Pistol Power

[seanyboy]

Hi chaps. not posted for a while as have had a rough month, plus preparing for my first hft comp.
Any way's, was purchasing a hw45 but couldn't due too money boss saying NO!
I have been looking round the net at different pistols and have noticed something. The pistols that catch my attention nearly always end up being Co2 multi-shots. The thing that always halts my interest is the fact that these guns only ever seem to have very low power levels. I believe the 2240 is Co2 and as near as dam it, full power. So why can't I find a full power multi-shot?

[brucieboy]

I think it's because all these replicas use some kind of magazine that has to revolve to index each pellet and so a lot of co2 is lost on every shot as the fit between magazine and breach is not that good.The skiff has a bit more whack due to the inline mag,but that brings its own problems pf erratic feed.For the price they are as good as can be expected,pay 3 or 4 times as much and things improve somewhat.

[Jerry Cornelius]

For (nearly) the same price as a new HW45 you could get a second hand DU10 on here. Not quite the same as you are talking about but more powerful than an umarex thingie anyway.

[Jamie Norton]

You're quite right about the power levels. I have a Umarex 8 shot type (Walther CP88) which puts out about 2 fpe. I also have a Crossman 2240 which puts out 5.25 fpe in .22 calibre. My Walther is the 4" barrel version - I'm pretty sure you'd get more poke from the 6" version, but I've never had the opportunity to test one. Another factor you may want to bear in mind is the number of shots. I can easily get 80 shots per CO2 capsule from my Walther, but only half that from the Crossman. More importantly though (to me anyway) is that the Crossman is surprisingly accurate, whereas the Walther is much less so; more about rapid fire at tin cans!

[PALADIN]

.
You could always put a 'repeating' breech on a 2240 :)

http://www.bryanandac.com/new_page_5.htm

HIH ;)
Pete.

[WebleyCrosman]

A Falcon raptor FN8 is multi shot and is 6 FPE.

And one advantage with PCP is there is no change in power with the ambient temperature.

My 2240 and 2250 drop 1 FPE with every 8 deg C.

And the drop in power is worse if you shoot quickly.

Of course the power in a repeater will drop hugely if you fire off a magazine quickly.

So this a big advantage of buying a pcp repeater.

Of course you pick up a new 2240 for about a third of the price of a raptor.
And there is charging equipment to buy.

[BarryB]

Get a Rohm Twinmaster top if you want a PCP multi shot at a reasonable price. Can be tuned to over the legal limit if you were silly enough. Mine is set at 5.7ft lb with 8.4 JSB, ideal for the type of HFT we do at Ford. Mine is single shot.

[Target Bunny]

Hang on guys, my only rifle is a QB78 bought to take care of a backyard rat/mouse problem caused by next doors Aviary.

The guy keeps it spotless but we still get a plauge of vermin & cats.

So the QB78 at under 6ft/pounds was a good compromise. My pistols would be more sporting but I want clean kills. Imagine my shock and horror:D
when I discovered that it's not only possible to tune one of these things but the problem is keeping it BELOW 12ft/pounds and it's a simple technique.
I have no doubt that it will be possible to up the power of most CO2 pistols using the same methods so why are we all moaning about low power?
I have not tried any uprating since I do not have a chrono and this is a vital piece of kit if you are going to mess with the power output. As soon as I get a chrono (anyone out there got a flying pig smiley?) I'll have a go but it Wont be any time soon.

Jim

Mea imperare! Sputum facere tu felix laetitiam? Processus! Sputum fabricati diem.

[Snapshot]

I have no doubt that it will be possible to up the power of most CO2 pistols using the same methods so why are we all moaning about low power? Having no doubt does not mean you're right. The Umarex pistols simply cannot be uprated any meaningful amount.

[Target Bunny]

Hi Snapshot
OK it will not necessarily be simple.

However I would be interested to know why the Umarex can not be uprated by any meaningfull ammount.

