How the AR15 open hold bolt works w/pics

[JDPhx501]

Hey guys, this is my very first AR-15 build. I have had no prior experience with these kinds of modern black rifles, other than curio and relic Mausers which I have taken apart to clean.

I have a few questions and concerns regarding the bolt catch for my build. It is a modified bolt catch for the LAR-OPS4 ambidextrous side charging upper.

I fear I may have put the wrong spring in for the bolt catch.

Is it suppose to be pushed up by the magazine follower like this when empty?


Side view


The reason I am concerned is that I noticed that I cannot pull the bolt all the way back and push it forward all the way since the mag follower when empty pushes up the bolt catch in such a way that it blocks the bolt.

However, when the magazine is loaded, the follower is not there to push up against the catch and block the bolt's movement.




With the safety on and extreme caution, pointing it in a safe direction, I pulled the bolt back all the way and forward all the way. As long as there is a round, the bolt will catch a round and push it forward and its movement will not be impeded.

However, when the magazine is empty, the bolt catch is once against pushed up by the follower and locks the bolt back so it cannot move forward all the way.



thanks in advance for any input!

[Droppin Deuces]

That's how it works. Good job.

[clcolin81]

Looks good to me. Bolt is supposed to stay locked back when the mag is empty.

[clcolin81]

Nice pictures by the way. It's much easier to get help when you have clear, focused pictures

[Droppin Deuces]

If you're wondering how you get the bolt to go back forward and chamber a round, you just pull the charging handle and let it slam home. Otherwise you have to drop the mag, pull the handle, and let it go.

[JDPhx501]

Thanks guys!

I wanted to rationalize that "oh, it must do that so it locks the bolt back when empty" however I wasn't sure. I always wondered why my SPX930 seemed to magically know when to lock back once the last shell had been fired.

I figured good pictures are worth a thousand words, as I tend to be redundant and wordy sometimes.

[zeus45c]

This is referred to as a bolt hold open feature. Most modern rifle and pistols utilize this function. When the magazine is empty, the slide (pistol) or bolt will be held to the rear notifying the operator of an empty magazine and leaves the weapon ready for a fresh magazine.

On the AR15, you can still slam the bolt home on an empty magazine. You need press the bolt catch on the upper paddle portion. This also applies after reloading the weapon. This is the preferred method.

[JDPhx501]

I'll remember that! thanks!

[dieselpower]

change the title of this thread to, "How the AR15 Bolt Hold Open works with Pictures"...so we can make it a sticky.

[shark92651]

change the title of this thread to, "How the AR15 Bolt Hold Open works with Pictures"...so we can make it a sticky.

LOL!

[straykiller]

change the title of this thread to, "How the AR15 Bolt Hold Open works with Pictures"...so we can make it a sticky.

haha agreed

[FatalKitty]

change the title of this thread to, "How the AR15 Bolt Hold Open works with Pictures"...so we can make it a sticky.

Indeed - this is the best write up of how the AR bolt catch system works that I have ever seen!

[Cokebottle]

That lower is completely messed up now and will never work properly.
I'll meet you at your local gun shop and take it off your hands and dispose of it properly. I'll even pay the $35 transfer fee in the interest of getting this dangerous, evil, black rifle part secured in a location where it will do no harm.