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):

 

[mike278]

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.