I improved the operation of my rifle this evening. The bolt operates so much more smoothly, it surprised me. Essentially, I cleaned off some rust underneath the bolt shroud.



Winchester makes the firing pin/striker assembly for its M70 Classic rifles by pinning two pieces together, then bluing. Bluing salts leach out around the seam and the pin, and this causes rust. Because the rust roughens surfaces that rub together when the bolt is worked, the presence of rust makes bolt operation grittier and more strenuous than it should be.



I had sent my rifle to a gunsmith, and as near as I can tell, he didn't use the same oil as I usually do, so the striker was visibly rusty and it was difficult to lift the bolt handle when I got the rifle back.



I doused the area with Break Free CLP and dry fired and wiped off rusty oil and repeated until the oil stopped coming out rusty. The bolt worked about as well as it did before I sent I out. Actually, when I bought the rifle, it had rust there too, and I had done the same treatment. Perhaps Break Free is just a little better than some other oils at inhibiting bluing salt rust. Anyway...



I decided to look a little further. I stripped the bolt according to the owner's manual instructions. That doesn't get you any closer to seeing where all the rust is coming from. To do that, you need to take the firing pin/striker assembly out of the bolt shroud. It's not an impossible job, but it's not as easy as, say, adjusting the trigger. It does help if you have fairly strong hands, and if you have three hands, it's a piece of cake. I found it was easier putting the thing back together than it was taking it apart. That's nice, because it's so embarrassing bringing a bringing a bag of parts to the gunsmith to see if he can re-assemble them for you.



Anyway, the firing pin spring must be removed first. It's held back by a washer and a C-clip. The clip will fall right off the shaft of the firing pin, once spring tension is released, so you don't need special pliers. Maybe I should call it a U-clip. The opening in the side of the clip is a parallel-sided slot, and it doesn't bend in like a C. The action of the clip doesn't involve any springiness. I hope that's clear enough.



Strip the bolt according to the manual. You can make the rest of the job a lot easier by releasing some spring tension and giving yourself some room to compress the firing pin spring. To do this, clamp the body of the firing pin in a padded vise. You're going to be pushing the firing pin back and the bolt shroud forward, so butting the firing pin's second shoulder up against the vise padding is helpful. Grab the bolt shroud, and push "forward" (in the direction of the firing pin). This will compress the firing pin spring. Put the safety in the "Fire" position, and release the spring tension slowly. The firing pin will come forward a little, and you'll find it much easier to remove the C-clip and washer as described in the next paragraph.



Stand the striker/shroud/firing pin assembly on the benchtop. A towel under the striker helps to keep it from sliding around. Actually, you can get yourself another 1/8" of room to work if you put a small object (I used a Q-Tip head) under the rear of the striker to hold it forward. Grab that firing pin spring really good and push down to compress it. Pull the C-clip off the shaft (or ask your third hand to do so). Carefully release the spring and washer. Put the safety in the "Fire" position (if you haven't done so already). Now you can slide the firing pin out the back end of the bolt shroud. Easier said than done, unless you have a third hand.



My guess is that you will see some rust on the striker, particularly right in front of the little ramp that engages the safety and around the little pin on the top of the striker body that Winchester pinned the two parts together with. Clean off the rust with a bronze brush, bronze wool, and some oil.



What I did next may not be advisable. I used 600 grit lapping compound to lap the surfaces that ride on one another as the rifle is cocked. First I lapped the little ramped surfaces that actually do the cocking, and then I lapped both sides of the little channel that the striker bottom thing rides in through the bolt shroud. If I had a skinny enough stone, I would have used that. I just used lapping compound and the striker itself. I did no do any lapping on the striker channel of the receiver.



What I did next might not be advisable either. I de-greased the striker and boiled it to get out the bluing salts. Actually, I repeatedly immersed it in boiling and then cold water to draw in and expel water and so rinse out the bluing salts. The first few times, I heated with boiling water and then cooled using liquid dish soap to get the soap into the crevices. After that, lots of cycles with boiling and cold clean water. At the end, I heated it in a hot pan (to boil the water out) and cooled by dipping in Break Free CLP (to draw the oil into the crevices). I did this a few cycles, each time verifying by touch that the striker was a little hotter than the boiling point of water. You can do this by remembering how hot a pan full of boiling water feels. I didn't want to do any heat treating, but I did want all the water out of there. Only on the first couple of heated oiling cycles did I see droplets of water emerge with the oil. I'd have used my vacuum oven to really get the moisture out, but it's not quite set up yet.



After getting all the lapping compound off everything, I greased the surfaces that needed greasing and put the thing back together. While you've got it all apart, it's kind of interesting to work the safety and see how it holds the bolt down and the striker back, and why you can't engage the safety unless the rifle's cocked. That's if you're interested. If not, just put it back together.



Put the safety on "Fire", stand the firing pin/bolt shroud assembly on the towel and Q-Tip. Press that spring and washer down until you could put the C-clip back on (if you had a third hand). Ask your wife to put the C-clip back on. No, the other way, with the flat side going the other way. The way it was when we took it apart. It's just oil, Honey. No, I don't think it causes cancer. I hope not. Just,� Okay, wipe off the oil first. Here, let me. Okay, now, when I get this spring compressed, just slide that C-clip on over the little groove. There. Thanks Honey.



Okay, now, before you put the striker/firing pin/bolt shroud assembly back in the bolt body, you need to put the safety back in its middle position. Again, put the firing pin in your padded vise with the second shoulder butted up against the vise padding. Grab the bolt shroud, and compress the firing pin spring until you can put the safety in its middle position.



Then just put your rifle back together the way the manual say to.



I was amazed at how much slicker the bolt is with all that rust off and with grease on. I don't know how much the lapping helped matters, but I figure the places I lapped would have worn smooth like this eventually.



H. C.

Typos!

If the previous description left you scratching your head and saying "Sear of the striker? What the hell is that?", it's not Microsoft's fault. I typed that piece in Word and ran a spell check. Yes, sear is a word, and Word's spell checker doesn't highlight correctly spelled words for you.

It should have said "rear of the striker", not "sear of the striker".

Sorry about that.

I have corrected the mistake.

H. C.

Well, this morning, I had all of them out. I was trying to figure out why some of them shoulder so nicely and some of them feel awkward for one reason or another. How good the rifle or shotgun feels to me is not a simple function of length of pull, I've found. I also measured the length from the butt to the pistol grip (up about where my pinky sits), and again, there are good feeling guns that are long or short in this measurement; and there are guns in between that feel awkward. I've got more measurement work to do before I start sawing on stocks.

That's not why I've replied to my thread a second time.

A long while back, I commented at how much slicker my Browning A-Bolt II felt than this M70. I thought it was going to take a lot of getting used to a two lug bolt and all the force necessary to operate it.

While I had them all out, I worked the bolt on the A-Bolt II and the M70. Since the "bolt job", the M70 is much slicker than the A-Bolt II. The A-Bolt has so much friction, it feels as if you could stop anywhere in the middle of cycling the action, and the bolt would just stay there. By comparison, it feels as if you could practically toss the M-70's bolt back or forward and it would finish cycling. That's an exaggeration for illustration purposes. Remember, the A-Bolt II felt slick (compared to the M70) the day before yesterday. Today, the M70 bolt is much slicker than the A-Bolt II's.

Okay, my one eye's getting dim, and I maybe can feel some fuzz coming in on the palms of me hands. Done replying to myself for now.

H. C.

Good DIY topic Henry.

The LOP to the pistol grip is more critical than to the trigger.

Hope this helps.