[CollinLeon]

I have a Ruger Mini-14 "Ranch Model" in stainless steel. I probably bought it about 20 years ago. At some point, I decided to buy a Jonathan Arthur Ciener .22LR conversion kit for it and installed. I used it for plinking for awhile and eventually bought a Ruger 10/22 since the conversion kit just didn't work well with the standard velocity .22LR rounds -- definitely a waste of money.

It's been sitting in the back of my gun safe for a few years and as I was looking for something else in there, I stumbled across it along with some of the original parts, so I decided to go ahead and remove the conversion kit and reinstall the original parts. Of course, this meant that I got to spend the next 6 hours searching for the original parts (they weren't in the gun safe where they belonged).

End result was that I think that I found all the parts and it seems to manually cycle correctly, but I'm just not sure about one little part of it. I found the bolt, the Slide Spring / Recoil Spring (#KMS0501), Buffer Guide Rod (#MS03901), Slide Assembly (#MS23701), and Bold Assembly (#MS11001).

My Buffer Guide Rod does not look like the one that I see on the PDF file that I found on the web:

http://pdf.textfiles.com/manuals/FIREARMS/ruger_mini14ranch.pdf

The drawing seems to have a slanted end to it that fits into some sort of cup (Buffer Bushing #MS04010) whereas mine just a small pin type protrusion sticking out of the Buffer Guide Rod that fits in a hole on the forward edge of the receiver.

The only think that I have a question on is whether there is some sort of rod, tube, guide, or spring that goes between the Gas Pipe (#MS03600) and the Slide Assembly... The Gas Pipe has some ridges on it like what you sometimes see when a spring is screwed onto a rod, so I was thinking that many I'm missing something. Or does the Slide Assembly just slide along the underside of the barrel with without any sort of rod going through it? It seems that way, but I figured that I would verify it before I actually fired it. From looking at the drawing on page 41 of the above PDF file, I looks right. It's been too many years and the memory is just not what it used to be...

[LoonWulf]

there is no full length guide rod on the mini. The guide rod is what the spring goes over, so yes the oprod slides along the barrel.
Yours is an older style of mini a 180, Ruger redesigned the guide rod with a bushing to keep the slide assembly/op rod from peening the reciever (and destroying scopes). I would highly suggest picking up a shock buffer to go between your slide assembly and your reciever.
While these are actually designed for the mini they are known to cause some problems. http://www.midwayusa.com/product/300411/wilson-combat-shok-buff-recoil-buffer-ruger-mini-14?cm_mmc=Froogle-_-Gunsmithing+-+Gun+Parts+-+Rifle+-+%28Aftermarket%29-_-PriceCompListing-_-300411

or you can use one of these, which are cheaper and come in a pack of 6, they also work just as well and dont cause any issues with hold open or FTLs
http://www.midwayusa.com/product/241631/wilson-combat-shok-buff-recoil-buffer-1911-government-commander-polyurethane-package-of-6

this is the correct manual for your "180" series
https://ruger-docs.s3.amazonaws.com/_manuals/mini14-180.pdf

I just realized that the 180s have a smaller recoil spring then the 187+ (.316 opposed to .360). Those recoil buffers might be a little loose, but should still work well enough. A 180 owner can correct me, ive only taken one apart to clean a number of years ago.

Another option is to just find a hard rubber washer that has the correct ID to just go over your spring, and is about 1/8" thick.

[mtrmn]

It sounds as if you have assembled your mini properly. There is nothing that goes over the gas piston under the barrel except the slide assembly.

On the rear of the slide assembly there is a little tab that locks into a groove on the side of the receiver below the ejection port. Make sure you have that tab in the groove.

You are correct that the "pin" on the end of the guide rod just snaps into a hole on the front of the receiver under pressure from the recoil spring. Sounds to me like it's ready to test fire if all the above is correct. Since you did not mention it, I assume you remembered how the trigger assembly is installed.

As for yours being a "180", no it's not. The 180-series was ancient history by the time Ranch Rifles were introduced. Mine was a 183-series (1981 or so?) gun and it was bought a few years before I ever saw a Ranch model advertised. All you need do is look at the serial number prefix. The old 180-series was the original design and it is unique from all the later series guns. There were several changes made to the 181-series and later models.