As a hydraulic and pneumatic fitter I accept that there may be an inbuilt design specification which does prevent uprating, such as the size of the resevoir which provides the regulated fluid release being fixed as a machined or cast component. However my old Daisy powerline and the QB78 can both be uprated by increasing the open time of the release valve thereby increasing the volume of fluid released. There are at least three ways to do this without major modification but since I never had a need to do it I have not done so. The QB78 is so straightforward that the guy writing the article specifically emailed me warning that the second part of the upgrade would take it over the legal limit.

So I would like to hear from any Umarex experts or power tuners as to the reason for the inabiity to uprate these pistols.

Regards
Jim

Mea imperare! Sputum facere tu felix laetitiam? Processus! Sputum fabricati diem.

[jtw000]

There is a way to increase the foot poundage but it limits the life of the pistol and also adversely effects accuracy. Basically you have to throw the gun...

[Firestorm]

Basically you have to throw the gun...

LOL :D:D

Russ

[tayloriand]

In my opion the Umarex pistols are a waste of time and money, poorly made, not very accurate and lacking in power.

I suggest you look at the Crosman 2240 if you want something under £100

Or the 'tuned' Rohm is a good idea but double the price.

See my replyon pistol choice for more regarding buying Crosmans

All the best

Ian

[webranger]

I had a S&W, power was crap but quite accurate. Never thought of upping the power because IMO it would reduce the amount of shots per bulb making it more expensive to run.
John

[Stuart_B]

In my opion the Umarex pistols are a waste of time and money, poorly made, not very accurate and lacking in power.

I suggest you look at the Crosman 2240 if you want something under £100

Or the 'tuned' Rohm is a good idea but double the price.

See my replyon pistol choice for more regarding buying Crosmans

All the best

Ian


:eek: I've had countless thousands of shots through my S&W and its never jammed leaked or had any problem in the years I've owned it. Poorly made? You sure you've owned one or even seen one? Mine has a nice weight to it and the trigger for the type of gun is spot on. They are not full power guns nor are they tinkerers guns. They are however great fun to own and use.

The base crossman 2240 isn't the best and is generally accepted to be a tinkerers gun, really the equivalent of a QB78. Lots of upgrades to do or to buy and add to the gun. Or buy Crooked Barn if you want something ready made.

And as said multi shot and full power comes at a price.

[Target Bunny]

Hi Stuart B
tailoriand has said "In my opinion", it's his opinion, he's entitled to it no matter what our opinion is. We have different opinions, so what?
Daystate owners completeley fail to understand anyone saying, "HOW MUCH?" and although I would love to be in a position to hear folk say that to me I can only dream about it.

Mea imperare! Sputum facere tu felix laetitiam? Processus! Sputum fabricati diem.

Jim

[Target Bunny]

Hi Guys
http://i280.photobucket.com/albums/kk166/The_Dragonsinger/Flyingpig2-Messenger.jpg

Despite what I said previously I have now sent off for a chrono (don't tell "She Who Must Be Evaded") and I can now do some sensible tests on the Smith & Wesson.

I think that pistol tuning is pretty much frowned on by "authority" since if you get it wrong (right?) you end up with an automatic firearms offence as you have a handgun. So now that I can check out what is happening I can try out a few modifications to up the power. I said I could think of three ways without too much trouble and so I'll try them. There is a fourth simple way but since that involves changing to the 8" barrel I already have I can't count that, mind you if somebody wants to send me the 4 & 6 inch barrels I am willing to check them out.
OK so in the interests of staying legal I will do the work a stage at a time and check after each one to see the results.
First up I will pack the hammer. Have a look at the first picture and the light coloured area shows the rear of the gun and the back of the hammer and front of the striker plate.
http://i280.photobucket.com/albums/kk166/The_Dragonsinger/S%20and%20W%20Upgrade/001-1.jpg

