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How to HEADSPACE ?

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24 March 2005, 14:05
morton3
How to HEADSPACE ?
How does a gunsmith measure headspace accurately?

I`ve heard of these go/no go gauges & can get the drift of how they would work, but the more accurate rifles like bench rest stuff would rely on far more stringent tolerances than that I`m assuming ?

Also when it comes to reaming a centre fire chamber, is this done with the reamer only on the new barrel blank or do the gunsmiths machine some of the metal out to get close to the chamber size prior to using the reamer ?

How do you know when to stop boring the reamer into the barrel blank, giving the exact length you need ?

Is reaming done at a slow speed or fast ?

Is there a website that answers these sort of questions ?

Thanks in advance for your replies.

Morton


If it sounds too good to be true, It usually is !
24 March 2005, 15:52
rws
Headspace is measured with the go guages you mentioned. Some use a piece of brass, and that's OK if you're carefull. As far as methods, go to Mike Bryant's website, he has an excellent article on how he does his work. And he does excellent work.
24 March 2005, 17:19
jeffeosso
Goodness Morton...
There's at least one full book in your questions. I'll hit the high points, for directional answers.

quote:
Originally posted by morton3:
How does a gunsmith measure headspace accurately?

Some dont do it s accuractely!!! this is, roughly speaking, the amount of the brass that sticks out of the barrel chank as compenstated by the other end of the breech (bolt, block, whatever)



I`ve heard of these go/no go gauges & can get the drift of how they would work, but the more accurate rifles like bench rest stuff would rely on far more stringent tolerances than that I`m assuming ?

nope.. they relay on concentricity, tight necks, perfect alignment, awesome barrels, etc.. but zero headspace is zero head space... where it's in a handirifle or a 10K benchgun

Also when it comes to reaming a centre fire chamber, is this done with the reamer only on the new barrel blank or do the gunsmiths machine some of the metal out to get close to the chamber size prior to using the reamer ?

can be done either way. most of the time when you hear of a reamer, it's a finish reamer.There are roughers. Some folks use them. Some folks use a drill or a boring bar to get "rid" of the extra material

How do you know when to stop boring the reamer into the barrel blank, giving the exact length you need ?

I aint the best in the world on this, so I bore the reamer, stop, measure the head space, repeat

Is reaming done at a slow speed or fast ?
depends on the reamer. generally 120-150 rpm
Is there a website that answers these sort of questions ?
http://www.accuratereloading.com

Thanks in advance for your replies.

Morton



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What is an AR round? Case Drawings 416-458-470AR and 500AR.
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http://www.weaponsmith.com
25 March 2005, 05:35
Jim Kobe
I had a problem reaming at low speed. With the new PTG reamers, and depending on the size of the chamber, faster has always been better for me. The last 223 I did, I reamed at 280rpm and it came out great; cut like butter.


Jim Kobe
10841 Oxborough Ave So
Bloomington MN 55437
952.884.6031
Professional member American Custom Gunmakers Guild