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awesomedick · Member

Hello Everybody:

I have just acquired a new (old) air rifle. It is a Slavia 630. I am very pleased with it as it is very accurate. However I was wondering if there is any modifications I can do to it to increase it's power. It needs an overhaul and I thought this would be a good time to replace and improve any worn parts. Does anyone have any suggestions?

Thanks,
Rick

Slavia · Moderator

This gun was sold with two springs - I'm assuming you have the lower-powered (under 500 FPS) Canadian model. The full-power model is rated in the manual at 560 FPS. (My 631 with the same internals shoots 605 FPS.) The gun was never designed to be a powerhouse. Certainly there are things you can do to increase power, but the increase won't be huge, it will probably be harsher, and it will probably become a PAL gun. Additionally, the end cap screws in, so a spring compressor can't be used. Any extra preload force on the spring would have to be taken up by hand while trying to engage some very fine threads.

It's a great gun - accurate and solid. Instead of increasing power you might be better off working on smoothness and ergonomics (i.e., stock fit and sights).

awesomedick · Member

Thanks a bunch. It is a nice gun and I wouldn't want to spoil it. It has been outfitted with a Tasco Red Dot sight which works very well. I guess it would be best to just overhaul it with a new piston seal and breech seal and a proper lube job. It really needs to be re-blued and have the stock refinished as well. Something I can do over the winter months. Once again thanks for your input it reall is appreciated.

Rick

Slavia · Moderator

Personally, I like my 631 enough that if I were to re-blue I would "spring" for a professional job.

The gun is accurate enough that at 10m indoors a red dot hides too much of the target, but outdoors at 25 yards I can see where it would be fun.

Inside, I re-lubed, honed the trigger parts, polished the spring ends, and de-burred the rough metal edges. That was it - all my other mods are visible from the outside.

The 631 is 9 years old now, and I haven't had to think about replacing the spring or seal. If you do so, please post your source - I'm sure I'll have to deal with it at some point.

The front sight mounts in a dovetail with about 1cm of fore/aft play. I found the 631's groups to be sensitive to its position - you might have to tune it a bit. Also, check the tension of the barrel pivot. It should be just tight enough so that (after cocking) the barrel remains in position without falling.

You might find these links useful:
http://sites.google.com/site/cherrytwist/slavia631tune-up
http://www.czub.cz/zbrojovka/cz-manual/Instruction-Manual-Slavia-630-631.pdf

Have fun with it.

broommaster2000 · Moderator

One could argue that the barrel is to long, and the 630 stock may be to small. It's also a very old design, from the 70's.

It's not ment to be a powerhouse, it's just a very good gun. I think I would place it next to the HW30(s). Accuracy-wise it easily competes.

awesomedick · Member

Hello Broomster and Slavia:

I think you are right. A little "polish" here and there is probably the best thing. I wasn't really looking to make it powerful enough to bring down crows, it's just if there is anything available to make it better I would like to add it on. For Slavia; Try www.dlairgun.com . They are in the west coast of the Great White North and operate a mail order business. I have called and inquired about parts for the 630 and they stock is the piston seal and breech seal. They also have generic springs if you have the measurements. I don't think the barrel is too long or the stock too short, but as I am just a neophyte I may believe differently I become more used to it. Thanks guys, I appreciate your time.

Rick

broommaster2000 · Moderator

Most power I got out of it and had it still shooting smooth was at 10 Fpe. Not exactly sure if that's enough for hunting because I'm not that much of a hunter myself. Razz

To get a bit more power you'll want to put about 2 mm of preload on the "top hat" and about two or tree on the spring guide. I'm not sure if you're good at turning delrin, but that's what was used for mine. I had a buddy who made them and they're not hard to make if you're good with a lathe.

Slavia · Moderator

I like trigger shoes, especially with the very thin Slavia trigger.