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Posted: 12/3/2002 1:57:50 PM EDT
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I was told that on a AR-15 type rifle you can purchase a good quality/brand name upper without a bolt assembly, then buy a different brand/quality brand name bolt assembly, stick them together and your done....don't need to have the "headspaced" checked. Is this true ???? In another AR-15 web sight I found the statement as listed below in regards to headspace: "One of the nice things about the AR design is the manner in which it is "HEADSPACED". When a barrel is assembled, the headspace is "SET" via a nut that serves as the locking lugs of the chamber.In other words, if the barrel is assembled correctly/correctly headspaced to the locking lugs, just drop in your bolt assembly and your good to go. How can this be true when the U.S. military manuals warn about mixing bolts from one rifle to another? Please, anyone care to comment on this? Is it true???, just drop in your bolt and go, no headspace check????????? |
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I'm not an AR guy to the extreme, but I would NEVER install a new bolt on a rifle and fire without checking headspace. There are too many variables (read "humans") involved in getting that bolt from the foundry to you to just rely on someone's claim, "It's good." I'd approach the issue the same way as when someone tells me "It's not loaded." I check. Then I know. For what it's worth. |
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Not all the bolts are going to be dimentionally exact, nor all chamber depths either, so you "should" check the head space when you swap bolts. But, in reality, the tolerances are usually held tight enough that it is going to be rare to swap a bolt out and have the headspace out of limits. Also, even if the headspace is out of spec, it's not a huge disaster as some others will want you to believe. People like to repeat the BS they have overheard when they have no real first hand knowledge. I personally have fired many rounds with the headspace WAY out of spec and the gun will not "blow up". The cases will simply seperate right in the middle and it will leave half the case in the chamber and eject the back half. I have probably fired 50 or so like this, so I don't want to hear the BS about blowing up a gun with the headspace out of whack. |
| I agree that most of the time the headspace will be ok swapping bolts or using a used bolt with a newly installed barrel unless the rifle has seen a tremendous amount of use. I have read veteran's accounts of the guys field stripping their M16's after shooting at the range and throwing all the bolts into a tub of solvent to soak and everyone retrieving a bolt without regard to what rifle it came from. Since I have tooled up to do AR repair/assembly I have headspace guages on hand and use them whenever I swap bolts or barrels just to have confidence in the safty of the rifle. This is one area that I am very conservative. Others don't sweat it. |
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Brownell's is a good source of headspace gauges. I agree with TonyRumore 100%. Practical Headspacing Made Easy (1) Cycle by hand severaly different brands of ammo. Do they all feed smoothly? If yes, you have enough headspace. (2) Shoot the ammo. Is there signs of splitting brass, case head separation? Are their shiny ring markings just above the case head, running around the base of the case? Does the case appear to be bulged in this area? If not, Go shoot the heck out of your rifle, and have fun! It is good to go. |
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Thanks. I had the same question. I just bought a new Bushmaster M4 upper for my old Colt SP1 lower. I really didn't feel like spending $60 for the 3 headspace gauges they offered. Plus, I was in the military and we, too, swapped out bolts between 16s in basic training. Nothing ever blew up. Thanks again. Rob |
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