Blown primers

[praveen]

Background: I have a Savage FTR .223 with a 1:7 twist. It is stock with the original barrel. I’ve had this once since 2015 and because I wanted to shoot the 90s, my friend and I ran the ISSF reamer in by hand a bit to increase the freebore.
This rifle has since shot nothing short of spectacular for a straight out of factory rifle with Berger 90 BT, N150 and Lapua brasa.

Couple of months earlier when I shot it in a match, I had a few blown primers. The primers just came out along with some smoke. Primer pockets got loose.

Then I retried the same load with brand new Lapua brass and same result.
The powder load remained the same.
Also, I’ve been using the same 8lb jug of N150 for a while.
So, just for the heck of it, I tried 2 grains leas from my usual load and still the primers blew out.

I’m at a loss here. Why did it start all of a sudden after many years?
What can I do about it and/or how to investigate this?
And how do I make my rifle safe?

I’m thinking of loading some light bullets with Varget now.

Thanks,
Praveen

 

[Topstrap]

Ran into same thing with my 223. Gave it a really good cleaning, no more blown primers.

Topstrap

 

[fkimble@charter.net]

It's called a carbon ring. Develops over time if not cleaned out frequently.

Frank

 

[linebaugh]

You have a severe carbon ring. Heavy for caliber bullets in small calibers seem to carbon foul very fast. Have had this happen with same scenario in 22250AI. Clean more frequent and use bore paste in the throat area.

 

[toolbox]

Possible thick necks or case length to long.

 

[ridgeway]

Replace firing pin spring to get started.

 

[Bill K]

Clean the bore, especially in the area beyond the chamber neck. More than likely a build up of carbon in that area, raising pressures.

 

[Bill Norris]

Put a 6mm nylon brush on a short section of cleaning rod and chuck it in your drill. Put some C4 Bore Tech on the brush and spin it in the neck area of the chamber. Check it with your bore scope to make sure u have it all out. Problem solved.

 

[Link]

Put a 6mm nylon brush on a short section of cleaning rod and chuck it in your drill. Put some C4 Bore Tech on the brush and spin it in the neck area of the chamber. Check it with your bore scope to make sure u have it all out. Problem solved.

Bill, I don't know about C 4 but I have never seen anything remove a carbon ring like the new Through clean of JB. It's like lapping it out. ;[

 

[Bill Norris]

Bill, I don't know about C 4 but I have never seen anything remove a carbon ring like the new Through clean of JB. It's like lapping it out. ;[

Yea Im sure that would work too.

 

[243winxb]

blown primers.

Bad primers?

 

[Coyotefurharvester]

Type of primer and headspace matter more than the brand of brass.

 

[praveen]

Bad primers?

No that can't be. I used the same box of primers in my dasher and they've been working without a hitch.

 

[praveen]

I ordered some JB and tomorrow it'll be on brush chucked in a drill.

 

[linebaugh]

I ordered some JB and tomorrow it'll be on brush chucked in a drill.

I would not use it on a brush with a drill. It's an abrasive. the brush will work fine, wrap a patch into a nylon brush and elbow grease. if you have kroil mix a bit of it in the JB. You will want to stay directional with the rifling, spinning with a drill is probably going to be to aggressive.
One of the longest lived barrels I had in 22BRI with 90 and 95s I cleaned with JB every 250 rounds. I did this from the beginning as part of my regular cleaning. In the land of 1000 rnd barrels that barrel lasted 1700 ish if I remember right. You will know when your bore is toast with accuracy or blown bullets in flight.

 

[Rocketvapor]

One of those cheapo borescopes might help.

 

[praveen]

I have a hawkeye... and looked through it.
I suppose one could call what I saw as a carbon ring.. but I'm not too sure of it. It looked maybe 1/16" wide.
Still, that would explain the issue.

 

[Bill Norris]

In my opinion the nylon brush will not harm the bore but I would stay with something like C4 or other carbon cleaner and not get aggressive with Iosso or J B

 

[rardoin]

I use a quality bronze bore brush slightly oversized for the neck diameter on a chamber rod. I wet it with a straight carbon cleaner and twist/short stroke the neck and into the freebore. It will remove any carbon in the neck and throat. The reason for a pure carbon solvent is to avoid corroding the bronze brush. Use your Hawkeye to confirm the result, repeat if necessary. I also have a Hawkeye and have seen zero damage with the bronze brush sans abrasive. I favor Bore-tech brushes/solvents. My chamber rod is a Sinclair, I think. Green handle.

 

[Bill Rodolph]

You said you have a reamer. Use it, by hand, to cut out the carbon.