Convert Walther OSP to GSP?

[spacestout]

We have some fine Walther OSPs in our "club", and were thinking of selling them off due to the new ISSF rule changes to standard pistol in rapid fire.

We wonder if the OSP can basically be converted to the GSP. The GSP magazine seems to fit. Can the barrel be removed and replaced with one from a GSP? Or, can the OSP barrel be re-chambered to take the .22lr round and what would that cost?

Can the OSP trigger be adjusted up to where it would be legal in new rapid fire rules? Know the grips would need a change.

[FredB]

Do a search on this site for "OSP conversion". One really good one is:

viewtopic.php?t=10998&highlight=osp+con ... bb09ef42e7

but look for all the posts on this topic by Sandy (Santibanez). Sandy did this conversion for his daughter, who successfully used it for sport pistol in international competition. You can cut some corners on Sandy's version and still have a very usable gun, which is what I did with mine.

HTH,
FredB

[spacestout]

We have the Walthers, Pardinis, and FAS RF pistols. Trying to decide what to do with them.

I like what Sandy did.

[Mike M.]

I talked to Earl's about a year ago, ad was told that the GSP and OSP frames were the same. The most obvious (and expensive) solution is to get a .22LR upper and 1000g trigger unit.

[FredB]

It's true that GSPs and OSPs made after a certain date have the same frame. However the bolt housing is different. The GSP housing is squared off in back, and the OSP housing is slanted, which allows a significantly higher hand placement and more rake in the grip. So OSP and GSP grips are not interchangeable.

If you want to use a GSP top end on an OSP frame, you'll have to change the grip as well. However, if you convert an OSP to .22LR as Sandy described, you can keep the OSP hand placement and rake angle. If your OSP grip is one of the older ones, you don't have to modify it to make it ISSF-legal. If you have one of the newer wrap-around OSP grips, it is possible to modify it to make it ISSF-legal by cutting off the overhanging parts. That's what I did, and my conversion is a pleasure to shoot.

HTH,
FredB

[Dr. Jim]

Now that we know about Walthers, anybody have the techniques to change the Pardini? FAS 601s should be easy if a trigger box and slide are available.

[Tycho]

Pardinis should be doable, although not all .22lr parts seem to fit every .22 short frame. I have a bunch of both, and a ton of parts I bought from a ex-national team shooter - it's possible to put them together as a Pardini GPS in .22lr, but it doesn't work with every GP* frame, don't ask me why. And the triggers are a p.i.t.a. to convert to 1000gr. Personally, I wouldn't recommend that way, getting a new SP* would definitely be cheaper if one counts the hours.

The FAS is impossible, imho, as the mag is too short for the .22lr. The 601 has a different housing from the 602, where the slide is longer and travels further back. And the sight radius is too long, you'd have to change the front sight / barrel shroud. The ammo length issue eliminates most Hammerli RF models, too., as well as the Unique 2000.

[Dr. Jim]

Ah, I didn't realize that about the FAS as I only have 602 & 603, though Mark at Gunsnthings has a couple of 601's. Guess he's stuck with them, unless major machining is undertaken. Probably best that they end up in museums, unless folks want to hold "vintage" matches.

Cheers

[Retired]

Yes, OSP's can be converted to .22lr. You should change the recoil spring, weight down the bolt, change the barrel (so it's not ported) and the position of the front sight (so you don't exceed the maximum sight radius), and change out the other obvious stuff like grips. You should use a buffer in an OSP whether shooting shorts or .22lr.

Good luck,
Retired