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CZ LONG ARMS => VZ-58 semi auto rifle => Topic started by: jb2sea on April 06, 2015, 04:55:59 PM

Title: TBR/Bolt Hold open
Post by: jb2sea on April 06, 2015, 04:55:59 PM
OK, embarrassed to ask this, but how do I get the bolt to stay open on the VZ2008 while sitting at home?  I installed the TBR, but need to test it.  It doesn't seem to be moving at all when I depress it.  But I can't get the bolt to lock back, with a mag in or not.  IIRC, the bolt was staying open prior to my installing the TBR.
Title: Re: TBR/Bolt Hold open
Post by: RSR on April 06, 2015, 06:06:32 PM
Depressing releases.  Pushing up will lock it back.  And you have to use an empty mag for it to activate the bolt hold open feature.
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 06, 2015, 08:17:10 PM
That worked.  Pulling the bolt to the rear and pushing up on the TBR held the bolt open.  Thanks RSR.  But pushing down on the TBR is not releasing the bolt.  Isn't it supposed to release when I press down on the TBR?  Or do I have to have a loaded mag inserted before it will close?
Title: Re: TBR/Bolt Hold open
Post by: Brasky on April 06, 2015, 08:20:40 PM
That worked.  Pulling the bolt to the rear and pushing up on the TBR held the bolt open.  Thanks RSR.  But pushing down on the TBR is not releasing the bolt.  Isn't it supposed to release when I press down on the TBR?  Or do I have to have a loaded mag inserted before it will close?

Pushing down on the tbr should release the bolt. Try pressing down on the bolt stop from inside the bolt carrier while holding the bolt handle (so it doesn't smash your fingers).
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 06, 2015, 08:51:15 PM
Pushed down on the bolt stop and nope, it won't budge.  The only way I can close the bolt is to take the magazine out.
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 06, 2015, 08:52:26 PM
I was thinking I had seen a thread where someone else had a problem with the TBR being too tight.  Or am I remembering incorrectly?
Title: Re: TBR/Bolt Hold open
Post by: RSR on April 07, 2015, 12:03:02 AM
Take it out and see if it slides on the hinge pin without issue.  I believe yours was one of the later ones sent out since you paid by mail, which means I would have checked it for this issue prior to sending, after I discovered on the one I tried to install on my own rifle (was the only one of the 5 or so I had on hand at the time w/ that issue)...  So the pin channel tightness shouldn't have been the issue, but nevertheless might...

Is your empty mag installed when you're trying to do these manipulations?  If so, it takes quite a bit of force...
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 07, 2015, 07:30:45 AM
With the empty magazine installed, I have to pull up really hard on the TBR to get the bolt to lock back.  Since you mentioned it takes a lot of force, I pushed down as hard as I could on the TBR and sure enough, the bolt closed.  So it works.  But it is taking far too much force to close the bolt for this to be useable in the field.  I have not tried to lube the bolt stop.  Will that make a lot of difference?
Title: Re: TBR/Bolt Hold open
Post by: Enthusiasm on April 07, 2015, 08:34:48 AM
My TBR 's both move easily, but I did have to lube them well to get them to do so. I first installed with no grease and they didn't want to budge. STILL  It takes real force to actually use the TBR as intended on both of mine as well. Maybe it's the brand new springs, but it is tuff to get it to drop the bolt.
I still like having the oversized BHO button
Title: Re: TBR/Bolt Hold open
Post by: CitizenPete on April 07, 2015, 10:16:58 AM
That worked.  Pulling the bolt to the rear and pushing up on the TBR held the bolt open.  Thanks RSR.  But pushing down on the TBR is not releasing the bolt.  Isn't it supposed to release when I press down on the TBR?  Or do I have to have a loaded mag inserted before it will close?

Ideas:

If you have an empty mag in place, then the bolt SHOULD remain back.

Stupid questions on my part (just checking):
You did put the spring back in when you R&R'd the TBR?
Is the mag follower stock, or are you using the (-1 USA part 922r) polymer follower in the mag?
Are you pushing straight down, or down and inward toward the receiver? New TBRs can bind up a bit until they break in.
 
A new BR spring might also help a bit, if yours is worn out at all.
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 07, 2015, 11:25:56 AM
With an empty mag in place, it will not hold the bolt open.

Yes, the spring is in there.
The mag follower is stock as far as I know.  I have several mags.  I've tried 5 different ones, and get the same result with all of them.
I'm pushing straight down.
The bolt release spring looks new.

I'll try lubing the bolt stop really well and see if that makes a difference.  My impression is that it is binding.  Would removing it and filing on the side of it a little bit perhaps loosen it up?
Title: Re: TBR/Bolt Hold open
Post by: RSR on April 07, 2015, 01:44:30 PM
Take it out and check the pin channel on the tbr first.  Provided that is good, then that potential issue has been removed. 

Then the next issues would be user (wanting the TBR to release the bolt with an empty mag in -- takes a lot more force that way) and stuff like not lubricating your TBR.  Every metal to metal surface should always be lubricated on any machine...

Third and final would be that something on your gun's receiver is out of spec.  The Zendl TBR are made to much more rigid tolerances than the OE components.

You have to troubleshoot stepwise and look at each specific problem by problem.  Only by ruling things out are you able to reach the root of the matter -- otherwise, we're just left with a lot of stuff it could be...
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 07, 2015, 09:31:58 PM
I did check the pin channel when I installed it and all was clear. 

So will the bolt release work much more easily with a loaded mag inserted than with an empty mag?  I assume that is what you're saying.  Guess I need to get to the range and give it a try.  But I definitely need to lube the BR.  And I'm hoping/thinking that will solve my problem. 

Hopefully the receiver isn't out of spec. 
Title: Re: TBR/Bolt Hold open
Post by: RSR on April 07, 2015, 10:34:51 PM
Yes -- or invest $5-$10 in dummy/action proving/snap cap rounds...

Or use your empty mag to lock the bolt back.  Drop the empty mag using the mag release.  And then try to use the tbr.  Effectively the same forces as reinserting a loaded mag that puts no tension on the BHO.
Title: Re: TBR/Bolt Hold open
Post by: jb2sea on April 07, 2015, 10:59:03 PM
Thanks for that.  That worked fine.  Plus I've been sitting here working the TBR a good bit tonight.  I think lubing it and working it is what it needed.  Still stiff, but I think it will be OK once I wear it in some more. 

I do need to invest in some snap caps.  Just never have bought any before.
Title: Re: TBR/Bolt Hold open
Post by: CitizenPete on April 08, 2015, 05:49:26 AM
Thanks for that.  That worked fine.  Plus I've been sitting here working the TBR a good bit tonight.  I think lubing it and working it is what it needed.  Still stiff, but I think it will be OK once I wear it in some more. 

I do need to invest in some snap caps.  Just never have bought any before.

I am glad to hear its breaking in and not a receiver issue.

$10 Dummy rounds have proven to be great tools for in home testing on this sort of thing. I don't think they are designed for dry fire because they have no spring loaded primer, but they work for mag loading, cycling, and charging and testing TBR ;) .  note: Unless you mark them up like I do, (they don't have orange bullet tip) there may be a danger of confusing with a live round.  I keep one on my bench as a tool. http://www.dummybullet.com/inert_bullets.html