Range Report Popped Primers Causes?

[762Fundi]

My brother received a new Browning BAR 308 Heavy BBL. (It is a beast)

He was shooting with a variety of "hunting" ammo (Unfortunately I do not know which) and was getting lots of popped primers. Why?

It has always been my understanding that popped primers are usually from a tight chamber (that needs reaming), but I have recently read that it could also be short throat, short shoulder of chamber, ....

Could it be bullet weight (too heavy or long)?

I would have guessed the BAR would be a little loose in the chamber for reliability reasons and being a hunting rifle designed to handle longer, heavier bullets as well.

Ideas?

 

[Oakland Tactical]

Re: Popped Primers Causes?

I had one pop yesterday in my MWS and a bunch of gas leakage around the primer. This was Black Hills 175 grain red box. It was 82 degrees out. The last time I shot that ammo it was 30 degrees and no indication the read sealant was still on the primer after, but not this time. I thought the cause was it is loaded hot, I have had it happen on handloads not factory until now.

 

[Greg Langelius *]

Re: Popped Primers Causes?

My popped primers have been from hot loads, hot days, and sometimes water (condensation) on the ammo/in the chamber. They are the main reason I now avoid hot loads.

Protruding primers (as opposed to popped primers) are sometimes a result of too <span style="font-style: italic">light</span> a load.

Greg

 

[Jeffvn]

Re: Popped Primers Causes?

+1 on what Greg said. The only time I have had primers pop - including the wonderful gas back into your face, has been the result of very hot loads, leaving fairly hot ammo in the sun on a hot day, or water / condensation in the chamber.

I had popping primers as a result of water on the case from rain occur during a rifle match several years ago and it was an instant learning experience. Normal loads and results converted to popping primers in one trigger pull.

Jeffvn

 

[KYpatriot]

Re: Popped Primers Causes?

Greg, Jeff I assume what you are saying is that the water basically reduces the volume of the chamber since it is basically incompressible. Is that what is causing the pressure?

Seems like I would have noticed this before hunting...then again, it is usually cold if it is also wet where I hunt.

Interesting.

 

[MALLARD]

Re: Popped Primers Causes?

if you got something in your chamber you can pierce primers at low pressure

if the ID of the firing pin hole is signficantly larger then the OD of the pin , your going to peirce primers at low pressure to.

if you can i would test the ammo in a different rifle , if the ammo doesnt pierce your primers , then you got a gun problem.

 

[Greg Langelius *]

Re: Popped Primers Causes?

I've heard a couple fo explanations why water in the chamber is NG. None of them completely satisfy my suspicions. Good thing I don't need to understand why; all I really need to know is, water in the chamber ain't good. Just about covers it, eh?

My guess? Water, pressure, heat; something's happening that's spiking pressures. Pretty sure steam is involved. What? How? Beats me; but something's definitely happening.

Greg

 

[Frank Green]

Re: Popped Primers Causes?

Water in the chamber is not good because for an instance when the gun is fired the brass case should bite the chamber walls. If the chamber is wet from water or solvent all the pressure will go towards the bolt. As stated earlier the liquid is not compressible. So all pressure and thrust goes towards the shooter. This will cause the case to stretch more than normal. All the pressure and brass flow is trying to go somewhere.

Had a P.D. rifle in here about a two years ago. Guy showed me a fired case and asked what was wrong with it/gun? Primer wasn't popped but was flatter than a pancake. He also said he had a hard time opening the bolt. At first I said with out being there when it happened etc....I'm only guessing and my guess was a abnormal hot factory load (Fed. Gold Medal 168's). When we took the barrel off to rebarrel it I knew right away why and what caused it. He had so much oil/solvents inside the action and most likely the chamber and didn't dry it out that the oil was actually caking in the receiver and when we pulled the barrel off solvent/oil almost dripped off the threads. I never seen a barrel so oiled up before but what I saw told me what had happened.

I've been to some matches where if it starts raining they will delay the match so nobody is shooting guns with wet ammo/chambers for this reason. Some match directors (mostly hi-power service rifle/match rifle matches) make you shoot thru it.

Later, Frank
Bartlein Barrels

 

[762Fundi]

Re: Popped Primers Causes?

when the primers popped it was a warm (not hot), dry day. I will check and see if there was unusual lube problems, but doubt it.

I am thinking tight chamber, or headspace is too short or too long, or maybe the gun is prematurely unlocking bolt and case is not fully supported against the bolt face while still under pressure.