M98 hammer not blowing back/reseting.

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M98 HAMMER NOT BLOWING BACK/RESETING.
I am wondering what o-ring assists in resetting the hammer. is it the big oring on the hammer? posible that the velocity screw is in too far?

[Toestr]

Yep, the oring on the hammer is the main one responsible for blowback (the one on the valve also isolates the blowback gas from the propellant gas, but I doubt it would make much of a difference unless it's just completely gone). The front velocity adjuster has no effect on blowback. If you have an RVA it may impact blowback if it's too far in or out.

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cant get rid of 2nd image ......rrrrrr

[Axel]

There you go

[Twisted G]

cant get rid of 2nd image ......rrrrrr

Feel ya man. I just copy my text and delete my thread and start over when that happens. XD

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thanks-havn't worked 98's for a year

[Morgenstern]

You can usually rule out a sear/hammer problem by degassing it, pulling back on the cocking knob all the way, and let it snap forward violently. If the hammer or sear is worn it will most likely skip the sear when you do that. Inspect hammer o-ring next, though even a worn one should still work ok in my experience.

I notice you changed out the hose for a different fitting so I would inspect the plastic power tube for cracks. Even a hairline one from use or over torquing an air fitting will absolutely cause it to not recock. Can be hard to spot a crack especially if it’s along the mold seam.

Also, sometimes a stripped out valve screw (the two button head screws that hold the valve in place) can cause recocking issues.

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I used 2 different used hammers and still not resetting (posibly the o-rings). So perhaps the plumming. but not leaking - just firing and not resetting.
Would the bolt o-ring cause this problems?

[Chappy]

If the front bolt oring is swollen it can. Remove the oring and see if it helps. This will chew your detent up in the long run but it’s fine to test. Speaking of your detent it’s in right? Just want to make sure it can cause issue.if it’s backwards .
The hammer oring and the cracked power tube are both likely causes. Turbo is correct below, try testing it with the velocity screw all the way in, it can make a difference with back pressure. Get it recocking before you worry about velocity.
My money is on a cracked power tube
I’d remove the front bolt oring and the detent, screw the velocity adjuster in, and replace the hammer oring. If it still doesn’t recock then I’d replace the power tube.

[Trbo323]

The front velocity adjuster has no effect on blowback.

It does actually, I've come across this situation multiple times, it doesn't seem to happen in every tippmann but don't rule it out either

If you have the velocity screw pretty far out there is sometimes not enough back pressure to recock the hammer. Ive encountered this with and without paint. But the system seems to need a little back pressure so all the air doesn't rush down the barrel before resetting the hammer.

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[Morgenstern]

If none of that helped I’d check to make sure the bolt isn’t catching on anything with the barrel/breech mods that gun has going on. Also, it’s possible to cause the hammer to bind up by overtorquing the screws that hold the body together. The two or three towards the back should be tightened just a bit and no more.

[Sottyman]

My old 98 ate power tubes. Wouldn't recock when they cracked...maybe worth a look?

[Trbo323]

If none of that helped I'd check to make sure the bolt isn't catching on anything with the barrel/breech mods that gun has going on. .

O yeah I forgot to mention this, if you have a flatline its a good idea to take the bolt tip o ring off. It can catch in the barrel and causes recocking issues

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[Toestr]

O yeah I forgot to mention this, if you have a flatline its a good idea to take the bolt tip o ring off. It can catch in the barrel and causes recocking issues

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Now you tell me. Just finished shooting a Flatline'd 98 and it was double firing every few shots.

[Trbo323]

Now you tell me. Just finished shooting a Flatline'd 98 and it was double firing every few shots.

Yup, tippmann clearly did enough r&d before releasing it

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