Leftover parts after installation? Please help.

[DevinLSU]

I have the M&P 15-R. I disassembled the rifle almost completely (trigger and all). I also added a new front sight with gas block, handguard, pistol grip and stock. After putting everything back together I noticed I am left with a detent ball, a tiny silver colored pin and a slotted set screw. Can anyone please identify what these are and where they go? Thanks for the help!

 

[JaPes]

I have the M&P 15-R. I disassembled the rifle almost completely (trigger and all). I also added a new front sight with gas block, handguard, pistol grip and stock. After putting everything back together I noticed I am left with a detent ball, a tiny silver colored pin and a slotted set screw. Can anyone please identify what these are and where they go? Thanks for the help!

Did you remove the bolt release paddle? That's the only place I think there's a rounded detent like that. It sits over a spring and provides outward pressure on the bolt release. With a mag out, does your bolt paddle release provide any resistance when you push it?

The only other detent that I can think of is the safety detent. Does your safety lever function & not pull out?

The pin is odd. It looks like a broken spring leg. There's a slim chance it's a really broken hammer "J" pin, but there would be a little "J" bend in it.

I have no clue where the slotted set screw came from.

 

[oneyeopn]

What type and brand of mods did you add on that might help Identify where the parts came from.

 

[oneyeopn]

another question, can you manually make the lower function, pull back the hammer, kinda hold it while you pull the trigger and see if it goes forward, dont just let it fly but restrict the forward hammer motion with your other hand. make sure the safety works, check the magazine release, check the take down pins, my front one has some kind of detent in it.

 

[DevinLSU]

The safety and bolt release appear to be working just fine. I added a Yankee Hill flip up front sight gas block, Magpul MOE Handguard, MIAD pistol grip and CTR stock. Thanks for the help, I greatly appreciate any insight.

 

[DevinLSU]

With some resistance on the hammer it will go forward when I pull the trigger. Safety and mag release are fine. I see the hole for a detent on the front take down pin, but this ball is too big for it. I am left scratching my head here.

 

[OK Hog Shooter]

Ruh-roh... that's kinda like the time my Dad and I worked on my '64 Chevy Impala Super Sport. When we got everything put back together we had a handul of nuts, bolts and washers left over. It ran just fine... we never did figure out where the parts shoulda gone. Good luck with your project.

 

[Breechloader]

Might be something in this video.
Installing Takedown Pin and Buffer Tube - Building your AR-15 - CheaperThanDirt.com - YouTube

I think I saw a small ball like that held in by a spring when I changed the pistol grip on my 15-22.

 

[Ltlbear]

Always reminds me of the scene from Doc Hollywood when the mechanic hands Michale J Fox a box of parts and tells him he always has parts leftover after fixing a motor.


Got mo idea where the AR parts go though.

 

[Lee in Quartzsite]

Could look through this schematic:

MidwayUSA — Shooting Supplies, Reloading, Gunsmithing, Hunting, Ammunition, Gun Parts & Rifle Scopes

Whenever I am going to take something complicated apart, I always take digital photos as I go along and make notes....

 

[Dragon88]

I do not recognize any of those as standard AR parts, nor as parts from your stated upgrades. The detents in an AR lower look completely different.

Are you sure these weren't just random items laying about your bench when you worked on your rifle?

 

[smithman 10]

Left over parts

Ruh-roh... that's kinda like the time my Dad and I worked on my '64 Chevy Impala Super Sport. When we got everything put back together we had a handul of nuts, bolts and washers left over. It ran just fine... we never did figure out where the parts shoulda gone. Good luck with your project.

Everytime I rebuilt a carburetor years ago I ended up with leftover parts it seemed. Car still ran. Makes you wonder!

 

[BHarada]

No offense, but based on the mods you've listed, my only question is why you felt the need to fully disassemble the rifle?


-Bill

 

[Gunslinger808]

I do not recognize any of those as standard AR parts, nor as parts from your stated upgrades. The detents in an AR lower look completely different.

Are you sure these weren't just random items laying about your bench when you worked on your rifle?

I'm with Dragon on this, those are not parts from an AR.
The screw looks like it came out of a drilled and tapped scope hole, the round detent ball looks like a safety detent from a Mossberg shotgun, and the pin I have no idea.

 

[thndrchiken]

The pin looks like a detent for the take down pins, the set screw and ball I have no clue, I just put together my lower two weeks ago with a DPMS parts kit and don't recall any thing similar.