4 failures to fire out of 25 rounds

[Unknown]

Yesterday I took my 260 Rem to the range to see how the new batch of ammo shoots. Although it is the same load I have used before, I wanted to check again, because I was going back to a 142 grain bullet, and my last batch of ammo was 140 grainers.

In any case, I successfully fired 21 rounds, but during that time, I experienced 4 failures to fire. I waited the normal 30 seconds, and gave each primer a second, or third whack with the firing pin, but to no avail.

Today I took the bolt apart to see if I could find any problems there. The firing pin nose and the spring were intact, and looked fine. There was no grease or oil present as I don't use any inside the bolt. I did swab it out with a cleaning patch, and got a bunch of carbon out of it. I then blasted the inside out with brake cleaner and got more carbon out. I quit when the liquid coming out of the firing pin hole was clear...it took a bit.

The rifle now has 1090 rounds through it..I meticulously count each round fired. The brass is Winchester 7mm-08 necked down to 6.5, and it was recently annealed, and given a few days to dry out. After letting the cases dry, I even used the air compressor to blast out the inside of the cases. The cases have been fired 3-4 times, and out of the recent batch of 250 rounds loaded, only one round's primer was worthy of my noting on the side of the case that it was starting to get loose. I wrote on the side of the case with a magic marker, and that round fired fine.

Could the carbon from 1090 rounds cause the malfunctions I had, or should I look elsewhere for the cause? The ammo isn't a total loss as I could always use it as practice ammo, or break it down for components.

 

[Graham]

CCI BR2 primers?

 

[jimbowe]

Were the primers on those four rounds properly dented? Can you tell if the primers ignited?

 

[roggom]

Measure the case headspace of the fired vs the unfired, you probably bumped the shoulder a tad too much.

 

[Ultraman550]

^^^^^What roggom said. I just did this and found out I bumped the shoulders about .005 too much. Primers were softly dented but no ignition. I took apart my bolt as well, everything checked out fine. Factory ammo that has .005 length (shoulder to base) longer than the cases I fucked up shot perfectly fine.

 

[Graham]

Or you could have had the same bad lot of primers that I got.

 

[Pointman308]

People on this site never cease to amaze me. In a good way that is! What a source for info!

 

[tnichols]

Just a note for the future. Jeff Hoffman at Black Hills recommends that if you have a round that doesn't fire, don't keep hammering away on it. Why? If you want to send it back to the manufacturer for them to trouble shoot, if it's been struck more than once, they can't tell much from that. Kind of like a car wreck. The police while investigating don't keep backing up the 2 cars and wrecking them again and again to determine why the accident happened. In your case (hand loads) wait like you would on a hang fire (which you did) then extract, disassemble the round, and maybe send the case with primer back to whoever manufactured it. Let them have a looky lue. Just what I've read, but it makes sense to me. And, make sure you are closing the bolt fully.

 

[79jeepcj5]

You may want to check your compressor too. It could have moisture in it and you blew it out on the first few brass you were drying. You'd be surprised how much condensation can build up in the tank and lines especially if you don't have a water separator.

 

[Unknown]

Compressor checked, and it is good to go.

Primers ARE CCI-BR2 out of a lot that I purchased about 3 weeks ago. Lot #607U33.

I measured some unfired rounds from a previous lot and they were 1.660-1.6605, and these had a different lot of CCI-BR2 primers.
This lot hasn't had any ignition problems.

The rounds from the lot with misfires (new CCI primers) measured 1.6585. Fired cases measured 1.6605-1.661.

The more information I get, the more it is starting to look like a bad lot of primers...I wouldn't think that rounds that are only 2.5 thousandths shorter than the chamber should have ignition issues.


Graham,
Have you asked CCI about a possible bad batch of primers, and if so, what was their response? If they say they would replace the bad primers, I don't know if it is worth the work to send the remaining ones in. If they were willing to replace the ammo, then it would be worth shipping them the 200 rounds of handloads.