Zebra644 Posted March 9, 2014 Report Share Posted March 9, 2014 Ok I got a new Nickel Boron BCG today at gun show to put in this new upper. So when I changed uppers the barrel just went from one upper to the other. It will chamber and eject the rounds by hand cycling the charging handle do I need to check headspace on this thing before I go shooting. I've taken my digital calipers and measured the lugs on the bolt it all measures the same as the bolt I replaced, can yall give me some direction? Quote Link to comment Share on other sites More sharing options...
washguy Posted March 9, 2014 Report Share Posted March 9, 2014 Zebra heres a an article that will get you started http://www.rifleshootermag.com/2010/09/23/gunsmithing_headspace_0612/ the lugs aint got nuthin to do with it.....its chamber and bolt....a lot of folks dont headspace ar's,but should me.....I build one.....then give it to Char....stand behind her...and let her fire off a few :) nah....just kidding.....I headspace....then give it to her :) Wash Quote Link to comment Share on other sites More sharing options...
shibiwan Posted March 9, 2014 Report Share Posted March 9, 2014 Here you go for a minimally technical explanation. http://en.wikipedia.org/wiki/Headspace_(firearms) Quote Link to comment Share on other sites More sharing options...
Dane Armory Posted March 9, 2014 Report Share Posted March 9, 2014 Zebra heres a an article that will get you started http://www.rifleshootermag.com/2010/09/23/gunsmithing_headspace_0612/ the lugs aint got nuthin to do with it.....its chamber and bolt....a lot of folks dont headspace ar's,but should me.....I build one.....then give it to Char....stand behind her...and let her fire off a few :) nah....just kidding.....I headspace....then give it to her :) WashIts like the lottery... You can't win if you don't play. Wonder what the insurance company will pay ! Wash , was that you at the Ferrari dealership last week ? Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted March 9, 2014 Report Share Posted March 9, 2014 Ok I got a new Nickel Boron BCG today at gun show to put in this new upper. Before we go on about headspacing, is this a 5.56 rifle or .308AR? Quote Link to comment Share on other sites More sharing options...
Zebra644 Posted March 9, 2014 Author Report Share Posted March 9, 2014 (edited) 5.56 I got the torque specs right and she's all zeroed in with the old BCG, thats where I am kinda confused I measured every part of my milspec BCG and the measurements are the same with the new one. So if eveythings the same and I never messed with the barrel extension, and everything is good to go that way as well. I have been reading mixed answers on various forums, some say head space is checked when you insall a new barrel into a barrel extension. After this you can swap barrels with another mil-spec upper, becasue the index pin will fint into the U shaped notch in the receivier and line up the feed ramps, and the bolt will lock up. But it has to be all spec. By the way I hope Char doesn't know about your dastardly plan lol Edited March 9, 2014 by Zebra644 Quote Link to comment Share on other sites More sharing options...
washguy Posted March 9, 2014 Report Share Posted March 9, 2014 (edited) Its like the lottery... You can't win if you don't play. Wonder what the insurance company will pay ! Wash , was that you at the Ferrari dealership last week ? Dane Yep that was me...I wasnt buying one...I was selling one to pay for the lawyer ! <laughs> Wash Zebra can this happen to you? http://youtu.be/rQep2nWGfBw prolly not...I think a vast majority of folks do not head space their ar15...not saying its ok not to though.... Like Dane sez...spin the wheel of fortune and take a chance :) Wash video of headspacing an ar15 http://youtu.be/IWTpPMYW-CA Edited March 9, 2014 by washguy Quote Link to comment Share on other sites More sharing options...
shibiwan Posted March 9, 2014 Report Share Posted March 9, 2014 (edited) Zebra can this happen to you? http://youtu.be/rQep2nWGfBw That's probably they made us do the headspace and timing check on the M2 every day whenever we had it mounted on the M113's.... Edited March 9, 2014 by shibiwan Quote Link to comment Share on other sites More sharing options...
Dane Armory Posted March 9, 2014 Report Share Posted March 9, 2014 (edited) Seriously though three main components ; bolt carrier, bolt , barrel extension are all critical and changing one of these can move the round forward on backward a .001" into the barrel. The most common change would be swapping out a bolt and most people don't check after they have put a new bolt in. AR-15 is more stardard, headspace gauges are not that expensive. Buy it onceand your good of life. 308 gauges cost a little more but same deal buy once. Or if your cheap like me , go to your freinds shop and put the go guage in then the no-go guage and hope for the best. Here's a example your building an engine and you check the crankshaft to bearing clearance with a little piece of wax. You do it just so you know, doesn't mean you will remachine the parts but if its out of spec you know then a can do something to fix it. Same with go-no-go gauges ,peace of mind check ! Edited March 9, 2014 by Dane Armory Quote Link to comment Share on other sites More sharing options...
