Gunsmithing Adjusting Gas Key to lower receiver gap with a JP silent capture spring?

[M5/M4E1]

I just built my first AR15 and it is an 16” barrel mid length gas system rifle

I installed and Aero precision enhanced buffer tube and screwed that in all the way till level with inside of receiver.

I installed an JP silent capture spring and the buffer head sticks out about 0.060” as JP says that’s the max it should

My concearn is that, I was told that I should be able to fit the thickness of 2 quarters between the gas key and the lower receiver with the Bcg fully inserted.

I have a gap of about 2 quarters however i can’t slip the quarters into the gap as it’s too tight

Am i ok? Or should i shim the silent capture buffer system more? Causing more preload witch JP says not to do?

I just don’t want this receiver to get hit by the Bcg I can’t buy another

In my state

 

[Zak Smith]

You are overthinking this. You have a gap of about 2 quarters? Can you make it hit the receiver? If no, then you are fine.

 

[M5/M4E1]

You are overthinking this. You have a gap of about 2 quarters? Can you make it hit the receiver? If no, then you are fine.

Am I really ?

I mean I am reading about this quite a bit, in that you need to make sure your buffer and buffer tube are matched and adjusted properly so that, the Gas Key or the Bcg itself can’t strike the rear of the receiver , and saw a few pics of this damage

And it seems that , this is a widely known thing, for the most part?

I was told that , even if the gas key is not striking the receiver now, ..that as the Delrin part of the buffer , or the bumper on the top of the bumper wears out, that the Bcg rear travel will increase causing a strike?

I am writing with all respect ..and I just can’t afford for this to happen due to my situation, my Banned state that makes an Lower receiver hard to get, as it has to be IN the state before the last ban date went into effect to be grandfathered in

What this means is that, this Aero Precision STRIPPED, M4E1 Lower receiver that sells New for $99.00 ?

Cost me $800..as well as no way to Replace..or probably repair it.
I cant go to my FFL with my license and $99 and just grab another one…

I know it’s pathetic but, this is what we have to do if we want one of these rifles

 

[Zak Smith]

Yes.

If you are worried about the "Bumper" on your JP SCS wearing out, you can pull it out and check it every 500 or 1000 rounds and see if it shows any wear. If it does, you can get a new one in the JP "SCS Maintenance Kit".

I have original "version 1" SCS's from over 15 years ago with countless rounds that show basically zero wear. I don't personally know anyone who ever had a gas key strike part of the lower due to their buffer (of any type) wearing out.

All I've ever done is make sure I use quality/correct buffer tubes and buffers, and installed the buffer tube correctly, and then never thought about it again.

 

[M5/M4E1]

Yes.

If you are worried about the "Bumper" on your JP SCS wearing out, you can pull it out and check it every 500 or 1000 rounds and see if it shows any wear. If it does, you can get a new one in the JP "SCS Maintenance Kit".

I have original "version 1" SCS's from over 15 years ago with countless rounds that show basically zero wear. I don't personally know anyone who ever had a gas key strike part of the lower due to their buffer (of any type) wearing out.

All I've ever done is make sure I use quality/correct buffer tubes and buffers, and installed the buffer tube correctly, and then never thought about it again.

Ok , So I’ve installed an Aero Precision Enhanced Buffer Tube.I screwed or in all the way as well, until the tip of it lined up with the end of the lower receiver

I then installed the JP silent capture spring H2 Heavy version without any shims…The head or buffer end sticks out about 0.063” and the upper and lower closed smooth but i can feel some preload

I have a gap between the gas key and the receiver about the thickness of 2 quarters but not fat enough of a gap to slide the 2 quarters in the gap…

 

[Bantam1]

It will be fine. I have more than one lower that do not pass the "two quarter test" with a regular buffer set up. There is enough preload and I have yet to have a gas key touch the lower after thousands of rounds. None of the bumpers show signs of wear or deformation.

You can buy replacement bumpers if you are worried. Just shoot it and see if anything touches. My guess it will be ok and nothing will be harmed.

 

[TonyTheTiger]

Would probably have twice the answers if this was in the semi auto subforum.
Although the answers thus far pretty much covered it.