110 Firing Problems

[GodandGunsCowboy]

I have a 110 in 7 Rem. Mag. I bought used that has a history, as long as I've had it, with failing to fire. When I first purchased it and took it to the range it fired 9/20 rounds, light primer strikes on the other 11. We took it back to Gander Mountain where it was purchased from and they "fixed" it under their policy by replacing the mainspring. They said they put 7 rounds through it no problem. I got it back, shot it and took it hunting no problems as well, primer strikes looked normal. The next time I went to shoot it, it was back to not firing and light primer strikes. I adjusted the firing pin protrusion multiple times with no luck. Headspace, as best I can tell is about 3-4.5 thousandths (2 pieces of scotch tape on a spent case). The gun is has the old style bolt.

Is there a difference between the mainspring for magnums vs non-magnums?

Any ideas what the issue may be?

[wbm]

This is an odd 110 problem. Moon phase perhaps?

Since the spring was replaced and assuming the rear bolt assembly screw is tight I would think the problem is not there. There is a sticky on the forum that addresses the right way to adjust firing pin. I think I would go through that....especially the part about the cocking pins forward most travel setting.

[seanhagerty]

Have you checked your headspace? Maybe see the base to shoulder length on the brass that wouldnt fire vs brass has been fired? If there is a significant difference, then maybe the barrel have the headspace adjusted.

Sean

[wbm]

I thought BillPa had left the forum but he has not. Sorry Bill! Someone told me you had and I took their word for it. Bad on me.

[GodandGunsCowboy]

[Quote] Have you checked your headspace? Maybe see the base to shoulder length on the brass that wouldnt fire vs brass has been fired? If there is a significant difference, then maybe the barrel have the headspace adjusted. [Quote]


right now it has 3-4.5 thousandths of headspace. That's if my source/calculations for the thickness of scotch tape is correct. I don't have gauges.

[GodandGunsCowboy]

This is an odd 110 problem. Moon phase perhaps?

Since the spring was replaced and assuming the rear bolt assembly screw is tight I would think the problem is not there. There is a sticky on the forum that addresses the right way to adjust firing pin. I think I would go through that....especially the part about the cocking pins forward most travel setting.

It is an odd problem, I'm tempted to send it to Sharpshooter.

Are you talking about thomae's article on firing pin protrusion? I read it and the the firing line. I'll have to track down calipers, I don't have a set.

[wbm]

No it was an article done by Bill PA....had lots of photos etc. He left the forum and when he did he took down the article. I was having a problem with a long action and light primer strikes. I adjusted the firing pin protrusion and still had the same problem. Bill PA's article helped me cure the problem....and it was with the cocking pin. The cocking pin should not contact the bolt body in its forward most position. The firing pin hits the concave area at the rear of the bolt head and stops. If the cocking pin sits too far forward it hits the bolt body before the firing pin....that ain't good. When I adjusted the cocking pin travel the problem went away.

[thomae]

BillPa is still a member of the forum.

[eddiesindian]

whats changed from the time you went hunting and the next time you tried firing again?.....ammo?

[wbm]

BillPa is still a member of the forum

He is. Got some bad info....sorry bout that.

http://www.savageshooters.com/showthread.php?20789-Mis-Firing-Problems

[BillPa]

No it was an article done by Bill PA....had lots of photos etc.


and if I can locate them I'll copy them to the pic posting site I use now.

Anywho, you only want .035-.040" bench firing pin protrusion. Since the primer anvil stops the indentation at about .020" any more only shortens the pin fall and reduces primer impact energy. If the protrusion is .055" the pin fall is shortened .035". With .035" protrusion its only shortened .015". That mere .020" means more time for the spring to accelerate the pin assembly and create more primer impact energy, that pesky E=mass*velocity2.

But, before attacking anything, I'd rip it apart and give it a thorough cleaning, trigger,sear, bolt interior, pin assembly, bolthead bore ....everything! From experience cleaning a used gun is usually it's first....ever!

Bill

[GodandGunsCowboy]

whats changed from the time you went hunting and the next time you tried firing again?.....ammo?

Just a few months time :neglected: ammo was the same (rem. corloct and Win. XP3 or whatever they call it).

