Finding lands with a zermatt action

[NJRaised]

Like the title states….

I have previously used a fired case, slightly sized down the neck, inserted a bullet in long, closed bolt on the round and let the bullet slide back into the case. Then measure CBTO, and start with the bullet backed off another 15-20 thousandths from the lands. Then verify the bullet is off the lands by closing the bolt and making sure the bolt closes with no resistance.

With the zermatt (origin), there is a gas block and spacer between the bolt body. This always makes bolt close have some level of resistance. Would it make sense to remove the gas block and spacer, so that the bolt drops freely so that I can verify the bullet isn’t touching the lands? (I also remove cocking piece and firing pin)

I’ve always done this with one piece bolts, never a floating bolt head.

Thanks in advance.

 

[spife7980]

I can still feel the lands just fine with my origin.

If you take the spring and block out then there is no pressure pushing back keeping the cross pin in place so you pull back an empty bolt instead of extracting the case. The cross pin falls out and you gotta shimmy it back inside the bolt inside the action to extract the case.

 

[Maurygold]

Like the title states….

I have previously used a fired case, slightly sized down the neck, inserted a bullet in long, closed bolt on the round and let the bullet slide back into the case. Then measure CBTO, and start with the bullet backed off another 15-20 thousandths from the lands. Then verify the bullet is off the lands by closing the bolt and making sure the bolt closes with no resistance.

With the zermatt (origin), there is a gas block and spacer between the bolt body. This always makes bolt close have some level of resistance. Would it make sense to remove the gas block and spacer, so that the bolt drops freely so that I can verify the bullet isn’t touching the lands? (I also remove cocking piece and firing pin)

I’ve always done this with one piece bolts, never a floating bolt head.

Thanks in advance.

it's a floating bolt head do not remove those to find the lands it has to have that resistance as the lugs mate the receiver. Use a sharpie on the bullet to see if it the lands are marking it thats how I do it.

 

[NJRaised]

Good advice, thank you. First time doing this with a floating bolt/crf. Trying to avoid sticking one in the lands and having a major issue.

 

[Maurygold]

Good advice, thank you. First time doing this with a floating bolt/crf. Trying to avoid sticking one in the lands and having a major issue.

cleaning rod with a metal flat base and using a case without powder will help prevent any issues there.

Edit: also make sure you are inserting the round into the bolt face over (or under) the ejector and not trying to have it push over the ejector at close since this is CRF.

 

[Rio Precision Gunworks]

Good advice, thank you. First time doing this with a floating bolt/crf. Trying to avoid sticking one in the lands and having a major issue.

If your goal is to just avoid sticking a bullet in lands, you can use the Cortina method. Load a round long. Apply wax/lube to the bullet so it doesn't stick in the lands. Chamber and close the bolt so the rifling seats the bullet further into the case.

Subtract .020" from that measurement and start your load development there. The bullet will still be into the lands, but it won't stick.


If you're actually looking for the point where the ogive touches the lands, thats a different goal and method. As the touch point and the sticking point are quite different.

 

[MBanning]

Pull the firing pin assembly out of your bolt. The bolt handle will fall free when there is no bullet to land contact as long as your brass is properly sized

 

[CK1.0]

I have an Origin and IMO this is the best way to find the lands... just pull your firing pin assembly and do this (just be mindful of the cross pin, as it can fall out without the firing pin keeping it in place):

 

[Mike278th]

The way I do it is to use a Hornady measuring tool, but to get the best feel for it, I use it with a wooden dowel (carefully) inserted from the muzzle. Moving the bullet back and forth with the tool and the dowel, you can get a really good feel for the contact point. I use a comparator to measure, so I'm going off the shoulder and don't have to worry about overall length. If you want to take that variable out, you could make your own measuring case from a twice fired piece of brass.

 

[Vanilla Victorious Hydra]

I have an Origin and IMO this is the best way to find the lands... just pull your firing pin assembly and do this (just be mindful of the cross pin, as it can fall out without the firing pin keeping it in place):

The bolt don’t fall freely though - at least with my TL3.
Have you modified the above method for the origin or just accept there is some resistance to start with?

