Final say on O-ring for Mid-Length

[fifthward]

Researching this topic, I've seen arguments from both sides. From 2007-2012.

What's the latest?

I have a black one that I added to a BCM bolt on my 14.5 middie...and she runs fine.

If it doesn't affect function, over time - I will simply leave it in. If leaving it in WILL lead to malfunctions - that baby is coming out ASAP!!

I recently picked up another BCM middie, and bolt - and I was on my way of popping in another O-ring on that one as well - since I thought this was a common "upgrade"...and insurance if the spring failed.

Clear cut info on this is welcome and appreciated.

[seb5]

My thoughts are that it shouldn't need the O ring if everything else in good to go. The O ring is sort of a crutch if there's other issues. 3 of my 4 AR's are 14.5 middies and I don't use them and I've attended many high intensity classes without issues. If I had issues that required it I would just replace the guts on the bolt and drive on.

[Iraqgunz]

Not needed and I simply keep them in a parts container for emergency use or when someone insists on having one.

[Renegade04]

The upgraded extractor buffer and spring are usually all I would use. Not much of a reason for the O-ring in a middy and most carbines. I have used them on my Mk18 and my 7.5" AR pistol.

[markm]

Orings are ancient retarded thinking... before "we" collectively figured out to STOP over-gassing carbeans.

[fifthward]

Operation O-ring Out - successful!

Thanks!

[WS6]

The O-ring was a CRANE approved crutch until Colt fielded the current extractor spring. Use the milspec Colt and move on.

[Berserkr556]

When I bought my first BCM upper years ago I emailed BCM and asked about the O-ring. Paul sent me an email stating the O-ring wasn't necessary unless I started to have extraction problems. I've never used one since and have a dozen or so sitting in my parts box.

[turnburglar]

Is the current spring a 5 coil?

My bcm bolt just has a 5 coil spring.


My psa bolt has a 3 coil spring and o ring.

Shouldn't be hard to update the psa bolt.

[WS6]

Is the current spring a 5 coil?

My bcm bolt just has a 5 coil spring.


My psa bolt has a 3 coil spring and o ring.

Shouldn't be hard to update the psa bolt.

http://www.brownells.com/userdocs/products/p_160304025_2.jpg

[OIPactual]

Just curious, what bad things could happen if you left the o-ring in?

[sevenhelmet]

I have an 18" middy with no O-ring. No problems so far with brass-cased ammo. I don't fire steel-cased from that rifle, but I have heard that is one reason why an O-ring might be necessary.

I doubt there is any problem running with an O-ring installed, as long as you periodically take your bolt apart and clean the extractor. I guess it could collect gunk or break and foul the extractor, but I doubt that's very likely in a well maintained firearm.

[BufordTJustice]

Just curious, what bad things could happen if you left the o-ring in?
It becomes very brittle in cold temperatures. And I've seen then break in regular Florida heat (not because if the heat, mind you).

As others have said, it was a bandaid for a using a spring that was designed for the rifle in a carbine. The colt copper washed spring that WS6 showed, the BCM spring, and the Springco CS 5 coil have all proven to NOT need a donut. I have used the Springco for years with great success. I have run a decent amount of steel cased ammo without incident.