On this gun the hammer does not hit the gas release valve. It hits the striker plate and that in turn hits the gas release valve. This plate is also the safetey since it has to be moved up when the gun is cocked to move it out of the retaining notch and whilst it is in the down position it prevents the hammer from hitting the gas release valve.
I keep saying the gas release valve (GRV) as if it is some kind of mantra. It is! If this bit of kit fails on any co2 gun it becomes a club. What it does is allows a carefully measured dose of co2 to enter the magazine behind the pellet and we are on the way to that perfect score.
The length of time the valve is open dictates the ammount of co2 it releases. More co2 more power, less co2 less power. The length of dwell (time open) is a combined function of three things. The strength of the internal spring in the GRV, the strength of the trigger spring, and the clearance between the hammer and the GRV, or in this case the striker plate. Adjust any of these and you adjust the dwell, adjust the dwell and you adjust the power. So by packing the hammer I can override the GRV internal spring for a fraction longer because the hammer is now contacting the striker plate sooner and so staying in contact longer releasing more gas. The picture below shows the GRV on the left and the striker plate to the right of it in the light coloured square and when I have the chrono I will put a small piece of metal between the hammer and the striker plate then measure the speed.

http://i280.photobucket.com/albums/kk166/The_Dragonsinger/S%20and%20W%20Upgrade/003-1.jpg

Untill I do the check I have no idea how thick the piece will need to be and yes I will use more co2 per shot.

For mods to the valve the picture below may help.
http://i280.photobucket.com/albums/kk166/The_Dragonsinger/S%20and%20W%20Upgrade/ExplodedDiagramValve2.jpg

I'll come back when I have results.

Target Bunny


Mea imperare! Sputum facere tu felix laetitiam? Processus! Sputum fabricati diem.

[Snapshot]

> More co2 more power, less co2 less power.

Within limits. If you have too much CO2 released it will not have time to turn from liquid to gas completely and you'll just get a spray out of the barrel. I suspect making more efficient use of the existing amount of CO2 by improving the sealing around the magazine may be more useful but I'll be surprised if this isn't on your 'do' list.

Jonathan

[Target Bunny]

Hi Jonathon
Without knowing the actual pressures involved I can not be certain of the state of the co2 in the capsule and each shot decreases the pressure by a finite ammount and... you get the idea. I also do not know, no one will confirm or deny, whether the GRV is simply a valve or a resevoir. In other words does it charge up from the capsule (in which case my hammer mod will fail) or does it simply release co2? I think it's the latter but I don't KNOW. In either case I believe that I will reach the legal limit before allowing liquid to be released and since there is no syphon tube inside the capsule and co2 has a propensity to resublimate rapidly liquid release will be a low risk.This risk will also be reduced because of the length of the barrel.

Actualy improving the seals was not on the list simply because it will rely on fitting a seal to the barrel on the barrel side of the mag and a non standard thicker seal on the stock side to replace the standard seal and I do not have machining capabilities (no lathe) to do either. Also this would probably mean that the seals would be in constant contact with the mag and subject to wear.
However since sitting down to type this I am now wondering if I can get a couple of teflon washers and pierce them to fit on the magazine. Hmmmmmm.

The other ideas in order of simplicity were to remove the hammer mod & increase the trigger spring tension then to see if I could decrease the valve spring tension. If get as far as the last one I will also polish and relieve the valve piston and internals but stop short of opening the valve delivery nozzle since I have no information on it and could easily destroy it.
The final stage will be to see if I can combine any of the mods to get a bit nearer the limits.
I am not happy about the hammer mod simply because I do not know the internal clearances on the GRV and it could damage the GRV itself. This could be the basis of the comments that tuning these guns destroys them.

Thanks:D
Jim

Mea imperare! Sputum facere tu felix laetitiam? Processus! Sputum fabricati diem.

[Target Bunny]

Chrono has arrived:D:D:D
Test firing at weekend for datum readings.
Procedure will be: Gun out of case and capsule loaded. Leave for half hour. Ten shots at target. (Cry at crap shooting). Ten spaced shots single action. Ten shots double action.
Can't do ten rapid since chrono resets every shot (couldnt afford recording version).
Will repeat proceedure on all tests.

Target Bunny