Increasing power in a vintage springer - what is possible

[Lakey]

Following on from the active thread about upping the power on a vintage Cadet Major, I got thinking.

Now I am not much of a tinkerer or airgunsmith, but I was trying to get some of the basic principles boxed off in my mind.

If you wanted to raise the power in a vintage spring airgun, am I right in thinking that you have to work on the following list

(1) Cut down on air escape - check breech seal, check and spruce up piston seal, check tap if an underlever

(2) Try and get the piston moving down the cylinder faster - so fit a new spring, and properly resize any newly fitted piston washer etc

(3) try and remove any friction from the system

(4) Increase swept volume if possible ?? - maybe not easy when dealing with a vintage gun

(5) move from a leather piston seal to a properly fitted synthetic one ?


Is that about it, or are there any other ideas ?

I would have thought that manufacturers at the time of production would have done sufficient research to get their designs the most efficient, and powerful as possible for the size, or did the sub 12 ft/lbs rule effectively put a lid on their efforts ?

Lakey

[ptdunk]

I did a video on doing something like this on a 1905 Britannia, got the power from a harsh 7ftlbs, down to a very gentle firing 5ftlbs, then back up to a gentle firing 8ftlbs. All with the same spring.

Was more to get it shooting softly, but changing the Tranfer port size and piston weight got the power up a bit.

https://youtu.be/o6DUCHEPOsM

No point upping the power if it makes it harsh to shoot imo.

Cheers,
Matt

[ggggr]

Following on from the active thread about upping the power on a vintage Cadet Major, I got thinking.

Now I am not much of a tinkerer or airgunsmith, but I was trying to get some of the basic principles boxed off in my mind.

If you wanted to raise the power in a vintage spring airgun, am I right in thinking that you have to work on the following list

(1) Cut down on air escape - check breech seal, check and spruce up piston seal, check tap if an underlever

(2) Try and get the piston moving down the cylinder faster - so fit a new spring, and properly resize any newly fitted piston washer etc

(3) try and remove any friction from the system

(4) Increase swept volume if possible ?? - maybe not easy when dealing with a vintage gun

(5) move from a leather piston seal to a properly fitted synthetic one ?


Is that about it, or are there any other ideas ?

I would have thought that manufacturers at the time of production would have done sufficient research to get their designs the most efficient, and powerful as possible for the size, or did the sub 12 ft/lbs rule effectively put a lid on their efforts ?

Lakey

The Cader Major thread is something that somebody mentioned on Tother forum. I only plink so often use old springs. With some of these oldies, especially with a direct trigger, they are much nicer to use with a weaker mainspring----SO I dont really tune, I tend to detune or use old bits.
I've got a rough Cadet Major with a tired spring and I have left the sights off it as it is quite good for teaching someone to get their head down to the gun. At 8 yards, if you aim the barrel at the bottom of a bottle cap you will hit it.
Someone had a go at a Webley pistol for me, lightening the piston and making a head up. It took time to warm up and power would go up---THEN sort of by accident after the chrono broke. I was messing around and got a lower powered very nice pistol with a quick firing cycle.

I suppose Shedtuner will be along telling you what to do and what you could expect from a particular gun or guns if you name them.

I think part of it with some of these oldies is that they are quite fun for low powered plinking and if you fit a new leather seal and breech seal, probably most of the people in this section will be dead by the time they need changing again.

[bill57]

I wonder how many rabbits thought "It's only a Cadet Major?"

[evert]

I did a video on doing something like this on a 1905 Britannia, got the power from a harsh 7ftlbs, down to a very gentle firing 5ftlbs, then back up to a gentle firing 8ftlbs. All with the same spring.

Was more to get it shooting softly, but changing the Tranfer port size and piston weight got the power up a bit.

https://youtu.be/o6DUCHEPOsM

No point upping the power if it makes it harsh to shoot imo.

Cheers,
Matt

Yup, increasing compression is the way to go on some guns, especially if you are fitting a synthetic seal in older leather sealed guns.
That ususally means sleeving down the transfer port. In some cases you can also gain some stroke when you convert to a synthetic seal.

[duomatic410]

I wonder how many rabbits thought "It's only a Cadet Major?"

A lot in 1956 here,even the cadet did its share but we were over run and you did get some silly bunnies.👍😊happy days..

[jjjohn]

I always thought that leather piston seals were at their best if slightly oil damp
so as to give a slight burn and use the dieseling principle albeit ''slightly'' not the bang and wallop that
a badly lubed gun will produce.
As I type my mind went back to the ''Triflon days'' ...heck they really did think feeding the combustion chamber = happy days.

[duomatic410]

I always thought that leather piston seals were at their best if slightly oil damp
so as to give a slight burn and use the dieseling principle albeit ''slightly'' not the bang and wallop that
a badly lubed gun will produce.
As I type my mind went back to the ''Triflon days'' ...heck they really did think feeding the combustion chamber = happy days.

Used to have a small plastic oil bottle filled with aero fuel with ether, guaranteed to diesel, hitting the target wasn't.
Webley mk3 airsporter went really well,along with a model d. Happy days.👍😊🇬🇧