Blown primers

chill123

Well-Known Member
I recently purchased new 6.5 x55 Lapua cases . I loaded them with my normal 45 grains of Viht 160 and Speer 140 grain gamekings . The CCI primers I used seemed to push in with little resistance . I zeroed the rifle and 3 out of 10 rounds blew the primer . Any ideas ?

Thanks
Chill
 
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primer came right out?

slack pockets from new is either bad brass or a combo of that and small spec primers
some are slightly tighter to fit
but my first though is to take the brass back
 
Are the primers the same batch as previously used? If so it's likely the brass. (So much for Lapua quality) LOL!
If the primers are a new batch, you could easily measure the diameter of the primers to see if they are small when compared to other batches. Measurement of the case recess diameter is more difficult.
The fit of the primers depends on the combination of primer diameter, primer material stiffnes & case recess diameter - you should check out all three parameters. (Or just change the brass)
Did you see any other signs of high pressure?
Additionally did you use the same seating depth of bullets as previously - Deeper seating gives higher pressures.
Were your previous loadings with brass with the same internal volume? - Thicker cases also lead to higher pressures. (check by weighing clean sized & trimmed brass & comparing the batches)
You may need to work up a new load if the cause isn't aparent, or you have changed a parameter (or two).

Ian
 
Guess things are more modern, or different, now than when I learnt to reload rifle cartidges. Then you were told, informed, instructed, (take your pick) to work up again with any new component or change of component. All reloading manuals had this printed in them.

New cases or different make means you work up again as they can and do vary in capacity and or weight. Change bullet make again it's new or a change work up to be safe.

Obviously this is seen as old fashioned today so not bothered with.
 
I recently purchased new 6.5 x55 Lapua cases . I loaded them with my normal 45 grains of Viht 160 and Speer 140 grain gamekings . The CCI primers I used seemed to push in with little resistance . I zeroed the rifle and 3 out of 10 rounds blew the primer . Any ideas ?

Thanks
Chill

Well it's not an excessive load for a 6.55 SE, but define 'blown primers' for us.

Rifle/OAL too would help. :cool:
 
When you say blown do you mean the primer is dislodged or is the actually primer pierced ie appears to have a big crater in it and possibly pierced primer?

This is not uncommon when loading heavy bullets in .223 cases. Laurie on here is the expert but its caused by too soft primers so in .223 with heavy bullets bench rest primers are better than standard CCI, so in my case I use remington 7.5's and it resolves the problem.

D
 
The Viht data N160 load for 139rg Scenars seems lower than that for 'standard-shape' 140gr BTHP bullets.
The max load for the latter seems to be over 45gr, unless I'm misreading the Viht site.
Is this something to so with the length of bearing-surfaces, perhaps?
 
By gosh, you're right: forty five grains. I could have sworn the site read 43.7 as a max when I read it this morning. My bad.~Muir
 
:lol: I never even looked at the web site. Perhaps I am an old person in a younger body as I prefer books for such information and I seem to like be drawn to older styles of guns.
 
Laurie on here is the expert but its caused by too soft primers so in .223 with heavy bullets bench rest primers are better than standard CCI, so in my case I use remington 7.5's and it resolves the problem.

CCI used to list the standard small rifle primer for only moderate pressure cartridges. It was usual to have pierced primers with full pressure loads in 223 regardless of the bullet weight.

Magnum and BR primers had thicker cup. For a few years they've dropped the pressure remarks from usage chart, I don't have personal experience since I use either old stock CCI 400, or for higher pressure loads CCI or Rem BR.

Primer Usage Chart
 
I recently purchased new 6.5 x55 Lapua cases . I loaded them with my normal 45 grains of Viht 160 and Speer 140 grain gamekings . The CCI primers I used seemed to push in with little resistance . I zeroed the rifle and 3 out of 10 rounds blew the primer . Any ideas ?

Thanks
Chill
New Lapua has very tight necks with 2 or 3 thou more tension than once fired and sized, could be the extra tension boosted your pressures over safe max. I noticed this loading some new lapua 6.5x55 brass recently and as such I lightened the load slightly and still ended up with slightly flattened primers.

Also CCI primers but N150 and 120gr bullets.

For clarity are the primers pierced, or got gas marks around the edges?

If you still have some new unfired then measure the OD of the neck vs. some of your sized brass and you'll see what I mean.
 
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As it turns out, I was wrong: It's inside the MAX.
That said, I have run into a similar problem with my 300 Blackout. A starting charge of Lil Gun flattened CCI Small Rifle primers. A switch to Remington 7.5 primers had everything looking good with identical charges and components.~Muir
 
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