Pierced Primers and Light Strikes

[Rivethead]

I need some help with a Model-11 Hunter in .223 that I recently bought used, to replace my Rem 700. The Savage does Not have an accutrigger, it has a Basix (set to 3 lb pull) that was supposedly installed by a gunsmith somewhere up in Phoenix. I don't have any issue with it but have read that light trigger settings can lead to light strikes... but that doesn't address the pierced primers problem.

At every range session I have been getting several Light-Strike or Failure-to-Fire with almost all ammo tried. Also when it does fire, a high percentage of pierced primers result. If the primer does not pierce then it usually has a noticeable crater as shown in the pics. Not always but usually. This happens with my reloads as well as commercial and milsurp ammo. My reloads are often well below book max so it’s not like I’m pushing the limits. Also, many milsurp and commercial loads are full power and just crater or pierce.

This same ammo fires without any problems from the Rem 700 and from 6 different AR-15’s I've had for the last 20 years, so it appears to be a problem with the Savage. I have Forster headspace gauges and it closes on the GO and doesn’t on the NO-GO so it appears to be within spec. I have also checked the case shoulder setback with a Dillon case gauge and they look fine.

Dry firing sounds normal with a healthy click. When there is a light-strike, the sound of the click is very light and there is usually only a slight shallow mark on the primer, like when an AR pin sometimes hits when chambering a round. Sometimes it might fire on the 2^nd try but several times I have tried 5 times with no success, then put the shell in another gun and it fires fine.

I usually use Winchester primers but have tried CCI, Rem Wolf and S&B with pretty much the same results. (The soft copper colored Wolf don't seem to crater or pierce) Although some of the reloads are at the minimum charge, the primers often look excessively flat and fill the pocket like it was a hot load.

I measured the firing pin protrusion with a depth mic and it is protruding .052”. I have read .036" is preferred by some so I may try that when I pull it apart. I haven’t disassembled the bolt yet but it appears clean in every respect I can see. The gun is only a couple years old (Cabelas special) with low round count. I plan on pulling it apart if necessary to clean, debur etc, but would like to see if there are other ideas or solution first. The stock is original and the bolt handle doesn’t seem to be touching.

This seems to be a common problem by the number of threads with people having similar issues. I have searched thru many threads complaining about light strikes looking for solutions, to no avail.Why hasn’t Savage solved this problem?

What could cause both light strikes AND pierced primers in so many varieties of ammo?
So far the only causes I can come up with are:

1. The FP is protruding too far, thus not enough travel to develop the energy required to set off the primer.
2. The FP is protruding too far, Thus when the primer does ignite and is pushed back against the bolt, it is pierced.

Here are some pics..

M193Surplus Hirtenberg commonly pierces or craters primers.


62.FMJ pierced


55.FMJ




55.AcuTip Normal firing but shallow indent



70.JSP Pierced



70.JSP Cratered



I don’t have any pics of the light strikes yet, but thanks for looking and any ideas on what to do next is appreciated.

[BillPa]

Seeing you've checked the chamber headspace and tried various ammo( head clearance, primers,etc) we'll eliminate those as the cause.

Cratering and or blanking primers is mainly do the pin tip profile and any chamfer around the pin hole. If you look at the tip on the left you'll see its ground more on a taper about a .030" or so long instead of a radius.

A pin with the factory profile on the left and one I re-ground to a radius on the right.



The pins set for .020" protrusion in the same bolthead. The factory on the left, the re-gound one on the right.



Since the primer anvil stops the pin forward travel and indents a primer no more than .025" the taper allows a gap between the pin tip and pin hole. Most times the indentation is less than .025" leaving an even larger gap.

Unfortunately, squaring the bolthead face is the only way to eliminate any chamfer around the pin hole.

As far as the inconsistent strikes it could be a number of things or a combination of them. A piece of a blanked primer cup in the bolthead, the trigger over travel set too tight, the sear contacting the stock, the sear binding on the action, too much pin protrusion(.030"-.040" is all you need) and etc. Its one of those issues you'll have to eliminate the possible problems one at a time.

In times like this the "supposedly installed by a gunsmith" worries me!

Bill

[Rivethead]

Thanks A lot Bill, there is a bunch of things to look at.
I don't have the equipment to square the bolt head but I could try a replacement.

Let me see if I understand what your saying in various parts of your post....

If you look at the tip on the left you'll see its ground more on a taper about a .030" or so long instead of a radius.

A pin with the factory profile on the left and one I re-ground to a radius on the right.

Here your talking about the tip angle vs your modified tip radius and NOT the angle of the taper further up the shank near the top of the photo...right?

So what your pointing out is a more rounded tip instead of one that might tend to pierce the primer cup... right? I could stone my tip to match.

The pins set for .020" protrusion in the same bolthead. The factory on the left, the re-gound one on the right.



Since the primer anvil stops the pin forward travel and indents a primer no more than .025" the taper allows a gap between the pin tip and pin hole. Most times the indentation is less than .025" leaving an even larger gap.

The modified tip looks like it fills the hole better, leaving less gap for metal flow and craters. More of the tip also protrudes which will give a better strike. The factory tip, although protruding the sam looks to be more shallow due to the angle it is ground. Also the reduced length of protrusion (from factory .05") helps keep from pin from piercing thru the cup. I will have to take my bolt apart and see if it has a screw adjustment, then take it down to about .035" and test it out. This may only solve the piercing issue which I see as the bigger problem as I don't want to cut the bolt head and I don't want hot gas finding its way toward my handsome mug.