 

[CK1.0]

The bolt don’t fall freely though - at least with my TL3.
Have you modified the above method for the origin or just accept there is some resistance to start with?

Mine does. I'm not sure why the TL3 would be any different?

Did you forget to remove the firing pin assembly?

 

[Vanilla Victorious Hydra]

Mine does. I'm not sure why the TL3 would be any different?

Did you forget to remove the firing pin assembly?

Nope, firing pin removed. There is more resistance compared to a defiance, Borden, rem & tikka actions with there FP removed.

I have to use my finger to help the bolt drop with the TL3

 

[memilanuk]

I've done it before with one Origin; can't recall if I ended up pulling the washer from between the bolt body and head, as well as the firing pin assembly. I recently got a second Origin, so maybe I can try it tonight for comparison.

Some actions are just enough tighter that it doesn't work quite the same. On my Savages, a stripped bolt falls closed with an audible 'thunk'. On my BAT Neuvo ($2400 BR/F-class action) it's more of a slow close - definitely not a drop or fall. Whether that's the fitment of the bolt body in the receiver, or the barrel breech to the bolt nose... dunno.

 

[NJRaised]

Nope, firing pin removed. There is more resistance compared to a defiance, Borden, rem & tikka actions with there FP removed.

I have to use my finger to help the bolt drop with the TL3

Exactly how mine is. Firing on assembly removed. You still have to assist the bolt closed, it doesn’t fall shut.

 

[memilanuk]

Okay, I went out and played around with this a bit, and jogged my memory.

Take the wave washer out from behind the bolt head. Take the spacer / baffle out too, otherwise it'll rotate independent of the head, and cause all kinds of grief.

Yes, the toggle pin / cross bolt will then be loose, and prone to falling out now that it's no longer under tension. Not a new problem; Savage shooters dealt with this years ago.

There are a couple of ways to handle it if it were a Savage, but they kinda hinge on some particular quirks of the Savage bolt that do not generally apply here. The one that does is pretty damn simple: put some grease on the toggle pin, and stick it back in the hole.

The more 'sticky' or 'tacky', the better. But even the mil-spec TW-25B stuff will work.

Video clips of two different Origins

Caveat - if you let the bolt drop too much, or if your grease isn't very tacky, then the toggle *might* try to come part-ways out over the mag well. Just reach up thru the well, push it back into place, and continue pulling the bolt to the rear. By the time you get to the bolt stop, it'll be safe.

 

[Luckyshot]

Wth
My Origin bolt handle falls with zero resistance with FP removed

 

[Vanilla Victorious Hydra]

Okay, I went out and played around with this a bit, and jogged my memory.

Take the wave washer out from behind the bolt head. Take the spacer / baffle out too, otherwise it'll rotate independent of the head, and cause all kinds of grief.

Yes, the toggle pin / cross bolt will then be loose, and prone to falling out now that it's no longer under tension. Not a new problem; Savage shooters dealt with this years ago.

There are a couple of ways to handle it if it were a Savage, but they kinda hinge on some particular quirks of the Savage bolt that do not generally apply here. The one that does is pretty damn simple: put some grease on the toggle pin, and stick it back in the hole.

The more 'sticky' or 'tacky', the better. But even the mil-spec TW-25B stuff will work.

View attachment 8705783
View attachment 8705786


Video clips of two different Origins

Caveat - if you let the bolt drop too much, or if your grease isn't very tacky, then the toggle *might* try to come part-ways out over the mag well. Just reach up thru the well, push it back into place, and continue pulling the bolt to the rear. By the time you get to the bolt stop, it'll be safe.

Thank you, I will remove the washer and spacer & see if that makes a difference.

I notice you are running 2 different triggers on your origins… do you notice any difference in bolt close / lift with them? Is 1 a TT 2 stage and the other is?

 

[memilanuk]

The one is a TT Diamond, 2-stage, and the second is a TT Special. I haven't had that one long enough to really say anything about it one way or another, besides it 'feels' about the same as the first, at home in the shop. The first one is an earlier model, so the bolt has been back to Zermatt a couple times to get it where it's at now.