I recently sent my A5 back to the factory for a little fix up before the warranty ran out, and when it came back; I was surprised to see an internal piece that I had never seen before. I had been having pressure problems and full auto firing and had replaced all of the neccesary parts to fix the problem, but was at a loss and therefore sent it in.
As I pulled off the stock and removed the spring and pin; there sitting on the back bolt was a thick black o-ring. My A5 is firing great now, but I'm confused. I can take my A5 apart and put it back together in my sleep, but I had never seen this o-ring before.
Is it possible that this o-ring was never put into my gun from the factory, or is this something that Tippmann does when they have a gun that isnt functioning properly? Anyone else have this happen or have any answers for me?

That's a new one for me - the last o-ring buffer I saw behind a bolt was on a '98.

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I agree with VVulfe that sounds like a 98 thing to me!

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Some A5s (particularly older ones) were shipped with a black o-ring to buffer against the back.

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Jack, any noticeable difference in functionality? IE, is there any reason to drop an o-ring into a newer A-5 to act as a buffer?

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This has been done in some cases where people continuously broke the push pins in the rear when they were using a stock. It was used to absorb some of the shock of the rear bolt on the stock. There may be other A5 uses that i'm unaware of, but this is the one i've seen people post about using it for.

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Question: I have a Tapco stock (see image below) which came with an O-Ring. Looking at the stock, between the 2 protrusions which hold onto the push-pins, there is a round protrusion which slots into the receivers behind the bolt. This protrusion has a groove running along it's edge which I assumed was for placing the O-Ring on. I've had it like this forever, but was I supposed to just place it like this? I'm getting this impression now that I should place it loosely behind the bolt (so that the bolt makes contact with it each time the marker is fired).

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Any chance you could throw up a close-up of the groove?

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if you have an aftermarket endcap or stock, typically you will need that -oring that sits on the spring. On the stock A5 endcap, it isn't necessary because the buffer oring is integral into the endcap. Its that oring that keeps everything snug inside. Even when you look at the diagram for the A5 you will notice that specific oring in the endcap is called the buffer oring.
http://www.tippmannparts.com/downloa...un_diagram.pdf
So a secondary buffer oring really should not be the fix they did to relieve you of your low velocity issues. They may have changed something out like a drive spring or new valve and you may not have noticed.

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SilentDeath12886's Compilation of A-5 Projectshttp://www.a5og.net/5-photo-gallery/...tml#post125307
The E-bolted A-5http://www.a5og.net/5-mods-upgrades/...tml#post108414
The X7 egrip retrofitted A-5 http://www.a5og.net/5-mods-upgrades/...tml#post122941
The old A-5 http://www.a5og.net/showthread.php?t=5009
The 98c backuphttp://www.a5og.net/showthread.php?t=5893

I've always used a black O-ring behind my bolt. My A-5 didn't come with one but my first tapco stock did and I never took it out. I call it a preventative upgrade.

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