Will a leaking transfer port seal affect accuracy?



Author Topic: Will a leaking transfer port seal affect accuracy?  (Read 1163 times)

Offline Raizer

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Will a leaking transfer port seal affect accuracy?
« on: October 12, 2012, 01:08:50 PM »
As above, will a leaky transfer port seal affect accuracy on a qb79 or will it just be down on power?
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Offline Backyardsniper1

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #1 on: October 12, 2012, 01:48:08 PM »
I'm inclined to believe that it will do both. More air or gas wasted and not directed to where you want it to go.
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Offline 21grains

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #2 on: October 12, 2012, 02:06:07 PM »
Hi Raiser;Had one in Disco, POI change, Power down,Accu. same for awile than POI change again,Power down alot. Accu. bad string up & down..Sent for Seal and extra one. OK now.....Franky
« Last Edit: October 12, 2012, 02:07:51 PM by 21grains »
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Offline Motorhead

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #3 on: October 12, 2012, 02:12:40 PM »
BOTH ... temperature, weight of pellet along with any other influence that changes ever so slightly the degree leak actually leaks will change POI and velocity.

FIX IT !!
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Offline Raizer

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #4 on: October 12, 2012, 02:15:31 PM »
That sounds like what mine is doing, will have a go at making a new seal soon.

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Offline Raizer

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #5 on: October 12, 2012, 04:06:49 PM »
Just realized if you look close you can see exactly where the leak is, has been like this the whole time I've had the gun, I had just never thought about it or fired it with my hand by the seal.



The other side doesn't have that gap and doesn't leak.
I read somewhere you can use a 007 o-ring as a transfer port seal, does that sound right?
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Offline Motorhead

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #6 on: October 12, 2012, 04:54:50 PM »
o-rings can work if diameter and thickness fill the space.
Short piece of squarely cut correct length plastic tube or hose can be made to work as well.
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Offline Raizer

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #7 on: October 12, 2012, 05:00:26 PM »
Just fixed it, all it took in the end was removing the breach then putting it back on square.
I think I must have knocked it or something when I was mucking around with the clipping issue the other day as the gun has just gotten a fair bit quieter, it got a lot louder the other day when I drilled the hole in the end of my LDC out another mm, I thought the increased sound was from that  :-[

Now to have another go at sighting it in as soon as this wind dies down!
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Offline Ribbonstone

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #8 on: October 12, 2012, 08:38:34 PM »
They never seem to leak consistently, so it does seem to make accuracy a bit sucky (occasionaly too high/too low shots).  Might not notice it with 3 shot groups, but will notice it with 5 shot.

Offline Raizer

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #9 on: October 12, 2012, 10:39:08 PM »
Have taken 2 thrushes and a black bird at close to 40 meters so far today, am thinking the accuracy is back now!
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Offline jimmie lee

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #10 on: October 13, 2012, 04:37:50 AM »
I had accuracy issues with my Disco, changing POI, etc. Before tearing it down I was on the phone to Crossman explaining that I thought it had a bad crown. In retrospect, I remembered when I first got it and removed the front sight, the barrel end was not square (as the barrel end has a flat area that the grub screw contacts through the front sight), and was cocked to the side. I didn't think much on it at the time not being familiar yet with my Disco and the posts I made never got to the root of the problem I was experiencing which is why I changed the barrel. When I reassembled the breach and barrel I was extra careful to make sure the transfer port and barrel matched up square and flush. Whoever assembled the gun at the factory failed to mate the transfer port to the barrel properly and I suspect, when there was a rash of complaints on the forum regarding the Discovery poi issues, that it may have been as simple as a shoddy factory assembly. Many of you will remember back in the early summer that the darkside had this issue going on for almost a month with newly bought Disco's from several members. The overall consensus was "bad crown", bad barrel although I do remember MustangMike mentioning transfer port alignment.
 Glad you posted this thread Shiloh; it jogged my brain and the solution I sought but couldn't find was there all along.
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Offline rkr

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Re: Will a leaking transfer port seal affect accuracy?
« Reply #11 on: October 13, 2012, 06:50:24 AM »
I had nicked transfer port o-ring in my Scorpion but it didn't affect accuracy, only the power was low.
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