primer seating depth and misfires

[s.stimson]

I have been having some trouble regarding misfires in my 300 win mag reloads. I'm getting a nice clean dent in the primer but no bang. If I try the round 3-4 times it will go off ok. In an attempt to sort out the issue I primed 10 cases and measured the primer depth (all were carefully primed so that they were flush with the bottom of the case)

So the 10 primed cases all fired 1st time so I'm thinking that the primer depth may be the route cause of the misfires. So the question is how far below flush with the bottom of the case is acceptable? For information I am using a rcbs hand primer.

Thanks

[Simon_S]

Try doing some a bit more deeper mate, if your still having trouble you could have some
faulty primer.

[lilguy43uk]

If your primer pockets are a tad on the loose (and large) size, the primer could be moving fractionally forward with the impact of the firing pin and not getting a clean strike.

Or it could be as has already been mentioned, faulty primers.

[Turnup]

Primers should be bottomed out. If they are not fully seated then they will move forwards with the impact of the firing pin, weakening the strike. Below flush is OK, above flush is not OK.

[Vermin Al]

About 5thou according to Chuck Hawks: When reloading, always seat primers slightly below flush with the head of the cartridge case. This insures that the anvil is properly pressed against the priming compound for reliable ignition. Failure to properly seat primers is the biggest single cause of misfires in reloaded ammunition. A good depth to aim for is .005" below flush. With some experience this can be determined by feeling the case head after the primer is seated. Any primer that is flush or protruding should be very carefully removed and the case reprimed. Decapping a live primer can set the thing off, so behave accordingly and take all necessary precautions, including ear and eye protection.

http://www.chuckhawks.com/primers.htm

Other references, 2-6thou.

[Mike95]

Are they Gynex primers! Bought a load for my club, very hard. My Marlin 30/30 needed several taps to ignite them. i have never noticed any problem with Sellier and Bellot, however they are seated.

Mike95