R3M eccentric stock screw (mis-adjusted) causes inaccuracy?
I think I had my eccentric screw too tight causing too much tension on the action. I had noticed my matador was very hold sensitive and if I held the gun too tight the groups would open WAY up. I also had a weird issue when taking my first shot of the day/session the trigger was super heavy but lightened up after that and was consistent.
I finally adjusted the screw to have the least amount of tension while still keeping the action from rocking and it seems to have cured my odd flier issue and trigger issue. I have shot almost an entire tin of pellets in the last few days and it shoots great each time with consistent 1/2″-5/8″ groups at 50 yards when I can do my part. I’m happy now my EDgun is a shooter!
Now GKU told me how to adjust that screw and not to over-adjust it but instead of doing it over step by step the way he told me I just thought “Ah ok, that’s the way I did it so it should be good”. Oops! You can yell at me now Greg, oh and you were right your way works! :smilen:
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Greg, I have no doubt that my matador is capable of shooting very small groups now that it is shooting great. It took me some time to get the small things sorted but it’s all part of the journey when buying a new air gun. I would like to thank Ernest because when I told him I was not getting the best accuracy he offered to take a look at my gun and polish the barrel. I was going to but then figured the reason I bought an Edgun is because I want to be able to work on and maintain the gun myself so I resolved to figure it out myself. I’m glad I did.
For now I’m done fuxing with it and I’m just going to shoot the piss out of it. I did have a sidewinder as well but recently sold it because I never used it. I wish I’d have kept it to use for accuracy testing like you do Greg.
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Hum, you should be able to achieve some 1/4 – 3/8″ ctc groups at 50 yards, I use a higher magnification scope then 12x to check accuracy on paper.
It’s hard to see one’s heart beat rhythm movements or maybe I’m just old … can see shit ?
This small subtle movement from POAing – A to B can multiply/influence the POI by as much as 3 times.
I have a Hawke Sidewinder 6.5-20×42 and 8-32×56 that I use for testing.
12 – 16x for pesting ……….
~ Greg
Thanks Greg, I just filled my gun and tried the paper test and there was no binding at all. Would have been interesting to see if the AT was touching there before I re-adjusted my eccentric screw but I’m not changing anything now that it’s shooting good!
It depends on the EDgun with the tension mid frame support some may differ, but YES in some cases it can cause POI shift(ing) read below also.
If adjusted to an extreme it can cause the AT to bridge up onto the inside of the stock in areas and when shot down the AT reduces diameter slightly which is enough to cause POI shift down range.
I was contacted so many times about how to adjust the rear eccentric stock screw.
Here is how I adjust it:
First off check to see if you have a washer between the inside of the stock that the stock fastening bolt goes through. Some owners lose theirs from it not being glued in placed at the factory. If you have yours don’t glue it in use a good thin double stick tape to hold it in the stock, gluing it will only come off again later.
Then with the stock in the action with the stock screw tightened and the rear eccentric stock screw loose and not making contact with the inner action cut out.
Usually to loosen it from the left side of the stock you need to turn it CCW.
(note that if not the eccentric is on the wrong side and needs to be on the back end, not the front)
Check to see if the stock has a gap in the front foregrip that cradles the AT, at this point there should be no gap. (note that most that have lost their washer will have a gap)
Turn the rear eccentric stock screw CW till you feel that it made contact to the action.
Then give it about an hour turn CW more to pull the action down a tad into the rear of the stock.
If for whatever reason you have removed the barrel nut tensioner and retension.
You should check with what I call the Paper Clearance Test and this test applied to ALL EDguns with the tension mid frame support.
Top fill your EDgun and slip a piece of paper in between the AT and lower frame gap as shown, per curling the paper helps.
Slide it to the front and back ……
If it bind and gets stuck along to way I’d suspect that your gun is getting at least some POI shift(ing).
How to remedy this problem ?
First check by loosening the stock screw and retest the clearance, if the paper does not bind you need to add an additional washer to bring the AT down a bit.
If by loosening the stock screw and the paper still is binding apply the below.
After shooting down to about 120 bar.
With scope removed, loosen all the way the hex screw that holds the scope rail closest to the receiver (you may hear a slight pop as the rail releases its tension) and retighten.
Top fill and retest, if your POI/zero changed there was a preloaded tension on your scope rail.
Also if you ever again loosen up the Barrel tension nut you might need to do this once more.
Hope that helps ……. some owners with POI issues, it surely helped with my new Lelya 20 cal. 
~ Greg
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One thing I love about swfa is the absolute repeatable tracking no matter how much you crank on the turrets (I suck at holding over so I always click to get on target). That is the main reason I have been hesitant to change to a different brand variable power scope with more magnification. I’m afraid the scopes tracking will disappoint (at least in my price range anyway).