S510 Classic with bad grouping

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Roger5
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Location: Hampton middlesex

Re: S510 Classic with bad grouping

Thu Jul 09, 2020 8:27 am

Which A/A moderator/silencer is it, aQ-tec possibly ? but starting to look like the shroud putting pressure on the barrel via the barrel tube support ( the little silver thing with the O-rings S600-3 ) I'd remove the shroud complete with silencer,
And see what happens . Rog

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tonyc
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Re: S510 Classic with bad grouping

Thu Jul 09, 2020 10:53 am

You said that the distribution is flat or sometimes 2 peaks. I think this indicates something is moving. I agree with Rog, it could be caused by pressure on the barrel.

I'm assuming it is not simply a parallax error with the scope.

I don't know what model of Hawke scope you have but I'm not a fan of the cheaper models. A possible problem comes from the design of the turrets and reticle adjustment. I think the reticle may be supported by a single diagonal spring. If the spring is broken or damaged the reticle may be moving both horizontally and vertically.

I try to mount scopes so the reticle is close to optical centre and near the middle of the adjustment range, using adjustable mounts or shims if necessary. (If the mechanical and optical centres are not close to each other the scope must be faulty). Is the reticle set close to the mechanical centre of the adjustment range? If it is near the end of the range, where the spring is under little/no pressure, the reticle can "float".

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bgaltd
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Location: Somerset
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Re: S510 Classic with bad grouping

Thu Jul 09, 2020 1:49 pm

just to let you know i received your 191 page pdf Michael , it might take me a few days (make that years of studying some of those formula's you've used , they are way above my pay grade / academic grade :-) :-) ) to get through it :D :D :D :D .

take care Michael and fingers crossed we'll get to the bottom of your problem :-).

has it been suggested that you try shooting it without the shroud or anything on the barrel , what ftlbs is it doing ? have you tried lighter pellets or weighed and graded pellets ?

rgds.

julian.

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Raj
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Joined: Sun Feb 15, 2015 9:36 pm
Location: Rugby

Re: S510 Classic with bad grouping

Thu Jul 09, 2020 8:07 pm

Hello Pat ... (Hope you dont mind me shortening your monicker)
Where are you in the country?
If anywhere within striking distance of Rugby, Warwicks. come round to our house and we can do a side by side test with some of my rifles and draw up a rectification plan. I have the time to spare for a detailed investigation. You are welcome!

PS ..I have an S400 and a couple of S200s that group like something crazy. We can use them as a reference..
“It's the Indian, not the arrow"

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Roger5
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Location: Hampton middlesex

Re: S510 Classic with bad grouping

Thu Jul 09, 2020 9:56 pm

Hi Raj, the man is in Belgium, so don't put the kettle on yet 😊

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Jammy13
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Location: Northumberland

Re: S510 Classic with bad grouping

Fri Jul 10, 2020 6:53 pm

Hi Patratel,
I've read through the various posts about your problem.

Early in your postings you said you glued a washer onto the barrel because it was moving around within the shroud and it was still moving, if I read it correctly. You also had Al fillings showing. The Al spacer needs 2 new 'O' rings or if worn/rubbed it should be replaced and new 'O' rings fitted. Its a push out part towards the breech end of the shroud. The washer you fitted should be removed. The barrel should not move around inside the shroud.

Remove the moderator and tap the threaded end onto white paper and see if any lead fillings come out. Also, carefully check just inside the pellet exit end of the moderator for grey lead marks. Both these would indicate pellet clipping.

Here is a link to a post on how I resolved clipping.

viewtopic.php?f=15&t=5706#p40675

In an attempt to decide if the barrel has a problem, fill the rifle to 160bar, remove the moderator and clamp the rifle firmly and shoot 10 pellets at a 30mtr target(you may have to move the target around to line it up) and check the grouping. If good it's almost certainly moderator clipping so follow the link. A loose barrel inside the shroud can also cause poor grouping.

If you still have problems after the 30mtr target test remove the shroud and check the barrel isn't loose within the breech. If not try the 30mtr test without the shroud and with the barrel supported.

Julian can supply any parts you require.

To check if the loading the pellets is damaging them don't use the magazine and manually load them into the breech and test again at 30mtrs.

If I think of anything else I will post my thoughts.

