Smoothing up a bolt gun

[cabezaverde]

Any tips on how to smooth up the action on a bolt gun?

My Interarms Mark X mauser has somewhat rough bolt movement through parts of it's cycle, even on an empty rifle. I suspect I am getting some drag on the floor plate but it seems smooth.

Function is fine, extraction and ejection is 100%.

Any tips from you experienced tinkerers?

[waksupi]

It seems the most common area of drag, is the top of the receiver ring, behind the ejection port. You may be able to polish it a bit, without buggering the finish. Also, sometimes an extractor will drag. Straightening the spring a bit can help.
Putting a coat of fine lapping compound on the bolt, and in the raceways, and working the bolt a few hundred times will smooth it out quite a bit.

[yondering]

I've dealt with this on several Mausers as well. Polishing the bolt and reciever contact surfaces didn't help; I don't know if the steel was a little soft or what, it just felt sticky, whether is was oiled, dry, polished, or rough. I think there is enough slop in the bolt guides that the bolt can get a little off-center and bind up. I tried different lubes and greases, none of them helped long term.

The one thing I found to completely cure the problem was the Brownell's teflon/moly bake-on coating. This stuff is pretty slick, and when applied to the bolt and receiver, eliminated all sticking. Of course, this is only an option if you want to coat your gun with it. I used the black, which looks pretty decent.

If you have a nice finish already, you could probably mask off the external surfaces and just put the teflon/moly coating on the inside of the reciever rings and other contact surfaces. It does require blasting with aluminum oxide or similar grit before application, so it's not just a quick and easy fix.

I imagine the NP3 coating from Robar would accomplish the same thing, if you liked the nickel look better.

[cabezaverde]

Think it will smooth out if I shoot the crap out of it?

[JW6108]

I had a copy of an old Shooting Times a few years ago that had a good article on this. Some things I remember offhand are:

Remove the extractor, lay it on edge on emery paper, etc. and polish. (If you want to tackle it, you can remove the extractor collar and polish it and its mating groove in the bolt body, but careful; it can be easily bent.)

Remove the magazine follower; polish tray and all sides.

While the follower is out, polish the bottom edges of the magazine opening (the underside of the feedway where the cartridges lie).

Polish the area where the cocking piece mates with the bolt body.

What waksupi said will handle most of the roughness, but be sure to just work the bolt back and forth. You definitely don't want to get any abrasive on the bolt lugs.

I've done most of this on my Ruger 77, and it is really smooth.

If you are not sure what to smooth up, work the bolt enough to get some wear areas to start showing up, then polish those places. You'll miss a couple of things like that, but that is the easy way.

[mooman76]

I have heard of some sitting down in front of the tv and just working the action a couple thousand times.

[crgaston]

Think it will smooth out if I shoot the crap out of it?


Definitely. Just keep shooting till there's no crap left and you'll be good.

[waksupi]

One thing that occassionaly shows up, is a reciever and bolt too close to the same hardness. They need to have a fair amount of difference, or there will always be some drag. Or wear, whichever way you want to look at it.

[Bret4207]

The cocking surfaces benefit from judicious stoning too. Sometimes they come out from the factory in rough shape.

[JW6108]

The cocking surfaces benefit from judicious stoning too. Sometimes they come out from the factory in rough shape.

Absolutely correct, and thank you for stating it more clearly than what I came up with.

My 77 was really rough in that area of the bolt, and I think that might be the place that benefited the most from the stoning, followed up with polishing. A mirror bright surface here does wonders when lifting the bolt.

[cabezaverde]

Actually, the stickiness is midway through the bolt cycle. Opening and closing is fine.

I am sure my problem is with the mag follower. Came to realize it is no problem when there are rounds in the mag, but the drag is there when the follower is rubbing on the bolt bottom. I guess I am just going to work on smoothing it (the follower) up.

[Ricochet]

I have heard of some sitting down in front of the tv and just working the action a couple thousand times.
Exactly what I was about to suggest. It's always worked for me.

Oh, and anhydrous lanolin on the cocking cams and lugs smooths things up better than any other lube I've tried.

[NoDakJak]

Waksupi is right. I once owned a very early Mini-MkX. The bolt in that da--ed thing was the stickiest of any that I have ever seen. No amount of polishing seemed to help nor did various types of oils or grease. If you were very careful and centered the bolt just right it would glide home slicker than snot. Just forget about normal bolt manupilation though. A few months later a firearms dealer in Rapid City told me that MkX had changed the steel formulation in the bolt and cured the problem. That news was a little late as I had dumped the little SOB on another unsuspecting soul. I have owned a couple more since then and have never run across the problem again. Neil

[725]

Aside from all the good advice above, practice / pay attention to, pulling and pushing in a straight motion. Side pressures induce the binding.

[phaessler]

Just my $0.02 here, alot of good thoughts are already here as far as smoothingthis up, but my own personal experience has been to remove some of the variables before you strat cutting/filing/grinding/polishing.
Remove the floor plate, does it cycle easier? Remove the trigger group, does it cycle easier? Take the extractor off, ( I would be thats what it is) does it cycle easier? Take the action out of the stock, does it cycle easier?
Sometime we all have trouble seeing the forest throught the trees.

Pete

[cabezaverde]

Using phaessler's approach, it is definitely the mag follower, as I suspected.

As soon as I dropped the floorplate, things smoothed right up. Now I have some polishing to do.

[MtGun44]

Why? You will be cycling over a cartridge, not a follower when you are
actually using the rifle.

Bill