Zebra644 Posted March 10, 2014 Author Report Share Posted March 10, 2014 Thanks for the heads up, it was checked by a compitent smith and good to go, I even let him shoot the first mag as I stood a safe distnace behind, I dont know where I got that idea from? Shot like a champ, and didn't miss a beat and better yet didn't go bad boom like that M-2. On a side note, damn I love a Nickle Boron BCG. So much easier to clean and after 120 rnds smooth as silk. Quote Link to comment Share on other sites More sharing options...
washguy Posted March 10, 2014 Report Share Posted March 10, 2014 I even let him shoot the first mag as I stood a safe distnace behind, I dont know where I got that idea from? Shot like a champ, and didn't miss a beat and better yet didn't go bad boom like that M-2. On a side note, damn I love a Nickle Boron BCG. So much easier to clean and after 120 rnds smooth as silk. Glad you got it checked! remember...ive got your back <laughs> Wash Quote Link to comment Share on other sites More sharing options...
unforgiven Posted March 10, 2014 Report Share Posted March 10, 2014 Glad you got it checked! remember...ive got your back <laughs> Wash Waaay back. <thumbsup> Quote Link to comment Share on other sites More sharing options...
Zebra644 Posted March 10, 2014 Author Report Share Posted March 10, 2014 <thumbsup> Quote Link to comment Share on other sites More sharing options...
shibiwan Posted March 11, 2014 Report Share Posted March 11, 2014 Waaay back. <thumbsup> Like this? Quote Link to comment Share on other sites More sharing options...
unforgiven Posted March 11, 2014 Report Share Posted March 11, 2014 ^^^^^ Great pic..... <lmao> <laughs> Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 11, 2014 Report Share Posted March 11, 2014 Before we go on about headspacing, is this a 5.56 rifle or .308AR? Best question in the thread - 5.56 stuff is made to a standard, and should all work together based on that manufacturing standard. Am I saying not to check headspace on a 5.56 build? Not really - but they're made to the same specs, and the same tolerance ranges. Well, they SHOULD be made that way... If you're buying 5.56 parts from reputable manufacturers or vendors, you shouldn't have to worry about headspace being an issue, most of the time. Due to machining tolerances and the comditions of machine equipment, you can end up with something out-of-spec. It's not common. It's not un-possible, though. Headspace on a 5.56 build is not one of those tolerances (in machining) that they let slack, though. Any flavor of the 308 ARs is a completely different story. Basically, if it's not A 5.56 build, you BETTER check it every single time. Quote Link to comment Share on other sites More sharing options...
Madhouse Posted May 5, 2014 Report Share Posted May 5, 2014 So I'm about to build out the upper end of the AR that I'm having hydro dipped. Would a set of go / no go gauges be a good thing to have? Quote Link to comment Share on other sites More sharing options...
sketch Posted May 5, 2014 Report Share Posted May 5, 2014 What do you do for no go buy a new bolt? Or can it be fitted to match with the barrel? Quote Link to comment Share on other sites More sharing options...
shibiwan Posted May 5, 2014 Report Share Posted May 5, 2014 (edited) Headspace - an illustrated explanation Edited May 5, 2014 by shibiwan Quote Link to comment Share on other sites More sharing options...
survivalshop Posted May 5, 2014 Report Share Posted May 5, 2014 What do you do for no go buy a new bolt? Or can it be fitted to match with the barrel? A new bolt may work , providing the Barrel Extension is with in spec's . The bolt ,is ,a wear component . Quote Link to comment Share on other sites More sharing options...
survivalshop Posted May 5, 2014 Report Share Posted May 5, 2014 So I'm about to build out the upper end of the AR that I'm having hydro dipped. Would a set of go / no go gauges be a good thing to have? Absolutely. Its not just for a build or replacing a barrel/bolt , its maintenance, checking head space as round count goes up , assures a safe operating firearm. Some components wear out faster than others . Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted May 6, 2014 Report Share Posted May 6, 2014 Absolutely. Its not just for a build or replacing a barrel/bolt , its maintenance, checking head space as round count goes up , assures a safe operating firearm. Some components wear out faster than others . I hadn't thought of a bolt being a maintenance item. I can see the rings getting sloppy, but the bolt face? I don't see a lot of friction happening there, although I can see it deforming from repeated -- is this the right word -- peening? Repeated blows to a steel part will deform it over time. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted May 6, 2014 Report Share Posted May 6, 2014 Not the bolt face - the locking lugs. <thumbsup> Quote Link to comment Share on other sites More sharing options...
survivalshop Posted May 6, 2014 Report Share Posted May 6, 2014 Not the bolt face - the locking lugs. <thumbsup> Yep. From locking & unlocking the bolt lugs wear to the point of them not locking as tight as when first tested ( head spaced ) & that loosening will alter bolt face to chamber clearance ( head spacing ) A little out of focus , but look at the deep set back on some of the lugs . I will see if I can get a better photo. Quote Link to comment Share on other sites More sharing options...
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