light primer strikes
- Thread starter 458lott
- Start date
- Location
- Western Manitoba
Is not likely to help you, but I am going through similar with elderly german made "boy's rifle" in 22 Long Rifle - a YouTube guy pointed out how misalignment can create drag or "ticking" on that firing pin as it goes forward - slows it down - still working on this one to resolve that - getting 50% "clicks", but always fires if I re-#### it - so doubt very much this applies to your case, but maybe some food for analysis?? Is your firing pin completely clear and free within that bolt, or is it caked up with factory grease, etc. - I know was not too difficult to tear down the bolts on my Model 70's - but I found much grease crap in one, that got all flushed out with solvent - bore brush and patches inside the tunnel within the bolt, etc. I replaced with very thin coat of painted on oil on the spring - not sure that any bolt rifle that I use needs grease in or on the firing pin or firing pin spring. Just looking at options what would cause that symptom, without going looking for replacement firing pin spring - which might be the final solution, anyways.
Is also firing pin protrusion from bolt face, firing pin tip shape, etc. or cocking piece dragging on burr or whatever within bolt shroud that could be the culprit.
Is also firing pin protrusion from bolt face, firing pin tip shape, etc. or cocking piece dragging on burr or whatever within bolt shroud that could be the culprit.
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How used is it? Checked with different brass, different primers, different ammo, as the case may be?
Start with checking the pin protrusion. Heavier spring won't push the pin farther through solid metal of the bolt. Typical should be somewhere in the 40 to 60 thousandths of an inch range. And I may be wrong, there.
Clean out the pin space in the bolt. Really dig, at the forward edges on the inside, anywhere mung can be pounded almost solid by the pin, as it travels, esp if the pin protrusion seems short. While the bolt is apart, check for wear on the one side of the pin spring, seeing if it is dragging. Same for the pin, and other parts. Drag isn't going to help.
Check Headspace. Belted round, so should be lots of gages around. Gyppo move... Scotch tape or thin parcel tape can be built up in layers on the case head, and the added thickness measured with a digital caliper or micrometer from the front of the belt or the full length of the case... Would not rely on this, but it would give me reason to have at a proper set of gages if it seemed out of line... Safety applies, use an empty, or do it while the pin is removed, if using a live round. Don't force the bolt to close on the stuff either. Not hard to clean up, but a PITA.
You don't state if this is across several ammo suppliers, reloads, etc., or just one type and source. A short belt and a deep chambered belt cut may both be in spec, but the combo can do you issues. Min/Max Chamber, and Min/Max Cartridge dimensions can be found online.
It is possible that a different ammo supplier's product, will change everything, or it may be you got 'that' gun, where every part is technically in spec, but the tolerance are all stacked up in just the wrong way that it is right at the wrong far end of the possible range.
Start with checking the pin protrusion. Heavier spring won't push the pin farther through solid metal of the bolt. Typical should be somewhere in the 40 to 60 thousandths of an inch range. And I may be wrong, there.
Clean out the pin space in the bolt. Really dig, at the forward edges on the inside, anywhere mung can be pounded almost solid by the pin, as it travels, esp if the pin protrusion seems short. While the bolt is apart, check for wear on the one side of the pin spring, seeing if it is dragging. Same for the pin, and other parts. Drag isn't going to help.
Check Headspace. Belted round, so should be lots of gages around. Gyppo move... Scotch tape or thin parcel tape can be built up in layers on the case head, and the added thickness measured with a digital caliper or micrometer from the front of the belt or the full length of the case... Would not rely on this, but it would give me reason to have at a proper set of gages if it seemed out of line... Safety applies, use an empty, or do it while the pin is removed, if using a live round. Don't force the bolt to close on the stuff either. Not hard to clean up, but a PITA.
You don't state if this is across several ammo suppliers, reloads, etc., or just one type and source. A short belt and a deep chambered belt cut may both be in spec, but the combo can do you issues. Min/Max Chamber, and Min/Max Cartridge dimensions can be found online.
It is possible that a different ammo supplier's product, will change everything, or it may be you got 'that' gun, where every part is technically in spec, but the tolerance are all stacked up in just the wrong way that it is right at the wrong far end of the possible range.
Donny Fenn1
CGN Ultra frequent flyer
- Location
- East Kootenays
"new" as in just out of the box?
check/clean the firing pin channel and spring (disassemble the bolt) could be gummed up with factory lube grease etc
check/clean the firing pin channel and spring (disassemble the bolt) could be gummed up with factory lube grease etc
Says new model 70, I took that to be the new model, not a New, Model 70. But when the OP gets back to us with better information, we'll know.
I had this happen with a new Tikka CTR. They apply some sort of heavy grease on the pin at the factory that can sometimes cause drag issues inside the bolt. I pulled it apart and cleaned off the excessive grease and it’s been fine ever since. I’m not at all familiar with model 70s but that’s where I’d be looking
- Location
- Western Manitoba
More evidence to me - see Post #2 - my "fight" with a german made boy's rifle and light strikes - appears to be related to how the trigger is pulled. Entirely different trigger mechanism than the Model 70's that I have. Although, I suspect the basic principles of operation are still similar - firing pin has to strike the primer with enough energy to set it off - weight has not likely changed, so that leaves speed (velocity) - so about anything slowing that down - weak or inadequate spring, drag, grunge, congealed or dried grease - might be enough to slow it down to cause light strikes? It appears on this elder rifle that a "tentative" or "dainty" trigger pull allows the sear bar to apply spring loaded tension to the underside of the cocking piece - likely slowing it down enough - by using much more "firm" and more "rapid" trigger pull, I went from 50% "clicks" to no "clicks". I am assuming for now, was how it was designed - 105 years ago ... And as aside, I do note that every "click", did fire, when I re-cocked and tripped the trigger a second time.