Regards

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poguemahone
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Location: stoke

Re: S510 Classic with bad grouping

Sun Jul 12, 2020 11:01 am

patratel wrote:
Tue Jul 07, 2020 5:11 am
poguemahone wrote:
Fri Jul 03, 2020 9:45 pm
if the 510 has 2 little pads inbetween the cylinder and stock at the front, same as the 4*0 series, then float the cylinder ;)
most guns are fine with the 2 pads, the few that arent wont shoot accurately unless you float the cylinder. mine was one of those guns :lol: takes less than 5 mins to do .
I donnow about those pads, I will need to look -- put it on my TODO list. Anyway, I will check it. I will have to remove cylinder pressure for that, I guess. Perhaps anyone else knows about the (non-)existence of these pads on S510?
do the £5/banknote or piece of paper test. feed it between the stock and cylinder on the side of the gun. it should come out t'other side, and should slide the length of the stock. if it doesnt then the stock is touching the cylinder, which is touching the barrel through the barrel band. if it fails this test, get rid of the 2 pads and float the cylinder.
just undo the stock bolt and take the action out of the stock. the 2 little square pads should be at the front of the stock, or stuck to the cylinder. takes 5 mins to do. you'd be surprised how many people do this check, AFTER they've spent hours trying everything else. :lol:
stock bolt too tight is another major cause of accuracy problems.
worth noting that tony brayford at staffordshire custom rifles, floats the cylinder on all air arms 4*0 series he works on
viewtopic.php?f=5&t=632

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patratel
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Re: S510 Classic with bad grouping

Wed Jul 15, 2020 4:57 am

Roger5 wrote:
Tue Jul 07, 2020 12:15 pm
Just out of interest, have you tried shooting it without the shroud fitted?
I've never liked shrouds on the S510, would have preferred a full length barrel,
And never really understood why they didn't do it, they did it on the ultimate sporter,
So why not the S510 😡
I haven't tried this one, yet. Although, I wonder what difference it would make. Can it help me find the root cause?.. I heard of others who did it, though, without much improvement. BTW I think it's hard to try, because we have some noise limitation on the shooting range and I'm not allowed to shoot without shroud and/or silencer..

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patratel
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Joined: Tue Jun 30, 2020 4:35 am

Re: S510 Classic with bad grouping

Wed Jul 15, 2020 5:09 am

tonyc wrote:
Wed Jul 08, 2020 10:23 am
some update on these possible failure modes
- changes in POA vs barrel alignment, i.e. something loose either in the scope, action or stock
--> changed scope and tested last week thanks to a colleague, no noticeable changes in grouping noted; will compare again this week, if wind stays down.

- barrel either damaging pellets or not directing them consistently
--> could be, but then I'd need to be able to 'catch' some pellets before they get damaged on the impact and inspect them.. any idea how?
--> some people are mentioning the choke as a potential root cause, which is indeed very tight.

- pellets deflected by shroud/moderator.
--> tried with&without moderator; indeed, it is a matter of small differences before the moderator will kill grouping; but if you do it right, you don't increase variation by adding a moderator, I found out.
If you've checked the action and stock as far as you can, that leaves the scope, barrel or, as Rog says, the shroud.
I'd check with a different scope before involving AA, just to avoid embarrassment that it's not the rifle. I'd also try without shroud end cap and moderator.
--> like mentioned above, I tried with other scope, no difference;
--> trying without shroud end cap.. won't the shroud rings fly away? I did not see any sign of impact to the end cap so far..

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patratel
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Joined: Tue Jun 30, 2020 4:35 am

Re: S510 Classic with bad grouping

Wed Jul 15, 2020 5:18 am

Roger5 wrote:
Thu Jul 09, 2020 8:27 am
Which A/A moderator/silencer is it, aQ-tec possibly ? but starting to look like the shroud putting pressure on the barrel via the barrel tube support ( the little silver thing with the O-rings S600-3 ) I'd remove the shroud complete with silencer,
And see what happens . Rog
I believe the moderator is a Q-Tec, yes. Strictly spoken I don't need it (I do most tests without it), but it helps with limiting the noise.

What happens if I remove the shroud? I get kicked out of the club. :) We must limit the noise levels and it is prohibited to shoot without shroud and/or moderator..

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