Go Back  HuntingNet.com Forums > Firearms Forum > Reloading
Blown primers...overpressure >

Blown primers...overpressure

Reloading Share techniques for reloading, where to get the hottest in reloading equipment and learn how to reload from fellow hunters.

Blown primers...overpressure

Old 08-15-2009, 08:57 PM
  #1  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default Blown primers...overpressure

I was shooting the .243 AI yesterday and had 4 rounds blow/smoke the primers. They blew holes between the primer and case. The other rounds had a slight tight bolt lift but not bad at all. All the other primers were fine, not flat at all.

What could it be? Just too much powder?

I went ahead and pulled all the bullets and I'm starting over anyway...
jeepkid is offline  
Old 08-15-2009, 09:28 PM
  #2  
Typical Buck
 
LaneNebraska's Avatar
 
Join Date: Dec 2004
Location: Nebraska
Posts: 601
Default

I would make sure the bullet was NOT touching the lands, and would back the load off by at least .5-1 grains.

Might be the difference between standard and magnum primers as well.

Sticky bolt, means you are already well over-pressure in my safety world.

You should also check your bolt's extractor and firing pin for any physical damage.....


.

Last edited by LaneNebraska; 08-15-2009 at 09:34 PM.
LaneNebraska is offline  
Old 08-16-2009, 08:06 AM
  #3  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default

Originally Posted by Ridge Runner
how many loadings ya got on those brass? what brand are they? and do you notice a different "feel" to seating the primers. Check casehead expansion on one of the blown primer cases.

Thats the thing with custom chambers, If a min. spec reamer is used, the first pressure sign you'll see is the primer pocket gets a bit loose. Now is when you look for a happy medieum of velocity and case life. I get 3 firings from my 6.5 Gibbs, 5 from the 7mm AM.
RR
Second loading with Lapua brass (first loading was fireform). Didn't notice a difference is primer seating, used CCI magnum primers.

I'm going to load up some right now with 1.5 grs less and then work them up again...
jeepkid is offline  
Old 08-16-2009, 09:35 AM
  #4  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default

Originally Posted by Ridge Runner
are the bullets jammed? that will cause a pressure spike. same lot# of powder? why a mag primer? I've shot 110 gr of WC872 (real slow ball powder) down to 20 lit up by a 210.
RR
Not jammed, just touching. But I'm also going to back them up a little more also. Same powder. Don't really have a reason for mag primers, I just always seem to use them...
jeepkid is offline  
Old 08-16-2009, 11:16 AM
  #5  
Fork Horn
 
Join Date: Feb 2009
Posts: 107
Default pressure

use the same load and just seat them deeper, velocity would probably go up a tad and pressure go down by just giving them a lil jump.
I don't follow the logic of that. If he uses the same load - showing at this point two classic signs of overpressure - and seats the bullet deeper, he is burning the same amount of powder in a smaller space. That would result in higher pressure, not lower. That little jump to the rifling may not be enough to lower pressure if the real cause of the pressure signs is another factor.
Pete

Last edited by Pete D.; 08-16-2009 at 11:19 AM.
Pete D. is offline  
Old 08-16-2009, 11:25 AM
  #6  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default

Originally Posted by Ridge Runner
grasping straws mostly here, if this is the first full power load on them its probably just overpressure, but you could probably use the same load and just seat them deeper, velocity would probably go up a tad and pressure go down by just giving them a lil jump.
RR
Old ones were 2.737 OAL, just loaded 9 at 2.730 and 47.0, 47.5, 48.0 grains instead of 48.5. Will test them out in a couple hours and see what happens. I have shot this load many times in another batch of Lapua brass and never had the primer thing happen...
jeepkid is offline  
Old 08-16-2009, 11:49 AM
  #7  
Typical Buck
 
LaneNebraska's Avatar
 
Join Date: Dec 2004
Location: Nebraska
Posts: 601
Default

Originally Posted by jeepkid
Old ones were 2.737 OAL, just loaded 9 at 2.730 and 47.0, 47.5, 48.0 grains instead of 48.5. Will test them out in a couple hours and see what happens. I have shot this load many times in another batch of Lapua brass and never had the primer thing happen...
That 2.730 and 47.0 sounds like a winner

Will you run them over a chrony? And what bullet/weight ya shooting?

Last edited by LaneNebraska; 08-16-2009 at 11:51 AM.
LaneNebraska is offline  
Old 08-16-2009, 12:18 PM
  #8  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default

Yep, shooting them over a chrony. 105gr Berger VLD. Leaving in about an hour to shoot them...
jeepkid is offline  
Old 08-16-2009, 03:25 PM
  #9  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default

Just shot them and the 47.0's were fine, then one out of three of the 47.5's blew a hole next to the primer and then I shot one 48.0 and it also did so I didn't shoot any more.

Could it be a bad batch of primers? Its the same load that I've shot over 50 times with no trouble before...??
jeepkid is offline  
Old 08-16-2009, 03:47 PM
  #10  
Giant Nontypical
Thread Starter
 
jeepkid's Avatar
 
Join Date: Mar 2006
Location: ****ifornia
Posts: 5,052
Default

Went out and checked the rest of the primed brass...picked one up and the primer fell out...thinking that's my problem...
jeepkid is offline  

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.