The safety on my Mod. 70 Win .375 H&H works hard when moved to the on position. So I am fixing it so that the safety works smooth. I polished the mating contact surfaces of the safety and firing pin to correct the problem. I then noticed that the firing pin is a two-piece assembly; it�s a .29� Dia. X 6.5� long pin inserted into a hole in a .46� dia. X .75� long lug for an overall length of 7.25� long firing pin. It would appear that the hole in the .46� dia. lug to accept the pin is not straight, so the pin tip is off the centerline by .06�. or you could say that the lug axis is not parallel to the pin axis. When I say the lug, it is the part that makes contact with the trigger assembaly. If the pin is straight to the bore of the gun, then the lug is crooked and bends in toward the safety and maybe the crooked pin assembly is causing the problem with the operation of the safety.

If this makes any sense to you;
1. Is this normal and/or acceptable or does it need fixing?
2. Should I straighten the pin assembly?
3. Should I take it back and get a new pin?
4. Should I just put it back together and see if it works ok?

So far on this rifle I have found that Winchester has trouble drilling a round hole (chamber reamer chatter) and now I see they also have difficulty drilling a straight hole. Doesn�t Winchester know that a guy needs a good hole for his gun?

The firing pin assembly is threaded together...then pinned. The pin shouldn't effect the alignment of the cocking piece and firing pin, but god only knows for sure what their entire process is and it's faults, but I would assume that there shouldn't be an alignment problem that would be causing your sticky safety.
The most likely cause is the safety lever itself. They are investment casted, and often times the detents that are casted into the safety are done very poorly, causing excessive friction and misalignment with the bolt-locking plunger.
The unfortunate part of all this is, you may have no choice but to replace the whole assembly, praying that you get a good one, but I wouldn't bet the farm on it.
Your other option would be contacting Jim Wisner as I'm pretty sure that he's making replacement safety levers for existing shrouds.

We do machine a replacement M70 lever for the factory sleeves.

They will fit the pre 64 from about 1946 to 1964 and the post 64 up to about 1992 when they changed the shape of the lever and sleeve.
Now for the bad part, this lever is restricted to GUNSMITH installation only.

Now to double check a few things.

Check the sear pin, up till the mid 90's the sear pin is only held in by the spring pressure, and the stock. It will
back out and cause lots of problems. The current production has serations that binds it into the hole.

The edge of the cocking piece were the angle for the safety lever stops, is sharp. It can be slightly radiused, and polished to help the camming process.
DO NOT remove any material from the angle flat, or CHANGE the angle this is the surface that retracts the firing pin.

You can put a small amount of moly dee or RIG on that surface to lube the safety lever as it rotates.

Jim Wisner
Wisner's Inc.

I fixed it; The safety works great now. I removed the firing pin and ground some metal (about .01 to .015�) off it at the angled flat adjacent to the safety�s cam on the .46� dia. I know now that the position of the firing pin when in the cocked position is critical to the safety�s operation. The recess cut into the pin (that�s the angled flat) must allow the cam of the safety to work freely and without interference. In other words, when in the cocked position, operating the safety should only make slight contact with firing pin. The safety�s cam should just miss the pin. Anyway all three positions of the safety now work the way they should. I am not a Gunsmith, but it seem fixed correctly to me. Better than new, for sure. The only other test is to impact the butt with the trigger pulled and safety on; veiwing the safety mechanisium and the way it works I don't see how the pin could move forward when the safetys engaged.

JBM,
The safety has to cam the cocking piece (firing pin) back off of the sear about .020" when you put it on. This is to insure that if the trigger is pulled and then released when the safety is on there is enough clearence for the trigger to move back into position to catch the sear when you take the safety off. If too much material has been removed from the angle on the cocking piece (firing pin) and the trigger has been pulled and released while the safety is on you may get an accidental discharge when you take the safety off.

Good Luck,
Headache

Humm.....Thanks headache. I will check this out. I have pulled the trigger with the safety on and then taken the safety off with no problem; but will take a closer look see. Thanks for the input, I know what to look for now.

Headache, I looked the rifle safety over and found; While the gun is assembled, the cocking piece can be viewed at the rear of the bolt. When the safety is moved from the �off� to the �on� position the cocking piece moves rearward a distance of, as near as I can measure it, 0.020 inch plus or minus 0.005 inch. This should be acceptable and safe.

It appears that the safety will work hard or not at all, if the cocking piece is too far forward and the safety has to move it back much more than 0.02�. If the safety lever has to move the cocking piece back say 0.04� or more, the loads will be high and the safety lever or cam will eventually fracture. The two surfaces that control how the safety contacts and loads the cocking piece is the surface that contacts the sear. Removal of material from this surface moves the cocking piece forward and increases the loading. The other surface is the angled flat of the cocking piece adjacent to the safety�s cam. Removal of material from this surface will increase the distance between the safety�s cam and the cocking piece which will decrease the loading. Adjusting these two surfaces so that the safety moves the cocking piece and firing pin back only 0.020� (viewed and measure on the rifle at the back of the bolt) and your safety should work smooth. This is what I found during my analysis of this mechanism, but please note, I have no gunsmithing education.

JBM,
You have it correct. The factory grinds the cocking piece where it contacts the sear at final assembly to compensate for the tolerence stack up. It is designed to have material removed until the proper 'lift off' is reached. If you do not have enough 'lift off' you would remove material from the bottom of the cocking piece where it contacts the sear. Too much 'lift off' and you would work on the angled area of the cocking piece where it contacts the safety.

I think I had the material thing backwards in my earlier post.

Headache