Zenith Z5RS bolt gap question
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Thread: Zenith Z5RS bolt gap question

  1. #1
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    Default Zenith Z5RS bolt gap question

    I recently picked up a new unfired Z5RS, and after checking bolt gap itís sitting at .013. I have not fired the pistol yet so the bolt gap may change. Sorry if this is a stupid question but should I be concerned about a .013 bolt gap? I realize itís in spec but itís awfully close to the minimum of .010 especially for a new unfired firearm.

    On my PTR91 and old PTR built C93 the bolt gap was also within spec but much closer to the maximum side so I didnít worry about it, but this seems on the lower end for being unfired.

    Again sorry if this is a dumb question, just wanting to help put my mind at ease.

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    When it drops below .10 is when you might need to do something but I think it will take a whole lot of rounds down range before that happens. Some are above the .015 and still functioned with no problems.
    Like you said there might be a change being unfired after you do a break in session if there are any issues I would contact Zenith CS and send it to them from what it sounds like some members have had too and they did make it right. My Z5RS has fired without issue I don't think there's much to worry about but shoot it and then check it if there's 0 issues then fire away 5 yr. warranty should cover any immediate gap issues being its new.

    Congrats on your new gun!

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    This is from PTR's manual but it applies to basically all roller delayed weapons:

    The acceptable bolt gap range for the majority of the life of the firearm is .010"-.018" after the break in period is completed. PTR firearms can be expected to maintain this range for several thousand rounds, after which the gap can be expected to lower. Safe operating range is .004".
    .013 is fine. Fire off 1,000 rounds and recheck it.

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    Yeah, just continue to monitor it. Also, as long as it's cycling well, it's probably ok. If you see bulges in the side, then it's probably not ok any more. And that's why you monitor the gap.

    I've gotten so used to what the proper bolt gap looks like, I can generally just glance into the mag well and see if it's still ok or not. I've been running HK and RCM bolt groups for years and haven't seen either of them shrink enough to notice. I haven't shot my PTR 9CT enough to make that claim yet.
    "Sometimes change sucks."- Anne Frank

    Reloading: A low impact exercise with a high impact payoff.

    Take your wife or GF to the range more. If you want her to get the bug, you've got to expose her to the disease.

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    So if after shooting this the bolt gap decreases below the minimum spec, what am I looking at for options? Plus size rollers/a new locking piece or would it just be better contacting Zenith?

    I’m not worried about it too much and I expect it’ll be fine, but after shooting it and letting it wear in I’d rather have an idea of what my options would be for the worst case scenario just in case.

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    Quote Originally Posted by CapnJazz View Post
    So if after shooting this the bolt gap decreases below the minimum spec, what am I looking at for options? Plus size rollers/a new locking piece or would it just be better contacting Zenith?

    I’m not worried about it too much and I expect it’ll be fine, but after shooting it and letting it wear in I’d rather have an idea of what my options would be for the worst case scenario just in case.
    Bolt gap will be reduced over the life of the weapon, as shooting wears down the internal components. The easiest way to get it back in the correct spec range is to replace the rollers with the next larger size.
    As always, if you have concerns with your Zenith firearm, I recommend contacting Zenith Firearms. You'll find the staff motivated to help you.
    SF,

    James

    Heckler and Koch Certified Armorer (Heckler and Koch)
    Heckler and Koch Pistol, Submachine Gun and Rifle Instructor (Singleton International)

    Owner, Teufelshund Tactical

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    I finally got around to shooting it today, I only had enough time for 200 rounds and I know that that is a drop in the ocean for round count but it was an incredibly fun gun to shoot. The third round in the first magazine failed to feed but I’m blaming that on ammo (124 gr Winchester Winclean, it’s very conical in shape and has given me problems feeding in otherwise reliable pistols), otherwise the rest of the time shooting the gun functioned fine. This was my first pistol caliber roller delayed gun I’ve shot and I’m hooked, it blows my PTR91 and old PTR C93 out of the water. I’ve put a few thousand rounds through a Beretta CX4 Storm and all the talk about MP5s recoiling softer than direct blowback is both absolutely true and considerably softer shooting than I expected.
    gt40doc likes this.

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    I noticed many MKE owners say they get .013 bolt gap. When i checked my Z-5rs i stopped at .013 with some slight resistance. I was able to go up to .015 with some slight force . .017 was a no go. Was i being to gentle ? Can you force open the bolt gap by mistake with a feeler gauge or is it too hard to seperate the bolt and carrier this way ?

    Thanks !!

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    Quote Originally Posted by Darkside View Post
    I noticed many MKE owners say they get .013 bolt gap. When i checked my Z-5rs i stopped at .013 with some slight resistance. I was able to go up to .015 with some slight force . .017 was a no go. Was i being to gentle ? Can you force open the bolt gap by mistake with a feeler gauge or is it too hard to seperate the bolt and carrier this way ?

    Thanks !!
    It sounds closer to 0.015 inches. You're looking for a firm drag according to printed instructions on this website:

    https://www.hkpro.com/forum/hk-refer...tructions.html

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