Ruger Precision Rifle - Light Primer Strikes?

[phaedra1106]

Anyone with a Ruger Precision Rifle had problems with light primer strikes?.

Finally had mine out for a decent session during the week and ended up with 28/100 light strikes, primer indent looked perfectly OK to me and all fired on a second strike.

I've discounted the primers (Murom) as I've been using the same batch of 12,000 in 4 other rifles over the last 3 years without a single problem. We were also shooting my T3 and Steyr with ammo using primers from the same 1000 box.

Spoke to my RFD who put me in touch with Derek at Viking who's asked for photos of the failures, unfortunately my son kindly de-capped all the cases we'd used. I'm shooting again tomorrow and have 3 lots of primers loaded, CCI, Magtech and the Murom so will see what happens.

Only things I've found on the net are a missing push pin allowing the firing pin to move (mine is fitted ok) and a couple of people needing the firing pin replaced.

[ovenpaa]

Have you measured the firing pin protrusion?

[phaedra1106]

No, I assume I'd have to de-cock the bolt to do that? it warns against it in the manual.

[ovenpaa]

Not in the manual I have here and the process is very easy, it is a matter of gripping the front and bolt handle and twist the back section, to cock is a reversal of the procedure however I would suggest gripping the back end with a cloth to save your hands. Would you like me to send you a scan of the pages?

EDIT Pages 44-45 cover the process.

[phaedra1106]

Thanks :)

Re-cocking is fairly simple then, I fasten a loop of wire onto the bench, slip it over the lug and pull on it

OK, worked it out at .05"

[phaedra1106]

Just measured my T3, it's .064"

[ovenpaa]

.050" is well down at the low end of things however it should be OK, I don't suppose your son noticed any pierced primers when he de-capped them? The FP hole on the RPR is quite large so it is conceivable some debris managed to end up inside the bolt, albeit not very likely.

I usually set FP Protrusion at 1,45-1,60mm (.057"-.063")

[phaedra1106]

No pierced primers and the bolt is very clean, it's had less than 200 rounds from new and I clean the bolt after every outing with Birchwood Casey Gun Scrubber, an aero duster and apply a very, very small amount of CLP for lubrication.

I don't have a case comparator but I do have a set of digital calipers so will check 5 cases to the shoulder before and after firing to get a rough idea of headspace.

Idea, I have a CTS case trimmer which has an internal tapered nylon insert it uses to index off the shoulder when trimming, I can use that to get a better reading :)

http://www.ctstrimmer.com/case-trimmers ... immer.html

I measured 10 cases by eye to the shoulder and got 1.49" which seems to agree with the SAAMI spec for the case so probably not the shoulders being bumped back too far either.

[ovenpaa]

If it was mine I would check the shoulder to case head distance on new and fired brass and see if there is a significant variance. Is this factory brass or re-sized 22-250? If there is a significant variance in the above send it back. (If it was a wildcat I would jam the bullet by .020" and shoot to move the shoulder forward)

f you want to check the head space you need go and no-go gauges however you could remove the firing pin then open and close the bolt on new and fired/sized brass and see if there is any difference in bolt close force. Then do the same with a small square of electricians tape stuck on the back of both cases. If the bolt closes with the tape on the case it is almost certainly going to fail to head space.

Out of interest why are you dealing with the distributor and not the RFD you purchased it from?

[phaedra1106]

I fire-formed 22-250 then set the die so the bolt would close with no friction. I've just taped up 5 fired and full length re-sized cases and tried them, the bolt will close but it needs a fair bit of pressure and you can feel it squashing the tape.

Dromia is my RFD and suggested ringing Viking to see if they had any suggestions.

Interestingly I just did the same test on my Tikka T3 in 260Rem, 5 new fresh out of the bag cases and 5 FLS, all taped up and the bolt closed on each one with very little effort at all!. I know it's not an exact test but it would suggest the Ruger cases have better headspace than the Tikka!.