Range report 8/1/13

[DrMike]

I do prefer the steel cups. However, having said that, when I pay attention to preparation of the primer pocket and ensure a proper seat, I have no particular difficulties with either Winchester or Remington primers.

 

[PJGunner]

Hey DrMike....that was a good tutorial on the construction of primers. I too have had problems with win primers in the past and now may know why.
BUT....maybe you can tell us more about the interaction of the win primers with todays primer pockets?
I always use a primer pocket uniformer to clean the primer pockets and use a rcbs hand primer to make sure they are well seated. But I still have trouble with win primers from time to time.
What "I think" I see more and more on todays brass....especially winchester....is the floor of the primer pocket is sort of cone shaped. Maybe the middle of the floor moves in as they punch the flash hole??
Anyhow I say this cause often when I hit them with the uniformer it only takes the very outside of the pocket off and leaves 95% of the middle still soot covered. I just don't remember seeing this in the old days. I use finger pressure to clean. I supposed I could hook up the drill and really go at it but you've got me thinking......are win primers prone to having ignition problems with this kind of pocket?

Not Dr. Mike but maybe this will help. I picked up the primer pocket uniforming tool primarily to see if it would make cleaning the primer pockets an easier job. Like you, I learned that the primer pockets were "coned" raher than flat. I mounted the tool on mu RCBS case prep tool and tried to see just what it would take to had a "perefectly" flat bottomed primer pocket. On some brass that cone runs deep. What tsting I have done seems to ell me that reamimg the pockets to a flat bottom does not hurt anything, albeit a bit labor intensive.
As I understand things, when a primer is seating, it should ne seated firmly enough that the anvil slightly stresses the primer pellet. I believe it probably creates a situation for a more consistant ignition procress. Certainly seems to make sense to me.
I'm thinking, did I maybe screw up my brass. I looked up primer pocket uniforming and it said to just remove enough for a ledge that the primer can have a firm seating. So I then loaded up an accurate load for one of my rifles and wih some trepidation when to the rne. Did I mess up that brass? The load was 49.0 gr. of W760, 140 gr. Ballistic Tip, Winchester brass and WLR primer in a Winchester M70 Featherweight 7x57. Accuracy and velocity were unchanged as far as I could tell. I shot four 5 shot groups witrh shots spaced about five muutes apart.
Since then, I've been doing this to all my primer pockets when it's too hot to actually reload ammo and I have to have the A/C on.Been doing the flash holes and insuring brass is all trimmed to the proper trim to length. Make me feel like I'm gtting something done when I can't actuall charge cases and seat bullet because of the "hurricane" produced by the A/C even at the slowest fan speed. I usually get my loads done up in the winter and spring time and do the shooting in the summer heat. If a load is safe at 110 in the shade then it should be OK come hunting season.
About the only actual loading I do this time of year would be handgun ammo. My powder measures are pre-set for the loads I use so it's just put the powder in,then check the dropped weight. If OK then it's load away. I've gone to Bullseye,W321, 2400 or W296 for handgun ammo as they measure quite well. I only use the RCBS Chargmaster 1500 for rifle ammo.

 

[kraky]

Fwiw...I have the rcbs trim station too. I had the uniformer on there but didn't like it as there is some wobble via the gear mesh and I felt it was opening the pockets as it walked around a bit. Didn't think it did it right away but over the course of several cleanings. I could have been over reacting on this bit I filled the stations with what I felt were a little more useful (to me) tools.

 

[Oldtrader3]

If you use Norma or Lapua brass the pockets are machined not hobbed and are straight walled. This helps to seat the primers fully, straight, and give good ignition. Ideally, the primer cups should be seated about .005 inches below the case baseline. The anvil in the primer has to be struck by the bottom primer cup wall in order to spark when the firing pin impinges the cup base wall. Seating the primer cup consistently and deeply enough helps to achieve good ignition each time the firing pin strikes the primer cup metal.