What is the vintage of you 375 H&H? I have two newer model 70 Extreme Weathers, love those rifles, however one has developed light primer strikes. I took both bolts apart and the one with light primer strikes the firing pin spring is visibly shorter; and when measured comes in at 4.318” vs 4.464” in the functioning rifle. The shorter spring was also easier to compress to take the retaining clip off the firing pin to remove and reinstall the spring.
I’m trying to source a replacement, but the newer post 2008 rifles use a different spring and appear to only be available throughWinchester directly.
- Location
- Saskatchewan
I have a similar problem with my 2 year old Winchester M70 Alaskan .375 H&H. Light firing pin strikes. About one in 5-10 cartridges fail to fire.
I completely stripped and cleaned the bolt inner surfaces, firing pin, and spring and re-lubed with light synthetic oil, but the problem persisted.
My gunsmith checked the headspace with proper gauges, and headspace from bolt face to front of the cartridge belt is within specifications.
He said firing pin protrusion is at minimum, but still within normal specs.
So I asked my local gunsmith to increase the firing pin protrusion, but he was not able to do that, not sure whether or not he knew how.
So I seem to be left with three possible options - send the bolt out to someone who can increase firing pin protrusion, or perhaps just buy a new firing pin and / or spring in the hope that new parts will work better.
It's frustrating. Any suggestions?
I completely stripped and cleaned the bolt inner surfaces, firing pin, and spring and re-lubed with light synthetic oil, but the problem persisted.
My gunsmith checked the headspace with proper gauges, and headspace from bolt face to front of the cartridge belt is within specifications.
He said firing pin protrusion is at minimum, but still within normal specs.
So I asked my local gunsmith to increase the firing pin protrusion, but he was not able to do that, not sure whether or not he knew how.
So I seem to be left with three possible options - send the bolt out to someone who can increase firing pin protrusion, or perhaps just buy a new firing pin and / or spring in the hope that new parts will work better.
It's frustrating. Any suggestions?
- Location
- Western Manitoba
Longwalker - not sure at all whether relevant to your case - I had bought a Model 70 new in 1976 - in 308 Win - so headspaces on the shoulder of the chamber, not on a belt's recess. I used it many decades - then my son "inherited" it - in minus 30 weather, using my hand loads - he had a mis-fire - primer is dented, but was no "bang" - claims he lost that deer as a result. Only happened that once - and I had been reloading for that rifle since at least the 1980's. My solution was to install a "Wolff"(?) brand firing pin spring - said on the label it is rated at slightly higher foot pounds than I believe was factory original. No reports of similar since - but was my attempt to fix a "one of" occurrence - over perhaps 40 years of using the rifle - many hundreds, if not thousands of hand loads fired without incident, except that "once". Was no evidence of chips missing from firing pin tip, etc. - so was no reason that I could find - except that bitter cold, and perhaps a somewhat weakened coil spring after the decades - at least was my thought at that time.
Longwalker and 458lott: maybe check sear drag too. Have you adjusted the trigger lately? It’s easy to adjust them out of reliable range depending how the adjustment mechanism works on your rifle. Headspace is usually the culprit when handloading (always headspace of the shoulder not the belt and only bump the brass back 2thou. With factory ammo, I’d be looking at sear drag or something else going on with the trigger/cocking mechanism. I’ve even seen this issue happen because of contact between the stock/bedding and trigger parts.
Good luck.
Good luck.
- Location
- Saskatchewan
Never thought about the sear dragging, it makes sense as a possible cause. Thanks for the suggestion. I'll check that out.
I read an article in the light gunsmithing column of rifle magazine in which the author stated you should use graphite lube for the firing pin assembly, not normal lube. The product he suggested was an alcohol suspension which evaporates leaving the graphite. Is it possible the synthetic lube you are using might be the culprit? I have a MRC 1999 in 35 Whelen which had the same issue with three factory loads right out of the box. I disassembled the bolt and cleaned thoroughly, wiping off the lubricant, theoretically leaving only a slight residue of lube. Problem went away. You can get graphite lube at the hardware store which is intended for door locks. My only concern was the idea of the alcohol suspension removing the rust preventative element of the normal lube, so I haven’t tried the graphite yet. The only other light primer strike issue I had was with a Remington 722. That was cured with a new firing pin spring.
- Location
- Saskatchewan
I spoke with a warranty gunsmith for Winchester today. The light firing pin strikes were a known issue with magnum chamberings in a few Model 70's from a couple years ago. Mine will get a new spring and possibly new firing pin which should solve the problem.
My first thought as well. I experienced light strikes when I pushed the shoulder way back when resizing (I was sloppy!) Some of my reloads didn’t even fire.
I had light primer strikes / misfires now and again on my Marlin 17 HMR rimfire. Then it got worse, half were light strikes. Ordered a new firing pin from Numrich and same results. Found a local here with the same rifle and his bolt worked perfectly in my rifle.
So went to take the bolt apart and found the retaining screw near the back end of the bolt was loose. Tightened it up and no more problems. Wish I had found that first as the old firing pin was probably just fine.
Sometimes it’s the simplest of things…
Here’s a pic of the bolt and you can see the screw.
So went to take the bolt apart and found the retaining screw near the back end of the bolt was loose. Tightened it up and no more problems. Wish I had found that first as the old firing pin was probably just fine.
Sometimes it’s the simplest of things…
Here’s a pic of the bolt and you can see the screw.
