Parts questions old k frame

[hovercat]

I am reclaiming an old m&p from the 'sold for parts only' to functional category and could use a little help.
5 screw, 6 shot 38 special or US service ctg. Replacement grips. Serial 90456, no prefix, which from my reading here makes it a model 1905.

The questions. Can I use the extractor spring that Numrich lists for the M&P? And under the yoke is a small hole which had a tiny spring inside and nothing else. I am certain there should have been a something else, but I do not know what to order. It does not seem to affect functioning.
Thank you for any help.
I also need sideplate screw # 5, this was my fault, lost. The one closest to the hammer, it is a different size than the others. Is there a source?

 

[2152hq]

For the usually out of stock 'large head side plate screw',,they can be found on Ebay quite often.
In fact if you search there for 'S&W side plate screws' one of the hits will be just for the K frame 'Victory Model (same gun) large head side plate screw. I think they are $3. 'Victory' parts may not be as finely polished/finished as peace time production but are generally easier to find and cheaper.
The others are available too. Commercial production price /per screw gets into the $8 and $9 range.

The Victory/M&P extractor rod spring will fit OK.

The small hole in the yoke w/the spring in it was an early feature of the handejectors. Missing is a small plunger. That plunger usually launches away when the unsuspecting take the yoke out of the frame.
Being under spring tension, it takes a ride as the yoke is pulled free of the frame.
The spring loaded plunger was to gently hold the yoke and cylinder in the open/loading/unloading position for the shooter. That is done by the plunger dropping into a shallow detent milled in the frame opposite the assembly when the yoke is full open.
It works fine w/o it, but can be easily restored by making a new plunger out of suitable dia steel rod or even cut off a short section of the shank of a twist drill that fits the hole w/a slip fit. Bevel the edges of the plunger slightly so it doesn't snag in either the hole or in the detent.
If you can find a suitable dia steel ball,,that'd work fine too. Can't think of anything common that might work but there must be something around.,,the ball inside a Zerk grease fitting maybe?!

 

[DWalt]

Yours was probably made in 1906. If it has the square butt it is a Model of 1905; with the rounded butt, a Model of 1902. Screws, etc., have not changed much, but there were many lockwork changes made over the years. What you describe about the yoke is probably the cylinder hold-open detent. It was later dropped. You don't need it. If you need the upper sideplate screw, you should be able to find one. Sometimes Sarco has Victory parts, look there (Sarco is a good source for all sorts of parts, mainly military guns). Also eBay. Gun Parts/Numrich usually has the upper sideplate screws, but they are shown in the parts list for the Model 1917.

 

[hovercat]

Thank you DWALT and 2152hq for the helpful replies. It is a great help.

 

[cgt4570]

Cylinder hold open plunger

Numrich (Firearm Parts & Accessories | Military Surplus | Numrich Gun Parts) has a listing for N frame 1917. This listing has/had the hold open plunger (that often flies across the room when taken apart). It's the same for K or N frame. They should also have the large head upper sideplate screw under this section. If you strike out, send me a PM and maybe we can do some 'horse trading'.