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Posted: 3/27/2006 10:24:26 PM EDT
So, how much accuracy does a fitted bolt really add to a precision rifle. All esle being equal, what kind of changes would you expect if the "fitted" bolt was replaced?

I'm just curious since some of the top barrel makers ship their barrels with the headspace fitted specifically for the included bolt.

Has anyone tried this to see what kind of accuracy changes they get? Someone should take three bolts--one fitted for the barrel and two not--and have them blindly installed (have your buddy do it) to see if you can spot the "fitted" bolt. What are the chances?
Link Posted: 3/28/2006 3:03:28 AM EDT
[Last Edit: 3/28/2006 3:04:25 AM EDT by bigbore]
Link Posted: 3/28/2006 5:15:05 AM EDT
Link Posted: 3/28/2006 10:21:32 AM EDT
.
Link Posted: 3/28/2006 3:03:22 PM EDT
[Last Edit: 3/28/2006 3:09:13 PM EDT by chargedmr2]
Steve, Wes - Thanks for the replys. To further entertain my curiosity, what would be the ideal headspace for accuracy. Or what does Frank or John shoot for with regard to headspace (if either of you have the numbers)?

Also, does tighter headspace (within reason) lead to the bullet feeding into the throat/bore more consitently, therefore, enhancing accuracy?
Just curious how this all works--I'm not a benchrest shooter, so this is more for personal information than practical application.

Thanks

ETA: Wes, just to be clear, I'm not suggesting that barrel makers are trying to "pull one over" on anyone. In fact, I've done business with John and own some of his products. Again, I'm just curious as to how this all works.
Link Posted: 3/28/2006 3:37:48 PM EDT
[Last Edit: 3/28/2006 3:41:15 PM EDT by bigbore]
Link Posted: 3/28/2006 3:42:11 PM EDT
Has anyone tried this to see what kind of accuracy changes they get? Someone should take three bolts--one fitted for the barrel and two not--and have them blindly installed (have your buddy do it) to see if you can spot the "fitted" bolt. What are the chances?

--------------------------------------------------------------------------------



---You would never see any difference


YEP---What Steve said
Link Posted: 3/29/2006 8:53:20 AM EDT
Link Posted: 3/29/2006 11:05:39 AM EDT
Headspacing is not the only dimension that matters in relation to a custom barrel, another big reason for a fitted bolt in an autoloader is endspacing/overshoot play (the distance between the rear of the barrel and the face of the bolt in an AR). Tightening this up can significantly reduce the amount the brass is worked when it's chambered. Not that this is a major contributor to accuracy like throat concentricity and diameter is but it does has a roll.

The biggest thing that will be noticed to a handloader is the brass will be worked hardened less in the shoulder area.
Link Posted: 3/29/2006 12:37:47 PM EDT
over 200yards

good statement
Link Posted: 3/29/2006 6:51:18 PM EDT
Link Posted: 3/30/2006 4:45:35 AM EDT
Link Posted: 3/30/2006 3:39:23 PM EDT
[Last Edit: 3/30/2006 3:40:28 PM EDT by new-arguy]
Link Posted: 3/30/2006 4:08:17 PM EDT
Link Posted: 3/30/2006 4:23:12 PM EDT
[Last Edit: 3/30/2006 4:24:50 PM EDT by chargedmr2]

Originally Posted By bigbore:

Thats the point of AR bolts, they are all "fitted". Bascially all a "matched" bolt is, is a fitted bolt serialized to a specific barrel.



Can you clarify what you mean when you say they are all fitted? Are you saying that there is no difference between fitted and non-fitted bolt/barrel combinations or just that the difference is not significant in terms of accuracy?
Link Posted: 3/30/2006 4:29:25 PM EDT
Link Posted: 3/30/2006 6:12:30 PM EDT
Gotcha...thanks for the explanation.
Link Posted: 3/30/2006 10:29:26 PM EDT
Link Posted: 3/31/2006 8:52:27 AM EDT
John Holliger:

8 time Presidents 100
2000 Pershing trophy winner
Distinguished Rifleman Badge
Many time IL State HP Champion
2002 Coast Artillery Trophy winner
High Master Classification HP and LR HP
2002 National Civilian Service Rifle Champion
Holder of team and individual national records
Link Posted: 3/31/2006 2:28:14 PM EDT
All I can say is that ABS mentioned that threre is no such thing as a fitted Ar15 bolt.

They said that as long as the bolt is in spec it is going to fire as well as anything else.

I was a little surprised buy have always though that the spring loaded ejector is going to take up the couple thousandths of slack that may exsist and press the bolt into firm contact with the barrel extension lugs, so theoretically if that idea is not terribly stupid, that would suggest these guys are right and there is no need to fit a bolt to get full lug contact with the extension.
Link Posted: 3/31/2006 3:03:46 PM EDT
[Last Edit: 3/31/2006 3:52:03 PM EDT by pcurtis]
Originally Posted By bigbore:
AR10 bolts/barrels are more finicky, they usually come with matched bolts
[/qoute]

How is this the case? I have swapped entire BCGs between a 20" S/S A2 Armalite upper and a 16" C/L A4 and haven't seen a difference in reliability or accuracy on the 20" or 16". There are no indications from Armalite (eg: don't use any other BCG or bolt). The '99 vintage 20" with a 1:11.25 twist still shoots one hole groups (5rnd) at 100M with Federal Match 168gr ammo with either BCG.

Fitted bolts to me means guaranteed to be properly head-spaced for the match barrel and centered between min and max spec as close as possible. 600M is the max range I routinely have shot. So any benefits as PaulE said are "anecdotal" .

ETA: In the real world I believe anything past 800M, a .338L, .50BMG and maybe a .416 Barrett are the only solutions. IMHO.
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