Buffer Stand-off

[HKGuns]

Prepare, thanks for the correction.

556Cliff, is that you? Cool videos. Also, I think I need to watch again to count that stack of Colt boxes.

-Deleted- because I may have been FOS.

[556Cliff]

No that is “TacticalSpeed.” He’s pretty full of himself.

He has 2 accounts here??? Or maybe I was incorrect in thinking he was "the AR-15 Junkie"???

[556Cliff]

Except the buffer does not start moving off the pin when it is first contacted by the carrier in the upper. You can hold the lower up and see that the spring has the buffer face cocked on an angle. Push the top of the buffer and see how much movement it takes to get the buffer face at 90 degrees with the lower and the buffer never moves off of the pin. You would have to adjust for that and other factors to arrive at an accurate distance the buffer is pushed off of the retaining pin. One other factor is the uppers lug back corners can hit the back curves in the lower and stop the rearward movement of upper before the gap close and the rear retaining pin may still push in. Any leftover gap needs to be accounted for.

Hmmm, well this throws a wrench into the works... You are correct in your assessment and I have noted the same myself when looking at how the buffer interacts with the buffer retainer.

[prepare]

Is there a specified amount of standoff noted in the drawings?

[HKGuns]

He has 2 accounts here??? Or maybe I was incorrect in thinking he was "the AR-15 Junkie"???

You may be correct and have me questioning my initial response now.

[the AR-15 Junkie]

He has 2 accounts here??? Or maybe I was incorrect in thinking he was "the AR-15 Junkie"???

lol, I only have 1 account here. Not everyone uses the same screen name on every forum. No requirement for that.

Try this method if you dont like the other.


https://www.youtube.com/watch?v=uMsc1a4EJJ8

[556Cliff]

lol, I only have 1 account here. Not everyone uses the same screen name on every forum. No requirement for that.

Try this method if you dont like the other.


https://www.youtube.com/watch?v=uMsc1a4EJJ8

Haha! That's awesome! I didn't even know you had a video on the offset retainer pins. It's almost like YouTube hides some of your videos from me.

[NoveskeFan]

So, my method is not super technical and I don't know the answer. What I do is hold the upper & lower with the rear take down pin out, as I close the upper, I have a flashlight in my other hand shining back on the buffer. As the lower closes, I can see the buffer being pushed back and light becomes visible between the detent and buffer face. Kinda hard to explain and requires some weird angles to view the area as you close it up, but it works for me. I have a few builds where the BCG wouldn't budge the buffer, so I installed the offset detent for piece of mind.

[m4luvr]

When you close the upper and lower the BCG makes contact with the buffer and slightly pushes it off the buffer retainer.

Is there a minimum specified gap or measurement between the buffer and the buffer retainer when the upper and lower are together? If so how can it be measured or gauged?

fwiw : unless there is a problem with functioning this is overthinking a problem that doesn’t exist. my understanding is that the buffer retaining pin only serves to keep the buffer and spring contained in the buffer tube when the upper receiver is pivoted away from the lower receiver. when the upper is closed on the lower the bcg pushes the buffer back slightly and removes pressure on the retaining pin. as a side note the rifle will function properly with the retainer and its spring removed entirely. it just requires care to take it apart and put back together for proper function.

[HKGuns]

fwiw : unless there is a problem with functioning this is overthinking a problem that doesn’t exist. my understanding is that the buffer retaining pin only serves to keep the buffer and spring contained in the buffer tube when the upper receiver is pivoted away from the lower receiver. when the upper is closed on the lower the bcg pushes the buffer back slightly and removes pressure on the retaining pin. as a side note the rifle will function properly with the retainer and its spring removed entirely. it just requires care to take it apart and put back together for proper function.

Not if the carrier is beating the crap out of the rear of your lower because the clearance isn’t correct.