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Alright guys I'm doing my first ever ar build I'm installing a cmc flat trigger into a spikes tactical lower and I install the anti rotation screws and I tightned them down but I can still spin them are they suppose to be this way or are they not suppose to move at all once tightned down?
 

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I'm assuming you are using the pins supplied with the CMC trigger...I had the same thing happen with my build...the diameter of the pins was small enough that they would rotate inside the receiver (and they were long enough that they would protrude from one side or another of the receiver)...which in itself wasn't really an issue for me...but what was bothersome was the trigger-unit had too much play inside the receiver. I ended up buying the KNS pin set (larger size .1555) and they fit perfectly and there was absolutely no movement of the trigger-unit inside the receiver. If you don't mind the play/rotation you will be fine with what you have...but if it annoys you (as it did me) I would recommend the KNS pins.
 

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+1 for the KNS pin set it will square your issue away. I went with a Wilson Combat TTU-3G for my last build and ordered the KNS set thinking I would need it but WC designed their trigger unit to work with standard pins so it isn’t necessary. If the pins that came with the CMC unit work as intended and dont interfer with function the choice is yours to replace them with something else.<O:p></O:p>
<O:p></O:p>
 

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I shorten the pins so they will pull on the side of the lower a little. I use a sanding pad on my Dremel to grind them down
 

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Alright guys I'm doing my first ever ar build I'm installing a cmc flat trigger into a spikes tactical lower and I install the anti rotation screws and I tightned them down but I can still spin them are they suppose to be this way or are they not suppose to move at all once tightned down?
I installed a CMC trigger in one of my AR's, went too tight and snapped one off. Emailed them, they sent a pack with new pin and screws, quickly. You might call or email them for an answer, they got my problem fixed, good CS.
 

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What I got with mine was two pins that u put 2 little torx head screws in each side. I've put them as tight as they would go and I can still rotate the pin. I will look into getting the kns pins thank you guys for the help
 

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What I got with mine was two pins that u put 2 little torx head screws in each side. I've put them as tight as they would go and I can still rotate the pin. I will look into getting the kns pins thank you guys for the help
That's what you should have received they are anti walk pins with c-clips which prevent some of the issues, most commonly over tightening tiny machine screws and breaking them or screws loosening and falling out over time. The KNS sets are good but if you want perfection some fitment is usually required as others have stated.

And sanding down the end of a c-clip will do nothing to change its fit other than possibly ruin it.

With the pins that are threaded sanding them down is fine as long as the hole is drilled and taped deep enough.
 

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What I got with mine was two pins that u put 2 little torx head screws in each side. I've put them as tight as they would go and I can still rotate the pin. I will look into getting the kns pins thank you guys for the help
Unless it bothers you just ignore it. The fact that the pins rotate won't hurt anything. The idea is to keep the pins from walking out since The drop in style triggers don't have the springs to hold the pins in place like mil style triggers do.
They are not "anti rotation" pins. They are anti walk pins. The KNS pins are non rotating anti walk pins.
 

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That's what you should have received they are anti walk pins with c-clips which prevent some of the issues, most commonly over tightening tiny machine screws and breaking them or screws loosening and falling out over time. The KNS sets are good but if you want perfection some fitment is usually required as others have stated.

And sanding down the end of a c-clip will do nothing to change its fit other than possibly ruin it.

With the pins that are threaded sanding them down is fine as long as the hole is drilled and taped deep enough.
The first CMC that I got a couple of years ago had the C-clips, the last few have the torx screws, I'm not sure when they changed them out. I usually don't use them anyway, prefer KNS pins. If anyone wants some extra pins, I have a few sets with screws.
 
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