New build problem - ignition issue

[tiny68]

I am building a 223 for my 11 yr old. I started this over a year ago and just got back to the project. Long action. Used a SSS extender for the 223 bolt head. Problem is I am only getting about 1 of 5 to fire. I have check the headspace again. Bolt closes fine with go gauge and it very tight to close with a single piece of Scott tape on the go-gauge. I have used the same method for 20 + plus barrel swaps with no issues. The fired rounds have a minimal increase in the shoulder, ~+0.002". This combo of action, barrel, and stock are all new to each other. I bedded the action with Devcon last year. I know originally I had some clearance issues with the trigger/sear and the sear wasn't cocking/dropping cleanly. I am fairly sure I have that fixed with a little cleanup work in the stock. I original set the firing pin protrusion at 0.035". The when I took it out last year I had this problem. I adjusted the firing pin to have a 0.060" protrusion and got the same results this year.

I am a little stumped on what to try next.

FYI - LC brass, 52 gr Bergers, 205M, and Benchmark (24.2 gr).

Suggestions? Thanks, Tim

One in the middle is the one that fired. The other 4 seem to have ok primer strikes but don't fire.

http://i159.photobucket.com/albums/t151/tiny68_photos/3b40951f-699c-4e36-bc3b-0f4c7c597491_zpscf59e294.jpg (http://s159.photobucket.com/user/tiny68_photos/media/3b40951f-699c-4e36-bc3b-0f4c7c597491_zpscf59e294.jpg.html)

[RyanG]

Is it possible you have bad primers?

[tiny68]

I don't think it is a primer issue. I have use the same box of primers in my 6BR with no issues what so ever.

[stangfish]

How do you clean your brass? Did you check the flash holes for media?

[Hotolds442]

How do you clean your brass? Did you check the flash holes for media?
+1
Or bad primers

[floydboy]

I believe this is a very common problem with an easy fix. I too have experienced this. Measure the length your firing pin spring is set at. The measurements are listed in this site on the home page. If the length isn't almost perfect the pin won't have the proper force to hit the primer. The dent in the primer can look just like a fired one leading one the think it is a bad primer. At least mine looked like they had been hit hard enough. Don't get too worried yet. A lot of us have had this situation.

Good luck...Floyd

[bootsmcguire]

I believe this is a very common problem with an easy fix. I too have experienced this. Measure the length your firing pin spring is set at. The measurements are listed in this site on the home page. If the length isn't almost perfect the pin won't have the proper force to hit the primer. The dent in the primer can look just like a fired one leading one the think it is a bad primer. At least mine looked like they had been hit hard enough. Don't get too worried yet. A lot of us have had this situation.

Good luck...Floyd

+1

Also just for fun, run a case through your FL die, and then using it as a headspace gauge keeping adding scotch tape to the base 1pc at a time just too see if there is and how much difference there is between your die and your go-gauge you set the barrel with. You may have a short die or a long gauge. Just something to think on.

[tiny68]

After supper I went to the shop and took some measurements. I took one of the brass that did not fire and pulled the bullet and primer. I started adding scotch tape. On the 3rd piece I couldn't close the bolt. If a took a piece of the brass that did fire I couldn't close it with one piece of tape. I measure the brass to the shoulder with a 0.330" gauge: The go headspace gauge measures 1.455. The fired brass measured 1.452-1.453". The misfires all measured that 1.448-1.449", which would have been what I set dies for. This brass had previously been shot in this barrel, but installed on a different action. I measured some of the LC brass that I purchased in bulk 5-6 years ago as once-fired, which all was 1.455-1.462" at 0.330". I couldn't even close the bolt on any of it. I assume this was fired in some type of an auto with a lose chamber.

I guess I will pick out a new set of brass and process them with a longer shoulder. I still don't see why this doesn't ignite when I extended the firing pin to 0.060" protrusion. This is way more than the extra couple of thousands I have in headspace play.

Tim

[tiny68]

How thick is a piece of Scotch tape? I have forgot. Tim

[Dennis]

First, scotch tape is about .002 thick unless it's heavy duty, which is .003.

I had this same problem with my BRX several years ago. The problem was the sear. I had to replace it and my problem was fixed.

You could have a different problem. It could be in your bolt-head, firing pin and/or spring, excessively dirty bolt, is this virgin brass or ?, or something could be binding on the trigger, sear, or your bolt.

If your using regular scotch tape, put two pieces on it and the bolt should not move over an inch. It should close very easily with no tape on the go gauge.

Dennis

[Mach2]

Simplify things a bit. Stop using reloads for your tests. When you get the factory stuff to fire then use your reloads. You have too many variables you are looking at. You are looking at ammo and rifle issues at the same time. Pick one problem a time.

[tiny68]

What is this "factory stuff" you mention. Sorry. Haven't brought any factory ammo other the FGMM 308 175 SMk in a long time.

[handirifle]

I think I would also get a No-go gauge as well. Sorry, but the scotch tape thing, to me, is soooo un-precise it's not funny. In addition, the tape will compress, might be a little might be a lot.

