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 Post subject: ACCURIZING 2240 family
PostPosted: Tue Aug 20, 2013 12:32 pm 
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Joined: Mon Jun 24, 2013 6:54 pm
Posts: 361
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I've rooted around trying to find nuggets of wisdom on how to shrink the groups of my 2240 family airgun, but the bits that talk about it are spread out pretty wide. If I've missed a golden thread, I welcome a link, otherwise I hope to gather them here for the next wonderer.
Leave me a good link and I'll edit these points as they grow to make for a sticky.

In order of imagined effectiveness, or bang for your mod.
1. Muzzle recrown

2. transfer port
a. alignment - is it cockeyed to barrel
b. chamber polish - is it clipping/shaving pellets on load

3. loading probe - extended or hollow
a. porting
b. polish

4. Trigger
a. Sear polish
b. hammer face and bearing surface polish
c. trigger respring
d. overtravel stop

Some may argue that trigger should come first, but I suggest that even a crappy trigger can be overcome to the point where these other things make a bigger difference - at least over sessions of shooting. I beg to be disagreed with for eventual clarity.


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PostPosted: Tue Aug 20, 2013 1:17 pm 
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If you've done all that and are still getting unsatisfactory group,s, then I suggest you try different pellet,s. JSB,s are the best.

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PostPosted: Tue Aug 20, 2013 2:19 pm 
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wow first time i hear of a 2240 not being accurate... bang for buck i would say longer barrel and steel breach no doubt


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PostPosted: Tue Aug 20, 2013 4:33 pm 
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Location: Waterdown, Ontario
Definitely a steel breach. The plastic one's do not hold the barrel consistently.

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PostPosted: Tue Aug 20, 2013 5:02 pm 
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Location: r Alberta
I have had good luck with just a steel breach , recrown and trigger mods.


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PostPosted: Tue Aug 20, 2013 5:42 pm 
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Crap. Can't edit and facepalmed when I realized I didn't add steel breech to the list.
Not saying 2240s are inherently lacking accuracy, not so, most will outshoot most shooters.
That's true for most guns.

I would love to read about group size changes after having done mod x or y in one thread, but that won't happen.
Maybe it should have been a poll?

Anyway, ya, steel breech somewhere in between 1 and 2.
It is the first thing I do, so got forgotten as a given.


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PostPosted: Tue Aug 20, 2013 6:26 pm 
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Mine shot good right out of the box and yes! there are many mod's you can do to improve the 2240 but if yours is not shooting good groups yet then something serious is going on with it "or" and i mean this as no disrespect maybe it's the shooter :wink: :wink: :drinkers:

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PostPosted: Wed Aug 21, 2013 1:07 pm 
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I have no doubt part of it is the shooter, and always will be. Same goes for everyone...
I'm not sadly disappointed with my gun(s), but I do know others shoot better.
I'm just trying to remove the reasons mine doesn't match them, at least the ones I can do at home.


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PostPosted: Wed Aug 21, 2013 1:24 pm 
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how about this take some shots at a paper target from 5m/16ft gun rested on something.
then do the same from 10m/32ft take your time and shoot at least 3 shots from both detenses then post your results im very curious to see it.

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PostPosted: Wed Aug 21, 2013 6:11 pm 
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I could do that, but I simply never shoot that close.
At minimum I shoot 25 yards, usually 65 and 100.
In gusty conditions today I managed to hit a 2" bell gong @ 100 twice in a 12grm cart of 35?? shots.
Not bragging because I am lucky to maintain a 12" circle @100 in calm conditions.
Range is flagged for windage. I am not yet expert at applying wind dope, and may never be due to mixed winds in back yard.

This is why I'm looking to remove all the "accuracy burrs" so I can only blame myself.
I suspect a lot of the misses are power curve related as I can use four scope 'graduations' @ 6power @ 65 yards to hit the same mark over a cart's useful life (27C here today). The flat part of the curve is not that wide.

I have seen leading cause spiral pellets and wild (and confusing) alternate target strikes. I get that, bores get dirty.
That's quite a sight at 100yards with the sun behind the pellet. Sometimes you get lucky and hit anyway, but then nothing afterwards does until you see the vortex and clean yer pellhole. That deal sucks.

My crown looks good under magnification so I haven't modified it yet.
The trigger has predictable creep, but breaks like glass due to sear and hammer polish. Follow thru adds a lot of miss if I am not careful.
Scope is cheap but one of the same has stood up to tens of thousands of pump cycles on a 1322, so I have discounted zero changes as cause. Even removal and teardown-rebuild has not affected zero. I have tried a brass body automatic centerpunch as a temporary muzzle brake/tune, but results were the same as without it.

