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Discussion Starter #1
I only just recently got the black rifle sickness. Only issue is I found I like the vintage stuff/A1/A2 rifles. I'm not a big fan of the flat tops or anything with accessories like the kitchen sink.

Anyways I wanted to build my lower so I purchased a cheap one from my local shop and a parts kit. After looking up a few tutorials on how to it went together w/o an issue...just took my time. It was actually pretty simple once you figured out what springs went where.

Now the upper I bought complete. It's a armalite 20" chrome lined 1/9. I'm actually very happy with it. The fit to my lower was a little loose but I made a little spacer and she is nice and tight now.

I have since ordered a real armalite lower to go with this rifle just so I can have one nice matching rifle that will stay together. I have since bought another uppper to go with the lower on the rifle now and it will be my "mix and match" lower.



 

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Why whats wrong with that?
At my peak, I had (3) M4's; one Stag and (2) that I built myself. Both of my builds utilized an RGUNS stainless LPK. The pic below is of the first build's fire control group. See how the hammer has smashed in the disconnect? There's a thin red circle around it--that's not supposed to happen/look like that.



Despite the damage to the disconnect, the first build never had an issue. The third, however, had multiple issues immediately after completion. FTF and actually rapid fire bursts at times. The disconnector looked like a 6-year-old had carved it into shape; completely out of spec. I left the stainless triggers in place, but replaced the hammer/disconnect with a TiNi setup (thanks, Allstar Tactical) in the third rifle, and a replacement DPMS set from RGUNS (they sent me two sets, no charge) in the second rifle. No issues with either M4, and no damage on these (steel) disconnectors.

My buddy and I also built his first M4 with an RGUNS LPK, and he had issues similar to mine from the get-go. I'll never use another one of their LPK's again.
 

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Lol...To the OP, you should invest in a Stag LPK, they are only $65 and you won't be disappointed.
Nothing wrong with rguns lpks. most company's lpks are cobbled together from various suppliers parts and simply rebranded / repackaged . CMMG, Delton, Rguns, Essential Arms, DPMS, etc.Edit: never seen an issue as pictured above. Interesting.
 

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Nothing wrong with rguns lpks. most company's lpks are cobbled together from various suppliers parts and simply rebranded / repackaged . CMMG, Delton, Rguns, Essential Arms, DPMS, etc.Edit: never seen an issue as pictured above. Interesting.
The picture above is actually how both of them looked--one worse than the other, just because it had so many more rounds through it. Between my buddy and I, we had a 2-out-of-3 failure rate in the LPK's. Definitely not worth the $10/$15 we saved at the initial purchase. At this point, I would go with a Palmetto Armory LPK and not look back. Nice trigger and comes with a Magpul trigger guard and Magpul pistol grip.
 

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It was actually pretty simple once you figured out what springs went where.
Just to satisfy curiosity could you take a pic looking down into the lower receiver like the pic above?

The fit to my lower was a little loose but I made a little spacer and she is nice and tight now.
The only thing wrong with a loose fit between upper and lower is how much it bothers some people. :)
They all do it, its normal, expected and 99+% common on non~matched receivers.

If you want full tight fit without resorting to shims (*cough*BSfix*cough*) you pay mucho extra and get a precision matched receiver group where upper and lower are hand selected then hand fit to each other for snuggest connection.
And even some of those have a little play...

Spec is if there is less than .020" side play between the pivot pin boss on the lower and the boss on the upper when the rifle is fuilly assembled.
More than .020" and its worn out or out of spec, otherwise there's no issue with some slop.

There is no spec for up/down play that I'm aware of.
Also take into consideration that if that type of play is 'snugged up' it can sometimes result in the BCG not aligning quite right with the receiver extension.
Net result is wear inside the RE and if bad enough, malfunctions,

On same note, accuwedge can over time make wear on the upper receiver takedown pin hole due to the type or force it applies to that area to take up the slack. Basically it can egg the hole at the bottom side as the pin works it every time its pushed/pulled.

@ RDFABSREP:
It looks like the hammer spring tail is splitting/wedged between the two coils of the trigger spring on the right side (top of pic)
This would be a bad thing.
 

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Yes it is isn't it.
Sorry I didn't mention in other post.
Just kinda zoned it.


Wildman1024, condolences to the spouse as once you go black you don't want to go back :)
 

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Discussion Starter #15
I'm heading over to the range with it now. Hope to get a good range report when I get back. Also gonna try out my new used trijicon rx01 reflex sight.
 

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Discussion Starter #16
Just got back from the range. The rifle shot extremely well and is very accurate. I'm super happy with the upper.

Now for the bad. I'm not to happy with the lower. I think the problem is with the LPK. What is happening is you fire a shot and while letting go of the trigger for the reset some times it will fire. So basically you fire a shot and maybe 50% of the time it will fire again while on the trigger reset. Then you obviously have to charge the rifle again. Not quite sure whats going on but not happy about it.

I do have a complete armalite lower coming to make this a complete armalite rifle. Hopefully it does not do it with the new lower. I also have a 14.5" postban HBAR A2 bushmaster upper coming to put on this lower. I guess we will see what happens.

Pictures of it with the new optic. It's pretty sweet to shoot. Once you use a quality optic you will never go back.





 

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fire a shot and while letting go of the trigger for the reset some times it will fire. So basically you fire a shot and maybe 50% of the time it will fire again while on the trigger reset.
Are you positive the LPK is in there right?
What you describe is usually associated with the disconnect spring being upside down and/or trigger spring put on wrong.

Well, that or something is radically out of spec.
 

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Discussion Starter #18
Are you positive the LPK is in there right?
What you describe is usually associated with the disconnect spring being upside down and/or trigger spring put on wrong.

Well, that or something is radically out of spec.
It appears to be together ok. It seems to function correctly otherwise. When i get home here tonight ill take a pic of the inners
 

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Now for the bad. I'm not to happy with the lower. I think the problem is with the LPK. What is happening is you fire a shot and while letting go of the trigger for the reset some times it will fire. So basically you fire a shot and maybe 50% of the time it will fire again while on the trigger reset. Then you obviously have to charge the rifle again. Not quite sure whats going on but not happy about it.

I do have a complete armalite lower coming to make this a complete armalite rifle. Hopefully it does not do it with the new lower. I also have a 14.5" postban HBAR A2 bushmaster upper coming to put on this lower. I guess we will see what happens.
Change out the disconnector to a mil-spec component and you'll be fine. Honestly, I'd change the hammer while you're in there, too. Like I said--these LPK's are waaaay our of spec; you're having the identical problem we were having with 2/3 of them.
 
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