Question: is it the notorious C3 or the famous C3 ???

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Vana2

Vana2

Member
May 11, 2015
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Ontario, Canada
I have an Impact MKII on order and have been reading anything and everything I can about it. Can someone please clarify what is going on with the C3??

  • Is the stock C3 O-ring prone to failure?
  • Does it need frequent replacement? How often?
  • Does the delrin C3 work better/last longer?
  • Does the delrin C3 improve performance?
  • SHOULD I change it right away or leave well enough alone until it needs attention?
  • What are the symptoms of a C3 problem?

I know where it is and can probably change one without a problem... Just trying to understand WHY it is mentioned in the posts so often. Sorry for all the questions LOL!

...Oh, if someone could post the dimensions of the C3 I will make a couple up to have ready for when I need them. Appreciate that!

Thanks

Hank 


 
I suggest replace it asap. Mine went back in 2 months. When it goes bad you lose fps. I went from 850 down to 600 fps. Replace with derlin washer and been 6 months and still shooting great. I dont think you will need to be replacing it once you switch to derlin. Also once you switch to derlin, you will grain about 30 more fps. Down side is, you cant go back to low power. Even on min setting, you will get high fps due to the derlin being harder and when the hammer hits, it opens more vs the c3 o ring which will absorb the hit. You can still go lower fps with the valve under the barrel. 
 
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I can’t speak for the MKII’s but the previous gens used a DURO90 oring sandwiched between the hammer and hammer seat. It simply provides a cushion so you don’t have metal-to-metal contact when the hammer slams into the seat. The DURO90 is a harder rubber than typical oring material, but eventually will deteriorate and cause inconsistent hammer stike. 

I would probably just wait to replace until you have the internals opened up for other maintenance, or suspect the oring has failed (eradic fps or sudden loss of power). Chuck sells replacemwnt delrin bumpers that will last much longer than the DURO90.

https://www.airgunnation.com/topic/wts-fx-impact-delrin-c3-bumpers-sized-set-of-three-3/#post-583015


 
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So why don't they come with a delrin bumper from the factory???U read so much here about changing to a delrin bumper cause off failure.

I really don't understand why they don't fit one straight away.

Am I missing out on something here?

Maybe someone can explain this?
Click to expand...

Fx already explains why. Just as mentioned above. Once you switch you the harder delrin, you will not be able to go to low power. Even at min, it will be as strong as when it's on 5 or max with the stock c3. That is why they dont change it. Cause the impact is also a .177 cal. It would be too powerful in that caliber. 
 
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Hello, my experience:

  • Is the stock C3 O-ring prone to failure?

Usually, not always. SPecially in 0.25 and .30 cal and .22 shooting redesigned

  • Does it need frequent replacement? How often?

No, just 1, from poly to acetal

  • Does the delrin C3 work better/last longer?

Yes

  • Does the delrin C3 improve performance?

Yes, will add around 5+ fps

  • SHOULD I change it right away or leave well enough alone until it needs attention?

Depends on cal if you are shooting .22 and 18.2 gn or lower, I would not change it, I have never had a C3 delrin problem (1.5mm or more)

  • What are the symptoms of a C3 problem?

Low and unstable FPS reading over the chrony
 
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Thanks Guys!!

Now I understand. Notes made and squirreled away for reference.

Have a .22/700mm on order and will be shooting 18.2 JSBs to start then trying ReDesigned Monsters and slugs later. The plan is to use the default factory configuration for pellets then doing the TP mod and switch to a delrin C3 Bumper for the heavier stuff. Will see how it goes.

Appreciate the help! Cheers!

Hank
 
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I don’t know why the nose of the hammer is not tapped out to say 6mm then a delrin bush screw in that slides over the valve stem. The delrin bush would move with the hammer, reduce friction and you could fit the c3 bumper for low power and remove it for higher power. 


Slightly off topic...

Can anybody tell me, does the US spec version of the impact have a delrin hammer guide that is free floating? It does on the UK spec but the rattle in the action drives me nuts!



Bb
 
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Slightly off topic...

Can anybody tell me, does the US spec version of the impact have a delrin hammer guide that is free floating? It does on the UK spec but the rattle in the action drives me nuts!



Bb
Click to expand...

Not sure if there is from acetal/delrin but all impacts have a spring guide, that sounds when you tilt the impact. (as far as I know)
 
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Not sure if there is from acetal/delrin but all impacts have a spring guide, that sounds when you tilt the impact. (as far as I know)
Click to expand...

Thanks, I suppose the extra noise a high power gun generates masks the noise of the spring guide as it shuttles backwards and forwards during the firing cycle, in a low power gun, the noise is really annoying.

i am going to swap the one that is fitted for one made from PTFE being softer it won’t clatter about as much.



thanks again.



Bb
 
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