Here are a couple pics of my bolt head & protrusion (yes its dirty from not cleaning yet)





There looks to be quite a bit of gap around that pin... I don't know if reducing the radius and lowering the protrusion will help with the cratering. Guess I'll have to try it but order a new head and pin just in case.



The light strike issue could be from a completely different cause as you indicate. I will have to hunt and peck around for a while and see what I can figure out. I'll update here as I can.

Yes, I agree with the 'gunsmith' comment and it is the first place I will look. You know how people say all kinds of things when they are selling their car or their gun. I'm not saying it isn't true, but people seem to like to tinker with their guns. I believe the guy probably did have it done by someone he felt was qualified, but I might have a different opinion (having been tinkering around with these things since the 60's :)).

I've already give the trigger install a once over and it does look "right" but will get familiar with the Basix trigger system and see if there is anything that might be binding or rubbing. The backlash might be a good place to start. I used my trigger scale and it has a fairly consistent let off just a hair under 3#. I'd like to keep that but IIRC some indicated light pulls can be problematic and might result in misfires with a Savage. Maybe they were talking about a stock trigger IDK. I can live with 3 1/2 or 4 Lb (maybe)

Thanks again and if you think of anything else...
Al

[KRP]

Your primers aren't being pierced, as in the firing pin is punching a hole through them. A piece of the primer cup the size of the firing pin hole is being forced out, think cookie cutter/dough in reverse, it's known as blanking. With the light strikes and blanking my first thought would be a weak or mis-adjusted firing pin spring and/or binding in the trigger or bolt. The tip profile and sloppy pin to bolt face fit aren't helping matters though as far as the blanking.

[sharpshooter]

99% of the time misfires are due to lack of firing pin travel. The cratering and blanking is just what Bill and KRP said. A weak or mis adjusted firing pin spring will not support the primer after it is fired. After the primer has detonated the powder charge, it creates about 60,000 psi that expanding in all directions, including on the little dimple that the firing pin just created. There must be some tension on FP to hold that dimple in place, or it will shear out, thus blanking the primer.
One thing you do want to check: after blanking a primer(s), disassemble the bolt and check the FP assembly. Typically when a primer is blanked, there is enough gas passing through the FP hole that it compresses the firing pin and spring to solid height, resulting in the damage to the cocking piece lock washer.( The one in the front of the cocking sleeve) They will typically break into pieces. Besides that, there will be soot everywhere.

[Rivethead]

Thanks for the insights, I appreciate the info.
I've never run into this type of blanking before, just run of the mill piercing, but I did think it was odd they were punching such nice even holes. Some of the primers look like the blank may still be down inside but I also suspect some of the metal could also be inside the bolt too (it has happened so many times. I will find out when I decap them. What is punching the hole? is it the edge of the firing pin hole in the bolt face as the primer is forced back? It looks to be about the right diameter.

So the next step is to dissassemble the bolt and see what it looks like. I probably should replace the spring and locking washer too wouldn't you say? Since I'm going this far would factory parts be the way to go or are there upgraded parts to consider (such as wolff springs)?

[pinsnscrews]

It is also possible, that the small gap around your firing pin is allowing a small amount of burnt powder into the bolt internals. This extra carbon is causing your firing pin to bind, not allowing it to strike fully, hence your light strikes. As you work the bolt, which retracts the firing pin, it frees it up slightly. Which is why you may be able to 'second strike the primer and it fires no problem, or you get frustrated trying to get that primer to fire and just put it in another gun. (The light strike from carbon build up is from experience with another firearm)

One thing you didn't mention, is if your light strikes are happening with a particular brand or not. For instance, my .308 has fits with Winchester White box. I can guarantee at least 2-3 light strikes out of a box of 20 rounds. It has not had that problem with any other brand I have run through it, not even the Win Razorback.

[Rivethead]

Wow,I thought this gun was a couple years old but I just looked up my S/N on Partsfinder and this gun was born June 5 2013 and I bought it used Dec 2013 so take a few weeks off for shipping to a distributor, then to Cabelas then to the actual sale, the PO must have had this problem right from the start and didn't know or want to deal with it, so dumped it. It's still under warrantee, but I'll be d***'d if I will pay the freight back to the factory for them to fix their mistake and poor QC.
I'll pay the extra for a PTG bolt head or for a local smith to sleeve the fp hole. Looks like those are the only fixes I see as viable (other than the FP work above)

Thanks guys for all the help, I learned something here.

ETA.. I took the bolt apart and found out I have the new style assembly, so there isn't any adjustment to the firing pin other than a one-way grinding of the tip. Also firing pin springs are the 2 (3) piece variety so Wolff EP are out unless I want to replace all the parts with the old style. I may end up doing that depending on what Savage says when I call them tomorrow. I did use a stone to reduce the FP tip radius a little and at the moment the protrusion .045". I didn't find any debris, carbon, fouling or other junk anywhere in the bolt and the spring washer was still one piece. I did notice a line of polished metal along the thin part of the FP shank so it was/is rubbing on something. I suspect it is the guide/head retaining pin in the forward part of the bolt. That may be the source of the light strikes but the amount of finish worn off the FP is about an inch of travel, similar to the distance the retaining button moves when released.
Also as a FYI, I used a torque wrench to break the factory BAS loose and it popped loose right about 40-45 Ft.Lb. , using a straight 1/4" Allen with no offset from the wrench lug. I put it back at 30#.