Tikka T3X Failure to Fire

[Rugger7622]

I've shot 200 rounds of Starline and had no issues......but because it drives me nuts, I've gone back and done more brass prep work on the LC brass, I haven't shot it yet, but I did find I wasn't seating/crushing primers and my primers were basically flush (.000) below the case, which was .007ish away from the primer pocket bottom.
Another thing I found was the brass that I had FTF's on, the shoulders were also pushed back .007-.010, after at least two attempts of getting them to ignite. I would not have believed a firing pin would do that, but I've got 15 pieces of brass that all started at .000 and ended at the numbers noted above, which indicates the force of the firing pin went into seating the primers and not setting them off. Hard to believe, but I did dig up a couple of threads where others saw this same thing.

I did a bit a primer pocket uniforming (that is so fun) and bought a FA hand primer that has adjustable depth and I'm now crushing about .006, which should be fully seated. I've got 200 LC prepped in this manner and will load in the next couple weeks and shoot them. The only thing I can fall back on is "stacked tolerances" of a tight chamber, not fully seated primers.....but I don't know. If I shoot and have any FTF, I don't know what to do and will move back to just Starline brass, which makes no sense.

I've stuck with this barrel and Starline because it shoots so damn good, basically .75" groups of whatever bullet throw down it for 10-15 shots, it's a great barrel.

More to follow after I shoot.

 

[mtnbound]

I've shot 200 rounds of Starline and had no issues......but because it drives me nuts, I've gone back and done more brass prep work on the LC brass, I haven't shot it yet, but I did find I wasn't seating/crushing primers and my primers were basically flush (.000) below the case, which was .007ish away from the primer pocket bottom.
Another thing I found was the brass that I had FTF's on, the shoulders were also pushed back .007-.010, after at least two attempts of getting them to ignite. I would not have believed a firing pin would do that, but I've got 15 pieces of brass that all started at .000 and ended at the numbers noted above, which indicates the force of the firing pin went into seating the primers and not setting them off. Hard to believe, but I did dig up a couple of threads where others saw this same thing.

I did a bit a primer pocket uniforming (that is so fun) and bought a FA hand primer that has adjustable depth and I'm now crushing about .006, which should be fully seated. I've got 200 LC prepped in this manner and will load in the next couple weeks and shoot them. The only thing I can fall back on is "stacked tolerances" of a tight chamber, not fully seated primers.....but I don't know. If I shoot and have any FTF, I don't know what to do and will move back to just Starline brass, which makes no sense.

I've stuck with this barrel and Starline because it shoots so damn good, basically .75" groups of whatever bullet throw down it for 10-15 shots, it's a great barrel.

More to follow after I shoot.

Thanks for the update. So, confirming you are thinking the firing pin is seating the primers and pushing the case shoulder back?

 

[Rugger7622]

That’s my thoughts after going through all the other possible things it could be. I reload for 3-4 calipers and shoot pretty low volumes of 1K-1.5K and have never had FTF. Weird that my same priming method was used with new Starline and through 4 reloads it’s never happened. A smart guy might just continue to shoot the Starline…….it just drives me crazy that I can’t figure it out with the LC…..

 

[Choupique]

drives me crazy that I can’t figure it out with the LC….

I just read the whole thread. In troubleshooting very complex systems we have a rule: always fix what you know is wrong before you go on a witch hunt. You know you have a headspace problem, you should fix that, even if it appears unrelated to the issue at hand.

 

[Rugger7622]

I’ve had it to a smith that confirmed the headspace is tight but within spec. Still confusing that starline brass works with zero issues. I worked on the LC brass over the winter out of boredom.

 

[Lawnboi]

The firing pin is setting the shoulder back?

Sounds like you had some pieces that sized too much.

 

[Choupique]

The thread was difficult to follow but I thought you had a FTF with something other than lake city brass? Hornady maybe?

Regardless, the first thing id do is take the barrel off and re-install it to correct the suspect head spacing. Being it shoots so well it's certainly worth figuring out.

 

[Rugger7622]

I know it sounds strange, but I set all the shoulders to Sami 0 verified in a Wilson chamber case gauge to make sure everything was the same and consistent.

The brass that fired had .015 of shoulder growth verified with the same gauge. The brass that didn’t fire had .070-.010 of shoulder set back varied on the same gauge. Keep in mind, I bolt cycled and tried to reignite at least 1 additional time and in most cases it was 2 times.

I’ll shoot the newly prepped brass in the next could weks as are WI winter thaws a bit.

 

[Rugger7622]

One reason, I haven’t taken the barrel off is that it shoots so well and I don’t really want to mess with it. It was tight with a set of Forster go/no gauge set but I could get the bolt to the close. The gauge my smith tried it closed tight byt acceptable. Also, I’m it sure what a tight gauge would have to do with a FTF? A loose gauge makes sense to me but not a tight one.

 

[Rugger7622]

Once I reshoot the LC I hope I learn more. Logically, this issue doesn’t make sense to me!

 

[Choupique]

Alright stick with me here - im just trying to understand what I think I read without having to go back through it all and take notes. Im drinking coffee in my chair and not at work so I don't want to treat this like a work porblem

Did you ever have a FTF with something other than a lake city cased cartridge?

Does the bolt close on the go gauge without substantial force as it is supposed to?

How do you know, 100% for sure, factually, that you do not have a head space issue?

 

[Choupique]

I’m it sure what a tight gauge would have to do with a FTF?

I understand where youre coming from. Dont take this as me being a dick - I spend a lot of hours of my life on the phone with mechanics and electricians trying to walk them through solving a problem after they've given up on it. What you just said right here is a variant of what everyone says at this stage. It cant be that, because that would be too simple and I dont understand how it could be that. I dont understand exactly why it could be the problem either, but from my interpretation of what you've posted, its the only known potential issue, so fix that first. Miraculously almost every single time when you fix the known issues, the original symptoms go away. That applies to light switches, turbines, high voltage motors, ink pens and nuclear reactors.

Its incredibly difficult if not impossible to re-track to the beginning after your head gets deep into a problem, so im going to continue beating on the basics.

How do you know, 100% for sure without a doubt, that you do not have a headspace issue? You installed a barrel without having headspace gauges on hand in the first place, which is a red flag.

If youre happy with what you've got right now then by all means carry on. A good barrel is a good barrel and I dont think youre at risk of messing up your groups by taking it off. I guess the decision youd have to make is being able to use your suspected problem brass worth the work and risk of removing the barrel?

Again, not trying to be a dick. Just applying some professional problem solving.

 

[Rugger7622]

I have a a FTF on other reloaded brass, Hornady.

Bolt closes tight on a gauge but does close

Only way I know for headspace is go/no gauges, I should point out the brass on fired grows .0015, I think I mistyped growth earlier

The one new discovery are primers not being fully seated and crushed. The LC brass primer pocket depth measures .119, using CCI 450’s with a primer cup thickness of .113, to be fully seated I would need primers sitting .007 below the case head. All mine were .0000, leaving .007 between the bottom of the primer and the primer pocket.

Is this enough to cause FTF’s? Logically it makes some sense to me, practically, I’ll find out!

 

[Rugger7622]

I understand where youre coming from. Dont take this as me being a dick - I spend a lot of hours of my life on the phone with mechanics and electricians trying to walk them through solving a problem after they've given up on it. What you just said right here is a variant of what everyone says at this stage. It cant be that, because that would be too simple and I dont understand how it could be that. I dont understand exactly why it could be the problem either, but from my interpretation of what you've posted, its the only known potential issue, so fix that first. Miraculously almost every single time when you fix the known issues, the original symptoms go away. That applies to light switches, turbines, high voltage motors, ink pens and nuclear reactors.

Its incredibly difficult if not impossible to re-track to the beginning after your head gets deep into a problem, so im going to continue beating on the basics.

How do you know, 100% for sure without a doubt, that you do not have a headspace issue? You installed a barrel without having headspace gauges on hand in the first place, which is a red flag.

If youre happy with what you've got right now then by all means carry on. A good barrel is a good barrel and I dont think youre at risk of messing up your groups by taking it off. I guess the decision youd have to make is being able to use your suspected problem brass worth the work and risk of removing the barrel?

Again, not trying to be a dick. Just applying some professional problem solving.

I don’t think you are being a dick at all. Until switching brass I was convinced I should pull the barrel ( have my smith do it), however, after no issues with Starline and inspection by my smith our conclusion was we would probably reinstall the barrel at essentially the same spot using gauges

FYI…I bough the gun with the barrel installed and the installer used gauges, also previous owner had 400 shots and stated he had no FTF’s

 

[Choupique]

should point out the brass on fired grows .0015

How are you measuring this to within a half thousandth? Anytime somebody starts talking sub 0.001" measurements, I raise an eyebrow. Thats very difficult to actually achieve.

I dont think the primer pocket depth is a certain issue. I feel like this is true because I know I seat my primers not bottomed out in the pocket and never had a problem. I can always apply more force and seat them deeper, sometimes much deeper. They should be recessed slightly below the case head in any case. You have a very tight heads pace and having the primer protruding even a very tiny amount might be enough to prevent the bolt fully closing, I dont know.

Sticking with my original post, I'd fix the headspace problem first, unless the rifle is strictly a target rifle. I wouldn't be ok with anything resembling a reliability issue on a huntkng rifle.

 

[Rugger7622]

I have no issue not using the LC brass and sticking with Starline, I just was digging into it a bit being bored over winter and discovered the primer seating difference and prepped some to see if it could have been the problem, more out of curiosity than need

 

[Rugger7622]

How would you fix the headspace? The bolt closes on the gauge, tight but closes. Make it a bit less tight?

 

[Choupique]

smith our conclusion was we would probably reinstall the barrel at essentially the same spot using gauges

Whats the difference between a go and no go gauge for this caliber? As in what's the length variance tolerance for it? Id definitely put it a little bit longer if I went through the trouble of taking it off.

Apologies for mis-speaking. I forgot you bought the rifle already barreled.

The primers not being recessed and a short headspace could well be stacking to prevent the bolt closing all the way on those rounds. Thats a solid theory I think.

 

[Lawnboi]

When you see brass, especially cheap brass, sized based on a gauge that is not your chamber for measurements, chances are those pieces got over sized and are causing your problems.

Oversized brass will cause exactly what you’re seeing. There will almost always be variation in sized brass, and varying amounts of spring back.

 

[Rugger7622]

I’ll ahoot 50 and see what happens. If they fire I’ll shoot s couple hundred more, if they don’t, I may keep at it or might just load up Starline and go at it or might pull the barrel and re headspace just for the heck of it.

Appreciate the added comments and questions. This is weird one for sure.