Results 1 to 7 of 7

Thread: Switching Primers.

  1. #1

    Switching Primers.

    I started loading for my 308 Norma Magnum again and was surprised last week to find NO magnum primers available at any of the shops. I have thousands of primers but had only one single box of large rifle magnum primers: CCI 250. Wanting to assure a supply of whatever primer I used so for my initial loads, I just used regular Federal 210 primers. Groups were pretty horrible. Largely vertical and 1.5 to 2 inches using 70 grains of H-4350 as fuel under 165 grain SSTs. The vertical tendency seemed to spell 'ignition' so this week I again searched out some primers and finally found 1000 Remington 9 1/2M (mag) primers to use in today's loads. With only the change in primer, the groups were now 1/2 to 1" in a pretty nasty cross wind... and this with just a fore-end rest.

    Though the use of magnum primers when lighting large piles of slow burning powder is pretty much common sense, today's experience was a reminder of the times in my shooting career when simply changing primers made a dramatic improvement in accuracy. Don't be afraid to change up primers when a load isn't doing the things you think it should.~Muir

  2. #2
    SD Regular
    Join Date
    Dec 2008
    Location
    East Midlands M1/M69 Junction 21
    Posts
    5,385
    Yes. I found that in 270 WCF with CCI Standard primers the extreme spread was just quite small over five reloads whilst with Remington 2 1/2 Standard primers it was considerably more. Also, with the CCI the velocity was slightly higher.

  3. #3
    The Remington 9.5 is a lot hotter primer than the CCI 200, and the Winchester LR is even hotter. I am finding some of these newer, denser powders, where you can get more weight into the case, do better with a hot primer or even a magnum primer, in a non-magnum long case. So many variables. It is chemistry, a chain reaction of burning, and occurs in microseconds, so a little change can have a big effect.

  4. #4
    A magnum primer also has harder walls than a standard primer and will resist piercing when subjected to high pressures.
    If you can get away with standard primers then by all means use them as they will initiate more reliably if a firing spring starts to soften or the rifle simply has a softer firing pin blow.
    Don't ever use pistol primers in a high pressure rifle case. They are softer still to allow for the lighter pin/hammer fall in a handgun. Less compound too unless you use a Magnum pistol primer.

  5. #5
    hello Muir

    I have similar experience with mag primers but only due to t hem being the only ones available when I went to t he shop. they have improved things dramatically. who would have thought that such a small thing would make that difference. I was new to reloading and am still learning

    ES

  6. #6
    hi muir if you want pop round I can let you have a couple of thousand cci mag primers . after not being able to get any cci 200 normal large rifle I have started using the cci mag primers and vit 165 with good results .

  7. #7
    Quote Originally Posted by ndt man View Post
    hi muir if you want pop round I can let you have a couple of thousand cci mag primers . after not being able to get any cci 200 normal large rifle I have started using the cci mag primers and vit 165 with good results .
    That's a kind offer and I thank you for it, but I'm in the US. It would be a long flight and then they probably wouldn't let me take them home! ~Muir

Similar Threads

  1. CCI small pistol primers vs cci magnum small pistol primers
    By gixer1 in forum Ammunition, Reloading & Ballistics
    Replies: 3
    Last Post: 13-11-2014, 04:03
  2. RWS Titan...barrel switching
    By white van man in forum Rifles & Calibres
    Replies: 8
    Last Post: 17-04-2014, 21:08
  3. Primers
    By swarovski in forum Ammunition, Reloading & Ballistics
    Replies: 16
    Last Post: 21-07-2013, 18:21
  4. switching between subsonics and standard velocity
    By Mungo in forum Ammunition, Reloading & Ballistics
    Replies: 6
    Last Post: 24-08-2012, 11:42
  5. Primers
    By RPA 6MM BR in forum Ammunition, Reloading & Ballistics
    Replies: 6
    Last Post: 25-06-2012, 19:15

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •