AR Assmebly Canundrum...

[Saluki91]

I am assembling a new 300 Blackout from components, and have run into a bit of a road block.

The charging handle will often only move about 1/2" before it stops cold, or if it makes it past the initial 1/2", it feels like it is catching something on the way back. It may even freeze going back into battery. It never feels free and smooth.

At first, I thought the cause was the Wilson Combat trigger I selected, as I never noticed this behavior until the trigger in question was installed. However, when I removed the trigger, the charging handle continued to behave in the same manner.

When I removed the BCG and charging handle for closer inspection, I noticed wear on the tip of the charging handle, additional wear where the charging handle engages the BCG beneath the gas key, and wear on the "roof" of the upper receiver where the charging handle rides.

Is this merely a matter of incompatible components, or is something else afoot? Perhaps a buffer spring issue...?

Is the wear that I noticed significant enough for me to pursue replacing these components?

Thanks!

COMPONENETS:
Charging Handle - Breek Arms Warhammer
BGC - AO Precision C158
Upper Receiver - Anderson

 

[BigBlue 94]

Has it been shot a decent amount? Thats normal wear as far as im concerned.

 

[Saluki91]

Has it been shot a decent amount? Thats normal wear as far as im concerned.

No - it hasn't been fired. I haven't even put the barrel on it yet... these are brand new components. The wear is from trying to run the charging handle. Seeing that wear - especially the amount and severity on the charging handle - really threw me for a loop.

 

[CapnMac]

If you only assemble the upper, does the charging handle bind up?
Or is it only when assembled to the lower?

There are a lot of things all in a line when fully assembled. The charging handle is pulling on the BCG which then impinges on the buffer. This also has to track over the hammer.

The other test that might be easier to try out in the immediate time would be to take the bolt out of the BCG, and assemble that into a different upper. The geometry of lower and upper is nearly, forgiving the phrase, "bulletproof"--but that "nearly" can be a bear.

This probably needs @Skylerbone

 

[Saluki91]

If you only assemble the upper, does the charging handle bind up?
Or is it only when assembled to the lower?

There are a lot of things all in a line when fully assembled. The charging handle is pulling on the BCG which then impinges on the buffer. This also has to track over the hammer.

The other test that might be easier to try out in the immediate time would be to take the bolt out of the BCG, and assemble that into a different upper. The geometry of lower and upper is nearly, forgiving the phrase, "bulletproof"--but that "nearly" can be a bear.

This probably needs @Skylerbone

Per your suggestions, I was able to narrow it down to the charging handle. It is now in file 13, and a different one is on the way.
Thanks again!

 

[mcb]

I suspect there is no issue at all. If you have no barrel installed in the upper yet then you are likely catching the head of the cam pin on the edge of its recess in the upper. Don't change anything until you have a barrel installed and test the components. The bolt needs the barrel and barrel extension to proper rotate at the end/beginning of the BCG movement. The bolt rotates and the cam pin moves into a clearance in the upper as everything goes into battery. Without the barrel there is nothing that ensures the bolt full rotates into the locked or unlock position and thus you are likely feeling the cam pin hitting the edge of the clearance and that is forcing the bolt to rotate to the unlock position but its not fully rotating and that is the extra friction you are feeling.

Even if the charging handle is a slight bit tight that will wear itself in with a little real world use.

 

[Skylerbone]

I’m with mcb, wait till the tube is on before proceeding. Funny tidbit; my BIL is a former SEAL and while showing him my AR collection he pulled a bolt to inspect it. Went to reassemble and it wouldn’t go. He froze a moment before snapping the bolt forward and all was good. With a little patience you will figure it out.