858 Bolt Hold-Open

Homesick Alien

Homesick Alien

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So, at yesterday's TacRifle my rifle seems to have developed a gremlin. I'd fire 5 rds and the bolt wouldn't stay open on the empty mag about 3/4's of the time.

After cleaning it really well tonight I started playing around with it and the problem seems to be that it 'sticks'. I sprayed a bunch of degreaser in there and worked it manually a bunch of times and then put some penetrating oil on and let it sit.

It seems that if I work it for a bit it'll hold open the first one or two times but then let go. To push it in manually takes a bit of effort and a bit of a wiggle and the mags just don't push on it hard enough.

Is this my mag springs getting weaker (doesn't seem to be so and they feed really reliably) or has something gotten out fo wack with the mechanism and if so how would I go about correcting that?

It's annoying as hell to have to count rounds, especially when you're trying to compete and have better things to concentrate on like trying to shoot a stage left-handed that was designed to be 'difficult' for right-handed people.
 
How difficult is it to strip down?

You need a schematic because something seems broken on it - that bolt release spring has way too much tension on it IMO.

Any 858 gurus in the house?
 
is it a new rifle? mine did the same thing till i took a file and filed the mags so they all fit perfectly then ran 500 rounds thru it. no problem now with the bolt catch but now it turned itself into a bolt action because of the sear problem.
 
Did you try a different mag?

There is a tab on the mag that pushes up the bolt catch on the last round.

On one of my mags, it's chewed up and often the bolt will not hold open.
 
OC-3 said:
Did you try a different mag?

There is a tab on the mag that pushes up the bolt catch on the last round.

On one of my mags, it's chewed up and often the bolt will not hold open.
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On one of my mags the tab is 'loose' so that would definitely be a problem. The others are all fine in that regard.

beergut, the rifle's had about +1000 rds through it just fine. The problem mag mentioned above wasn't holding open the odd time when I was out at PoCo the Sunday before.

The tab on the other mags is in the right place and is pushing up just fine, the tab that it pushes on in the receiver though is what's sticking, it requires a fair amount of 'push' by hand, much more then would be reasonable to expect from even a 'perfect' mag spring.

It seems to have a bit of a 'wiggle' and I am wondering if it's because it's loose that it's 'binding', for lack of a better word. The problem is that it's not really feasible (from what I can tell) to dis-assemble just that bit.

Like I say, I did degrease and then oil it as best I could, there certainly doesn't seem to be any foreign matter in there. It actually goes quite smoothly when it's being worked, it's just that it seems to 'seize' when it's in the normal 'down' position.
 
I don't know what to tell you HA. It's a simple mechanism, so the reason it's not working should be easy to suss out.

Can you compare it to someone else's?
 
I'm gonna try the compare and diagnose route and hopefully get somewhere with that; good suggestion spi.

I have a gut-feeling the reason is that it's either worn or loosened somehow so that rather then moving straight up and down it's got some wiggle room which is causing the problem.

Let me know if yours starts becoming a bigger problem, velocipede.
 
beergut said:
no problem now with the bolt catch but now it turned itself into a bolt action because of the sear problem.
Click to expand...

There are solutions to this problem if you haven't fixed it already.
 
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