.25 mk2 erratic
Hi Guys
After 350 shots put gun through my chrony.
220 bar fill using jsb kings
Extreme spread of 29 fps standard deviation of 5.9 fps. 40 shots before it fell off the regulator at 150 bar.
Barrel was cleaned from new.
This seems rather poor performance. Range was 880 fps to 910 fps.
Any thoughts?
Cheers
All Replies
Yep, that’s been pretty consistant during the break in process, comes off regulator at 160 Bar. When I get to 700 shots ill chrono again and see what adjustments I need to make. I use the gun for hunting and would like to increase my shot count.
:5: :4:
Hi BG
Thanks for info.
My shot strings were from 220 bar down to 160 bar, total 42 shots
Think I should use another tin or two and rechono again.
Are you really using 50 bar for 18 shots?
Best regards
Mike
Mike, as you requested I have pulled the ole Pro Chrono out and let the lead fly….calm down Leaddy I didn’t let your lead fly….anyway here is a picture of my written results. 2 strings 18 shots each (250bar down to 200bar) re-filled AT to 250 bar after first string: string 1 JSB EXACT King, string 2 JSB EXACT King Heavy
While shooting I tried to remove all the numbers and the red ink of the bullseye!!
You should try to increase velocity. Start from 900 then slowly increase fps and see if it settles in better at higher velocity. If regulator is set for higher velocity then the es will be tighter in that range. Mine is in the single digits at 905
Sent from my Z30 using Tapatalk
Hi Lurker
Yes I have now tried the kleenex test borh dry firing and inserted pellet with no magazine in and fired. Same result no paper movement.
Will fire off anothet tin (350) and re chrono again.
Regards
Mike
Good Point Lurker, I forgot to mention that.
FM, in the .22 they’re different sizes, but I used one of the breech o rings that came with my gun as a breech o ring. They’re thicker than the breech o ring. It pooped right in and you can feel that it seals better when closing the bolt. I used silicone grease to lube it before insertion.
What size are the breech Orings? Are they the same as the fill probe Orings?
Beachgunner Hello
Curious why the heavies have similar ES and SD to my results.
Have you chronied your Vulcan with 25.40 Kings since results of your heavies?
Surely the ES and SD should be similar with both pellets.
Mike
Tried that, Kleenex over breach, tested twice and no movement.
Did you think large Extreme Spread is unuusual?
Hopefully as you say more shots needed .
Regards
Mike
Mikewh,
Did you dry fire it or shooting a pellet ❓
It could make a big difference.
I think it’s a higher than what I have experienced with my Vulcan. Some things that cause my ES to jump are: not being careful with the chrony and how much sun it gets, bad pellets, shooting the gun below the regulator, varying my distance from the Chrony, a new gun, and an over greased regulator. Obviously it could be other things as well but these are the most common problems I have had. When my Vulcan is filled past the regulator it almost always has around 2-3 FPS ES.
Mike
I do not think your ES of 29 is erratic. I shot these figures recently with my 25 Vulcan: Avg fps 784, Es 29 and SD 7. (JSB King Heavy 33.95 gr) This same gun shoots the JSB King 25.39gr with these numbers: Avg fps 899, ES 6 and SD 1. I’ve sent 350 or so pellets down range to this point. My other Vulcan took about 700 shots or so to settle in FYI. Keep on :4: and have fun.
PS went hunting the other day with my Vulcan….4 shots…..4 dead squirrels 😀
Yes thanks good idea
Tried that, Kleenex over breach, tested twice and no movement.
Did you think large Extreme Spread is unuusual?
Hopefully as you say more shots needed .
Regards
Mike
I would lay a Kleenex over breech, if it blows up and off your breech o-ring is leaking. Mine did the same as yours but mines in .22, shot a few hundred more and it clear up. I also changed my breech o-ring.
Hi Zonk
Ok will run through a couple of hundred more shots.Not being a gunsmith how do I check the breach O ring is not blowing back?
Do you also think the extreme spread is not normal?
Appreciate your advice
Best regards
Mike
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Hi again BG
Just fired about 20 mags this pm.
Shooting at 5o yds and a 100 yds on my land.
Have to say almost more accurate at the longer distance.
My scope is an Edgun 10 power 44 lens. Recommended to me by Keyser soze. Suspect there is less wobble at the longer distance. I am not a good shot but maybe 10% of the shot fired miss a two inch target. I can’t be that bad can I?
Will continue to blat off another 20 mags or so and then rechrono.
Used to do a lot of hunting in UK but now living in France only on my own land or pals.
Think I moved to wrong country, envy you your varied and wonderful hunting grounds
Safe shooting
Mike