FTF problem

I’m reasonably sure I know what caused this problem, but I want to run this past all of you anyhow.

Here as a little background on the problem. The rifle is a Kelbly BB Panda action with a 1-10 twist 308 barrel. I bought the barrel as a blank and had it chambered up by a well-known gunsmith late in the season of 2018.

I started break-in/load development with new Alpha brass that had been neck sized only and only about 30% of the rounds loaded would fire using CCI 450 primers.

I didn’t mess with this rifle until a few weeks ago and bought 200 pieces of new Peterson brass. (Couldn’t seem to locate the Alpha brass) Again, neck sized only and the same issue appeared again. I took measurements from fired brass, as opposed to new and the new brass is .007 shorter as measured to the datum line of the shoulder.

Well that explains the FTF, but the “why” is the question.

My solution:

I started to do a little load development with the Berger 200-20x bulled jammed .010 but the results were poor. So rather than burn up components and bbl. life, I gave a modified COW method a try.

I put 15 gr. of VV 3N37 in a case with a small wad of paper towel and lit it up with a small pistol mag. primer. (I’m reasoning that the pistol primer would light up easier that the hard cup #450 primer.)

SUCCESS!! Now all the brass measures the same.

Your thoughts as to what caused this issue are welcomed.
Thanks,

Lloyd

 

I'm reaching here...
Weak spring combined with excessive head space?

 

Couple things to check before going any further:

- Firing pin protrusion

- Check how tight the extractor fits the extractor groove of the case. The fact that one brand of case works better than another would have me looking there first. Also, use a piece of Lapua and check it. If that fit isn't tight, the cases can 'croquette' back and forth when the firing pin hits it. If the Panda in question has a combo PPC/BR extractor, that can also contribute to it.

Looking forward to what you find out. -Al

 

Lloyd,
Al had some good thoughts and here’s some more food for thought. The 450 have a pretty hard cup you might try some 205s or something different than the 450s also I wouldn’t think with a panda but maybe your firing pin needs bushed. Another option would be expand to .325 or .338 and neck size part way and create a false shoulder.
Wayne

 

I suspect most if not all factory ammo would have at least as much headspace.
I would look to see if the firing pin spring needs replaced. After that the firing pin protrusion as mentioned above. That Panda bolt action aught to handle any primer you toss it’s way. If it won’t, the good folks at Kelbly’s will want to know about it ASAP.
CW

 

too much headspace

 

Don't have a clue. All factory ammo is short and it goes off all the time. Whenever I had a fail to fire it was because the primers were not seated to the bottom of the primer pocket. All firing pins protrude about 0.055" so I don't know why people think it may not protrude enough. My wild guess is that it has something to do with the f pin pushing the primer deeper or a combination of the pin pushing the primer deeper and pushing the case forward losing energy even thou it's still denting the cup. If the primer is seated all the way to the bottom of the pocket and the bullets are jammed to force the case head against the bolt face and they still didn't go off I would be lost for an answer.

 

I would guess the why is that the headspace is longer in the chamber than standard. I had a rifle that was around .008 long in the chamber and it was a PITA with new Lapua brass in 223 Remington. The Lake City brass hardly was a problem and that was messing with my mind. Eventually, I finally got all 100 rounds of Lapua brass fire formed (after leaving bullets long to jam, primers long to jam, bullets and primers long to jam, wet notebook paper laid on shoulder during chambering). I never had a problem after that and had the Lapua brass, along with some winchester brass, last as long as the barrel which I shoot to over 5000 rounds.

 

Lloyd, try pulling the firing pin out of the bolt body and clean it out. You may have some "junk" in there that is hampering the firing pin from sliding forward with it's usual 23+ pounds of force. I have had this problem a few times.

