Winchester model 100 expert needed

hats off

Dixie Gunsmith,

Hats off to you for a comprehensive and apparently knowelegable set of posts, and a desire to see the issue through.

Big fan of the M88, and its semi brother the M100.
 
Shot the model 100 yesterday. It cycles now most of the time. About once per magfull it would cycle but the trigger would not pull. Not sure what its was doing. If the disconnect was not releasing or if the hammer was not going all the way back. It ejected and had a new round in the chamber. I shot it 15 times and this happened twice. I would cycle the bolt and it would work again. It still is giving me fits. lol to top if off I put a different scope on it and it wont adjust high enough to be on at even 25 yards.
 
If the hammer wasn't going all the way back, it would follow the bolt forward. If so, you would be able to see the hammer behind the bolt, thought the operating handle slot in the receiver. Also, it would probably dent the primer on the cartridge, but not enough to fire it.

You may have something fouling the trigger spring. It is under the trigger at it's front. If it was to foul, it may not let the trigger be pulled back far enough to release the sear. Another place could be some debris in the safety, which would foul the trigger being pulled far enough back too.

The gun looked pretty clean to me, but something could get into it.
 
There was no dent on the primer. I had the whole trigger assy apart so it is clean other than the slight chance of something falling in there. I will have to try it again. I was just agrivated about the scope deal also. lol
 
Since you had the trigger assembly apart, then you can see how it works. It may be possible that the hammer loses enough force to indent a primer, if the hammer follows the bolt, but you'll have to fire it until it does it again, to catch that, by looking through the cocking handle slot at the end of the bolt. If it does do this, it sounds like it could be a gas problem, etc. In other words, there's not enough pressure to force the piston back hard enough to fully push back the bolt. That could be a leaky piston seal, or the gas hole in the barrel may be dirty.

Mounting scopes has made many a man curse their gun
 
Dixie, I think we got off into two different areas, I am still think’en ,
The recoil block and group assembly should be tight, it looks like I can see a little chatter of the two over the years.
What does the recess of the screw hole shoulders look like. Would a thin washer used with the screw tighten things back up???
Click to expand...
Just seems like kiss is in order, after all, everything was working until this..
This would accomplish the squeeze 98 220 was doing, would it not??

 
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It could be from that, but it also sounds like it could be the action bars binding, if not the gas system. I always check the gas system first, before I start looking for binding.

If the receiver to recoil block was a little loose, I would think the bars would have slack in them. That's why I believe he was having problems out of that trigger lock. The cam on the one bar was not pushing the lock all the way down, due to the slack or wear. I think that was why Winchester quit using the lock in later rifles.
 
I can't see how the washer would help. I have assembled the rifle out of the stock and the block is very tight against the trigger housing. To me its just a bad design.

I looked at the rifle last night the trigger "cocks" its self long before the bolt is fully back. Too short to pic up the next round from the mag. So It can't be "short stroking". I will need to get some more ammo and try again.
 
Being that the case, if it does it again, before pulling back the bolt handle to eject the round, look through the slot in the receiver at the back of the bolt, and see if the hammer followed the bolt. If it did not, then you'll see the end of the firing pin, but if it did, its hard to miss the hammer.

For the hammer to follow the bolt, the rear disconnector hook would have to not catch the hammer after firing. Check to make sure the hook spring is good, and that it works freely. Also, check the teeth on the hook, and the notch in the top of the hammer that the hook catches, for being rounded over, etc. It's job is to catch the hammer, with the trigger pulled, and not allow the hammer to follow the bolt. The front hook is the sear, which is used to fire the gun.

When the gun fires, and the bolt goes back, the hammer is mashed down, and the rear disconnector hook supposed to catch the hammer, at the rear. When you let off on the trigger, the sear hook at the front, catches the hammer, as the disconnector hook releases it. Then, it is cocked, ready to be fired again.
 
Update

Took rifle out yesterday to sight in scope. Put in two rounds pulled trigger both rounds shot off. Tried again same result. I have not done anything since last time out other than put scope in different mounts. Did not even remove stock. Trigger works fine if dry fire and work bolt manually.

It is time to throw in the towel. I guess I will need to find a gunsmith that can fix this rifle.
 
It has a bad rear disconnector hook on the trigger, or hammer notch is worn for it then. It could also be the disconnector hooks spring bad.

Check the notch on top of the hammer, to see if it is rounded off, and not square. That notch is what the rear hook catches. Also, check to see if the hook is rounded over, or if the spring isn't pushing the hook forward hard enough. The rear hook should be engaged firmly with the hammer notch, with the trigger held back, and jarring it shouldn't make it let loose.

The last to check, is make sure the hammer has no sloppy movement about its pin. It should rotate, but not move side to side, or rock, etc.
 
May not be relevant at this point, but back when I was in the business, if I recall correctly, there were 2 or 3 different sizes of extractors for the M100. Something like a-b or c or the like. The size was related to how long the extractor was. Seems as there was enough variation with the bolt machining to make this necessary.
 
Have a post 64 model 100 in 308 Win with the impressed checkering.
I've owned several Winchester model 100s.
If you find one that consistently prints 1 1/2" or less 3-shot groups at 100 yards consider yourself very lucky and hold onto it.

Rules of engagement:
1) gun needs to be stripped and cleaned after each & every hunting season. If you get the gun wet you need to strip it down & clean it.
2) each & every time before going into the field check and make sure the screw that is part of the forearm sling swivel ring assembly that secures the barrel to the stock is snug.
3) my Winchester model 100s showed a propensity for shaking loose scope base screws. If you're scoping your model 100 thoroughly clean the top of the receiver and bottom of the scope base as well as all the screw holes with degreaser and then securely Locktite the base screws in. Any residual oil finding its way onto the scope base screw threads will prevent the metal to metal Locktite grip that you need to hold the base secure.
4) don't drown the model 100s action in oil. Use only a drop or two of high quality gun oil that won't turn to sludge in cold weather and work it in by cycling the action. Too much oil attracts dirt and the 100 even more than other SA rifles is very dirt/grit/rust sensitive.
 
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