Modern Sporter - Build Discussions

Yeah she is tight to the lower, I can tap the pin in with the rubber mallet but I dont want to go all the way incase I cant get the pin out again.
 
MBaker said:
The front pivot pin wont insert into the upper...the hole look off by a hair it. Anyone else had this? Whats the solution?
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Yes, everything on this receiver set is ridiculously tight. The mag release is super tight, the gas tube hole is super tight, the safety selector is super tight, etc. At least there's no play between uppers.

You're gonna need lots of oil and probably a replacement pivot pin for when you wear through the first one.
 
Compared to the SLR the MS is loose. If I'd do it again I'd buy two MS sets. They are tight but are workable. Slr with the thick cerakote is ridiculous. My Midwest industries upper rod won't even fit and all the pin holes need cleaned before any pins are installed.
 
Yeah I think I've got to break it in, would totally agree she is tight like a tiger. Hopefully just needs to be broken in a bit. At least it's on and the pin comes out with some extra effort....went in easier the second time hopefully that trend continues.
 
MBaker said:
Yeah I think I've got to break it in, would totally agree she is tight like a tiger. Hopefully just needs to be broken in a bit. At least it's on and the pin comes out with some extra effort....went in easier the second time hopefully that trend continues.
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Anodizing will add a tiny bit to every dimension so pin holes could be decreased in diameter by 1/2 a thou which given the tight tolerances ATRS keeps is possibly your problem. CeraKote adds about 2 thousanths so can cause some problems if the holes are not plugged when the coating is applied.
 
hellsrelentless said:
Compared to the SLR the MS is loose. If I'd do it again I'd buy two MS sets. They are tight but are workable. Slr with the thick cerakote is ridiculous. My Midwest industries upper rod won't even fit and all the pin holes need cleaned before any pins are installed.
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I only have experience with MS and AR-15s. I really like the quality of the MS receivers and do appreciate the tight fit between receivers, but everything else will take a little finesse to work with.
 
MBaker said:
Yeah I think I've got to break it in, would totally agree she is tight like a tiger. Hopefully just needs to be broken in a bit. At least it's on and the pin comes out with some extra effort....went in easier the second time hopefully that trend continues.
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Yes it will wear in. I spend an hour watching TV just popping the pivot pin in and out. Eventually it gets easier.
 
It’s a lot easier if you have the proper tools and don’t forget the black electrical tape . The roll pin holders and half cut out punch for the bolt release save a lot of assembly scares
 
SuperDeadlyAccountant said:
Idk why this is, but I have an Aero Precision AR15 Enhanced M-LOK Handguard Gen 2 and the barrel nut doesn't align with the gas tube hole in the upper. With no spacers it sits a little ways between two holes in the barrel nut. I had to use all 8 washers/spacers and even then I can only hand tighten it otherwise it won't align again which isn't safe. Even then, the hole in the upper receiver is slightly too high and doesn't allow it to pass through.

On my both my AR-15 uppers (Aero and PSA) it only needed 2 spacers and alignment was perfect so the gas tube slid right in.

... What can I do to fix that?
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Turning back the internal shoulder in the barrel nut (so it tightens closer to one of the holes) and slotting out the hole in the barrel nut the gas tube passes though would be the only solution i could see, if you were dead set on using that handguard.

Edit: You might also need to modify the anti-rotation tabs on the handguard so it can sit flush with the upper receiver. I had to remove them completely to use an Aero Atlas S-One.
 
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Agent Law said:
Turning back the internal shoulder in the barrel nut (so it tightens closer to one of the holes) and slotting out the hole in the barrel nut the gas tube passes though would be the only solution i could see, if you were dead set on using that handguard.

Edit: You might also need to modify the anti-rotation tabs on the handguard so it can sit flush with the upper receiver. I had to remove them completely to use an Aero Atlas S-One.
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The barrel nut is a solid piece of aluminum so I can't adjust anything on it. Luckily the anti-rotation tabs aren't in the way and it can sit flush. The only solutions I can think of is are either lap the receiver (which aTRS advises against) or drill a new gas tube hole ... somehow.

I'm selling the handguard now anyways so it won't matter. Let this be a warning to anyone else with this handguard.
 
SuperDeadlyAccountant said:
The barrel nut is a solid piece of aluminum so I can't adjust anything on it. Luckily the anti-rotation tabs aren't in the way and it can sit flush. The only solutions I can think of is are either lap the receiver (which aTRS advises against) or drill a new gas tube hole ... somehow.

I'm selling the handguard now anyways so it won't matter. Let this be a warning to anyone else with this handguard.
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You would need a lathe and mill to make the modifications I suggested. I wouldn't modify the upper unless absolutely necessary; it's better to modify the cheaper part, which in this case is the barrel nut.
 
A BAD Levers works but i had to file down the side not visible when installed slightly because it installed fine but, didn’t have the range of motion to work. You can’t see it because its the part touching the upper receiver and it took about a minute with a file. Its just a tiny amount to remove so don’t get carried away.
 
For people who have a bsf barrel, Mike told me he used a bsf 223 wylde barrel, maple ridge armory handguard and a troy non adjustable gas block. Fits with room to spare. He originally had a superlative arms clamp on gas block. It didnt fit without rubbing on the top
 
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