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Posted: 7/14/2009 6:35:25 PM EDT
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I see that some manufacturers (like WOA) sell barrels with a matching bolt . Is there an advantage to this or will any high quality
BCG work well with a good barrel? Just wondering. |
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Quoted:
The difference is between functional and optimal. There is every chance that a randomly selected bolt may be an optimal fit to the barrel extension, then again... This. The process was explained to me by a reputable source as selecting a particular bolt from a group which provides a specific headspace target value within the range of accepatble values for a given barrel to provide optimized balance of accuracy potential and reliability appropriate for the intended shooting application. |
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Quoted:
Quoted:
The difference is between functional and optimal. There is every chance that a randomly selected bolt may be an optimal fit to the barrel extension, then again... This. The process was explained to me by a reputable source as selecting a particular bolt from a group which provides a specific headspace target value within the range of accepatble values for a given barrel to provide optimized balance of accuracy potential and reliability appropriate for the intended shooting application. What do they do, keep pulling bolts out of a pile until they find one in the middle of the acceptable range for headspace values for a given barrel? Jay |
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Quoted:
Quoted:
Quoted:
The difference is between functional and optimal. There is every chance that a randomly selected bolt may be an optimal fit to the barrel extension, then again... This. The process was explained to me by a reputable source as selecting a particular bolt from a group which provides a specific headspace target value within the range of accepatble values for a given barrel to provide optimized balance of accuracy potential and reliability appropriate for the intended shooting application. What do they do, keep pulling bolts out of a pile until they find one in the middle of the acceptable range for headspace values for a given barrel? Jay Bingo. |
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I am not able to comment generically on what every supplier considers "bolt matching", as the process is likely somewhat subjective.
The published minimum headspace spec for 5.56x45 is 1.4636", and the maximum is 1.4696". The particular individual who has been gracious enough to share some insight with me has advised that through his extensive experience, he has developed some target values between these limits, depending on the operator's intended application. It stands to reason that a weapon to be run hard in dirty environments with a variety of ammo might benefit from greater headspacing to maintain reliability, whereas one that will only be used in a comparatively clean environment with top shelf ammo might benefit from an accuracy perspective with a tighter headspacing. Needless to say, the process requires more precision gauges than the standard go, no-go, field variety.....as well as a selection of bolts to choose from for a given barrel. All I know is that the multiple barrels/bolts that I purchased from that particular source have all been quite accurate and reliable for my uses. YMMV |
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I fell for the "matched" bolt trick ONCE with a 6.8SPC Noveske barrel
paid extra for what i found out from Noveske later on was to simply "check the headspace" (which i doubt they even did) and the bolt ended up have a defective 5.56 extractor in it rather than a 6.8SPC extractor my first "high end" upper failing to go into battery was embarrassing to say the least... when i contacted Noveske they told me to dremel the defective 5.56 extractor to make it work rather than send me a good 6.8SPC extractor |
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From what i have discussed with Kreiger and WOA, pretty much everthing above is correct. most reputable vendors (Jp, Sabre, DPMS etc) have extensive bolts inventories that are manufactured within a given spec and then they assemble a barrel / bolt combination ( obviuosly with the barrel nut in place) they get the bolt which fits within the tolerable range allowed
however, a Match bolt barrel combination ( Kreiger, coz I HAVE ONE) they use a given bolt, measure the dimensions and then THEY machine the barrel extension tofit the bolt to the barrel withing a very tight spec. that said, my barrel / bolt combo can shoot .25 moa all day long if FED with quality ammo. if not ( regular surplus) then that rifle simple chokes and stops working. the downside of a truly match system is reliability. i have tried for years to get this rifle to work reliably ( i.e 3Gun competitions) and IF my ammo is NOT dimensionally within the specs it wants, then JAMS occur, my 02 cents |
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