Modern Sporter builds Q&A

Brianma65 said:
Taking that pin out is a Beaach!
The small screw is locktited in.
You have to grip on the needle nose with the grip of Thor :)

After removing the pin , I got the U:L together, but it wasn’t easy.
You have to tip the upper on a coward angle to the lower( kinda like putting them together backwards.
The front will not pivot, once the back pin is out.
So now for the weird stuff.
Riding the CH will allow the trigger to work.
Slamming the CH will not engage the trigger.

Trigger works with a mag when you release the bolt via the bolt release, but not when you release it manually.. (dummy rnds)

Then it’s opposite on an empty mag.
Also the maritime bolt catch is very stiff.

I think the trigger is causing all these issues and is a no go.
Click to expand...

I see what you mean about the front takedown pin, there’s no bevel on the front to it won’t swing open even with a proper rear pin. My uppers all have zero play, I can hear the JP SCS weights slightly rattle and that’s it.

v4383BF.jpg


Let the fun begin.
 
purplezuk said:
The KNS rear pin ( self captured ) will work. I used one in my prototype until the rear pins were available.
I actually have 2 sets of them at home not being used...
Click to expand...
will the KNS pins be flush with both sides of the lower? Or will it protrude out one side of the lower?
 
Kratos said:
I see what you mean about the front takedown pin, there’s no bevel on the front to it won’t swing open even with a proper rear pin. My uppers all have zero play, I can hear the JP SCS weights slightly rattle and that’s it.

v4383BF.jpg


Let the fun begin.
Click to expand...
yes , it’s kida of a ,push straight down and in.
 
Anyone having mag seating issues? Both metal mags and pmags won't work in either upper. Have one lower currently. It seems the upper sits rear ward on the lower, creating a lip inside the magwell that prevents the mags from seating. The upper and lower fit snug with very little movement so this seems strange..
 
hardyshooter said:
Anyone having mag seating issues? Both metal mags and pmags won't work in either upper. Have one lower currently. It seems the upper sits rear ward on the lower, creating a lip inside the magwell that prevents the mags from seating. The upper and lower fit snug with very little movement so this seems strange..
Click to expand...
What do you mean by , don’t work?
My PMAG 30, MFT pistol mag and BEO hi cap( lol) work great.
 
hardyshooter said:
Anyone having mag seating issues? Both metal mags and pmags won't work in either upper. Have one lower currently. It seems the upper sits rear ward on the lower, creating a lip inside the magwell that prevents the mags from seating. The upper and lower fit snug with very little movement so this seems strange..
Click to expand...

I've had a similar issue with some lar15 mags that have a certain style of feed lips, my posts are on page 8 and 12.
 
Brianma65 said:
Taking that pin out is a Beaach!
The small screw is locktited in.
You have to grip on the needle nose with the grip of Thor :)

After removing the pin , I got the U:L together, but it wasn’t easy.
You have to tip the upper on a coward angle to the lower( kinda like putting them together backwards.
The front will not pivot, once the back pin is out.
So now for the weird stuff.
Riding the CH will allow the trigger to work.
Slamming the CH will not engage the trigger.

Trigger works with a mag when you release the bolt via the bolt release, but not when you release it manually.. (dummy rnds)

Then it’s opposite on an empty mag.
Also the maritime bolt catch is very stiff.

I think the trigger is causing all these issues and is a no go.
Click to expand...

Guys are just NEVER happy. You would complain if the rear pin that is supposed to be permanently installed rattled out and you compalin that it is difficult to remove. Ever think that was part of the design?
I have a Maritime bolt catch on mine and it works perfectly. No issue with install at all, but then again I just installed the parts without screwing around with the lower or upper. Any chance you buggered something up installing it?
 
hardyshooter said:
Anyone having mag seating issues? Both metal mags and pmags won't work in either upper. Have one lower currently. It seems the upper sits rear ward on the lower, creating a lip inside the magwell that prevents the mags from seating. The upper and lower fit snug with very little movement so this seems strange..
Click to expand...

Mine has a bit of overlap as well:

Mz8C1OM.jpg


My Pmag won't drop free either but the magazine rivet is rubbing inside the magwell. I blame the liberals for this problem.

R1JjC6y.jpg
 
bo02FzM


Mine has a lip too. Elander mft magpul 20 and 30 acs all drop free and seat just fine. Little hard to seat loaded but that's due to ammo not the mag or mag catch

I cant post pictures so if some one would post it for me that would be great
 
Last edited:
no-one special said:
Guys are just NEVER happy. You would complain if the rear pin that is supposed to be permanently installed rattled out and you compalin that it is difficult to remove. Ever think that was part of the design?
I have a Maritime bolt catch on mine and it works perfectly. No issue with install at all, but then again I just installed the parts without screwing around with the lower or upper. Any chance you buggered something up installing it?
Click to expand...
WTF are you talking about.
I said the trigger wasn’t compatible and that I’d try a work around.
I never said the the rear pin should be removed, only that I removed it and it was difficult.

And ,as for the Bolt catch, I said it was trigger related.
 
You must log in or register to reply here.
Back
Top Bottom