Other than that, I agree with Mach 2. Cut variables as much as possible, and eliminate them one by one. One thing for sure about media being in the primer hole. You most likely will NEVER find it on one of your FTF cases, because when you punch out the old primer, you wil also punch out the media interfering with it, if there is any.

Might try borrowing a no-go gauge and checking it. With the tape method, seems like every thread I have read on it says it (the bolt)should not close on TWO pieces, but again, not my preference. To me it's like using a 5/16" wrench on a 10mm bolt. It might work this time on this bolt, but.....

[Mach2]

What is this "factory stuff" you mention. Sorry. Haven't brought any factory ammo other the FGMM 308 175 SMk in a long time.

The first test should be to find whether it is a rifle issue or an ammo issue.

[DanSavage]

I had worked up a nice load for .243 over the summer and it shoots great in my 110. We tried it in my buddies Axis .243 and it shot great in his rifle too. The Axis began to have miss fires once in a while, while the 110 never had one.

I traced it back to the primers. They are CCI #34's. They seem to be a really good primer it's just that when I seated the primer with the hand held seater They seemed to want to seat .010-.012 below flush. Thought it was an easy fix so I primed on the press so it would set the primer .003-.004 below flush were it should be. Right?.... Well the Axis still miss fired and I found that the firing pin would push the primer in the primer pocket upon a strike rendering another miss.

I haven't checked yet to see if the primer pockets are too deep on the brass or if the primers are too short. But you may want to see if your firing pin is pushing the primers in upon impact.

[BillPa]

After supper I went to the shop and took some measurements. I took one of the brass that did not fire and pulled the bullet and primer. I started adding scotch tape. On the 3rd piece I couldn't close the bolt. If a took a piece of the brass that did fire I couldn't close it with one piece of tape. I measure the brass to the shoulder with a 0.330" gauge: The go headspace gauge measures 1.455. The fired brass measured 1.452-1.453". The misfires all measured that 1.448-1.449", which would have been what I set dies for. This brass had previously been shot in this barrel, but installed on a different action. I measured some of the LC brass that I purchased in bulk 5-6 years ago as once-fired, which all was 1.455-1.462" at 0.330". I couldn't even close the bolt on any of it. I assume this was fired in some type of an auto with a lose chamber.

I guess I will pick out a new set of brass and process them with a longer shoulder. I still don't see why this doesn't ignite when I extended the firing pin to 0.060" protrusion. This is way more than the extra couple of thousands I have in headspace play.

Tim

Looking at your brass dimensions, even if the primers are seated another .002" below the casehead thrown in for good measure, a .035" protrusion is more than enough to ignite a primer. As a matter of fact the shorter protrusion allows the firing spring more time to accelerate the firing pin increasing its primer impact energy. Increasing the protrusion beyond .035" does the exact opposite. More isn't always better.

Looking at your primers I'm seeing inconsistencies in the pin fall, less impact depth which is a result of something padding the pin fall. At this point I'd pull it out of the stock, primer a few pieces of brass then try firing them. If they ignite then its something with the stock. Typically its the sear making contact.

If they don't ignite then you have an action issue.

The very first thing I would look at is the sear. Remove the trigger leaving the sear installed and check it's movement making sure it moves freely it's entire length the travel. Next reinstall the trigger and check it's full length of travel again.

Next, you'll have to look at the bolt assembly. There's a laundry list of possible problems that can cause padding of the pin fall, the cocking piece sleeve out of round( egg shaped), the firing pin bent or ground off center, the bolthead retaining pin hanging up, crud in the bolthead shaft at the step past the vent..... the list goes on. Its only a matter of finding which one or a combination of them.

Bill

[stangfish]

Excellent post bill. Another thing to consider along the lines of sear interference is you trigger travel. If you have a trigger with adjustable over travel the trigger itself may obstruct the path of the sear. A dirty bolt with something internally restricting movement could be another place to look.

[tiny68]

I went to Wally World and got a box of winny super X 55 gr SP. It was the only 223 they had in stock. Fired 10 for 10. That tells me it was an ammo issue. Either I had sized them down to far with 0.004-0.005" extra headspace or the primers pockets were cut to deep or some combination of them. I ordered a box of Lapua 223 brass today and will start again. I will process another 20 of the LC brass and see how it fires until new brass Arrives. I will update this post once I try sme new brass. I would have bet money it was an issue with the gun.

Thanks, Tim

[sharpshooter]

205M's are not that hard to light up, they have one of the thinnest cups of any primers. You have a lack of impact energy, either from not enough compression on the spring or short firing pin travel. Basic spring compression length on a long action is 2.600". A combination of trigger and sear tolerance can cause the cocking piece pin to engage late and essentially de-cock, shortening the firing pin travel.

[tiny68]

I am pretty sure I set the spring to 2.600" when I put it together last year. I originally set the firing pin protrusion to 0.035", then later tried to set it out to 0.060" when I first started this build last year. I am hoping the sizing issue will solve the problem. Tim