Bartlein Barrels

[59FLH]

From experience how much do you actually need to cut off the muzzle?

Indicating both ends of the barrel from basically .25” in to approx 2.25” l detect no dimensional change ( maybe a 1/10th or 2 ) on either the lands or grooves.

The general rule is 1” but if you don’t see it on the indicator are your lying eyes playing tricks?

 

[jackieschmidt]

It has always been 1” just to be on the safe side.
The reason is when the barrel is lapped, it supposedly has a slight bell moth at the very end.
Like you, I have stuck a .0001 indicator in a muzzle and found them to be perfect at about 3/8 inch in.

But I still cut at least 1” off.

 

[ELR LVR]

From experience how much do you actually need to cut off the muzzle?

Indicating both ends of the barrel from basically .25” in to approx 2.25” l detect no dimensional change ( maybe a 1/10th or 2 ) on either the lands or grooves.

The general rule is 1” but if you don’t see it on the indicator are your lying eyes playing tricks?

As an experiment, I got a 34 inch Krieger 6mm barrel once to chamber for my rifle
I went ahead and chambered it without cutting any off the end other than facing off the 60 Deg countersunk area at the end
Also if I had a problem with the barrel , leaving the stamping marks proves who the maker is and the specifics of the barrel should I need to send it back...
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It shot fine
Then went and cut 1 inch off at a time until I arrived at a 30 inch barrel
It shot just as accurately at each length
Theoretically, it should or "Could" be approx .0005" oversized at the ends as Jackie Stated from the lapping process
but
I do not know how much time or how many strokes they actually take in lapping
Some barrels may only be .0001" oversize and will likely not show up on target with something like a 30 inch barrel.
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But if you have your own lathe, it is an easy process to simply cut an inch off and recrown
Def a good practice for "Somebody Elses" rifle
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I also specifically chose a 34 inch barrel mainly knowing I would likely be cutting some off the end but wanted to test how it shot without doing so.

 

[59FLH]

The choice was inletting the stock for a longer shank length, or rolling the dice and cutting a 1/2 “ at a time until the barrel was shorter than I wanted. After talking to Bartlein I chicken shitted out and decided to cut the 1” off the muzzle and inlet the stock. But my OCD has me second guessing the decision based on my observations when indicating.

What data point(s) am I missing from reading the indicator?

 

[ELR LVR]

The choice was inletting the stock for a longer shank length, or rolling the dice and cutting a 1/2 “ at a time until the barrel was shorter than I wanted. After talking to Bartlein I chicken shitted out and decided to cut the 1” off the muzzle and inlet the stock. But my OCD has me second guessing the decision based on my observations when indicating.

What data point(s) am I missing from reading the indicator?

I don't understand what you mean by what data points are you missing?
Mainly ensure your land and grooves reveal the proper Bore/Groove diameter
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IE:
If you have a .236" bore and .243" groove
then your indicator should show .0035" land Height
if not - then cut it back until you do
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You are concentric when the indicators tip falls into every groove on the same number
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You must also decide if you want to focus your concentricity on the lands hitting the same number
or the grooves hitting the same number
Since it is the grooves that are cut after the bore is reamed - one groove may be off by .0001"
but still be concentric
A barrel dialed to within +/- .0015" is fine although I try to start it off to be within .0001"
or the tip of the indicator hitting the same number when indicating in the grooves

 

[59FLH]

Data point. The short of it is this:

If the indicator reads 0 on the lands and -.0035” in the groove 2.25” into the bore and 0 on the lands and -.0035” in the groove .25” into the bore, where is the “bell” that requires cutting 1” ?

I don’t do barrel work for a living, figured those that do might know something I don’t.

 

[ELR LVR]

Data point. The short of it is this:

If the indicator reads 0 on the lands and -.0035” in the groove 2.25” into the bore and 0 on the lands and -.0035” in the groove .25” into the bore, where is the “bell” that requires cutting 1” ?

I don’t do barrel work for a living, figured those that do might know something I don’t.

Sounds as though your muzzle is not bell mouthed
Did you indicate the other end also?
Cut your chamber where it has the most bell mouthing
Looks as though you dont need to cut your muzzle
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Like I say, I bet many barrels barely get 20 swipes of lapping, which at the grit they use
only burnishes the surface more than removes any dimension
Their cutting process is likely so smooth by itself, it requires little lapping afteward
It is mainly to smooth out any tool marks
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Also
If they start from the breech end, and do not reverse the lap backin from the muzzle
and always go from breech to muzzle
it will not bell mouth
But I have never seen or heard of any barrel maker revealing their process
Just that if any happen to lap back and forth, reversing the lap back in from the muzzle
it will Bell Mouth by the reversion process
It may take a certain amount of strokes before this happens,
And if not enough strokes happened, then no bell mouthing happened
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I spent 2 hours once lapping a bore and barely enlarged it by .0001" (tight bore)
I seriously doubt any barrel maker puts even 1 full hour into lapping

 

[59FLH]

Sounds as though your muzzle is not bell mouthed

That was my impression.


Did you indicate the other end also?

Yes, same. But not concerned due to the amount of material removed during chambering.