Occasional misfires

I bought a used Savage 116,it has an F 24xxxx s/n, so it could have been made as early as '89(doubt it's that old) Are Savages prone to firing pin springs getting weak,especially when stored cocked like most people do? I've already disassembled the bolt and cleaned it,saw some wear nothing too bad.Lightely lubed it and reassembled it. Still had 4 misfires,some light firingpin strikes. Bedded stock since then, found some high pressure spots,possible problem? Anyway has anyone heard of f-pin springs getting weak ? Paul

Springs lose tension from use, not being compressed. I have had yet to replace a firing pin springs in any of my Savages in the 20+ years I been shooting them.

Light strikes can be caused by a number of things outside the bolt. The sear may be be binding on action, making contact with the stock, the trigger over travel set too tight, and etc. All or any one of those things can pad the pin fall.

Bill

I have checked the sear/trigger clearance after release ,I can see light.As for binding on the stock,it did it w/orig.sav.synthec(plastic)and now w/a Boyd's stock. Now the Boyd's is bedded, haven't shot since bedding job. I'm using handloads, they work fine in another 7 mag,new Win.brass-FL sized. Checked fired brass vs. misfired ctgs. best I could w/a dial caliper.Minor differance-as you would expect fired vs.new/FL.sized.

I've seen instances where too much head-space will cause this. You should set your F/L sizing die so that it only bumps the shoulder back 2 thousandths. Your brass will last longer too.

I normally try not to mess w/the shoulder on rifle dedicated brass.I try to neck size only.I compared fired brass w/misfired brass using a dial caliper and found almost no differance in dimensions ,like if you had a out/spec. chamber,headspace prob,etc. Thanks,Paul

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Originally Posted by scpaul

As for binding on the stock,it did it w/orig.sav.synthec(plastic)and now w/a Boyd's stock.

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The sear could have been contacting is both stocks. Since you reload pull it out of the stock, prime a few cases( obviously no powder - bullets!!!) then try it. If it goes bang then you'll know its a stock issue.

Maybe the firing pin protrusion is set a little shallow? The correct protrusion is between .05 and .062 inch.

BillPa ,I had tried that,since the misfires were so sporatic not sure it was a fair test. I have bedded the Boyd's since then,1st time it wasn't exactly right,did some light grinding/roughing for good adhesion,another thin coat and it came out better than I expected. During the 1st bedding I did find the bbl. nut binding against the stock.It is now floated from the front, bottom,and sides(+3-4 layers of electrical tape)of the recoil lug to the rear action screw. When I get the piece I broke I'll try it again in the stock,torqued down. Thanks Paul

http://www.savageshooters.com/images...quote_icon.png Originally Posted by sharpshooter http://www.savageshooters.com/images...post-right.png

The tip of the firing pin will never indent the primer over about .025". It will bottom out on the anvil of the primer. Typically the protrusion is set from the factory at about .055", which is plenty long and all it does is limit the firing pin travel, giving less impact energy. .035" is optimum.

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Originally Posted by thomae

http://www.savageshooters.com/images...quote_icon.png Originally Posted by sharpshooter http://www.savageshooters.com/images...post-right.png

The tip of the firing pin will never indent the primer over about .025". It will bottom out on the anvil of the primer. Typically the protrusion is set from the factory at about .055", which is plenty long and all it does is limit the firing pin travel, giving less impact energy. .035" is optimum.

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Not sure where he came up with that optimum protrusion. At .055" my Savages won't even fire. I set mine to .060". Maybe there's a difference in the method of measuring?

Here's the method of measuring firing pin protrusion that I use: http://www.firearmstalk.com/entries/...l-10-Bolt.html

If you are not even getting a primer strike (no indent at all?) then you may have a headspace issue. It's a used rifle, so have you rechecked your headspace?

Storing a pin cocked will not weaken a spring, to the best of my knowledge.

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Originally Posted by Mr. Bruce

Here's the method of measuring firing pin protrusion that I use: http://www.firearmstalk.com/entries/...l-10-Bolt.html

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Here's a simpler method: http://www.savageshooters.com/conten...rotrusion-Data

Tomorrow I'll ck the pin protrusion. Steve the tech. @ Savage Shooters Supply said that the pin should protrude .055". I didn't know that the firingpin was adjustable;it will be working soon! Thanks Ya'll,have-a-good-one Paul

Some of the newer firing pins are not adjustable.

Thomae, G-mornin', I'll ck. it by ck'ing the pin diameter to see if it is a newer one (modified because the s/n would indicate thr older style system) Thinking about it there must have been a problem of some sort;all else being the same(pin weight,spring pressure,protrusion,etc)reducing the pin diadeter increased the P.S.I. due to the reduced impact area. Paul

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Originally Posted by thomae

http://www.savageshooters.com/images...quote_icon.png Originally Posted by sharpshooter http://www.savageshooters.com/images...post-right.png

The tip of the firing pin will never indent the primer over about .025". It will bottom out on the anvil of the primer. Typically the protrusion is set from the factory at about .055", which is plenty long and all it does is limit the firing pin travel, giving less impact energy. .035" is optimum.

