Winchester Model 52 barrels were known for top accuracy.  Looks like some enterprising gunsmith replaced a shot out/rotted out Ballard barrel with a Winchester.  How's it shoot?

David
Montezuma (temp's 13 and rising!) IA

You also can tell something about the original configuration of the receiver by looking at the firing pin.  If it appears to have been unchanged from the factory (nos signs of alteration of the block, etc) it was probably a .22 rf from the factory (#3 or #3F) but if it is altered from a centerfire or reversible for another caliber, or if the breech block has been bushed, then it was one of the many other models.  

If you look under the barrel tenon on the inside (you need to take out the block to do this) you can determine whether you have a cast action (as most rimfires were) or the heavier forged action.  The cast action has a hollow space under the barrel tenon while the forged action is solid there.  

How is the rifle stocked?  It should have a classic looking stock (almost a field-looking stock) if original, while many of the Ballards that gunsmiths built up for competition had more modern looking stocks designed for multi-position or straight prone shooting.  

The Winchester 52 Barrel, as David said, is a very logical and likely gunsmith replacement, and could have occurred any time from about the mid-20s on.  It is a classic piece of work regardless, since of course the Model 52 is long discontinued as well.  I'd guess the work was done no later than the '50s, but that's just a SWAG.  

Regardless of what you find, it's a neat piece of competitive shooting history.  Congratulations, and enjoy shooting it!

Froggie

PS  What about the trigger(s) on this rifle?  Is it a single trigger or double set, and if single, is it mounted on a plate on the bottom of the breech block?  If this last, it was a DST action that was converted to single trigger to make it legal for NRA competition. Sure would be nice to have DSTs though! 
How about a picture?   

sixpack, the Winchester bbl probably is already drilled and tapped with two pairs of holes a little over 6" between pairs.  They are for the older styled Lyman and Unertl scope blocks for the old long tube externally adjusted scopes.  Any of these scopes look (and more importantly work) ell on this type of rifle.  If it is not predrilled, and there is a dovetail for rear sight, just about any standard field type rear barrel mounted sight will do.  A classier solution would be a tang sight, mounted in the two holes that Marlin provided for you on the rear upper surface of the receiver.  The hole spacing for the modern Marlin rifles should be the same if you want to buy new factory production, or any of the original or reproduction tang sights for Ballard could also be fitted. Yet another possibility would be to have a friendly gunsmith make up a long scope mount (to utilize the existing screw holes) from a blank available from Brownell's, etc and use Weaver-type mounts if you want a modern scope.  I would avoid drilling any new holes in the receiver...it's best left as original as possible, IMO. 

Froggie

Are all #3s supposed to lift the empty case clear of the chamber?  Mine does not and it is all but impossible to clear the empty with gloves on while squirrel hunting.

Brent

I had a ballard with such an extractor.  It did not cause accuracy problems and I don't feel that case bulging is really very important to accuracy. But the darn extractor would get behind the case occasionally causing a number of difficult and interesting problems.  Much prefer the straight lift extractor, but sure which mine would lift the case all the way clear off the chamber.  Still no answer yet as to what the norm was for this sort of extactor.

Brent

joe -

Dunno why you happen to be so dense.  Guess, you haven't seen every #3 ballard out there yet.  Oh well.

Brent

Brent, I was just funnin ya.   

                                                                     Joe.