Gun Maintenace and Repair - A5 rear bolt o-ring

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A5 rear bolt o-ring

Printed From: Tippmann Paintball
Category: Paintball Equipment
Forum Name: Gun Maintenace and Repair
Forum Description: Important info for keeping your marker in top shape
URL: http://www.tippmannsports.com/forum/wwf77a/forum_posts.asp?TID=176691
Printed Date: 03 September 2025 at 4:47pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: A5 rear bolt o-ring

Posted By: rkenders
Subject: A5 rear bolt o-ring
Date Posted: 06 July 2008 at 12:18am

I've had 2 A5's for about 4 years and other than an a very occasional ball break have been problem free until now. Both are doing pretty much the same thing. Today I went through 4 rear bolt o-rings and shot maybe 300 balls. Sometimes it's the first shot with a new o-ring and the gun is dead and others it may be 2 hoppers full of paint. What's happening is the real bolt o-ring is popping off the rear bolt and then getting mangled by the power tube and bolt when the gun is fired. You never know when it will happen. The guns are polished inside and have been for several years. The replacement o-rings are new. There's no debris in the guns. I've taken them both totally apart, cleaned/oiled everything including the valve parts. there's nothing in the guns to catch the o-rings. I've used the original o-rings for years until now. They seem to pop out of place as the bolt travels towards the power tube. I find the o-ring usually half popped out of it's groove and around the skinny part of the rear bolt. The rear bolt is totally stock and unmodified as is the power tube. After the o-ring pops off too much gas leaks out the back of the power tube and velocity drops way off and the bolt doesn't reset for the next shot.

These guns are identicle except for a slight age difference.

Replies:

Posted By: Nagash1959
Date Posted: 06 July 2008 at 1:48am

Sounds like the orings aren't the right size. Are you using tank o-rings on them? Not sure exactly which ones the A5 uses on the bolt but I doubt it's tank rings.

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98 Custom
Cyclone
Double E-Trigger
Polished Internals
Freak kit
X-chamber
CP Drop w/On/Off

Posted By: rkenders
Date Posted: 06 July 2008 at 2:59am

Like I said I was using the original o-ring for years and now suddenly I'm mangeling o-rings all day long. The white o-ring for the 98 and A5 are identical on the rear bolt. I tried a replacement A5 ring and 2 98 rings with the same results. All o-rings are from Tippman replacement kits.

Posted By: GBLoon
Date Posted: 08 July 2008 at 3:11pm

I had the same problem, My A-5 is about 6 years old and had the rear bolt o ring go bad only once every couple of years. A month or so ago it went out 3 times in one day. I replaced the bolt and haven't had the problem since. I think the front of the old bolt must have worn enough for the 0 ring to catch or drag. Since you said your bolt has a skinny part, it is the old model like I had. The new one is basically the same diameter all the way down. It uses a separate plastic insert to hold the spring. You have to order the parts separately. You can see it here: http://www.tippmannparts.com/index.cfm?fuseaction=catalog.prodInfo&productID=920&categoryID=13 - http://www.tippmannparts.com/index.cfm?fuseaction=catalog.pr odInfo&productID=920&categoryID=13 the insert is listed on the same page.

Posted By: rkenders
Date Posted: 15 July 2008 at 1:00am

Thanks for the information. I'll get a replacement rear bolt.