This is a parts build with an M5 receiver set...Bolt didn't hold open on 1st empty mag of the day (although it had during previous shooting sessions), so I loaded a new mag and cranked back on the charging handle, only to see something go flying to the right out of the corner of my eye. At the time I thought it might have been excess lube. Proceed to shoot the rest of the day (4-5 more pmags) and the bolt never locks back on an empty mag. So I'm thinking its a gas issue from the ammo I'm shooting. I go to clean it the next day only to find that the upper portion of the bolt hold open is gone - sheared off. So clearly that is what I saw go flying out of the ejection port when I pulled back on the charging handle during the first reload. I can't recall for sure what BHO was used on this build. So I order (2) DPMS style 308 BHO's as replacements and now neither one locks the bolt when empty; either while shooting, or from trying to manually manipulate.

So what's the problem? Anybody else have an issue like this? My first inclination is to now order an Aero brand BHO, but I don't see why that should make any difference. Thoughts?

In for the answer and an education as I have parts inbound for a build.

With your thread title, I thought the Man was going to chime in with his anti-gun thoughts.

Im gathering parts for a build myself. .


Ive seen dozens of these threads. Its a pattern. Bold hold opens breaking on 308 guns. Several people have broken the aero brand ones.

Makes me wonder if this is a weak part in any 308 kit.


Wonder if there's an aftermarket one thats stronger?

Everything you use for the m5 lower is standard ar fare except the pivot and td pins and bolt catch (buffer and spring excluded).

My plan is to use leftover ar parts or a build your own lpk from red barn with aero pins and a 308 bolt catch. I just have no idea what catch to use.