AR pistol with fixed Mag? (In mass )

Dennis in MA

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Question for the JC Arms lower folks. . . .

I have only shot mine once. But I was futzing with it last night as it has a red-dot I wanted to fiddle with on it.

There is a S-ton of drag on the BCG. I pulled another upper from another gun and dropped it on the fixed lower - same (although less so) problem.

The issue is so bad with the pistol upper that I can get the bolt to "stick" 1/2 open.

Thoughts on a remedy?? Call JC and bring it all in? Simple fix? Is there something wonky with the fixed mag or the bolt release (which doesn't feel quite right)?

Looking to see if I can remedy this BEFORE calling JC.
 

DosesR1

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Question for the JC Arms lower folks. . . .

I have only shot mine once. But I was futzing with it last night as it has a red-dot I wanted to fiddle with on it.

There is a S-ton of drag on the BCG. I pulled another upper from another gun and dropped it on the fixed lower - same (although less so) problem.

The issue is so bad with the pistol upper that I can get the bolt to "stick" 1/2 open.

Thoughts on a remedy?? Call JC and bring it all in? Simple fix? Is there something wonky with the fixed mag or the bolt release (which doesn't feel quite right)?

Looking to see if I can remedy this BEFORE calling JC.
Let me play around with mine but I didn’t have any issues that weren’t related to the mag loader last range day
 

Dennis in MA

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Thanks! I'd load the mag with a pile of brass, but I actually don't have any .223 spent brass and I'm not keen on leaving rounds in the gun. I'm just wondering if it's an overly aggressive mag spring. Strange.
 

Dennis in MA

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Hmm. I'll have to check that. Maybe pull the buffer from the well-working lower and test it out. I assume I've got a carbeeen buffer in there now.
 

jayhitek

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i started using a H2 in all my AR's. Had some weird problems with cycling before that.. Heavier buffer and shorter spring eliminated a lot of the issues.

Might help in your case.. Also might not. But maybe you'll get lucky.
I also have some old mags that will not work well in one of my guns. So I have them labeled to not use them in certain guns.
Aren't AR's awesome???
 

joe1231913

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Question for the JC Arms lower folks. . . .

I have only shot mine once. But I was futzing with it last night as it has a red-dot I wanted to fiddle with on it.

There is a S-ton of drag on the BCG. I pulled another upper from another gun and dropped it on the fixed lower - same (although less so) problem.

The issue is so bad with the pistol upper that I can get the bolt to "stick" 1/2 open.

Thoughts on a remedy?? Call JC and bring it all in? Simple fix? Is there something wonky with the fixed mag or the bolt release (which doesn't feel quite right)?

Looking to see if I can remedy this BEFORE calling JC.
Feel free to call and bring it in, I will do what I can to remedy it.
 

Dennis in MA

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I appreciate it, Joe. I swapped buffer/spring from another AR. It's grams heavier but it seems to be a lot smoother and won't hang up. Lemme get it to the range one more time and see how she runs.
 

PappyM3

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i started using a H2 in all my AR's. Had some weird problems with cycling before that.. Heavier buffer and shorter spring eliminated a lot of the issues
Many AR barrels barrels/uppers are over-gassed from the factory. That generally makes it able to shoot a wider variety of rounds. Heavy buffers help tame it a little.

It sounds like your problem is something other than the buffer being a standard carbine buffer/spring. It could be the stock buffer/spring binding in the tube, or the BCG binding somewhere and the new buffer/spring are strong enough to push the BCG past the binding spot.

Hmm
 

Da_lucche

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Hmm. I'll have to check that. Maybe pull the buffer from the well-working lower and test it out. I assume I've got a carbeeen buffer in there now.
H1 is my 14.5 Carbine GS
H2 in my two 12.5 Carbine GS
H3 in my DD 10.3 Carbine GS

For my 9" Blackout Pistol GS, I use a Carbine buffer for subs. I dont shoot supers.

The 9" blackout upper is what I'll be using for my fixed mag pistol.
 

ricca73

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Very late to this thread . But want to jump on board with a build . Can I use any stripped lower that I have purchased in the past that is virgin and never been registered . Purchased on bill of sales only? Also where are you guys installing the blind pin for the mag ? Orders the Malock and loader setup already .
thanks
 

DosesR1

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Very late to this thread . But want to jump on board with a build . Can I use any stripped lower that I have purchased in the past that is virgin and never been registered . Purchased on bill of sales only? Also where are you guys installing the blind pin for the mag ? Orders the Malock and loader setup already .
thanks
From my understanding the lower has to be manufactured as a FIXED MAG to be 100 percent on the safe side
 

ricca73

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djbradles

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Very late to this thread . But want to jump on board with a build . Can I use any stripped lower that I have purchased in the past that is virgin and never been registered . Purchased on bill of sales only? Also where are you guys installing the blind pin for the mag ? Orders the Malock and loader setup already .
thanks
DosesR1 is correct. Even though you have an “old” lower you are making a new build. Not a big deal though as fixed mags are pretty easy to reload. Easy to service with a pmag bottom plate. Easy to load either with a ejection port loader or top loading using extended takedown pins. Set screw for the mag can go right beneath the bolt release hammer which holds the last round open.
 

ricca73

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DosesR1 is correct. Even though you have an “old” lower you are making a new build. Not a big deal though as fixed mags are pretty easy to reload. Easy to service with a pmag bottom plate. Easy to load either with a ejection port loader or top loading using extended takedown pins. Set screw for the mag can go right beneath the bolt release hammer which holds the last round open.
So it definitely has to be a manufactured fixed 10 mag lower? Correct
 

pupchow

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If I'm buying an off-the-shelf fixed mag setup, I'm talking to these guys:
 

ricca73

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If I'm buying an off-the-shelf fixed mag setup, I'm talking to these guys:
Thank you very much, I will reach out to them and see if they have any available or when I can get one thank you
 

DosesR1

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Yes it fixed mag lower.
I purchased the malock and side loaders, thinking I could use the Malock and a retaining pin to make my own 10round fixed lower ..but guess I can’t do that .
JCArms is the way to go! Btw I didn’t like the ma loaders if you can return them do so .... got nothing but the most complex jams D6D769E4-50B8-40FC-949F-588DD0799FB7.jpeg
Try the BF-10 loaders waayyyyy better
 
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