barrel lapping

[inthebeech]

I have heard that, unless a full accurizing job is done on your bolt action, there is no use (presumably as it pertains to the striving for accuracy) in lapping lugs with no other work. Further, regardless of how much care one puts into making sure that even pressure is applied to the bolt face (usually with a rubber tipped rod down the barrel which is being pushed on gently by an assistant), the lapping should definately be done with barrel removed.
I was hoping to just do an effective and sensible job of increasing contact area, paying atention (with borrowed SAMMI gauges) to headspace, to not exceed maximum allowable, and be on my merry way.

Any input from you gunsmiths on do's and don'ts or general advice would be appreciated.
Ed

 

[Adair]

I just sent a Rem 700 to a reputable 'smith. He lapped the lugs, lapped the crown, polished the bore, glass bedded the action and adjusted the trigger (full trigger job was not needed) for $135. I could be wrong, but I can't imagine that he removed the barrel and did all the other work and only charged $135.

He also mentioned that any one of these things might not do a whole lot for accuracy, but the combination should provide for a more accurate rifle.

 

[Zeke/PA]

I responded to similar posts many times in the past.
An old guy that I met at Trinidad State Jr.College, SWORE that barrels had to be lapped.
He was so full of crap in other arenas that his "barrel lapping" theories fell on deaf ears.
In my opinion, there are a lot of variables to be addressed before barrel "lapping" should be considered.

 

[kaferhaus]

Lapping the bolt lugs can easily be done with the barrel attached. It will give a full contact lock up which does promote better accuracy. How much it helps is hard to quantify because there's so many other variables with a stock factory rig.

I have seen it turn a 2" gun into a 1.5" gun numerous times though.

once a rifle is already shooting MOA or better it becomes harder and harder to see any big improvements from doing one thing....

Even a blue printed action doesn't guarantee great accuracy.... it's a "all in" deal usually.

However good barrels and great bullets are the two most important items to a accurate rifle. Factory barrels are not "good" barrels when compared to target rifles.

The most accurate hunting rifles you'll ever "see" are online.... isn't it funny that you don't see these .25" and .5" grouping factory rifles at the range, yet they're everywhere you turn online??

 

[NCsmitty]

There is little to be gained from lapping a barrel that already has a decent round count fired through it. New factory or budget replacement barrels will usually respond to lapping the tool marks though.
Lapping the lugs does improve lug contact, and bedding the action and trigger work will usually contribute to better accuracy.
If you diy the lugs, you need to flush the receiver and bolt to remove traces of compound, then lightly oil.



NCsmitty

 

[Cookie45]

Once had a Sako [7mm Rem.Mag] and a Browning[25-06] rifles that I had a company named Blackstar hone [barrel only]. They used a computer contolled "electronic discharge" [??] and didn't remove the barrel. It turned both into 3/4 MOA guns! The gravy was that they were the easiest rifles to clean I ever owned! They were in Houston, Texas when I had the work done, but disappeared! Don't know if anyone else does it now.

 

[Jim K]

IMHO, the gunsmith quoted by Adair is correct. The whole combination of things can (and note that "can") add up to accuracy. I have also seen rifles that folks spend a whole lot of time and money on that never did shoot well and no one could figure out why.

I think there is a point at which a given rifle is shooting as well as it can, and the law of diminishing returns sets in.

FWIW, several companies are now rifling barrels by the electric discharge method. It reportedly turns out excellent barrels with no stress factors, since the barrel is not hammered, scraped, or swelled.

Jim

 

[inthebeech]

lapping followup

I was looking more for any concerns that would be detrimental to accuracy rather than advice on what I might be hoping would improve accuracy. As to why, I excuse myself such seemingly neurotic behavior. I am an engineer.

 

[Pond Scum]

Inthebeach, I have too much engineer also. There is no 30 minute job that I can't turn into a 3 day project! : )

Last night I was lapping a barrel for the first time. It was from a fairly new (less than 250 rounds) 1911. A friend came downstairs and asked me why I was doing it ..... I hemmed and hawed and finally said, "Well because I read about it online and thought I would try it out." Also, I had been bothered by some dimples in this barrel since I bought the gun. I really like how much better it looks after lapping. I just need to get to the range and try it out and then see if it is easier to clean.

-Pondy