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Lapping a bolt...

920 Views 7 Replies 5 Participants Last post by  Dan S
I've seen a few references to people lapping their bolts -- I'm assuming it's to smooth the action a bit.

My son's Scout is really tight for him; I can operate it OK but he can't, so I was thinking about lapping the bolt (and also on my Special.)

I know what lapping is, as in valves, scope rings, reel mowers, etc.

What's involved with lapping the bolt in a rifle? Does one need to completely disassemble the action? I would imagine so since you'd want to get all the lapping compound out of the action (I can't quite reconcile a glob of grit left in the trigger assembly!)

What grit is typically used to lap a bolt? And is water based or oil based usually used?

Any hints or tips would be very appreciated!

Thanks,

Mark
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1200 grit

use 1200 grit and you may as well lap the lugs while your at it.
The 452's upper lug (bolt open) tends to have less or no contact
than the lower lug. On mine the lower lug is what was causing
most of the problem. It rubs on the sides of the lower groove in
the receiver.

I used 1200 grit on the bolt body and the contact face of the lugs
and a dab of 600 grit on each side of the lower lug as it contacts
the sides of the receiver groove. Use moderation here as you can
remove a little material at a time but you can't add material ;) .

when you done disassemble rifle and the bolt and clean with brake
cleaner and compressed air.
 

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homersapien said:
...and destroy the plastic mag well while you're at it :eek:

The bolt on my trainer was tight...for about 500 rounds. I find a brick of ammo is much more enjoyable than lapping :D
Thats why I recommended that he disassemble the rifle in the first place.

since one of the magwell screws retains the ejector plate
this would be a good time to modify the ejector.

The ejector usually binds/scratches the cleaning rod especially if you
use a rod guide. I modified my scout and trainer and this fixed
the problem.

see my other posts for details ...
 

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Nothing wrong with lapping...

a bolt. All high end rifles have hand lapped bolts. I also used JB's and then Flitz. The bolt really shines after being polished with Flitz.

Lapping the bolt provides more of a controlled wear situation. Using a compound has benefits over manually breaking in two surfaces.
 

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Discussion Starter · #7 ·
Thanks guys; I'll try the JB and Flitz method. I prefer a 'tuned' action also instead of letting it wear in 'naturally'.

I've already had the action out to install Brookie's trigger kit so that's no biggie and I figured disassembly and a good cleaning would be required.

Regards,

Mark
 

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Its not that difficult and...

when you clean the bolt/reciever all the metal debris will be cleaned off. CZ's recievers have machining ridges that are like a washboard surface.

Dwight is right about galling. JB's is an oil based compound that will polish both surfaces without galling by acting like a buffer between the two surfaces. The compound emulsifies while collecting the metal particles.
 
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