 

We had the same issue with a couple of pandas that had new barrels installed on them 3 years ago with BR4 and to a lesser degree 450 primers. The issue was found to be several problems.
#1 Both had too much headspace. Getting that fixed helped, but still had some issues on one of the rifles more than the other.
#2 Replaced both firing pin springs. That again helped slightly, but we were still getting 2-5 no fires out of 15 rounds.
#3 Called CCI and they instructed me to always seat their primers deeper..... .005-.007 below flush with the head of the case AND seat the bullets further out into the lands with a bit more neck tension on NEW brass. This fixed the problem on one rifle, but the other one was still getting 1 or 2 out of 20 BR4's that wouldn't go off.
#4 Switched lots of primers and the problem solved and no issues since.

So the moral of the story is you may have several issues and all should be checked out.

It was a heck of a month getting that all figured out and rectified, but a learning experience to say the least. Good luck with your issue and hope it is less harrowing and time consuming as ours. Kelbly's were a great help as always to get the issue resolved. Fantastic folks to do business with. JME WD

Edit: And if you have the bolt apart, clean it thoroughly to get critters or goo out of it that might be in there.

 

Had same problem. It turned out that the shoulder of the cartridges was too far back. Seated long with junk projectiles to fire form and after that all was good.

 

I routinely load new brass that measures .010" shorter than fired brass (with Comparator tool) and have no FTF's. That is in Rem. 700's.

Not long ago, however, I bought a used Rem 700 7mm-08 that had occasional FTF's with the factory FP. Thorough cleaning of the FP did not change anything. Neither did installing a new extra-strong FP spring. Finally just bought a new FP and that eliminated the problem. Measured and the factory FP was just a little too short.

As you gain experience you can tell by looking at the FP indention in the primer on fired brass when you are going to have problems, even before any problems appear. With the factory FP my strike was too light, but I wasn't paying any attention because the ammo was going off.

The change also improved accuracy.

 

While checking things, be sure to check your firing pin fall. Kelbly's recommends a .240" fall minimum.

It is easy to get the fall too short when trying to get a perfect handoff to the sear.

 

Are you sure .240" is correct. Is fall and projection two different things. Are you talking about the firing pin assembley protruding 0.0240" outside of the bolt shroud. Everything I ever read stated that the firing pin should project about .050-.065" thru the bolt face???

 

I am referring to how far the firing pin moves from the time it is released until it comes to a stop at the forward position. The firing pin protrusion is a completely different subject, and only roughly related.

An easier way to say it is the difference between the cocked and released position.

I hope this clarifies the comment.

 

Measure the amount the firing pin protrudes from the shroud when cocked. Dry fire the rifle and measure the amount the firing pin is recessed in the shroud. Add the numbers together and you have the firing pin fall. At a minimum the fall should be .240. A little more is better.

 

All,
A couple of additional points of information to be considered.
1. This receiver is about three years old with the original firing pin spring.
2. I shot this receiver at the BSWN in Feb. with a different barrel on it and it performed flawlessly.
Now to answer some really good questions from all of you.
The firing pin protrusion is .058" as measured from the bolt face to the tip of the pin.
Primers are set .005 below flush with a hard crush from a 21st Cen. adjustable hand primer. They won't go any deeper, I tried.
I measured the firing pin in both the cocked position and the fired position and there is .189" difference. This receiver is "as issued" from Kelbly's.
@Keith Glasscock, I've never taken this measurement before. Is this the correct way?
@ShootDots, I'm fairly OCD about cleaning my bolt body and the parts contained within. Nonetheless, I gave everything a good blast with brake kleen to eliminate that possibility. Thanks Ben.
As a final note, I pulled down all of the rounds that FTF, punched out the old #450 and seated a Wolf SR-M primer. All went off on the first try.
Also, This case of @450's are working flawlessly in my 6BRX, so I don't think I have a bad batch of primers.
@WyleWD, I think you are on to something, thanks.
The weather is cold/drizzle today so I will wait for a better day to resume testing.
Thanks,

Lloyd

 

@Keith Glasscock,
Just measured mine. .233”

Lloyd

 

1shot:
Any chance you can post a picture of the primers in the case head that did and did not go off? It might be helpful to see that. WD

 

Sorry,
Didn’t take any pics of the fired rounds

Lloyd