Firing pot length

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John814ce
Posts: 34
Joined: Mon Jan 07, 2019 6:19 pm

Firing pot length

Wed Jan 09, 2019 7:24 pm

I own a s510 1.77, i tuned it straight away when purchased last year... 1st ventrui screws removed and i purchased single piece hex head stainless steel screw and ground down it down to exactly 13.6mm and tapered the end. Then i removed anti tampers and stripped the gun down. I found to my surprise the buffer o ring on the loading bolt was the wrong size ( to big) and it was split. Firing pot i adjusted to exactly 56.5mm. Put back to together and filled to exactly 190bar and chronograph tested.... i get 40 shots in the sweet spot at 158bar exactly to 118bar. 3-5 fps spread @ 11.60 ftlbs jsb exact diabolo 8.4gn, check my video on ytube......"john hookway delta Stryker scope "

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Roger5
Posts: 743
Joined: Sat Jul 25, 2015 8:04 am
Location: Hampton middlesex

Re: Firing pot length

Wed Jan 09, 2019 9:16 pm

Not unusual to find the detent buffer damaged, I've replaced about 3 in the S510s I've worked on. Rog

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John814ce
Posts: 34
Joined: Mon Jan 07, 2019 6:19 pm

Re: Firing pot length

Thu Jan 10, 2019 9:18 pm

This was brand new gun straight off the shelve

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TenMetrePeter
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Joined: Wed Jun 29, 2016 5:40 pm
Location: Luton Beds UK

Re: Firing pot length

Fri Jan 11, 2019 1:47 pm

Is the venturi now adjustable without tools?
S400 MPR Precision 10m with TMP alloy stock.

https://www.youtube.com/channel/UCaCf9G ... A-mGhZQlGw

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tonyc
Posts: 160
Joined: Mon May 29, 2017 10:55 am

Re: Firing pot length

Fri Jan 11, 2019 6:25 pm

John814ce wrote:
Wed Jan 09, 2019 7:24 pm
11.60 ftlbs jsb exact diabolo 8.4gn,
I would suggest you do a chrono check with JSB Heavy 10.34gr. I'd not be surprised to see over 12 ft lb as they usually give an extra 0.5ft lb relative to AA DF. If you used 8.40gr in your ME calculation your 10.6 will probably be lower than true ME. Contrary to what is printed on the tin, AA DF are 8.44gr and generally don't vary much from this weight.

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John814ce
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Joined: Mon Jan 07, 2019 6:19 pm

Re: Firing pot length

Fri Jan 11, 2019 7:43 pm

I dont use jsb heavy nor do i have or own or shoot any other pellets apart from jsb exact diabolo 8.4gn (tin weight) the police can only test the pellets which were on your person at the time and the pellets you use with your gun. They was a legal court case a few years ago which clarified this. As for the ventrui screw its set and i have filled hex head with solder and ground to a perfect dome.. just looks the same as the original shear bolt, so no the ventrui cant be adjusted. Check it on my ytube channel " john hookway delta Stryker scope."
Last edited by John814ce on Fri Jan 11, 2019 7:56 pm, edited 1 time in total.

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John814ce
Posts: 34
Joined: Mon Jan 07, 2019 6:19 pm

Re: Firing pot length

Fri Jan 11, 2019 7:52 pm

The gun, i chronograph tested from new and in the sweet spot it went over 12ftlb several times with barracuda match 10.64gn from standard before tuning... only to 12.15- 12.17 ftlb that was around 135-125 bar, around 10.85 ftlb with jsb exact diabolo 8.4gn. Thats the idea once you've got the pellet to suit your barrel then you just use and own and buy that pellet and then adjust tune your gun to under 12 ftlb with that pellet. Check google about the court case were the guy took the police to court stating he only used a certain pellet with his gun and he won the court case.

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Roger5
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Joined: Sat Jul 25, 2015 8:04 am
Location: Hampton middlesex

Re: Firing pot length

Fri Jan 11, 2019 8:07 pm

If that's true, it's very interesting, myself, I haven't heard anything about it, anyone else know about this?

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tonyc
Posts: 160
Joined: Mon May 29, 2017 10:55 am

Re: Firing pot length

Fri Jan 11, 2019 8:59 pm

I haven't heard of this, and discussions on this and other airgun forums generally express a different view.

This would be an important precedent as the wording in the legislation "capable" of exceeding 12 ft lb refers to the gun with no reference to pellet and no direct qualification as to what is meant by "capable". The generally accepted meaning is taken from other clause(s) not relating to airguns inferring any adjustment to FAC status would require tools not normally in domestic/DIY possession.

Any further info to help find this case would be appreciated.

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TenMetrePeter
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Joined: Wed Jun 29, 2016 5:40 pm
Location: Luton Beds UK

Re: Firing pot length

Fri Jan 11, 2019 11:06 pm

I prefer just to replace the venturi dust cover with a security type torx head screw and make sure I leave the key hex bit at home. Not sure how easy yours will be to readjust. There is no statute about tool free adjustment that I have seen apart from forum opinion. We just need to satisfy any officer that in-the-field power boost is not out intention and is difficult to do. I stand to be corrected of course.

Thete is widespread forum opinion that you should set Pcps with heavies to be safe.
S400 MPR Precision 10m with TMP alloy stock.

https://www.youtube.com/channel/UCaCf9G ... A-mGhZQlGw

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