AR Sponsor
Posted: 2/12/2008 4:45:47 PM EDT
|
This is kind of a piggy back on another thread, but I don't want to totally hijack it so... I'm curious, does adding the option for a chrome lined barrel change the internal dimensions of the chamber? I ask as I've had multiple brands of ammunition not fully chambering in two Del-Ton mid-length builds I recently received. My issue is not being able to pull back on the charging handle and extract a live round in the chamber. I tried swapping several bolts/carriers I have and the result was the same. Here are the brands I've tried...all with issues: UMC 55gr, South African 55gr, HSM 55gr, Guat 55gr, and Black Hills 68 gr! I thought for sure the BH 68 grainers would function without issue, but approximately 2 in 5 will not extract when chambered. Mind you, these are all live rounds I've been testing. So...is it possible this could be a chrome lining issue? Thank you! |
|
Dano, I have a follow-up question...I was just thinking, could these chambers be mis-marked? I was reading a Pat Rogers thread and he was saying a lot of his students have barrels marked 5.56 but in reality are .223. If I'm having trouble fully chambering multiple brands of 5.56, and the bolt and carrier end up getting locked shut unable to extract, could a .223 sized chamber be my issue? Thanks! (edited for question to make sense) |
No. the difference lies in the leade of the chamber [throat] which is longer on the 5.56 due to higher pressure ammo [5.56] and auto fire capabilites/reliabilty in automatic weapons. A chrome lined BBL not cut oversize for the plating would tend to have issues with tight chamber specs and higher then normal pressures. |
|
As stated, the real difference between two chamber types is the leade/angle for the throat. Where the real problems lies is that that often civilian barrel makers will chamber their barrels (cross wall dimensions) on the tighter side to promote accuracy. Also, some chambers are less than desirable due to reamer chatter or rough plating (read tighter cross wall to begin with), and with rough conditions, have even more problems releasing a spent round at extraction. If you looking for sure bet on a true government dimensioned and smooth conditioned chambered barrel, then Colt or FN is the answer*. Simply, I have chamber gauges that are based on these dimensions (10.5” through 20" with both cross wall and head space dimensions) and when tried on a few more popular civilian barrels, they fail to accept them. * Government batch tests lots of barrels/parts before accepting them (read at least the third time that the barrels have been checked to be correct). If the samples pulled from the lot are rejected, the entire lot is rejected (read at a cost to the supplier). |
AR Sponsor