Ar bolt issue

[JGIBSON]

On my Ar pistol. The bolt catch will not grab the bolt when mag is empty. I have tried multiple mags, also noticed that the problem is that the bolt does not even go far enough back to allow the bolt catch to grab it. Pics included, do I need a new BCG or Buffer setup?

 

[Whisk604]

I'm guessing wrong spring or buffer. How long is buffer? How long is your spring?

 

[JGIBSON]

I'm guessing wrong spring or buffer. How long is buffer? How long is your spring?

I'll check when I get to the house I think I need to order rhe SB tactical one to match the brace and buffer.

 

[Tyler-The-Piker]

It almost looks like your buffer tube isn't screwed in far enough...which in turn is not holding the buffer retainer & spring down in place, causing binding and or hold-up...

 

[JGIBSON]

It almost looks like your buffer tube isn't screwed in far enough...which in turn is not holding the buffer retainer & spring down in place, causing binding and or hold-up...

 

[JGIBSON]

Works just fine on my lower lowers so definitely something wrong with this lower setup.

 

[SEIndSAM]

MAGPUL® ARMORER'S WRENCH – AR15/M4​

https://aimsurplus.com/magpul-armorers-wrench-ar15-m4/

AR-STONER Armorer's Wrench Multi-Tool AR-15 Steel​

https://www.midwayusa.com/product/1020737242?pid=489452

 

[Tyler-The-Piker]

Can you show pictures of the bolt itself and inside both upper and lower?

 

[JGIBSON]

Can you show pictures of the bolt itself and inside both upper and lower?

 

[Tyler-The-Piker]

Thanks for the pics. I'm struggling to see anything out of place on the surface. Someone more knowledgeable than I will surely pop in soon and be able to help...

 

[JGIBSON]

Can you show pictures of the bolt itself and inside both upper and lower?

View attachment 128136 View attachment 128137 View attachment 128138 View attachment 128139 View attachment 128140 View attachment 128142

Thanks for the pics. I'm struggling to see anything out of place on the surface. Someone more knowledgeable than I will surely pop in soon and be able to help...

Same here buddy I've been around these rifles for years and have built several of them. This one has me stumped for sure. Literally I put this upper on any of my other lower and have zero issues. But this lower does not get along with this upper. I'm trying to figure out why and how the bolt will not go far enough back to lock up in thr bolt catch. Weird for sure.

 

[d.kaufman]

Have you pulled out the buffer and spring? I would take measurements of both of those and compare to another

 

[JGIBSON]

Yessir I have there is a difference. How ever when I swap them it still doesn't change anything. I took the buffer out of the lower it works on and put it in this lower and still have the same issue.

 

[Tyler-The-Piker]

could just boil down to tolerance stacking.
Highsmith here in Hancock County can take care of you but out east in Richmond I don't know...

 

[Whisk604]

Is there a length difference of your buffer tubes? You mentioned SB sold a spring for your setup. Could it be that the SB tube is shorter for some reason?

 

[JGIBSON]

Is there a length difference of your buffer tubes? You mentioned SB sold a spring for your setup. Could it be that the SB tube is shorter for some reason?

I'm going to order one of theirs and see if that is the issue.

 

[BGDave]

I'm guessing wrong spring or buffer. How long is buffer? How long is your spring?

This right here.

Remove the buffer spring and put the buffer in and see if that allows the bolt to travel far enough back. Coil bind is a real thing.
Naturally don't shoot it that way.

 

[JGIBSON]

This right here.

Remove the buffer spring and put the buffer in and see if that allows the bolt to travel far enough back. Coil bind is a real thing.
Naturally don't shoot it that way.

Well took the spring off and the buffer is too long will not allow it lock up. I ordered sb tacticals buffer and spring hopefully that fixes it.

 

[JGIBSON]

So since I have ordered a other one. I decided to mess with this one. I shaved 1/4 inch off the back and now I have zero issues with the lock up. My question is action and functionality what would happen if I ran it like this? View attachment 128263

 

[BGDave]

I would try it. Check it after 20 rounds or so.
Don't think it would hurt a thing.