[Walter]

Today, I was mounting a scope on a friend's stainless Mini-30. It's equipped with a Butler Creek folding stock. I personally installed the stock several years ago, and the rifle has had a hundred or so rounds fired through it since the stock was installed.

When I cycled the action, the piston came loose and rattled around. Because the piston was out of place, the bolt wouldn't close. I removed the gas block and replaced the piston. Cycled the action a few times and the same thing happened.

To make things worse, I rounded off two of those ridiculous hexhead gas block screws. Got new screws on order. Will probably have to drill the old ones out.

Does anybody have any ideas as to why the piston all of a a sudden won't stay in place?? Also, does the tapered end of the piston go towards the breech or the muzzle? Any input would sincerely be appreciated.

I haven't worked on a Mini since I gave mine away six or seven years ago, and I don't have a manual for this one.

 

[Boar Hunter]

I don't know why it's falling out, but the manual says tapered portion of the rod must go under the cross pin at the time of reassembly, which is at the chamber end of the rifle. I hope this helps .

 

[Walter]

Boar Hunter:

I appreciate the response. I'll go ahead and completely field strip this mully and see if I can get it to work. This thing sure is more aggravating than my AR!!

 

[Boar Hunter]

I was just looking at this manual and happened to think is he missing the cross pin that holds rod assembly in.

 

[Walter]

When you say rod assembly, are you talking about the gas piston that fits in the end of the operating rod and into the gas block??

 

[Boar Hunter]

I'm looking at this manual and I see the gas piston, it looks like they show a gas port bushing holding the piston in place. The tapered end to the breech.

 

[Walter]

Does the manual happen to give the torque specs for the gas block screws??? Thanks for your help.

 

[Boar Hunter]

Walter, it doesn't give any spec's, it wants you to send it to ruger for gas block work, that figures. I hope have helped.

 

[4v50]

Boar Hunter diagnosed the problem correctly. The little gas tube which keeps the gas piston from rotating is missing. You can order replacement parts from Brownells (and order 4 new hex screws while you're at it). No biggie to fix it.

 

[Walter]

I already ordered the four hex screws from Brownell's. Do you know the name of the part that keeps the piston from turning?? Since the gun hasn't been disassembled since I put the stock on several years ago, what could have happened to the missing part??? The rifle's been fired a hundred rounds or so since I put the folding stock on.

Thanks for the help.

 

[Boar Hunter]

Walter, in my ruger manual the part is called a gas port bushing, part number KMS02500 and it's priced at .50

 

[Walter]

Boar Hunter: I really appreciate the effort that you've made to help me with this. The guns is owned by my best friend, who, by-the-way, recently gave his 1992 Caddy Seville to my lawschool daughter. I really hated screwing up his rifle.

I found a schematic of the Mini in Gunparts Corp's cat. Brownell's carries the part and I just ordered it. I can't imagine what happened to the original part, unless I left it out when I installed the stock, several years ago, and it just took until now for the piston to malfunction.

Looks like I might have to drill out the rounded-off hexscrews and take them out with a screw extractor.

 

[abc]

I think the bushing will deteriorate over time and disappear. My mini-14 did the same thing. I just ordered a new bushing from gun parts corp. No problem.

 

[Walter]

I think, in my case, that the guy who put the folding stock on just left the gas port bushing off. At any rate, I got the Mini sighted in this afternoon, and it seems to be working o.k. I delivered it to its rightful owner, and hope to never have to shoot it again. (Since the owner is my best friend, that's highly unlikely.)

 

[Boar Hunter]

Walter, I'm glad to see everything worked out with the mini-30. Good shooting!!