"modifying" air gun

SMLE 303

SMLE 303

Regular
EE Expired
Rating - 100%
1   0   0
Location
Ontario
I've heard that you can ' stretch the spring' on a break barrel to make it more powerful, and was wondering if any one knows how to do this. i have a Crosman 795 that I woould like to improve and make scope-worthy. its currently rated for 495, but if some one could tell me how to mod it it would be appreciated:needPics:
 
Just so you know if you modify it, and its already rated for 495, anything pass 500fps is considered a firearm
 
I did something similar to an air file of mine a few years ago. I don't think stretching the spring is a good idea. I havent done this but im thinking it would lead to some pretty inconsistent velocities. Instead of stertching the spring I spun up a shim and reassembled the rifle with the shim behind the spring. There is a limit tho... When the rifle is in the cocked position the final compression length can't exceed the length of the fully compressed spring + the shim length. I never checked it with a chrony but I do believe it produced increased velocities.
 
You can replace the spring with a stronger one, or block one of the vent holes in the barrel if any.
If this pushes you into firearms territory, inform the CFC in advance.
 
If you pull the spring and measure the diameter of the coil ( gauge) and measure the length of your spring, then you could go by Princess auto or a similar store and get a spring of a slightly bigger diameter and or a little longer. Or if you buy a gun like a CZ-631 there a guys like Jim Maccari that manufacture tune kits that help the gun shoot smoother and faster.

You will need to know that the laws change though at the magic number as stated above. From my experience with the CZ-631 they are de-rated in Canada to 495 fps on paper only and actually shoot in the 650 fps range. I guess the cfc doesn't chrony all of the airguns sold here.

I bought a big spring from Maccari for my diana 48 to take it from the 1100 fps to somewhere higher..... it makes Magpies pop like balloons.
 
For $8 get a utility spring from D+L in BC.Polish the piston [fine emery cloth]to remove rough machine marks and lube with moly-paste.available from them also or e-bay.now you're doing 625fps and have a usefull gun instead of a toy.Mine kills grouse and crows cleanly now .................................Harold PS you need to measure the old spring and check to see if the piston seal is damaged while you're there.
 
srnm said:
Just so you know if you modify it, and its already rated for 495, anything pass 500fps is considered a firearm
Click to expand...

actually it has to pass 500fps AND have a rating of 5.7 joules, which it would do being a pellet gun, but it still takes both to make it a firearm! :D
 
I bought a big spring from Maccari for my diana 48 to take it from the 1100 fps to somewhere higher..... it makes Magpies pop like balloons.
Click to expand...

I have a Maccari spring and a venom seal on my HW-97,which increase the velocity,and make the gun smoother.
 
Yes I'm going to order a Macarri kit for my son's RWS 34/.22 A lot of RWS guns leave the factory with damaged seals.QC is getting PI$$ POOR these days even German...............Harold
 
Last edited:
I just put a Maccari kit in my RWS 34. I think the big advantage was not more power but how it smooths out the firing stroke. As you gain fps with a springer you make it more hold sensitive and difficult to shoot accurately.

I can't believe how much the kit reduced my group sizes both off a rest and off hand.
 
I'm hoping for the same miracle when I get around to ordering mine.What did they ding you for duty/shipping etc? if you don't mind me asking............................Thanx Harold
 
As well as the tune kit, I got a can of moly seal lube. Total cost to my door including S&H to BC,duty,Gst,exchange,etc. = $Cdn 134
 
I wonder if they would let it in the luggage at the airport as the wifes going to Vegas in 3 weeks?Harold
 
Can't see that bringing it back in checked luggage should be a problem and a good way to cut costs by $20 -30 bucks. It is not an item that needs a U.S. export permit and just looks like a spring with some spacer washers. You would have to arrange to have it shipped to an address in Vegas as it is not an item she could pick up at a store for you. Maccari has an excellent reputation for prompt service and if he doesn't have the kit ready to ship the same or next day will let you know. I had mine in 9 days using his preferred shipper USPS (NOT UPS). In the costs that I mentioned above, I forgot I also got one of his piston seals as well.
 
Yes like I mentioned earlier a lot of RWS gun come new with damaged piston seals.Time to pick up the phone and order it...............................Harold *Did you get the Telsa seal or the other one?Buttons for the piston?
 
Are there any online step by step instructions, rather than do's and donts?....... So a new srping, shim, and washer. btw, what about pba ammo? if it increases velocity by 25%, then a 495fps gun is then over 500, therefore a 'firearm'. do you have to register it? i have my non-restricted.
 
I was able to pull the spring on my Hatsan Mod85 and put it back together with no problems, or an instruction at that. Threw some washers behind the spring which did the trick. Takes out pigeons on the farm at a nice distance now.
 
One of the flaws with the Airgun laws is that it does not state a pellet weight for the rated energy/fps. The lighter pellets go faster but have less energy and visa versa. I would stick to a 8 gr pellet with lower fps as it has better knock down power ( in my opinion ) I want to get a pack of heavies for my 48 ( 12.5 gr. ) but I have oodles of power to spare. Illingworth Imports in North Battleford SK has a great web site for airgun stuff and sells allot of pellets/airguns do a google and check it out.
 
You must log in or register to reply here.
Back
Top Bottom