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I'd like to understand this; "limit the firing pin travel"??

Ok, I freely admit that I am nowhere as smart as Sharpshooter when it comes to Savage Rifles, but:

1a) scpaul: I believe the diameter of the firing pin (at least near the tip) is the same for both the adjustable and the non-adjustable firing pins. The only way I know to tell what kind of firing pin I might have is to disassemble the bolt. If I am wrong, please educate me.

1b) I looked up Savage Shooters Supply on the internet and could find nothing. Do you mean Sharp Shooter Supply? In that case we are talking about Fred Moreo who goes by the handle "Sharpshooter" on this forum. He is the source of the quote I posted.

2) joeb3305: The primer consists of a cup (soft metal) and an anvil (harder metal) behind the cup. When hit by the firing pin, the cup deforms and allows the priming compound between the cup and the anvil to be squeezed, hit, compressed (whatever you want to call it) between the cup and the anvil until it ignites. The firing pin will not significantly dent or deform the anvil, so the anvil is what stops the forward movement of the firing pin. In a properly headspaced rifle, any firing pin protrusion over and above what is required to ignite/detonate the primer, is, in essence, wasted energy.

Since the location of the primer relative to the firing pin is determined by the brass, if there is too much headspace, (due either to an incorrectly installed barrel, incorrectly sized brass, or some other lesser occurring issue) there may be room for the whole loaded cartridge to move forward "too far" in the chamber. If this happens, then the energy of the firing pin moves the cartridge forward and then reaches it's own limit and stops forward movement before there is enough energy transferred to the primer to initiate the ignition sequence.

I hope that helps to make things clearer. There are likely other forum members who can explain it better than I.

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Originally Posted by Mr. Bruce

Not sure where he came up with that optimum protrusion. At .055" my Savages won't even fire. I set mine to .060". Maybe there's a difference in the method of measuring?

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.055" is still a bit deep , in my 6.5x284 with the pin set for a depth of .058" i was getting false pressure signs on the primer... Reduced it to .040 and the load showed no more cratering ..

I will say that maybe where some folks run into trouble when they reduce pin travel is not ensuring the proper installed height for the spring , my target action when inspected was out of adjustment in this area as well... After the pin depth and spring height adjustment i not only noticed my primers looking better i also noticed my ES #'s dropped to single digits from previous 12-15fps deviations.

I have 2 dial calipers,1 dial & 1 electronic. I use them to ck. 1 against the other, the measurements are virtually identical. I'm the using the electronic for convience. Firingpin diameter is .066,the protrusion is.075-.077, is, .020-.022 enough to warrant adjustment ? According to the S/N (F24xxxx) shouldn't it have the larger diameter firingpin ? What is it's diameter, I'm wondering if the prior owner had these problems. Paul

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Originally Posted by scpaul

I have 2 dial calipers,1 dial & 1 electronic. I use them to ck. 1 against the other, the measurements are virtually identical. I'm the using the electronic for convience. Firingpin diameter is .066,the protrusion is.075-.077, is, .020-.022 enough to warrant adjustment ? According to the S/N (F24xxxx) shouldn't it have the larger diameter firingpin ? What is it's diameter, I'm wondering if the prior owner had these problems. Paul

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Those numbers (0.075-0.077") are your protrusion depths?? Or are they the numbers you got when you did your plunge measurement from the bolt lug face to the top of the firing pin in the fired position?

The reason i ask is if memory serves me correct my measurement from face of bolt lug to the floor (where pin protrudes from) is .105 or maybe .107... Those numbers would make more sense if they were the measurement from face of lug to tip of pin in fired position , thereby making your pin protrusion at somewhere around .032" which may be a bit short.

Is this how you measured your firing pin protrusion?

To measure firing pin protrusion, use the depth measuring rod on the butt end of a set of calipers, put the calipers on the rim of the bolt face, then set your zero on either the bolt face or the protruding firing pin (in the fired/uncocked position), and then, without changing your zero, measure to the firing pin or bolt face (whichever you did not use to set zero). The difference between these two measurements will be your firing pin protrusion.

Did you ever check that your crosspin was aligned correctly? a misaligned crosspin could add friction to the firing pin, inhibiting it's movement (although I don't know if this would be significant enough to prevent primer ignition)

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Originally Posted by scpaul

Firingpin diameter is .066,the protrusion is.075-.077, is, .020-.022 enough to warrant adjustment ? Paul

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At .075-.077" its about .040" too long. Reset it to .035", .040" max.
http://i59.tinypic.com/nqcnc5.jpg

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Firing pin diameter is .066. According to the S/N (F24xxxx) shouldn't it have the larger diameter firing pin ? What is it's diameter Paul

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The difference between the old (.140") and the newer(.095") pins is the portion that passes through the bolthead retaining pin and the bolthead shaft to the vent. Pass that that they're same size.

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I'm wondering if the prior owner had these problems.

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Could be. It might be why is was on the used rack.

