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PostPosted: Sun Mar 13, 2016 1:29 pm 
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Joined: Thu Nov 29, 2012 10:11 am
Posts: 320
Location: Near Montreal, Quebec
Hi all 2240 mod’ers,
I am contemplating the installation of an RVA for my 2240. Image
At present, I have modestly upgraded the stock C2240 with a Crosman Steel Breech (2240SBPK) and added an LPA MiM sight (all purchased from Eric). Also installed some customs crafted Rosewood target grips to improve hold/balance since the steel breech has added considerable ‘heft’ to my airgun. I mostly shoot indoors at 30 feet.
I plan to shoot at slightly longer distances while in the field – mostly plinking – not competition, or anything like that. I have 3 questions and hoping some of you can chime in with advice or comments:
1- Which of the Crosman RVA models are preferred: the Challenger Style or the 2300 Style? Both are listed on the scopesandammo webstore with identical pricing.
2- Will the addition of an RVA permit sufficient increase in FPS to hit a target at 40-50 feet without adjusting the sights from my setting for 30 feet ?
3- Could I simply change out the stock hammer spring for a more ‘powerfull’ spring (available on eBay) and not invest in an RVA ? (Accepting that my airgun will remain therefore at a higher FPS constantly.)
I realize that there are several ways to change velocity in an airgun: longer barrel or increase amount of air thrust thru valve opening. Of course I’m aware that an airgun pistol (hand gun) over and above 500fps becomes a Restriced-Firearm requiring a specific Licence such as R-PAL. My intentions with respect to the C2240 is getting some insight on the wheither of not an RVA is going to be useful or not with my existing pistol configuration.
Thank you and looking forward to your valuable input.
Cheers!
Hawk-i

_________________
Daystate Huntsman Regal XL .25
Weihrauch HW77 Sp Ed .22
DIANA Stormrider II .22
KRAL Puncher .177
S.A.G AR2078-B Match .177
Weihrauch HW50S .117
FAS 6004
Webley Hurricane
Weihrauch HW45 SS .22
Daisy Avanti 747
Artemis PP700S-A
'HAVE GUN. WILL SHOOT'


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PostPosted: Sun Mar 13, 2016 3:49 pm 
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Joined: Sat Sep 25, 2010 7:49 pm
Posts: 1246
Location: Southern Ontario
Any performance mod should be done in conjunction with a Chrony, especially if you're changing to a heavier spring.
An RVA is handy, to be sure, but I had to shorten my stock hammer spring by 2 coils to prevent pellet over-speed when the RVA was all the way in. Use light pellets when testing your settings...
I bought mine elsewhere, but either of the ones from scopesandammo.com would work-Eric also includes a correct hammer spring in his kit, and the're easy to install.
In my experience, if you use the RVA at, say, 1/2 way out, and shoot on target at 10m, additional spring load (RVA all the way in), will add pellet speed, but not in a linear manner. The speed increase will change the arc of the pellet path, and alter the POA and POI relationship. I just adjusted mine for the best shot count/fps balance, and readjust my sights if the target distance changes. I typically shoot 10m with my 2240, and this set up works well for me...

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PostPosted: Sun Mar 13, 2016 3:57 pm 
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Joined: Tue Oct 13, 2009 1:27 am
Posts: 2514
Location: Vancouver
Regardless of which device you decide to install (sorry, I'm not familiar with those pre-made parts for a 2240), the best way to ensure your zero doesn't have to change for two distances you normally shoot at is to use both zeros. Every gun potentially has two distances at which the projectile crosses the crosshairs or sight line with open sights or red dot or whatever. Some shooters for whatever reason prefer to zero such that the point of aim matches the highest point of the projectile's arc, but this wastes an opportunity for having two zeros. For the 2240 carbine I was using for much of a year, which I've now reduced in size and barrel length for my son to use, I zero such that the pellet crosses the 4x scope crosshairs at a near point which I find useful - 10 metres is good for me - then drops goes slightly above that, almost 1cm, then drops to the crosshairs again at a second point further out. Hawkes' free program 'Chairgun Pro' makes visualizing this rather easy. I just plug in all the measurements from an airgun, my chrony'd velocity and pellet type, my total desired shooting distance and nearest zero point, then use the menu option to 'optimize' the zero for a given 'kill zone' diameter. Chairgun takes a few seconds to run the calculations then delivers a simple graph showing the predicted pellet flight. I can print this out, adding to it another Chairgun chart, the rangecard for whatever range of distances and intervals between steps, and I've now got a handy pocket card for holdover at whatever range.

As for using an RVA, I'd recommend reading up on the SSG for the 2240, especially on GTA:
http://www.gatewaytoairguns.org/GTA/ind ... c=105520.0
These devices are proving to be virtually miraculous in terms of improving efficiency. Many more shots per fill. Quieter shooting. Less velocity spread from shot to shot for better accuracy. Truly a huge leap beyond an RVA in utility for accurate and fun shooting. Modest machining skills help, but just about anyone with a hand drill and a bit of imagination (and patience for reading up on the options through many threads here on CAF and elsewhere) can accomplish very nice results.

If you prefer to stick with a conventional RVA, then my suggestion would be to go to a slightly thicker wire spring and cut it quite a lot shorter, adding preload to the spring with the RVA until you get the velocity back up to where you want it. A shorter, harder to compress spring has proven to deliver considerable improvement in shot string flatness, though never quite so good as with an SSG or a regulated setup.


