MK-85 Questions

[rugerbh103]

I just picked up a new to me MK-85. It wasn't quite in the condition it was advertised but the price seemed reasonable, I hope I got an ok deal. Outside is pretty good, the bore however had been left fouled. There was a light coat of rust all the way down it. I had to hammer out the breech plug with a rubber mallet. To my surprise after a few hours it has cleaned up real nice. The bore rust seemed to be only on the surface and scrubbed all out. I replaced the breech plug with a hex head #11 I had as a spare for my LK-93. It went in almost to easy so I'll check if the parts are interchangeable. I also replaced the hammer spring with one off of an extra LK-93 action I had lying around. I can see some rust under the ramrod thimble, but can't get those screws to budge.

Now for my questions if you would be so kind?
- Did the MK's have an O-ring on the back of the hammer assembly? This one didn't have one but I suspect someone lost it. I added one off a spare LK action I have but now the assembly stands a bit off of the action. (pic #3)
- My LK came with a spacer between the trigger assembly and the screw. Again none on this gun, should it be there?
- Does anyone have a source for the O-rings on the hammer assembly or hammer springs? Waiting to hear from Knight and Numrich is sold out. Knight sells a kit but has more parts than I need and the safety parts seem to be of the newer style.
- There is still a slight amount of pitting under the nipple on the action and some very small rust spots near the muzzle end of the barrel. Any tips on how to attack those without messing up the surrounding finish? (pic #2)

I know that is a lot of questions. I'm truly grateful for any assistance.

I can't wait to shoot it. I bought the LK-93 on my 18th birthday. I wanted the MK-85 bad back then, but there was no way I could afford it. As I recall there was a big price difference.

 

[GM54-120]

Naval Jelly or EvapO-Rust will remove the rust but it is possible they might leave a slight stain on the surrounding finish. The rusted area needs to be submerged in EvapO-Rust for the best results. Also avoid getting it on blued parts. Naval jelly you could apply with something like a Q-tip to just the rust spot/s. It works pretty quickly.

Glass bead blasting to a matte finish is pretty cheap and it will leave a new even finish over the entire barreled action. See if a local machine shop offers the service. You may find it as cheap as $35.

The older MKs didn't use a O-ring on the hammer assembly. They had a set screw on the left side of the action at the rear. Later models did use the O-ring. If you need an o-ring i would just take the one you have to a hardware store and match it up.

 

[rugerbh103]

Thanks.
I'll get the o-ring off.

 

[sabotloader]

I just picked up a new to me MK-85. It wasn't quite in the condition it was advertised but the price seemed reasonable, I hope I got an ok deal. Outside is pretty good, the bore however had been left fouled. There was a light coat of rust all the way down it. I had to hammer out the breech plug with a rubber mallet. To my surprise after a few hours it has cleaned up real nice. The bore rust seemed to be only on the surface and scrubbed all out. I replaced the breech plug with a hex head #11 I had as a spare for my LK-93. It went in almost to easy so I'll check if the parts are interchangeable. I also replaced the hammer spring with one off of an extra LK-93 action I had lying around. I can see some rust under the ramrod thimble, but can't get those screws to budge.

Now for my questions if you would be so kind?
- Did the MK's have an O-ring on the back of the hammer assembly? This one didn't have one but I suspect someone lost it. I added one off a spare LK action I have but now the assembly stands a bit off of the action. (pic #3)

Some MK's the newer ones with a GM barrel - do have the "O" ring. Older models with a set screw on the left side of the receiver do not use the "O" ring - they can but they did not come that way.

- My LK came with a spacer between the trigger assembly and the screw. Again none on this gun, should it be there?

I have never seen this spacer you talk about on any Knight. So I can not help on that one.

- Does anyone have a source for the O-rings on the hammer assembly or hammer springs?

The "O" ring can be had at any automotive parts store just take the hammer assembly with you and find a ring of the correct size.

Waiting to hear from Knight and Numrich is sold out. Knight sells a kit but has more parts than I need and the safety parts seem to be of the newer style.
- There is still a slight amount of pitting under the nipple on the action and some very small rust spots near the muzzle end of the barrel. Any tips on how to attack those without messing up the surrounding finish? (pic #2)

I know that is a lot of questions. I'm truly grateful for any assistance.

I can't wait to shoot it. I bought the LK-93 on my 18th birthday. I wanted the MK-85 bad back then, but there was no way I could afford it. As I recall there was a big price difference.

 

[rugerbh103]

Thanks for the tips. I'll stop by the store tomorrow and start working on the rust spots.

I am finally out of scopes. I had a bunch laying around but all I have left is a Weaver Handgun scope that I can't seem to sell or trade.

Can't wait to see how it shoots. With any luck this will be my new deer hunting gun.

 

[tpcollins]

The older MKs didn't use a O-ring on the hammer assembly. They had a set screw on the left side of the action at the rear. Later models did use the O-ring. If you need an o-ring i would just take the one you have to a hardware store and match it up.

I bought an MK85 when they first came out. It has both the O-ring and a set screw on the side. The O-ring started to deteriorate over time so I took it to the hardware store and matched it up with a new one. I would think the O-ring is to keep the knurled ring from "sticking".

 

[gmstack]

I owned 2 mk85s and they both shot extremely well. an inch or less at 100yds was the norm for both of them. they both had timney triggers I suspect yours does also. they are a pure pleasure to shoot. good luck with it . It looks to be in excellent condition. guy

 

[rugerbh103]

Your right, it does have a Timney Trigger. It has the slightest amount of creep but breaks clean and is fairly light. Can I ask what your go to load was? I was surprised how well it cleaned up. The bore looked real bad, bit the price seemed low enough to risk it.