Lite primer strikes FTF

[mattri]

110 short action T&T by SSS 308.

Accuracy is great, 168 MKs better than I can shoot.

Once every 200(ish) rounds it will FTF. Sometimes if I re-cycle the bolt and just yank on the trigger it will fire the round but not always.

Thoughts?

[wbm]

Ok. Assuming you have checked your scope rings, base screws and crown. You HAVE checked those right? :rolleyes:


Is it an accutrigger model?

[celltech]

Does the primer strike look shallow...or is the firing pin even dropping? Are you accidently tripping the accutrigger safety feature?

[Revoliver]

I would contact SSS.

[Dave Hoback]

Lol! There is certainly no reason to contact SSS. There is no addition information at SSS which we lack here.

The above question is the first step. Is this an Accutrigger? And when it happens, do you have a Light Primer Strike, or NO Primer Strike?

[Revoliver]

Lol! There is certainly no reason to contact SSS. There is no addition information at SSS which we lack here.

The above question is the first step. Is this an Accutrigger? And when it happens, do you have a Light Primer Strike, or NO Primer Strike?

I don't understand, if SSS did the work, and now there is a problem, why would one not simply contact them first, before resorting to DIY?

[Blue Avenger]

if your looking for something to try your self. trip your firing pin and measure the pin protrusion. also is it appearing rounded or chipped?
are these factory or reloads?
have you changed the trigger settings since Fred worked on it?
when you pull the trigger, gun out of the stock is there clearance between trigger and sear. dragging will slow down a clean release.
first random thoughts.

[Robinhood]

I don't understand, if SSS did the work, and now there is a problem, why would one not simply contact them first, before resorting to DIY? There are only a few things to look at in this scenario. Is the firing pin actually striking the primer? No. It is probably an Accutrigger issue. Is the firing pin is striking the primer. Yes. Is it a light strike or full strike? Light strike? Do you have dried lubrication or dirt and debris gumming up firing pin or is it firing pin spring issue. Have you measured the case headspace dimensions.A short case can cause a light primer strike also Have you modified the firing pin travel thinking that the bolt lift is lighter and it was an improvement. A TT'ed action has several modifications that could be negatively impacted by backing the cocking piece off just a few turns. So you see, It is probably something that can, at the very minimum, be investigated so you have an idea if it is the trigger, the bolt or the headspace(directly correlating to the size of the brass).

[Dave Hoback]

Well, he didn’t say if the FP was contacting the primer or not. But this is mattri. And he knows what he’s doing & the normal things to look for. However Matt, I am wondering… you said it happens roughly every 200rds, but how many times are we talking? Has this been going on for some time, so it’s happening with regular consistency? Or is this something that’s happened a “few” times? Different lots of ammunition, or a few of one batch?

Obviously, if it’s an Accutrigger and there is no mark on the primer THAT’S it. But as I said, mattri is knowledgeable and I don’t think he’s using an Accutrigger anyway. I just sent him one of the Springs I make for the older non-Accutrigger style 2 & 3-Screw triggers.

[Nor Cal Mikie]

One out of maybe 200 FTF?? NOT a firing pin issue or a trigger problem.
First thought? Headspace, (AMMO not mechanical like in OAL) like ammo too short for chamber, round gets pushed forward in chamber and you get FTF.
Reloads or factory loaded ammo? Ammo too short? Increase the OAL by pulling the bullets out a bit to a jam, fire the round and if reloading, make sure you don't push the shoulders back too far again. KISS!!

OR, send it back to SSS, have him fire maybe 200 rounds and see IF it will FTF for him. ;)

[mattri]

Excellent replies- thanks.

To give a little more background rifle was originally a 110 308, then the action (non accu trigger) was sent to SSS and a Shilen barrel screwed on.

All rounds are handloads, proper shoulder bump and neck tension- headspace is controlled.

[Dave Hoback]

How ‘bout that other bit I asked Matt? Post #9.

[Revoliver]

OR, send it back to SSS, have him fire maybe 200 rounds and see IF it will FTF for him. ;)

Should make it 400 rounds to double the chances ;)

[Nor Cal Mikie]

My bet? On the rounds that FTF, the OAL of the case was shorter than the others that fired with no issues.
Move along, nothing to see here. ;)

[wbm]

+1.

[mattri]

Thanks for all the good replies. Sorry for the delayed response life has been nuts.

Case length on ftf rounds is the same as on rounds that did fire- measured as cbto and to shoulder.

Firing pin does strike, as well and as deeply as all others, am working on getting a measurement of impact depth.

Next step is to disassemble bolt and see if perhaps something is causing the firing pin to drag or bind? Kind of a reach but won't hurt to check.

Dave- the "every 200 rounds" was an estimate at best. It happens rarely, and sporadically- never more than once at a time. All rounds are weight sorted brass sized and loaded to the same specs- my first suspicion was a short case getting pushed forward so that is where I started looking.

Thanks again will post results.

[Dave Hoback]

I really think it’s one of those “once in a while” things that comes with reloading. Especially if using anything other than Lapua brass or the like.

But then, it is possible it’s a matter of stacking. Like, if your FP spring is slightly lighter & the FP tip itself is not not perfectly rounded and perhaps ever so often one of the primers is a harder than the others. Maybe? Yeah, take your bolt all apart and go over everything. I know you know what you’re doing, but feel free to post some pics of the FP tip, and def. measure protrusion.

[AZ_GUN_NUT]

Ok. Assuming you have checked your scope rings, base screws and crown. You HAVE checked those right? :rolleyes:


Is it an accutrigger model?

Huh??? Sorry had to make fun on ya...

[mattri]

Well yeah, obviously scope rings were the first thing I checked. Duh.

[wbm]

+1. http://www.savageshooters.com/images/smilies/cool.png