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PostPosted: Sun Mar 13, 2016 5:42 pm 
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Joined: Thu Nov 29, 2012 10:11 am
Posts: 320
Location: Near Montreal, Quebec
57scott wrote:
Any performance mod should be done in conjunction with a Chrony, especially if you're changing to a heavier spring.
An RVA is handy, to be sure, but I had to shorten my stock hammer spring by 2 coils to prevent pellet over-speed when the RVA was all the way in. Use light pellets when testing your settings...
I bought mine elsewhere, but either of the ones from scopesandammo.com would work-Eric also includes a correct hammer spring in his kit, and the're easy to install.
In my experience, if you use the RVA at, say, 1/2 way out, and shoot on target at 10m, additional spring load (RVA all the way in), will add pellet speed, but not in a linear manner. The speed increase will change the arc of the pellet path, and alter the POA and POI relationship. I just adjusted mine for the best shot count/fps balance, and readjust my sights if the target distance changes. I typically shoot 10m with my 2240, and this set up works well for me...

I use an F1 Chrony and will begin with my current fps as a baseline and have planned to go from there. I also realize the ballistics will need to be analyzed, as you pointed out..where I'll need to find the best fps to POA and POI relationship.
Thanks for the input.
Hawk-i

_________________
Daystate Huntsman Regal XL .25
Weihrauch HW77 Sp Ed .22
DIANA Stormrider II .22
KRAL Puncher .177
S.A.G AR2078-B Match .177
Weihrauch HW50S .117
FAS 6004
Webley Hurricane
Weihrauch HW45 SS .22
Daisy Avanti 747
Artemis PP700S-A
'HAVE GUN. WILL SHOOT'


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PostPosted: Mon Mar 14, 2016 7:23 pm 
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Joined: Thu Nov 29, 2012 10:11 am
Posts: 320
Location: Near Montreal, Quebec
GerardSamija wrote:
Regardless of which device you decide to install (sorry, I'm not familiar with those pre-made parts for a 2240), the best way to ensure your zero doesn't have to change for two distances you normally shoot at is to use both zeros. Every gun potentially has two distances at which the projectile crosses the crosshairs or sight line with open sights or red dot or whatever. Some shooters for whatever reason prefer to zero such that the point of aim matches the highest point of the projectile's arc, but this wastes an opportunity for having two zeros. For the 2240 carbine I was using for much of a year, which I've now reduced in size and barrel length for my son to use, I zero such that the pellet crosses the 4x scope crosshairs at a near point which I find useful - 10 metres is good for me - then drops goes slightly above that, almost 1cm, then drops to the crosshairs again at a second point further out. Hawkes' free program 'Chairgun Pro' makes visualizing this rather easy. I just plug in all the measurements from an airgun, my chrony'd velocity and pellet type, my total desired shooting distance and nearest zero point, then use the menu option to 'optimize' the zero for a given 'kill zone' diameter. Chairgun takes a few seconds to run the calculations then delivers a simple graph showing the predicted pellet flight. I can print this out, adding to it another Chairgun chart, the rangecard for whatever range of distances and intervals between steps, and I've now got a handy pocket card for holdover at whatever range.

As for using an RVA, I'd recommend reading up on the SSG for the 2240, especially on GTA:
http://www.gatewaytoairguns.org/GTA/ind ... c=105520.0
These devices are proving to be virtually miraculous in terms of improving efficiency. Many more shots per fill. Quieter shooting. Less velocity spread from shot to shot for better accuracy. Truly a huge leap beyond an RVA in utility for accurate and fun shooting. Modest machining skills help, but just about anyone with a hand drill and a bit of imagination (and patience for reading up on the options through many threads here on CAF and elsewhere) can accomplish very nice results.

If you prefer to stick with a conventional RVA, then my suggestion would be to go to a slightly thicker wire spring and cut it quite a lot shorter, adding preload to the spring with the RVA until you get the velocity back up to where you want it. A shorter, harder to compress spring has proven to deliver considerable improvement in shot string flatness, though never quite so good as with an SSG or a regulated setup.

Thank you very much for the 'ballistic revelation' of having 2 Zeros...Imageso I'll be working on that with the help of your 'referral' from Hawke's ( I have a Hawke Sport HD on my .22cal BSA SuperSport SE GRT )
With regards to an SSG...ImageI have done some of the homework you suggested ( and why it's taken me a few days to reply to GerardSamija)
Also, lead me to read-up on rsterne's thread here where: A NEW METHOD OF INCREASING THE EFFICIENCY OF A PCP that goes into great technical detail ...and deep experimental discussions ...but I bit overboard for me at this time. Interesting, though.
However, Sir, I do appreciate your advice on experimenting with a shorter spring on an RVA.
With respects to your other suggestion to consult the GTA Forum (BTW I am a member with same alias and avatar as with the CAF) I will have to spend more time researching further to get the full view on the 2240 mods. I'm not into machining stuff though.
The GTA Forum has been very informative to me mostly on the PCP Gate as I learned alot before acquiring my Benjamin Marauder 1st Gen. .22 cal a while back.

If anybody else would care to recommend which of the 'off-the-shelf' conventional RVA's you prefer on your 2240...I'd sure like to hear from...ya.
Thanks.
Hawk-i

_________________
Daystate Huntsman Regal XL .25
Weihrauch HW77 Sp Ed .22
DIANA Stormrider II .22
KRAL Puncher .177
S.A.G AR2078-B Match .177
Weihrauch HW50S .117
FAS 6004
Webley Hurricane
Weihrauch HW45 SS .22
Daisy Avanti 747
Artemis PP700S-A
'HAVE GUN. WILL SHOOT'


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PostPosted: Mon Mar 14, 2016 7:44 pm 
I noticed no POI change on my 1377 if I pump 3 pumps around 360, and 10 pumps 450 fps. At either 21ft or 30ft. Only way to find out is shoot.


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