Vulcan .22 100yard group
Hi all.
I sold my cricket .25 to get something lighter/quieter. I bought a Vulcan Gen4 in .22.
I came setup shooting JSB 18.13gr at 905fps. Accuracy at 50m was allright, but nothing amazing. So I took the velocity down to 870fps. These are the results. Prone position with front and rear bags, breeze blowing. All the groups are about an inch.
Then I went shooting at 100yards/91m @6am to eliminate all wind.
As you can see the groups are not great. I shot 6 more groups and the result was exactly the same. Never under 4.5cm. The shooting platform was really stable and there was zero wind.
I did sort all the pellets, and have checked the scope setup on a rimfire to eliminate it. Also the torx and allen bolts all over the gun have been checked. I have tried the thick and thin skirt JSB pellets aswell. Barrel has been cleaned with patchworm and ballistol. Gun has an ES of less than 10fps over the chrony. Removed the hugget aswell as the shroud to eliminate clipping.
What type of groups are you getting? Is this what I can expect from this type of gun? Not even the 50m groups are MOA…
I want to return it, as I really dont feel that it is performing well enough for a gun like this. Of course I can start polishing the barrel, ripping into the gun, ect. Ect. But I really dont have the time to do so…
Anything else to try?
Cheers from South Africa
David
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Viewing 12 replies - 1 through 12 (of 12 total)
The lands edges should look like that:
http://up.programosy.pl/foto/img-20170123-wa0004.jpg
Trapezoid shape.
Hi Shooter.
Yes, the barrel was leaded.
That picture of the crown and choke is terrible, but it looked faultless when I looked at it.
Your observation regarding the land edges is interesting, because they don’t look particutarly sharp. How big of an impact does that have on accuracy though? I have no idea.
The gun is currently back with the dealer. They are in the proccess of testing it. Wil keep you all updated if they find a solution.
How does the choke behave after 20 shots? It is leaded? I also noticed that the crown is not perfect. The lands are not cut off sharply. They look blunt.
The lands edges should look like that:
http://up.programosy.pl/foto/img-20170123-wa0004.jpg
Trapezoid shape.
Hi Kris.
Thanks for the massive reply!
Cricket was not super accurate at 50m, but it held its group much better at 100m and further. Zero flyers, all within a nice, round group (always under 4cm for 12 shots)
I can rule the wind out, there was nothing blowing with the 100yard groups.
Reagrding scope setup, my cheek weld is really good, and I check for paralax error before each shot. Scope is SWFA 12x.
I have not taken the gun apart, I only checked that all the external bolt are fastened, maybe that could be the problem….
Regarding POI shifting, yes shooting at graph paper would be best, but there is no vertical or horisontal POI shif throughout a fill. I adjusted the turrets that I did not ruin my POA for more precision.
few quick ideas:
parallax error (when the scope is not setup right) inconsistency of your head alignement
will result random POI shifts, when the scope is setup right head position at that fixed
range will not be a factor. but at different distance it will be.
are you not tilting the gun? how good you could shoot the cricket, was it much better?
pellet probe, check if it enters the barrel and stays centered. is it not wobbly?
magazine, try without magazine.
is the barrel loose in the front AT clamp? you cant check that without taking the side plates off
there were owners whose barrel fell out dont laugh, it is true, sniperqty made the video to show how robust it is.
but there were few of the guys who could not clamp the barrel down or when they dropped the gun
the barrel fell out.
wind effects, .22 will be always more affected by wind, shoot indoors if you can.
no point pushing the distance when it cant one hole at 20yards
i would clamp the gun down, that rules out scope rail, scope or you
actually i have seen similar shitty groups on white plates another forum, was it you with a different gun.
just joking.
ask the Man, i know it can be a genuine issue, if many people had perfect guns, they will not believe one
saying the opposite.
personally i chucked out the anti ping rubber sleeve from the hammer, as it was stuck between my
spring coils.
try to shoot at graph paper, i cant see any POA only POIs on your plate. are you chasing some imaginery aimpoint?
use this site to generate pdf and print,
http://www.printfreegraphpaper.com/
aim at the instersections. we need to see what does it do across the fill.
try not to fill it to 250bar but a bit less and see.
i had similar, taken the frame to bits, realigned it all on the AT with 150bar in put it all back together.
you had your shroud off, were you just looking at some small screws outside?
the vulcan is easy to tinker/work on. as long as you dont round of some screw slots on it, you will be fine. it is part of the hobby, if you cant be bothered, swap for a different piece will be less frustrating for you/faster.
Vulcan is a fairly lightweight gun which makes it a bit difficult to shoot accurately. As read on forums some had accuracy issues due to a loose scope rail. So I would suggest checking the rail.
I also shot a whole magazine into a pool at 40m to see if any of the pellets have damage to them. Even with a magnifying glass I could not see any imperfections on the pellet. I did however see that the choke is quite strong and reformed the pelletskirt quite a bit, dont know how normal that is.
Definitely a puzzler. All I can think of are.
1. Pellet mismatch with gun (odd but definitely check)
2. Burr at barrel transfer port
Yes, I have double and triple checked all the bolts.
Here is a really bad photo of the choke. It really is flawless.
I really don’t understand what it could be. With constant velocities and a (what looks like) good barrel the gun should shoot well.
It should be doing a bit better than 1 MOA. There is definitely something amiss. The gun will scatter with a pellet it doesn’t like. I foolishly tried some left over Crossman pellets. Those scattered like crazy. Required cleaning the barrel to get the gun back to normal after that. Worth trying the Air Arms, but I would have expected the JSB’s to be ok, but again it is a different weight.
I know you said you checked all the bolts, but I would like to verify you also checked….
Two bolts holding Picatinny rail to the rings. Rail isn’t permanently attached to top of gun. Only those two bolts & friction hold the rail in place.
8 bolts holding trigger assembly to the rings. The entire action wiggles in stock if these are loose.
No burr at crown?
Before returning the gun, I would at least try it with Air Arms Diabolo Field .22 Cal, 5.51mm, 16 Grains, Domed pellets.
Test at 850, 900, 920 FPS.
My Vulcan 22 really likes those.
I have never seen the 16gr AA pellets over here… but thanks for the info, will try and get them.
Different velocities made minimal difference in group size with the JSB’s…
Also, even at 20m this gun is not making a single hole.
Yes, it should be doing better than that.
Before returning the gun, I would at least try it with Air Arms Diabolo Field .22 Cal, 5.51mm, 16 Grains, Domed pellets.
Test at 850, 900, 920 FPS.
My Vulcan 22 really likes those.
Viewing 12 replies - 1 through 12 (of 12 total)
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I mean these areas should be sharp – a clean cut:
That’s the last touch of the pellet.
Your crown looks more like this one (50s):
1:05s – how it was fixed.