Bolt shim question

[Topwater]

Have any of you, who have used bolt shims for a CZ 457 bolt, used any lubricant ? I am considering coating the shims with a sparse bit of HBN to reduce future warping of the shims. Any thoughts or ideas ? Thanks.

 

[HGC]

The shims definitely take a beating, I use Hornady one shot lube and cleaner for the bolt after each range session.

 

[tmwinds]

Just curious, what did the head space measure before shimming and did you see accuracy improvement?

 

[mrh1958]

I would not shim the bolt, if the head space is in spec you wont see any improvement.

 

[Topwater]

I’m still waiting for the shims to arrive. I have two friends that have used the shims. Both claim a minor increase in accuracy for “ some “ Ammo.

 

[Lumpy’s guns]

I have a shim question, when is headspace to tight? I put in a.008 shim the bolt closes hard but accuracy is really good. I also had a bunch of misfires, not sure if related.
CZ 457 MTR

 

[stacy]

I have a shim question, when is headspace to tight? I put in a.008 shim the bolt closes hard but accuracy is really good. I also had a bunch of misfires, not sure if related.
CZ 457 MTR

Yes to tight of headspace will cause misfires

 

[Lumpy’s guns]

Thanks I will back it off a little

 

[Topwater]

Installed the .0015 shim to use with SK Ammo. I saw an discernible increase in accuracy. My buddy installed the .002 shim in his MTR To use with sorted SK Long Range. He’s seen a better increase in accuracy than me. I might switch to the thicker shim and start sorting my Ammo as well. Good shooting , everyone.

 

[BowChamp]

Installed the .0015 shim to use with SK Ammo. I saw an discernible increase in accuracy. My buddy installed the .002 shim in his MTR To use with sorted SK Long Range. He’s seen a better increase in accuracy than me. I might switch to the thicker shim and start sorting my Ammo as well. Good shooting , everyone.

I really appreciate you following up with with the results you are seeing!!

 

[wkdickinson]

I would not shim the bolt, if the head space is in spec you wont see any improvement.

Maybe I am missing something here, but why would you shim a bolt that was already in spec?

 

[Topwater]

Maybe I am missing something here, but why would you shim a bolt that was already in spec?

Improved accuracy with individual ammunition based on rim thickness.

 

[Topwater]

We participate in a 300 yd match. We need every little tweak to try and keep up with the top shooters. Also, I forgot to mention that, for some reason , I needed to adjust my tuner as well. My buddy didn’t need to move his.

 

[Hi-NV Shooter]

We participate in a 300 yd match. We need every little tweak to try and keep up with the top shooters. Also, I forgot to mention that, for some reason , I needed to adjust my tuner as well. My buddy didn’t need to move his.

So how do you know it wasn't the tuner adjustment that made the difference?

Lee

 

[wkdickinson]

Improved accuracy with individual ammunition based on rim thickness.

My interpretation of "in spec" was that the headspace was already correct.