[GodandGunsCowboy]

and if I can locate them I'll copy them to the pic posting site I use now.

Anywho, you only want .035-.040" bench firing pin protrusion. Since the primer anvil stops the indentation at about .020" any more only shortens the pin fall and reduces primer impact energy. If the protrusion is .055" the pin fall is shortened .035". With .035" protrusion its only shortened .015". That mere .020" means more time for the spring to accelerate the pin assembly and create more primer impact energy, that pesky E=mass*velocity2.

But, before attacking anything, I'd rip it apart and give it a thorough cleaning, trigger,sear, bolt interior, pin assembly, bolthead bore ....everything! From experience cleaning a used gun is usually it's first....ever!

Bill

I want to adjust the protrusion at the front of the pin and then back that stop pin off of the cutout in the bolt when the firing pin is in the forward position. Correct?

It's been cleaned a time or two since I've had it, but a good bath won't hurt it.

[bootsmcguire]

I am with billpa on this. Give the bolt one heck of a good cleaning.

Also I would check the headspace with gauges or at least several different pcs of brass (fired and un-fired). When I was setting the headspace on my 7 Rem Mag I was using the brass as my gauge. Long story short I discovered that the base to top of the belt varied in dimension by a pretty fair amount. Since the belt is what headspaces your round on virgin cases/ammo that is the important dimension. Now if you are reloading, you can neck size your cases and use the shoulder for your headspacing, but it sounds like you are using factory ammo.

I would compare the base to shoulder measurements on rounds that fired vs. rounds that did not and possibly see if you are getting a major difference in your headspace between them.

[sortafast]

I have some old bolt parts and FP if you want to try something different. Mine are out of a gun from 1958. If GM switched out the whole FP assembly, the older FP's where a different length than the newer ones (If I remember right) and that could potentially cause the issue. I switched my gun to the new style with a PT&G bolt head and bolt body and the old style FP doesn't really want to play well with it. I had to modify it a little, but I think it could still work in a different, older action like mine. Other than that I don't know what could be at fault here.

[BillPa]

I want to adjust the protrusion at the front of the pin and then back that stop pin off of the cutout in the bolt when the firing pin is in the forward position. Correct?



Basically your adjusting the firing pin assembly length to the bolt body you have.

First set the protrusion then adjust the cocking piece so the cocking piece pin has a just a bit of clearance at the bottom of the cocking ramp, maybe .010" or so. The amount of clearance isn't real critical, keeping it close only insures the fining pin spring is compressed as much as possible when cocking the bolt.

Bill

[GodandGunsCowboy]

Adjusted firing pin. Thanks Bill.

Testing on Tuesday.

[jonbearman]

If these are reloads then the problem could be there.If you adjust your die to touch the shellplate,you can induce more headspace and it sounds like your headspace is already out of spec.When I headspace,I use a go gage and after adjusting the headspace I use a piece of scotch tape to make the gage a no go gage.If it cloase's I start over.If you have .0045 plus possible induced headspace by sizing wrong and the pin is adjusted wrong,it all add's up.

[GodandGunsCowboy]

I'm using factory Rem and Win cartridge. I'm thinking it is a combination like you're saying, hopefully I can get it fixed before deer season opens, otherwise I might have to buy another one ... and that would be a shame :)

[GodandGunsCowboy]

and if I can locate them I'll copy them to the pic posting site I use now.

Anywho, you only want .035-.040" bench firing pin protrusion. Since the primer anvil stops the indentation at about .020" any more only shortens the pin fall and reduces primer impact energy. If the protrusion is .055" the pin fall is shortened .035". With .035" protrusion its only shortened .015". That mere .020" means more time for the spring to accelerate the pin assembly and create more primer impact energy, that pesky E=mass*velocity2.

But, before attacking anything, I'd rip it apart and give it a thorough cleaning, trigger,sear, bolt interior, pin assembly, bolthead bore ....everything! From experience cleaning a used gun is usually it's first....ever!

Bill

The shortest I'm able to get the protrusion is .11 with .2 of travel. I'll post pics tomorrow if it doesn't work.