Zermatt RimX headspace

[Doug Beach]

I’ve got a RimX in my hands. The boltface recess is .046” deep. With minimal (.001”) clearance to the breech face, that gives me a minimum headspace of .047”. SAAMI .22LR min/max is .043-.051”. Forster’s GO is .043, NOGO is .046”. Most .22 accuracy info shows .043-.044” as being desirable.
Am I missing something here? Anyone have one they can measure?

 

[urbanrifleman]

I’ve got a RimX in my hands. The boltface recess is .046” deep. With minimal (.001”) clearance to the breech face, that gives me a minimum headspace of .047”. SAAMI .22LR min/max is .043-.051”. Forster’s GO is .043, NOGO is .046”. Most .22 accuracy info shows .043-.044” as being desirable.
Am I missing something here? Anyone have one they can measure?

I think you mean gauge stickout?

 

[Doug Beach]

I think you mean gauge stickout?

To my understanding, the only headspace measurement on a rimfire is the gap between the bolt face and the breech face, IE the space where the cartridge rim will be.
In that sense, yes to your question.

 

[Tad_Earhart]

Yes, the headspace has to be set on the long side. I have only worked with one RimX but it was exactly as you described. I found out after I already cut the barrel to 0.0435" HS and the bolt wouldn't close lol. The bolt nose may can be trimmed back to get to a normal range but I did not investigate that myself.

Tad

 

[urbanrifleman]

To my understanding, the only headspace measurement on a rimfire is the gap between the bolt face and the breech face, IE the space where the cartridge rim will be.
In that sense, yes to your question.

You could increase the gauge stickout and the headspace would still be the same. If I'm not mistaken.

 

[wkdickinson]

I built a new RimX a couple years ago. I cut the tenon exactly as shown in the drawing (see attachment) that came with the action and it works perfectly. The complicating factor with a RimX is that it is a "controlled feed" action, so you have an extractor that doesn't move.

 

[urbanrifleman]

I built a new RimX a couple years ago. I cut the tenon exactly as shown in the drawing (see attachment) that came with the action and it works perfectly. The complicating factor with a RimX is that it is a "controlled feed" action, so you have an extractor that doesn't move.

What is that 350 thou ring?

 

[DaveTooley]

What is that 350 thou ring?

I be that's the diameter of the flat area

 

[Doug Beach]

I be that's the diameter of the flat area

Yes.

 

[Doug Beach]

I built a new RimX a couple years ago. I cut the tenon exactly as shown in the drawing (see attachment) that came with the action and it works perfectly. The complicating factor with a RimX is that it is a "controlled feed" action, so you have an extractor that doesn't move.

If I cut the tenon length to the 1.6855” shown in the print, the bolt would not shut. Reducing the tenon length by the .0015” tolerance shown in the print would give me .0005” clearance, and .0465” headspace.

 

[urbanrifleman]

I be that's the diameter of the flat area

Got it. That side view doesn't match to me.

 

[Cigarcop]

Their pretty simple

 

[Doug Beach]

Their pretty simpleView attachment 1618295

What headspace measurement do you end up with?

 

[DaveTooley]

Got it. That side view doesn't match to me.

I think the term is not to scale

 

[jpjulian]

Their pretty simpleView attachment 1618295

They're

 

[Doug Beach]

Emailed Zermatt. They responded very promptly. Stated the min/max headspace for the RimX is .0455/.0500”.

 

[Will Henry]

Cut the tenon for clearance on the bolt but leave a protrusion which is the same diameter as the rim to establish the desired headspace. The alternative is to reduce the bolt counterbore and make the tenon longer. I think I would go with the former. WH

 

[Jonnyofalltrades]

Cut the tenon for clearance on the bolt but leave a protrusion which is the same diameter as the rim to establish the desired headspace. The alternative is to reduce the bolt counterbore and make the tenon longer. I think I would go with the former. WH

A .003" rim, or boss around the chamber mouth would do the trick, and most probably wouldn't even be able to see it.
My OCD won't let me chamber a target .22 with .046" headspace. It probably doesn't matter as much as we think, but I just couldn't do it!

 

[Doug Beach]

A .003" rim, or boss around the chamber mouth would do the trick, and most probably wouldn't even be able to see it.
My OCD won't let me chamber a target .22 with .046" headspace. It probably doesn't matter as much as we think, but I just couldn't do it!

This would be my thought, but it won’t work with this action. There is a fixed extractor plate (it’s a controlled feed design). This plate would run into any boss created to reduce headspace.

 

[Doug Beach]