Tuning

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shw
Posts: 14
Joined: Sun Dec 31, 2017 3:31 pm

Tuning

Sun Jun 10, 2018 2:30 pm

Hi all .. is there any point /advantage in tuning a rifle .. I have an hft 500 and it seems to start running out of puff at 120 bar . (On the gauge) so the pellet starts to drop from there on . So I’m thinking (rightly or wrongly) that the gun needs a certain amount of air pressure to work efficiently...and after that it won’t give the results. So will an overall tune /service make it more efficient and consistent even in the sweet spot ?
Also what is actually done to the gun in a tune / service
Your thoughts and expertise will be greatly appreciated :)

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Roger5
Posts: 709
Joined: Sat Jul 25, 2015 8:04 am
Location: Hampton middlesex

Re: Tuning

Sun Jun 10, 2018 3:34 pm

shw wrote:
Sun Jun 10, 2018 2:30 pm
Hi all .. is there any point /advantage in tuning a rifle .. I have an hft 500 and it seems to start running out of puff at 120 bar . (On the gauge) so the pellet starts to drop from there on . So I’m thinking (rightly or wrongly) that the gun needs a certain amount of air pressure to work efficiently...and after that it won’t give the results. So will an overall tune /service make it more efficient and consistent even in the sweet spot ?
Also what is actually done to the gun in a tune / service
Your thoughts and expertise will be greatly appreciated :)
The gauges on these rifles are known to be not that accurate, next time your down to 120bar check it at the bottle gauge, I only fill to about 165/170 and that gives me enough shots (in the sweet spot) for what I do i.e. Pest control and a bit of plinking. All you need is a hammer rail polish to make these guns consistent, and VFG cleaning pellets should keep your barrel nice and clean, and they are nice and easy to work on, once the Antitamper is removed. Rog

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tonyc
Posts: 122
Joined: Mon May 29, 2017 10:55 am

Re: Tuning

Sun Jun 10, 2018 5:00 pm

I'd suggest you chrono a full string (or two) if you haven't done so already. That may show some variation or inconsistencies which would help with a diagnosis.

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Outandabout
Posts: 596
Joined: Tue Feb 17, 2015 8:13 pm
Location: Ferryhill Co Durham

Re: Tuning

Sun Jun 10, 2018 7:28 pm

What pressure are you filling to and are you using the gun gauge or bottle gauge?. You may not be filling to the correct pressure.
Kevin

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shw
Posts: 14
Joined: Sun Dec 31, 2017 3:31 pm

Re: Tuning

Sun Jun 10, 2018 8:41 pm

I’m filling to 170 175 off the bottle gauge ..

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Archer50
Posts: 138
Joined: Mon Jun 20, 2016 5:06 pm
Location: Perth

Re: Tuning

Mon Jun 11, 2018 3:18 pm

What pellets are you using? If not Air Arms 0.452, give them a try. It's a bit of a long shot, but easily tested and I'm still amazed at the difference the choice of pellets can make to just about anything!

If that doesn't make any difference, and it really is a drop off at 125 bar, rather than just erratic velocities, the next thing I would check is the valve pot length. It should be around 57 - 58 mm. If it is much less, that could be the problem, as it will be compressing the valve spring too much. That's assuming your anti-tamper has been removed...

Alan

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shw
Posts: 14
Joined: Sun Dec 31, 2017 3:31 pm

Re: Tuning

Mon Jun 11, 2018 10:40 pm

Hi Alan
The anti tamper hasn’t been removed ..it’s as is from the factory.. I’ve owned the gun from new..
The pellets I’m using are AA Diablo fields452.
But I’ve just bought some jsb so will give those a go

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