Light primer strikes

[Priley]

It should show up when measuring a fired case. Were these handloads? Excessive moving of the shoulder rearward when full length resizing will result in your unfired cartridges exhibiting light primer strikes. Load and fire one case 3 times, measure the shoulder to base and set your FL die to "bump" the the shoulder back .001" - .002". If you don't have the equipment necessary to take the measurements, you can remove the firing pin assembly and the ejector and bump the shoulder back until the bolt just closes with a very light or minimal resistance. Back 50 years ago when I didn't fully understand the reloading processes, I had a rifle getting some FTF's which exhibited light primer strikes. I took the rifle to two different gunsmiths and they correctly said nothing wrong with the rifle. Frustrated, I sold the rifle. The whole ordeal was simply me not having my FL sizer die set correctly and shoving the cartridge shoulder rearward too far.

Had the same problem with my .280 AI. The full length resize die was pushing the shoulder back to far creating light primer strikes. Once I understood what was happening I backed the die off and no more problems.

 

[DR Ray]

Sorry if wrong forum.
I've had 5 out of 90 what I'm assuming are light strikes with a new rifle.
After removing bullet and powder I chambered the primed empty brass and they all fired. Measured firing pin protrusion and best I can tell it's .046-.047 which from my understanding is what bighorn says it's supposed to be.
Big horn sr3 action
Proof steel barrel
Peterson brass
Cci br4 primers
Any ideas? Don't have headspace gauges but fired brass measures .003-.004 longer than new brass.

Get gunsmith to check headspace first of all . Maybe a weak spring??

 

[Dirtrax]

Re-read UncleNick and follow his direction.

 

[gator378]

It should show up when measuring a fired case. Were these handloads? Excessive moving of the shoulder rearward when full length resizing will result in your unfired cartridges exhibiting light primer strikes. Load and fire one case 3 times, measure the shoulder to base and set your FL die to "bump" the the shoulder back .001" - .002". If you don't have the equipment necessary to take the measurements, you can remove the firing pin assembly and the ejector and bump the shoulder back until the bolt just closes with a very light or minimal resistance. Back 50 years ago when I didn't fully understand the reloading processes, I had a rifle getting some FTF's which exhibited light primer strikes. I took the rifle to two different gunsmiths and they correctly said nothing wrong with the rifle. Frustrated, I sold the rifle. The whole ordeal was simply me not having my FL sizer die set correctly and shoving the cartridge shoulder rearward too far.

That is why I have Redding competition shell holders. Got rid of case separations on the 300 Weatherby and the FAL.

 

[WahooYahoo]

Sorry if wrong forum.
I've had 5 out of 90 what I'm assuming are light strikes with a new rifle.
After removing bullet and powder I chambered the primed empty brass and they all fired. Measured firing pin protrusion and best I can tell it's .046-.047 which from my understanding is what bighorn says it's supposed to be.
Big horn sr3 action
Proof steel barrel
Peterson brass
Cci br4 primers
Any ideas? Don't have headspace gauges but fired brass measures .003-.004 longer than new brass.

I haven't read all of the replies. First couple of pages seem to lack the likely cause. Remove the firing pin from the bolt and clean it all. Add NO oil to the assembly before reassembling it. One tiny bit of metal or trash will jam up the whole party. NO OIL

 

[greenejc]

Your brass expanded by 0.003 so its not a headspace problem. It isn't firing pin length if it is 0.048 to 0.052 extension past the bolt face. Take a used primer apart and flatten it and seat it. Then fire the rifle and see how deep the firing pin indents it. Do this with about 5 cartridges. See if you're getting any light strikes, and if you are, take the bolt apart and clean the inside of the bolt and the spring. Maybe replace the spring. Follow the advice about uniforming your primer pockets on new brass and getting a good primer seat. I've never had a problem with Remington or Winchester brass of any caliber, but I have had problems with Nosler and Hornaday brass having primer pockets that needed to be reamed to seat a primer properly. Since I get my Federal and such by scavenging at the range, I can't say what new Federal brass is like. Starline doesn't have primer pocket issues that I've seen yet, either.

 

[LoneTraveler]

While you have the bolt apart clean it, And clean it well, Check firing pin channel in the bolt and clean well, A small sliver of metal loose in the bolt channel from drilling the channel, Can cause the problem of miss fires. And will just do it once in a while.
Check the firing pin spring pressure also. The spring may have been weak from day one. Good luck in finding the problem and the cure.

 

[Bruce Treloar]

Sorry if wrong forum.
I've had 5 out of 90 what I'm assuming are light strikes with a new rifle.
After removing bullet and powder I chambered the primed empty brass and they all fired. Measured firing pin protrusion and best I can tell it's .046-.047 which from my understanding is what bighorn says it's supposed to be.
Big horn sr3 action
Proof steel barrel
Peterson brass
Cci br4 primers
Any ideas? Don't have headspace gauges but fired brass measures .003-.004 longer than new brass.

Modern actions cock on the opening stroke or bolt lift. If you remove the bolt and store separate to the rifle the firing pin spring is under tension for what could be months or even years. Suggest you replace the spring and get a tool to uncock the bolt when out of the receiver.

 

[kiwikid]

Update. To those that said clean the bolt, it is new 130 rds as of this morning but I did wipe out some grease. Took it to the range this morning loaded with new lapua brass and 2 diff primers. Cci br4 and fed AR match. No misfires out of 25. Thinking Peterson brass may be the culprit. More investigating to do lol. Thanks for all the advise so far.

Recently I had a very similar situation to what you have experienced but in my case it was with two 100 case boxes of Lapua 223 Match brass for two different new rifles . Just like you I thought it was the new rifles and with one of them I even got the supplier to send me a new bolt and barrel as it was a switch barrel system. I tried different primers, measured primer seating depth and checked firing pin protrusion. I even went to the extent of trying the 10 cases in my older Steyr rifle and they still wouldn't fire. At that point I ordered and duly received a Wilson Cartridge Case Gauge. All of the 10 faulty cases sat at least 0.010" below the minimum case length mark. I necked them up to .243 and then back down to .224 leaving a false shoulder and once they were fire formed I have had no more trouble.
In your case I wonder if when you pulled the bullets from the FTF cases that there was enough force to pull the shoulder forward a few thou which then allowed the firing pin to fire the primers?

 

[MagnumManiac]

There is a serious problem with brass elongating .020", especially if you are talking base to shoulder.

Not on a belted case it isn't.

Cheers.

 

[hunter0528]

Have you cleaned the Firing pin of all grease and Oil. depending on how tight fittings are it could form an air buffer.
I remember years ago looking at a luger Firing Pin it had a groove to allow air to pass through because the fit was so precise.

Just a though.

 

[JAYgs8163]

Guys, he updated the post around page 3-4. He cleaned it, switched brass, no more problem. He's going to try the Peterson brass again after cleaning and see if the issue comes back.

 

[jdyoung]

Guys, he updated the post around page 3-4. He cleaned it, switched brass, no more problem. He's going to try the Peterson brass again after cleaning and see if the issue comes back.

Was wondering if he was gonna' retry the Peterson brass. GOOD!!!

 

[JAYgs8163]

Assuming he's going to since he gave thumbs up to the suggestion.