Some recent Diana literature I have seen puts the muzzle velocity of, among others, Models 48, 52 and 54 in .22 at 230 m/s. This translates into 700 fps. The brochures indicate that "Velocity is controlled to meet the regulations of certain countries."

Does anyone know how exactly this limitation is applied to the gun, and, by extension, is it possible to override this limit and go up to 900 fps (approx 295 m/s) by replacing certain parts?

It was purchased earlier this year, you can search a few pages back and find my post with pics...tuning can increase/decrease velocity and improve shooting behavior...

Tony

A friend of mine also says his stock RWS 54 (.22) shoots at 780 fps (don't know the pellets), which is above the stated limit of 700 fps. I am wondering if my 48 is one of the "limited" guns while his is not.

I bought mine 8 years ago and don't have the paperwork. I'm getting about 625 fps with Gamo Hunters (in an earlier post I had reported 680 fps but that was with a 6-month old Mod 48 which I had foolishly assumed would be the same as mine. Live and learn). All in all, my 48 feels like it may have been a "limited to 700 fps" specimen which has naturally lost a bit of oomph after thousands of pellets. I am about to get it looked at by the only air gun guy here in Istanbul, so I figure I might as well try to get it up to say 800+ fps.

Any insight on the mechanical difference between these limited and "normal" guns would be appreciated.

and you will not look back .

Frank

and any place on the web where I can find those?

he will ship anywhere globaly .

Frank

for a GSI kit from Jim Maccari. He says a RWS 48 would do about 800 fps with the 14grn pellets I've been using. I'll be very happy if I get up to 800.

Thanks for the advice and I'll keep you posted on how things shape up. I figure it'll be a few weeks before the kit arrives and I can get it installed.

I don't know the answer to your real question--exactly how the different power levels for different markets are achieved--but it is interesting to note how this is regulated in different countries. Some guns may appear in quite a few different power levels, depending on their intended market.

In Germany, airguns were for many years limited to a muzzle energy of 7.5 joules (around 6 foot-pounds), a number probably influenced by the popularity of 10-meter rifle shooting there. I understand this has recently been raised to allow field-target type guns.

In England, the limit is 12 foot-pounds for rifles and 6 for pistols, unless one possesses and Firearm Certificate. This has had a great influence on the design of British airguns over the years, most being optimized for around 12 fpe.

In Sweden, the limit is 600 fps velocity. There is no limit on energy, therefore as you can imagine .22 and .25 are much more popular than .177 there.

In Canada, the limit is 500 fps unless having the proper certificate. Again, the larger calibers are thus more popular.

My experience working on Diana air rifles indicates to me that they change the springs to meet different market requirements.
They do not always change the part number.
The spring they currently supply for the 35 is much stronger than the original, even though they still use the same part number.
The #300374 spring they currently supply for the 27 is:
Airgun Express (US) 38 coils, .113 wire, .740 OD
London Arms (Canada) 39 coils, .110 wire, .729 OD
I find it best to take apart a Diana and measure piston ID and stack height available and source the best suited spring size and make a fitted guide.
Diana have used 3 different springs for the 24 so far, none of which made sense to me.

If it's just the springs, then can we go up to, say, 1,000 fps by installing an even stronger one?

I've never heard of a 1,000 fps .22, though, so there must be a reason. Perhaps that exceeds the limits of some other parts like the seals...?

Still, with all the tuning enthusiasts out there, I'm surprised no one has taken their .22 up closer to the sound barrier at 1,100 fps. Any reason for that, or are there .22s that are up there?

Out this site:
www.sportwaffen-schneider.de
Under Exportfedern you will find that Dianas and Weihrauchs and others being exported have different springs; or you can order the Exportspring seperately.
M.

...meant little progress. Any idea how their "export" spring compares to JM springs, power-wise?

No idea, cause they only state it's the export version. They do not give any specifics.
M.