Crane O ring needed on a middy?

**markm** · 01-11-17, 17:07

Odd for a middy to be acting this way. I'd suspect that there's a chamber issue. The o rings are an old fix for the industries monumental retardation in gas port over sizing. It's almost embarrassing that the o ring was ever a work around for the carbine AR/SBR.

**Iraqgunz** · 01-11-17, 18:53

Most properly built carbines (14.5/16) and even a rifle do not need an O-ring. I wonder if Fail Always is part of the problem?

**sinlessorrow** · 01-11-17, 20:33

Originally Posted by Iraqgunz

Most properly built carbines (14.5/16) and even a rifle do not need an O-ring. I wonder if Fail Always is part of the problem?

The O-ring stems from the Army's lack of care to include an upgrade for the M4 back in 2000 because it wasn't a huge weapon for them(they still had a lot of M16s). So the minor failure to extracts werent seen as an issue.

So SOCOM adds a O-ring while waiting for the Army to actually fix the extractor issue.

Fast forward 7(mid 2007 was first issuance of the gold washed spring) years and the Army I issuing M4's for Iraq/Afghanistan and now the problem is wide spread.

Thus the gold plated extractor spring.

The issue is the internet and everyone's mama saw "SOCOM adds a O-ring" and now everyone adds an o-ring, not knowing the reason why and how an o-ring is a stop gap measure for an actual properly tuned extractor spring, that now exists.

**nightchief** · 01-13-17, 17:00

Originally Posted by sinlessorrow

The O-ring stems from the Army's lack of care to include an upgrade for the M4 back in 2000 because it wasn't a huge weapon for them(they still had a lot of M16s). So the minor failure to extracts werent seen as an issue.

So SOCOM adds a O-ring while waiting for the Army to actually fix the extractor issue.

Fast forward 7(mid 2007 was first issuance of the gold washed spring) years and the Army I issuing M4's for Iraq/Afghanistan and now the problem is wide spread.

Thus the gold plated extractor spring.

The issue is the internet and everyone's mama saw "SOCOM adds a O-ring" and now everyone adds an o-ring, not knowing the reason why and how an o-ring is a stop gap measure for an actual properly tuned extractor spring, that now exists.

A couple of my BCM BCG's have the O ring and I've never removed it. I've not has any issue with extraction though. What would the result of the O ring in addition to a correctly tuned spring look like? Harder ejections?

**Iraqgunz** · 01-13-17, 17:32

Too much extractor tension can cause failure to chamber issues and can also delay ejection.

Originally Posted by nightchief

A couple of my BCM BCG's have the O ring and I've never removed it. I've not has any issue with extraction though. What would the result of the O ring in addition to a correctly tuned spring look like? Harder ejections?

**nightchief** · 01-13-17, 17:41

Originally Posted by Iraqgunz

Too much extractor tension can cause failure to chamber issues and can also delay ejection.

Would circular marks on the back of the ejected case be a symptom of this?

**Singlestack Wonder** · 01-13-17, 18:59

Borrow/buy a BCM bcg and try it. The FZ bcg is suspect at this point.

**twm134** · 01-13-17, 20:04

Originally Posted by nightchief

Would circular marks on the back of the ejected case be a symptom of this?

The circle on the back of the case is from the ejector recess in the face of the bolt. Under pressure the brass flows into the recess. It has nothing to do with a failure to chamber.

Too much tension on the extractor from the O ring can prevent the extractor from pivoting over the rim of the casing and thereby preventing the bolt from going completely into battery.