When the bolt locks open after magazine is emptied it won’t hold open like it should. The bolt will slam forward if a loaded mag is inserted without hitting the bolt release(bolt catch) or if the guns is bumped while locked back with no mag. If I am very careful removing empty mag and inserting new one it will usually work, but not the way it is supposed to. I am guessing its the bolt catch or bolt itself, but don’t know which. Is it possible the bolt catch spring is too stiff? Has anyone ever had this problem or heard of it? Thanks
Is the spring and buffer (for the bolt catch) installed properly? What parts kit is it?
Does it do this when you manually lock the bolt back, and are you sure you are fully depressing the paddle when doing so?
It could also be a weak buffer spring, it may not be putting enough pressure on the BCG which means the bolt catch can slip out from the bolt face more easily. That being said if you hit the gun hard enough the bolt will release when locked back, even if everything is working properly.
My Double star Lower Did that And I thought it was the spring ,so I cleaned it with a shot of CLP and a toothbrush, the Bolt catch had a little dirt in it, it worked Good after that.Lube it good And see if that Helps If not I would Disassemble the Bolt catch and Check the spring or replace it
It is a Daniel Defense parts kit, lmt bolt and upper. If I manually lock it back its even worse. It doesnt even need to be bumped to release it. I’ve cleaned it real good, so I guess I might just have to tear it apart. I’ve got an extra bolt catch and mag release with the kit. Not sure why, but if the other bolt catch works right I’ll be happy. Of course I have to remove the bolt catch roll pin which was the biggest pain in the ass in the entire build. Thanks for the advice guys wish me luck.
There is a special punch made for removing the bolt catch roll pin. You may want to get one at Brownells. I would take it apart and make sure that you used the right spring and that everything is correct. I have seen people mix their stuff up and use a disconnector spring.
I also suggest getting a new roll pin as they shouldn’t be re-used.
Take some pics, or at least a good hard look at what’s happening in there, specifically, where the bolt catch is hitting the bolt.
here’s some pics to hopefully help a bit.
First, bolt catch catching on the bolt carrier and not the bolt. This will drop the bolt with only a shake of the rifle, if it catches at all. If you can rack the charging handle back all the way and it works, then it’s something to do with the firing cycle, either under gassed, or something with the buffer is out of wack not allowing the bolt carrier to travel all the way rearwards when firing. Be sure that you can rack the bolt all the way to the rear by hand to see how the bolt catch engages the bolt face.
Second is an improperly assembled bolt catch. It’s a real common mistake to swap the disconnector and bolt catch springs when putting the lower together. The disconnecter spring has a large and small end, bolt catch spring has both ends the same size. A swapped spring will let the bolt catch lock the bolt to the rear, but because it is barely engaged, it will slip if you shake the rifle too much. Look closely at how high the bolt catch is raised compared to the bolt lugs.
Finally, a correctly assembled bolt catch, compare how high it rides on the bolt lugs, yours should look like this with the bolt locked to the rear.
Hope this helps.
After looking at those pictures mine looks like the one with the wrong spring where its barely engaged. I am pretty sure I have the right spring in there because the disconnector spring was already placed in the trigger when I got the kit and I double checked to make sure it was the right one. I am still going to check the bolt catch spring because it sits nowhere near as high on the bolt as the one in the properly installed picture. Thanks for the help guys.
Well I checked the spring, swapped bolt catch and no change. Bolt catch still barely engages the bolt. Back to square one. Im hoping my lower isnt out of spec
Who is your lower manufactured by?
Tactical innovations.
I have not heard anything bad about their lowers. I was afraid you were going to say it was a Roggio Arsenal, that is why I was curious. If you feel that the lower is out of spec call them. I have done a lot of NFA business with them and have always received the best service!
Good Luck & keep us informed!
Can you press the bolt catch in and make it go all the way up like the last picture posted?
No. The bolt catch spring and buffer can be pushed all the way in the receiver by the bolt catch and it wont go any higher on the bolt.
Could be the bolt catch itself? Have you compared it to another bolt catch?
Yeah. Two different bolt catches came with my Daniel Defense lpk and they’re both identical as far as the end result.
I’ve had similar issues, but it turned out to be dirty magazines, don’t know if this is your issue but you might want to check your mags out and see if they’re what’s screwing you up.
Here’s a thought. See if you can measure the hole and compare it to another lower. Or try and stick something behind the spring and then semi-install it and see if it persists. There is always a possibility that the lower is out of spec.
I have no idea who Tactical Innovations is or their quality.
If you have a set of calipers, measure the length bolt catch buffer and the position of the hole for the bolt catch roll pin in relation to the top edge of the lower. It should measure 0.190" from center.
I’ve assembled about 40 Tactical Innovatios billet lowers. On every one of them I had to shorten the bolt catch (bottom of the ping/pong paddle) about 1/16" and then round it a little and touch it up with cold blue. If you don’t the bolt catch can’t travel up far enough to lock the bolt securely when the rifle runs dry. If you don’t shorten it it runs into the raised area where the mag catch is which stops is travel.
So is this one of the tactical innovations that abound with this lower, along with the upper receiver tensioning screw?