Model 110 misfire and question about the cocking washer

[banjoguy]

I've been working on a late 60's project gun. It's got an aftermarket 257 Roberts Ackley barrel on it. I think the headspace is long because 3 out of a box of factory 257 Roberts failed to fire. The primers had light strikes, and on several of the ones that did fire (about a third), the primers were backed out noticeably (about 10 thousandths). I never really shoot factory, so I can work with that.

I worked some tricks at the reloading bench and got the 257 Rob brass fireformed nicely such that the fired cases have flush primers and their shoulders are consistent in length as measured with a comparator--so the case headspace is good. FL sized them per the instructions Forster provided which resulted in the shoulders being set back 2 thousandths at most (maybe the headspace is fine?). This morning to test some loads. I had one misfire out of around 30 rounds. The shoulder on this one measures essentially the same as all the others. Nice primer strike. Popped the primer out and it contained all the normal stuff. I've fired approximately 4k of these primers, all out of a single sleeve with never an issue (Remington 9 1/2's).

More back-story. Earlier this week, I noticed the telltale signs of ancient WD40 on the receiver and the body of the bolt. I took the bolt apart, hosed the body and firing pin down thoroughly with brake cleaner. Lubed the firing pin like it was a semi-auto pistol, and reassembled. I have since realized that I used too much oil on the firing pin.

Coming back from the range today, I did some googling, pull the bolt apart again, wiped off all the excess oil, and cleaned sticky stuff off the other parts of the bolt that I neglected last time around. Other than the excess oil I put on, I don't think anything else I cleaned off would have contributed to firing pin drag.

The cocking washer looks ugly. It looks like someone did some heavy-handed grinding on it to bring the lobes close to flush with the sleeve that fits over it. I'm wondering it that would cause drag, and I'm tempted to clean it up--it looks like there's some material to work with such that I can file more flush, and then polish it.

What exactly is the function of the cocking wash, and specifically, does it interact with the sear (i.e. is it part of the trigger pull equation)?

Also, it has the factory trigger (pre-accutrigger). It's very light. Very similar in feel to my Win 52D target 22.

[Robinhood]

What is a cocking washer? This diagram is complements of Numrich Gun parts. Can you see this well enough to identify the part you are talking about.

https://www.gunpartscorp.com/pub/schematic/Savage_110B,C,D,ESeriesJ,K_schem.jpg

[darkker]

Yeah, i don't know what a cocking washer is, or how one "lubes it line a semi auto pistol"???
But if you had it apart, yet neglected to lube parts and over lived others..... Then the first owner week could have done the same. So down where the firing pin goes through the bolt head could be crude. Or, what I think is more likely. The first guy stored the rifle cocked, the firing pin to a set, and is weak.
Also this is a Savage, loosen the nut and check headspace yourself.

[banjoguy]

Part #30 on the Numrich dwg above. Flat stamped washer part, cruciform outline, D-shaped hole in the middle. Goes between the big spring and the cocking nut on the back of the striker assembly.


I'll order a new spring. That seems like a good idea.

Gunk in the bolt and bolt head: I had spent a whole can of brake cleaner on/inside them and was in there with brushes, patches, q-tips and pipecleaners. Those were clean.

Lubing a semi auto: apply 2 drops of oil to each rail, reassemble.

[Texas10]

I have found that the cocking washer you mention can hang up on the last thread of the firing pin, causing a light strike. What I did was to polish the flat area of the pin, along with the corner of that last thread where the aft threaded portion transitions into the un-threaded portion of the pin. Also polish the inside of the sleeve, and the cocking nut #28. Assemble the firing pin being careful to center the flat on the cocking washer as it relates to the flat on the pin, and place it pin tip up on the work bench.

Using a suitable punch installed into the cocking pin (#29) hole, compress and release the spring repeatedly and notice any drag or tendency to hang up. If any is found, disassemble, polish and repeat until it operates smoothly. Lightly oil and carefully assemble being certain that the cocking pin is not hard against the bottom of the bolt body when in the fired condition.

YMMV, but I did this to all three of my model 12's and no longer worry about FTF.

[Robinhood]

The washer needs to be indexed so that the cocking piece sleeve(28) fits into the groove of the washer(30) and lines up with the hole in(25) along with Texas 10's info. Also measure the captured spring length.

[banjoguy]

Ok. Understand the alignment of the parts. Polished the pin (33) in the 3/4" run where there is a wear pattern from the washer (30). Cleaned up the lobes on the washer with 500# sandpaper as best I could and stuffed a dremil buffing tip in there to break the ID edges a little. Sanded the ends of the spring (31) smooth.

The relaxed spring measures 3-7/8". Long action btw. Can't find what length it is supposed to be.

When reassembling, I thread the sleeve (28) all the way down, then back off as necessary to get everything lined up, correct? ETA: figured that out. Sleeve is set to that the firing pin bottoms out instead of the cocking pin (29). I haven't moved the stop washer and nut (34 &35), so protrusion should be the same. It's 0.055" btw, and I don't intend to monkey with that.

Next up I think I'll pull the trigger apart, clean, lube (lightly), and adjust the pull weight up, and add a smidge more overtravel. It seems like that also could be a player.

[BillPa]

Next up I think I'll pull the trigger apart, clean, lube (lightly), and adjust the pull weight up, and add a smidge more overtravel. It seems like that also could be a player.


Yes, the trigger should had a little over travel.
http://s6.tinypic.com/zujb51_th.jpg

If you look close the sear travels in an arc and follows along the radius on the trigger. If the OT is set too tight it will drag on it disabling a clean release of the cocking piece pin and pad the firing pin fall.
As far as the trigger, get a bottle of Ronson lighter fluid then use it to flush the entire trigger group. Don't be cheap, keep dumping it on and working the trigger-sear until it drips out clear, no additional lube required. It will leave a fine oil behind which is perfect for triggers plus you won't have to rip anything apart.

Bill

[banjoguy]

Alright! Got the bolt all cleaned out, and adjusted plus the trigger cleaned and adjusted.

I also decided to save the last couple hundred of my Rem 9 1/2's for the rifles that I have loads already tuned for and switched over the Winchester WLRs. Things are much better, and we haven't missed a beat so far (60 or so rounds downrange). I think we've got the issue licked.