just waiting for a response. May take it to a local gunsmith to have then break it all the way down and see whats going on.
That fact that it's not violent makes me think even more that it's under gassed. It should be violent, it's an 8 inch barrel and all the gas has to come in all at once because of the short gas system length. you can weigh the buffer and see how heavy it is. Also you can test the gas flow by taking off the muzzle device, plugging the barrel with something and blowing into the barrel, (you can cover it with your hand and just blow into your hand). But air should flow freely through the tube, it's restricted a little and will feel like it's going through a straw but if it's hard to pass air through and not freely flowing then the gas block or the tube is clogged. I have had brand new gas tubes that had a clog, but more common is the block is misaligned. You can remove the gas block and you should be able to see a circle of carbon if it's misaligned away from the hole Ilin the block. If all that is freely flowing then the bcg may be out of spec or clogged
 
That fact that it's not violent makes me think even more that it's under gassed. It should be violent, it's an 8 inch barrel and all the gas has to come in all at once because of the short gas system length. you can weigh the buffer and see how heavy it is. Also you can test the gas flow by taking off the muzzle device, plugging the barrel with something and blowing into the barrel, (you can cover it with your hand and just blow into your hand). But air should flow freely through the tube, it's restricted a little and will feel like it's going through a straw but if it's hard to pass air through and not freely flowing then the gas block or the tube is clogged. I have had brand new gas tubes that had a clog, but more common is the block is misaligned. You can remove the gas block and you should be able to see a circle of carbon if it's misaligned away from the hole Ilin the block. If all that is freely flowing then the bcg may be out of spec or clogged
8in which means its not getting enough time to burn off the powder and is shooting most of it out the barrel IE its weak and need higher power ammo.
As my other comment stated but i got downvoted. I've been trouble shooting rifles for a very long time. 556 needs at least 14.5 to be opt.
 
On the forward assist. The good news is that JT takes the time to use threaded pins rather than roll pins so its a very easy fix. They pop out; not necessarily a JT thing. I pull em and replace them with the EGW plug.

Screenshot 2026-09-29 at 9.03.55 AM.webp

 
it's almost definitely not cleaning that's the problem because the new upper won't have like preservative grease. You did lube it so that's also not likely it. ARs do like to be run wet but you lubed it. There has to be another issue, the problem is there are so many things it could be. What magazines are you using, did you try other magazines? I would definitely suggest only use gen 3 pmags. how far was it ejecting and what direction? does it go to slide lock on an empty mag? If its undergassed and short stroking it would do what you are saying and would not go to slide lock. What buffer weight do you have in it? a lighter buffer would remedy if it's undergassed. Does the bolt move freely by hand all the way into the buffer tube? Gassing issues can be gas port, gas block, gas tube, gas block alignment or the BCG. I would honestly just bring it to juggernaut if you are local. Don't waste ammo without diagnosing an issue first, an AR doesn't really need a break in, if it does it's out of spec and that's it's own problem.
I agree on this. My Sig m400 worked perfectly out of the box I never did anything
 
I had similar issues. Ended up removing the Mag Lock portion of the Hellfighter and installing a Mil-Spec Bolt Catch. Problem went away.
 
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