Canadian Airgun Forum

Ok here's the problem my cx4 storm is very low power wise 200-300fps, I read a post on here by lleader suggesting it could be the hammer spring or valve bushing , has anyone else had this and what cured it only after around 600fps as its purely for target use any help would be gratefull as there is very little to be found on the internet even the umarexforum in the uk has nothing I can find

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Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

Ok quick update realised that if I push the pellets further into the magazine the fps is increased now doing 400fps so getting there

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

A chap named Kyle Kincaid with Smith Army Surplus in Kingston is most knowledgeable re the CX4 and can also offer you a bulk fill CO2 unit for your gun as well. I believe he does work for Umarex in Canada. You can reach him at 613-546-0305 or kkincaid67@hotmail.com.
BTW, the CX4 is well below average when used for target shooting but I'm sure I'm not telling you anything you don't already know.

Good luck.

I've already converted it to bulk fill using a modified 88g caplet , then using a co2 fire extinguisher as a source , had to drill a hole in the rear cover as the nipple protuded enough to stop it fitting correctly

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

Modified end cover

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

Well I guess you know what your doing Raven. Nice work. I sold my CX4 because it just wasn't accurate enough for me even with a Bug Buster Scope attached. Otherwise I really liked the rifle.

Joe

Raven: I see from one of your other posts that you have already seen my original post on the CX4. I haven't really done any more work than that on the gun. I had a couple of serious health problems and acquired a few more guns to play with so the CX4 has been on the back burner for awhile.

If you want more fps the only way I can see is to replace that "valve bushing" with the US spec part or drill the one you have out to the same size (5/32"). If you are adventurous you could try larger but you might only waste gas - if you do, let me know the results. I intend to sometime fill my drilled Canada spec part up with JB Weld and redrill it smaller to drop the fps down bellow 500 fps as required to make the gun legal for unlicenced users here in Canada.

One thing I would like to point out to you, or anyone working on the gun, is to NOT overlube the hammer. I had some 60% Honda moly handy and greased things up too heavily in there and the fps dropped like a stone. Live and learn.

For non-CX4 owners reading this - think of the "valve bushing" as what you would likely refer to as a "transfer port". It fits against the valve and carries the air to behind the pellet.

My original post here: topic63798.html

Lon

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A mask is not a political statement. It is an IQ test.

You're about where you should be, and maybe better. I could not understand your original post referring to 600 fps, but a Canadian version of this gun would never even come close. setting the pellets is the secret to max. power. Mine shoots 380-390. I, too have asked around to see if someone could push it closer to 500, and the two people whose reputation I know best and trust most said they would not attempt mods to this gun for various reasons revolving around its build.

Perhaps that's why lleader has put it on the back burner as well - maybe not; but meanwhile I'm waiting for someone to come up with the answer, too. I believe the only thing that makes this carbine inaccurate is the horrid trigger, which, again, no one seems to have any interest in touching (again, due to build anomalies).

Crazy fun gun to shoot!

$0.00

The spec in the uk states up to 600fps however as usual they don't say which pellets / weight used when producing these figures , hence my interest in getting close to there quoted figures using 7-8gr pellets if possible, which is well within our legal limit for .177 which is around 800fps using 8gr , one thing springs to mind is barrel lenght as since the acceleration of co2 guns can be effected by this , in my experience at least 20" is needed to give max performance without creating a gashog which could explain the 600fps figure quoted
As you have stated there is very little info concerning these guns hence my enquiries on here , as any info gathered is a plus , so any comments are appreciated

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

At the moment I am gathering as much information as I can about these , as you say it appears to be down to a combination of things valve bushing size aperture , hammer spring strenght and possibly barrel lenght,as for using moly paste the trick is to apply very little then burnish into the metalwork removing any remaining residue rather than just smearing it on as the grease component will dampen the action as you found out ,

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

In looking back over my notes and original post I see I had achieved a high of 588 fps with an average of 570 fps over 11 shots. This was with a small chrono intended for airsoft guns. I subsequently purchased an Alpha Chrony but have never shot the CX4 over it (yet). I did however do some comparisons of both chronys using my 495 fps Daisy 953. The Alpha Chrony yielded readings that were about 20 fps higher (approx.). That means that the CX4 should be hitting very close to 600 fps on the Alpha. No changes to the hammer spring were ever made. All tests were with Crosman Premier wadcutters weighing 7.9 gr. You can check out my chrono comparison thread here: topic64144.html.

When/if you decide to forge ahead with any mods be aware that you can shoot the gun over a chrony without putting the plastic housing back on. The trigger bar that hooks on to the plastic pin on the left side of the trigger will slip off if you don't hold it in place but you soon remember to do this.

Another couple of notes. Don't split the aluminum cases without making sure any CO2 is completely discharged from the gun. And I wish I had a buck for every time I rejoined the two aluminum case halves without remembering to put the barrel in place.

_________________
A mask is not a political statement. It is an IQ test.

Up till now been using my cb625 chrony but also have a f1chrono so will try a comparison just to check

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717

Interesting. Look forward to your findings.
https://www.youtube.com/watch?v=M-C_8kyUQbE

_________________
A mask is not a political statement. It is an IQ test.

Apologies. I don't usually miss location references.

Ok here's my results using the cb625 attached to barrel and f1 chrony 1ft away from muzzel
Using rws superdomes at 8.3grs
625 - 290,358,358,359,368,378
F1 - 284,351,350,353,360,370
Dynamit nobel 7.2grs
625 - 408,409,389,385,409
F1 - 403,401,384,378,400
Gamo match 7.5grs
625 - 366,355,368,351,373
F1 - 360,351,361,347,368
It appears that lighter pellets travel faster as expected,the difference between reads of the cb624 to f1 is purely due to distance f1 1ft away , variations in fps could be due to variations in pellet weight of pellets used as I didn't weigh them prior average power is just over 2.4ft/lb approx 3joules , have arranged to have a new hammer spring sent will see what happens after fitting

_________________
Qb78dl, xs78, xs79hpa
Berreta cx4 storm
Hw80k, Hw77
Logun solo
S200
Bam51, B2, B45-3
Xs19, xs20,xs36-1,xs36-2,xs38
Webley mk3, osprey
Lion
Crosman 1740,2250
Paratrooper .22
P17,Orginal10,webley senior,junior Cp1,powerline 717