Last year, I purchased a limited edition Noveske FDE SPR build. So far, I’ve put about 500 flawless rounds through it. I was cleaning the bolt today for the first time and noticed that there was no black O-ring on the extractor spring. I don’t think that this is normal since the Noveske website indicates their bolts have a Viton-2 O-Ring over the extractor spring, and my other Noveske has a black O-ring on the extractor. While it is possible that I somehow lost it, it highly doubt it because I’ve only disassembled the bolt once when I got the weapon last year.
I’m waiting to hear back form the folks at Noveske, but I wanted to get some of your opinions. If you guys think that it is necessary, I’ll see if I can get one from Noveske, or buy the Bravo Company extractor upgrade.
Now I think that I’m going crazy. I just cleaned a 6920 that I’ve had for a year and it didn’t have the black O-ring that The Chart says it should have (can you tell that I’m not into cleaning weapons ;)).
This made me a little paranoid so I check all of my other bolts - my LMTs have the O-ring and so do my spare BCM bolts.
I’ll take IG’s point one step further. I had a buddy who constantly had issues with his carbine properly returning to battery while chambering a round.
The bolt carrier would regularly fail to go 100% into battery. I had a hunch. I disassembled his LMT BCG and removed the o-ring, then re-assembled. The problem disappeared and has not since re-appeared on his gun. I’m making an educated guess that his BCG was not going into battery because the extractor was under so much pressure, that it was not able to ‘jump’ over the case rim as the bolt began to address the case head. I’m not a gunsmith…and it’s just a guess, but the issue has not resurfaced once since the o-ring was tossed.
The O-ring is the kind of thing you might put on in the event you are having extraction problems. It may fix that sort of thing by providing extra tension to the extractor.
If you have no extraction problems, you don’t have anything to fix.
If you “need” to make it more difficult for the extractor to go over the rim when feeding, something else is wrong. Some of this stuff actually may weaken the rim by slightly bending it forward.
The color of the o-ring is irrelevant. What the “chart” is talking about is the Extractor INSERT, which is blue or black, not the O-ring. Two completeley different parts.
There are sometimes issues with an O ring if used with an extra power extractor. There are no issues with an O ring and rifle spring.
Your rifle does not need an O ring to function, it will function LONGER with it in place.
Calling the O ring a “plumbing part” is cute but shows ignorance for the many industrial uses for them, and the fact it’s basically just a bigger version of the extractor spring buffer.
I have a Noveske SPR upper with a switch block. It did not come with an O-ring. I understood that the intermediate gas system(longer than mid length but shorter than rifle) did not need it to function properly due to extended dwell time and an action that unlocked under considerably less pressure than a carbine system with lower bolt velocities. I also have a 10.5" Noveske MK18 clone that did come with the O-ring. I understood that this was due to the shorter dwell time, higher pressure and faster/more violent movement of the bolt. I see the need on shorter systems, my 7" upper(range toy) will NOT function without one. It tends to work for a while and as soon as it gets warm it starts to fail to extract with M193 practice ammo.
Come to think of it, the only ARs that I own that did not come with an O-ring are mid length or longer gas systems. I couldn’t imagine needing one in a rifle length system and I couldn’t imagine running a carbine system without one. Maybe I have the wrong idea as to the correlation between the need for an O-ring going up as the gas system gets shorter. Let me know what you think.
You are correct, the shorter the barrel/gas system the harder the extraction and need for more extractor tension.
I consider the rifle extractor spring and O ring to be a general purpose set up, I would choose it over any other for a 7" to 20" AR.
Let’s hear some technical assessment of why the extractor tension should be only from a spring or why you think a spring alone will provide a longer service life.
There is no doubt that your technical expertise is higher than anyone’s here. You are certainly right as far as the supplementals increasing extractor performance.
My point of view though is that the system was poorly designed from the beginning. To my knowledge, no other military extractor requires a plastic assist for the spring to give reliable extraction. (possibly another based on the M16 bolt head does though)
First, the cartridge has a weak rim, since it an offshoot of a bolt action round, the .222 Remington. The Russian and Chinese rounds are far superior in this respect since they were designed for automatics from the beginning.
Second, the chamber pressure is ridiculously high. Again back to the other rounds.
Third, the pivot pin is way to far to the rear, and this is solely to retain the pin by the carrier. Poor leverage for the spring.
The polymer parts are thus an improvisation to compensate for poor design. An intelligent re-design would be far more reliable.
First, the cartridge has a weak rim, since it an offshoot of a bolt action round, the .222 Remington. The Russian and Chinese rounds are far superior in this respect since they were designed for automatics from the beginning.
This is the core issue. Not the spring tension, not inserts, etc.
The 223/5.56mm has a rim that is thinner and shorter than other major cartridges.
The original design was just adequate for the M16, shorter barrels proved that pretty fast.
The O ring works, is cheap, and doesn’t require any re-design to a more expensive and proprietary part.
I think the O ring is actually a very elegant solution to the problem, there just isn’t much room for more spring. It is pretty out of the box, that seems to offend some people.
EDIT
I’m interested in discussing/debating technical info with anyone, of any level of technical knowledge. I don’t know it all and apologize if I came across as wanting to squash a debate with my title/technical expertise, that’s never my intention.
I think markm could be a little less dismissive and offer a little more info, like what extracter spring he does recommend or why people pay too much attention the buffer color and not enought to the spring.
I saw a Mk18 in A’stan that was having occasional failures to chamber due to the O-ring. Once I removed it, it worked great.
In Iraq I added them to our 14.5" BM’s and we never had any issues. Personally I feel that their use is situationally dependent. I am currently using a Colt extractor spring assembly on my 11.5" and so far have never had a failure to extract. I think I have around 1800 rounds through it right now.
Not really. There is going to be a difference in gas port size and performance based on barrel length and manufacturer. I’ll double check my 11.5" but I am fairly certain I removed it.
On the BM’s though they were needed as extra insurance.