I have not modified the loading probe.
I have tried muzzle down loading vs horizontal and gravity loading vs probe push - with no noticeable shot pattern difference, but that's not to say the skirts are not getting punched on launch...

I am looking to regulate from a 4.5k source to 1.6k feed pressure into a hipac eventually so welcome sourcing pointers on gear, but until then I will chase the zero cross with carts.


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PostPosted: Sat Aug 24, 2013 12:04 am 
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blarg wrote:
I could do that, but I simply never shoot that close.
At minimum I shoot 25 yards, usually 65 and 100.
In gusty conditions today I managed to hit a 2" bell gong @ 100 twice in a 12grm cart of 35?? shots.
Not bragging because I am lucky to maintain a 12" circle @100 in calm conditions.
Range is flagged for windage. I am not yet expert at applying wind dope, and may never be due to mixed winds in back yard.

This is why I'm looking to remove all the "accuracy burrs" so I can only blame myself.
I suspect a lot of the misses are power curve related as I can use four scope 'graduations' @ 6power @ 65 yards to hit the same mark over a cart's useful life (27C here today). The flat part of the curve is not that wide.

I have seen leading cause spiral pellets and wild (and confusing) alternate target strikes. I get that, bores get dirty.
That's quite a sight at 100yards with the sun behind the pellet. Sometimes you get lucky and hit anyway, but then nothing afterwards does until you see the vortex and clean yer pellhole. That deal sucks.

My crown looks good under magnification so I haven't modified it yet.
The trigger has predictable creep, but breaks like glass due to sear and hammer polish. Follow thru adds a lot of miss if I am not careful.
Scope is cheap but one of the same has stood up to tens of thousands of pump cycles on a 1322, so I have discounted zero changes as cause. Even removal and teardown-rebuild has not affected zero. I have tried a brass body automatic centerpunch as a temporary muzzle brake/tune, but results were the same as without it.

I have not modified the loading probe.
I have tried muzzle down loading vs horizontal and gravity loading vs probe push - with no noticeable shot pattern difference, but that's not to say the skirts are not getting punched on launch...

I am looking to regulate from a 4.5k source to 1.6k feed pressure into a hipac eventually so welcome sourcing pointers on gear, but until then I will chase the zero cross with carts.


Sorry for offtopic question. You can shoot 100 yards with 2240? 460 fps gun?
I thought you needed at least 600+ fps to shoot targets at 100 yards.
my 1377 barely shoots 90ish yards with all mods. My gun can shoot at least 700 fps.


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PostPosted: Sat Aug 24, 2013 1:16 am 
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Location: Victoria, BC and Clarkston, WA
Blarg you need to reel it back and go to 16m like someone suggested. Find where the gun shoots, if throws a flyer occasionally or what? Is it at the beginning of the CO2 or near the end? What scope are you using? You know if you change the zoom you change the point of impact. If you are zeroed at 16m it might cross the zero at 37m also? You can find that in Chairgun software. Lots of variables.....

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PostPosted: Sat Aug 24, 2013 1:37 pm 
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100 yards with 500fps - sure - in .177 not so much, but mass makes a helluva difference for range.
There is a delay (as you can imagine, a little over half a second ;-) between firing and hitting the pot gong, but ya, very doable and since pellets double their width hitting aluminum, still significant energy. A plinking challenge.
I should note that I have found the pointed crosmans to fly at least one scope graduation better than round or hollow points of the same brand @ 100 anyway. I got a batch of hollow points once that had the hollows off center and everyone was a spiral to some degree. Cleaned the gun more then I ever did trying to figure that one out...

Dialling it back makes sense, and I did do it once inside last winter but frankly since I rebarrelled the gun to 24 anything less than 25 yards feels kinda like jabbing something with a stick easy to hit. My goal with this thread was more to lay down all the things one can do rather than troubleshoot my gun specifically.

Scope is a cheapy barska with range finding reticle so thick that at 9x it still obscures to much of the target at 100 (like more than a MOA). The most, and only power I shoot on is 6x which offers best useful magnification to fat (I may be guessing on this shot) reticle shooting. It is a rear focal plane, but fat like a road line. Parallax was a problem out of the box but since been adjusted. Since it is set to 100, I recognize the 65 will suffer but I do the owl check (depth perception head circle) as needed. Scope does not have an easily adjustable objective.

Noted on the POI change by magnification modification. Another reason I use 6x as it allowed for the easiest range drop use of the reticle graduations between my 65-100 targets.

I zero @ 25 but maybe I will try a fixed 4x bushnell with hairline duplex reticle. Maybe my cheap scope is providing cheap scope performance and my glass is a pain in the buttock. Kinda need graduations to play with across the power of a cart though, at least as my valve is setup now.


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