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3/23/2004 7:35:25 PM EDT
I just got a complete Colt Bolt for a spare on my Ar's.  My question is do I need to have  the headspace check after I installed the spare bolt in case my original bolt failed?  Could I just install the spare bolt and my rifle is good to go?  I have no experience in adjusting the headspace and I don't have the tools to do it.  In case I need too, any idea where I could send my AR to have my headspace checked and adjusted to spec?

Thank you and appreciate the input.

556man
3/23/2004 7:40:25 PM EDT
[#1]
Swap bolts and check headspace on the spare. Change them out, and if the primary ever goes bad, you can replace the bolts safely. A local smith should be able to headspace 'em, or you can get your own headspace gauges.

ADCO, mebbe?
3/23/2004 7:44:52 PM EDT
[#2]
I would just buy the headspace gauges. You can get a set of (3) for about $50.  
3/23/2004 9:26:45 PM EDT
[#3]
Yes, but what if the headspace isn't right, how could that be changed? how'd one correct a missheadspaced AR? i'm not saying check it, but fix the problem.
Thanks

HUNTER.
3/24/2004 5:44:48 AM EDT
[#4]
BTT,  we  like to  know. [:D]


TG
3/24/2004 6:05:51 AM EDT
[#5]
Quoted:
Yes, but what if the headspace isn't right, how could that be changed? how'd one correct a missheadspaced AR? i'm not saying check it, but fix the problem.
View Quote


This is my understanding... Headspace is determined by the fit of the bolt to the barrel extension. If the headspace was off (which almost never happens), the only way to correct it would be to replace either the bolt or the barrel ext. 99% of those situations would be cause by the barrel ext. being out of spec. So basically, check it once to make you feel better than forget about it.

If I am wrong, please feel free to correct me
3/24/2004 6:13:07 AM EDT
[#6]
Quoted:
Quoted:
Yes, but what if the headspace isn't right, how could that be changed? how'd one correct a missheadspaced AR? i'm not saying check it, but fix the problem.
View Quote


This is my understanding... Headspace is determined by the fit of the bolt to the barrel extension. If the headspace was off (which almost never happens), the only way to correct it would be to replace either the bolt or the barrel ext. 99% of those situations would be cause by the barrel ext. being out of spec. So basically, check it once to make you feel better than forget about it.

If I am wrong, please feel free to correct me
View Quote


That petty much sums it up. If your original bolt was fine, the replacement should be as well. A set of gauges is an excellent investment, just make sure you get the correct ones because they come in .223 Remington and 5.56 NATO.
3/24/2004 8:00:12 AM EDT
[#7]
Quoted:
Yes, but what if the headspace isn't right, how could that be changed?
View Quote

You can't.  Rifle is headspaced at the factory.


how'd one correct a missheadspaced AR?
View Quote

First get a the proper military headspace gauge (with the calibration card).  Fulton Armory (www.fulton-armory.com) sells them.

Summery from the -23&P:

Test Headspace:
1) If it fails try a new bolt - test again.
2) If it fails try a new barrel with the old bolt - test again.
3) If it still fails try a new barrel and a new bolt (this will always work - assuming you are using quality parts like Colts and Bushmaster).

That is pretty much it, and is how the military solves the problem.  Now if you have a Stainless barrel or a plain-jane (unlined) steel barrel and the headspace is short (i.e. the factory screwed up) then you do this:

1) Whack yourself upside the head with a large mallet for buying cheap $H!T.  The barrel is extreamly important don't skimp

2) With a finish chamber reamer, re-ream the chamber by hand; occasionally testing the barrel with a 'go' headspace guage (or test round).  If you head to the Maintenance secion the guys there can talk you through this procedure.
3/24/2004 8:09:42 AM EDT
[#8]
Quoted:
My question is do I need to have  the headspace check after I installed the spare bolt in case my original bolt failed?  
View Quote


Do what many of us do.  Every 6 months or year (depending on how much you shoot) test your rifle with the [b]USGI Field Gauge[/b] with its usual bolt, then check it again with the spare bolt.

That way if you do need to use is you can be assured it has been tested and is fine.


Could I just install the spare bolt and my rifle is good to go?
View Quote

Generally this it OK.  If you have a quality bolt & barrel you [i]should[/i] have no issues.  But the periodic testing (as noted above) will give you the 'warm fuzzies'.

3/24/2004 8:55:05 AM EDT
[#9]
Thank you and I appreciate all your info.  I would invest on a headspace gauge so I would be sure that the headspace is right.  Learned a lot from all of you.  Just wondering, what are the consequences of firing a rifle if the headspace is off?

Thanks,
556man
3/24/2004 9:13:19 AM EDT
[#10]
KaBOOM!!!!!!!

from Operators Manual TM 9-1005-319-10

available in the book section here for FREE reading & download @ [url]http://www.geocities.com/offroadaviator/[/url]

WARNING

• DO NOT exchange or switch bolt assemblies from one M16A2 to another. Doing so may result in injury to, or death of, personnel.
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