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When Does an Action Need to Be Re Trued and Lapped

 
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  #8  
Old 09-18-2010, 06:43 PM
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Re: When Does an Action Need to Be Re Trued and Lapped

Once it is done properly, it does not need to be done over if the rifle has been well cared for.

BUT if the lugs are galled OR the bolt face is eroded, then this would need to be remidied before/during the next rebarrel. I have been sent a few actions that showed some sevier wear. Those that are bad enough may require a new bolt/bolt head, or recutting lugs and abutments. which if bad enough may require repositioning/replacement of the bolt handle for proper primary extraction.

I have done complete single point "blueprinting" of 90% of the Remington actions that have gone thru my shop. Some customers request a skim cut and lap to save some money. Most of these guns are capable of sub 1/2 moa. I have seen many more complete BP rifles shoot sub 1/4moa right from the get go. I have only seen one skimmed and lapped rifle do 1/4 moa right from the start.

I would recomend the full BP to most customers looking for the most accuracy.

If a customer is looking for a 6-7 lb carry rifle for hunting under 300 yards, I would say he could skip the full BP and do a skim cut and lap. He likly wont shoot as well as the rifle.

But then again some guys are obsessed with the smallest groups possible. If that is you go for the full action recutting. The difference in price petween the skim and lap and full BP is not that much when considering the cost of the completed project.
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  #9  
Old 09-18-2010, 08:04 PM
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Re: When Does an Action Need to Be Re Trued and Lapped

Thanks for explaining. Its seems to me that it would be pretty pointless
to skim BP if your going to get any blue printing done at all.
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  #10  
Old 09-25-2010, 10:28 PM
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Re: When Does an Action Need to Be Re Trued and Lapped

I think Jim See said it very well. IMO if your going to spend a quarter for a skim cut why not just go for the 1/2 dollar and do it right. After all building a custom gun is a luxary if you cant afford it dont do it.
mike
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  #11  
Old 09-26-2010, 02:25 AM
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Re: When Does an Action Need to Be Re Trued and Lapped

Quote:
Originally Posted by CA48 View Post
Thanks for the responses guys but i guess i did not explain myself clearly. I meant after a factory or custom action has ALREADY been trued and lapped when does this process need to be done again. After 5,10, 15,000 rounds, or is the wear so minimal does it ever need to be done?
CA48-Your question means to me an explanation of what truing an action and lapping means, needs to be squared away first to answer your question.

Truing an action in laymans terms means to make the following three surfaces concentric/parrallel with one common reference/centerline...the bore. When truing an action this usually means-

1. Action threads are "chased" to ensure when the action is screwed on your barrel, that the centerline of the bolt raceway points straight down your bore.

2. Action face that contacts the exterior shoulder of the barrel and interior shoulder of the barrel meet with as close as possible 100% contact or "mate up" as the action is "screwed" onto the barrel. Ensures your recoil lug is flat/true and doesn't introduce any stress in the action/barrel junction on non-Wby builds

3. Bolt face is touched to ensure it's surface is exactly perpendicular to the afore mentioned centerline of the bore/action

Lapping lugs...

1. A lapping or "mild grinding" compound is placed on the bolt lug/action lug abutements. Rearward pressure is applied to the "trued" bolt face...bolt is cycled against the action lug abutments, until the smith sees 100% contact with all lugs/abutment surfaces, or as close as is possible.

So by understanding the above procedures, you can see "truing" shouldn't need to be done unless you had introduced a large amount of stress to the rifle (i.e. driving a tractor over it because it doesn't shoot like you want it to)

Lapping the lugs could potentially be a "wear" type item, but this would take an excessively high round count with the bolt being placed in some kind of binding/eccentric position over many rounds...or potentially bolt lug/action abutment setback due to overpressure loads that would cause one lug to start picking up the load before others.......both seem to me very specialized situations, not likely encountered.

During a rebarrel, a smith concerned with the precision capability of the rifle, especially if it was due to accuracy/precision concerns with the rifle in questions, would verify the above surfaces are true/lapped, and then decide it retouching the surfaces was required.

JE Custom or some of the other super smiths on this site that build lasers....please step up and fix me if I'm off base here.

Hope that helps.
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  #12  
Old 09-26-2010, 02:27 AM
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Re: When Does an Action Need to Be Re Trued and Lapped

Quote:
Originally Posted by Coyboy View Post
Once it is done properly, it does not need to be done over if the rifle has been well cared for.
Why did I just type all that in my post....here's the answer!
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  #13  
Old 09-26-2010, 08:07 AM
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Re: When Does an Action Need to Be Re Trued and Lapped

Quote:
Originally Posted by Autorotate View Post
Why did I just type all that in my post....here's the answer!
Maybe all that typing should be a reminder to all of us to read all the thread before responding. just an observation from afar, no jab intended
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  #14  
Old 09-26-2010, 09:02 AM
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Re: When Does an Action Need to Be Re Trued and Lapped

Quote:
Originally Posted by shortgrass View Post
Maybe all that typing should be a reminder to all of us to read all the thread before responding. just an observation from afar, no jab intended
It happens to me all of the time because I am such a slow typist that after I read the entire
post and decide that I may be able to contribute something by the time I finish there are
several new post that said it very well. OH WELL.

And autorotate's description was good and gave The reason to blue print in the first place.
(ACCURACY)

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