Bil

Well, I understand the firing pin/cup/anvil theory, but I never heard it before and am skeptical. I find it hard to believe that that little brass 3 legged anvil hitting the primer pocket can stop that firing pin. But-it doesn't matter.
I shoot almost only cast low velocity bullets. After installing a 22-250 barrel on a M10, got a few no-fires. 3 never went off, another half dozen fired on the 2nd try. I increased the firing pin protrusion from ~ .035"/.040" recommended to ~ .062", shot the same loads yesterday with no = zero misfires. More protrusion fixed misfires for me, yesterday.
joe b.

I am glad you cleared up the symptoms, however, I still would worry that something is not quite right if you need that much protrusion.
Here are some thoughts:

Have you checked the brass you are using with a comparator both before and after you fired?
Perhaps you need to adjust your sizing dies.

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Originally Posted by Mr. Bruce

I've seen instances where too much head-space will cause this. You should set your F/L sizing die so that it only bumps the shoulder back 2 thousandths. Your brass will last longer too.

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Were these cartridges loaded specifically for this rifle? If they were loaded for (and previously fired in) a different rifle, differences in the amount of headspace from one to another might be your problem.

If they were already shot in this particular rifle, could the brass is work hardened? If the brass is too hard, it might not take the shape of the chamber. This problem would be solved by annealing the brass.

How are you measuring for shoulder bump? You cant really measure bump correctly without a hornady kit which attaches to one blade of your caliper and uses a specific bushing to measure off the shoulder to compare cases. You simply can not eyeball it.

Remeasured the firing pin protrusion,it's a little over the spec. that Steve @ Shooters Supply gave me.(.055 vs. .069)I compared new full length resized brass to one time fired brass (same lot of Winchester brass)found very minor case body length difference.Notes outside in shop,measured w/digital caliper. If the headspace were off by much I'd have a noticeable differance in base to shoulder length.If memory serves the measured differance was .007 to.010,new F/L sized vs. fired. Can't prove it but I'm starting to get a gut feeling about the primers.I haven't had any problems with them before,but there's always a 1st. time. I've had this batch a while,they're Rem.9 1/2.They have been stored the same as the rest of my stock,several brands&batchs.Some older than these by 2 yrs.,and I'm still thinking about the bind on the bbl. nut I found when I bedded the stock. Guess I'll find out next range session.I'm in S.C., we've been having ice/snow/freezing rain. It's supposed to be over now ,so look out range here I come. Let ya' know how it turns out,THANKS all,Paul

Believe prob. is headspace. Shot today,had 3 misfires. Took 2 and w/ a pair/pliers and pulled the bullets out slightly, approx. 1mm. Before I pulled the bullets out I painted the bullet/case junction w/a sharpie so I could see the movement.Tried to fire them a 2nd time. The impact o0f the pin reset the bullets to the orig. O.A.L. I'm going to load a few more at a lower pressure and seat the bullet touching the rifling.There shouldn't be any slack movement,headspace prob. or not. At this point unless I have a bad f-pin spring the prob. is not the in the bolt. I don't believe the spring is the prob.,I can't see the pin impact changing that much nomatter where the ctg. happens to wind up with the bolt closed. Increasing the O.A.L. will position the ctg against the bolt face,and I plan to use a Lee crimp die to make sure it can't move when the f-pin impacts. F.Y.I. all tests have used the same batch of Rem. 9 & 1/2 primers. Thinking about that I'm going to load a few of the previously misfired cases w/CCI l.rifle primers just to be absolutely sure no primer prob. exists. Thinking about it I used my RCBS case checker to ck. for case streaching ,looking for the thin ring ahead of the the cases belt . The cases I ck'ed had been fired 3X. That should have been enough to detect case streaching if I had a headspace prob. I think in a.m. I'm going to disassemble the bolt again. Thomae, I think that you will find that a spring like a f-pin spring will loose strength from being left compressed for long periods of time or being exposed to high temps.(don't believe temp. has caused any problems here,it would need to be much higher than inside the rear window of a truck.(gun rack) Can't do any range work until next week, I'll let you know what happens. Glad I"m getting to work this out before it's rechambered or rebarreled. Thanks everyone,Wish me luck Paul

"Thomae, I think that you will find that a spring like a f-pin spring will loose strength from being left compressed for long periods of time or being exposed to high temps."

Lots of people want to believe that, but since the early 60's, firing pin springs have been made from "rocket" wire. Rocket wire as it is known, was developed by NASA and soon replaced music wire springs which were known to take a set. Even in the fired stage, the firing pin spring is still compressed @20 lbs. For heat to damage the temper, it would have to be in excess of 350 degrees. I check every main spring when I rebuild actions with a spring scale and have yet to find one that is below specs.

Sorry it's taken so long to get back with ya'll. I've been fighting compuker problems, one after another, think we finally found it. After numerous things I finally streched the firing pin spring +- 1/2 in., that got it, no more misfires even with the batch of cases that were causing the problems. I haven't changed anything else, dies,primers,seating depth, nothing. Maybe this spring wasn't up to spec. or who knows what the prior owner did. Guess I'll be ordering a new f-pin spring soon. Thanks everybody for the help, Paul