O.K. here's my problem and I hope someone can tell me whats wrong. The rifle is a Ruger 77 ultra light in 250 savage and the problem is every 2nd or 3rd shot it miss fies. When I extract the miss fire cartridge the primer is barely dented.I've taken the bolt apart and cleaned really good and the firing pin,spring and all internal parts look good.This is really starting to piss me off cause there doesn't seem to be any reason for it.If it was a problem within the chamber why doesn't it do it everytime ?This rifle is approx. 20 yrs. old and I can tell from looking it over that it's not a problem with being worn very much.Anyway any help would be great. Thanks.
Miss fires
- Thread starter Swifty
- Start date
I have only used reloads.
Works o.k. on the first couple of shots then it miss fires.
Actually the firing pin snap sounds weaker than my other rifles ?
Bolt handle down fully.
Another thing I noticed is the part of the bolt end (firing pin assembly)that drops into the slot on the bolt case doesn't appear to be bottoming out.
Works o.k. on the first couple of shots then it miss fires.
Actually the firing pin snap sounds weaker than my other rifles ?
Bolt handle down fully.
Another thing I noticed is the part of the bolt end (firing pin assembly)that drops into the slot on the bolt case doesn't appear to be bottoming out.
Make sure there is nothing in the bolt body that could be affecting the fall of the firing pin.
Easy enough to change the mainspring.
It is possible that your cases are over sized, creating a headspace issue. If there is excess headspace, misfiring could occur.
Try priming some fired cases, and see if the primers fire reliably - don't load powder and bullet, just the primer. Unsized cases fired in the rifle should be tight against the boltface.
Try some factory ammunition.
Maybe try different primers - although a rifle in good order should fire any primer.
Easy enough to change the mainspring.
It is possible that your cases are over sized, creating a headspace issue. If there is excess headspace, misfiring could occur.
Try priming some fired cases, and see if the primers fire reliably - don't load powder and bullet, just the primer. Unsized cases fired in the rifle should be tight against the boltface.
Try some factory ammunition.
Maybe try different primers - although a rifle in good order should fire any primer.
Swifty,
An easy way to see if you have sized too small is to half install a spent primer (not a live one - just press it in the pocket with you finger) and chamber it . Then, look if the primer seats flat with the head.
It is the best and easiest way to verify it if you don't have the right tools to do so correctly.
An easy way to see if you have sized too small is to half install a spent primer (not a live one - just press it in the pocket with you finger) and chamber it . Then, look if the primer seats flat with the head.
It is the best and easiest way to verify it if you don't have the right tools to do so correctly.
Thanks I'll try that.Upon thinking of this a little more there just doesn't seem to be a reason.The first cartridges I tried where new brass that I ran thru my dies like I do when I full length size and they would miss fire like usual about every 3rd shot.The next time I just necked sized so the Cartridge would be back against the end of the bolt and they where no better.I've also tried WLR and Fed.210M primers and both miss fire. It's kind of like the firing pin sometimes doesn't come out far enough to deliver a good hit to the primer ??.When it does miss fire I wait a few seconds and then extract the cartridge and you can see a small dent but not near enough to ignite the primer.If I take that same cartridge that miss fired and re-chamber it and slam the bolt forward and locked (bang) off she goes. I original thought maybe the firing pin spring was cracked but I can't see anything wrong with it.Also if I hand load a cartridge and slowly push the bolt forward and locked it will miss fire everytime.
You are assuming that the case normally stretches lengthwise.
Not true, unless your are using really hot loads.
Suggest you check for excess headspace by chambering a fired case with primer that stands proud of the head by about 0.015", remove and measure case length and case+remaining primer protrusion length.
SAAMI specification for headspace is no more than 0.006"
If not that, then it seems like either your firing pin is short or something is interfering with its travel.
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If it was a headspace issue, the misfiring could be unpredictable. If the extractor holds the case against the boltface, ignition might be normal. If the extractor does not hold the case, it can move foreward from the impact, and cushion the blow.
Make sure there is nothing inside the bolt that could impede the firing pin. Dirt, a disc from a pierced primer, etc. Grease and cold weather can cause problems.
If the rifle was firing normally, and then stopped, something has changed. Mechnically, there is no way for firing pin protrusion to have changed. It is not adjustable in a Ruger. A new mainspring is inexpensive.
Make sure there is nothing inside the bolt that could impede the firing pin. Dirt, a disc from a pierced primer, etc. Grease and cold weather can cause problems.
If the rifle was firing normally, and then stopped, something has changed. Mechnically, there is no way for firing pin protrusion to have changed. It is not adjustable in a Ruger. A new mainspring is inexpensive.
Can just the mainspring be replaced or do you have to buy a whole new complete firing pin assembly.In researching this problem another website fellow was having the same problem and a gunsmith fixed it by replacing the mainspring because he said it was an original ruger from factory 21# spring which was replaced with a 24# one and it fixed the problem.How do you take the firing pin assembly/spring etc; apart??
Does it have a factory trigger? When i swapped my factory out for a Timney on my M77 220 Swift, the sear was slightly dragging and would slow the pin down enough to make this happen every once in a while. Pissed me off too, but i got it fixed by a competent smith, not the hack who installed it, and everything worked perfect again.
Ruger 77 misfires
Since you have disassembled the bolt, check to see that the firing pin assembley is FULLY SCREWED IN. If you are one turn out, the firing pin will not hit the primer.
Next. Take the firing pin assembley out of the bolt, and thouroghtly clean the inside of the bolt. There just might be a bit of dirt, crap, or crud that is at the bottom of the hole, and is cushioning the firing pin when it falls. I would use some spray type solvent, like carburetor cleaner: connect the little tube that comes with the can and insert it into the bolt. Do this outside, be careful, wear eye protection.
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Since you have disassembled the bolt, check to see that the firing pin assembley is FULLY SCREWED IN. If you are one turn out, the firing pin will not hit the primer.
Next. Take the firing pin assembley out of the bolt, and thouroghtly clean the inside of the bolt. There just might be a bit of dirt, crap, or crud that is at the bottom of the hole, and is cushioning the firing pin when it falls. I would use some spray type solvent, like carburetor cleaner: connect the little tube that comes with the can and insert it into the bolt. Do this outside, be careful, wear eye protection.
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