Magnum primers

glockgrouptherapy

glockgrouptherapy

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Hey guys, im looking at using magnum primers to try something new, now I have a few decent loads that I cooked up but still tweaking and I wanted to know what path I should be taking to avoid injury to my self and rifle.
using Federal Gold medal match magnum primers No. GM215M
 
308, couple different loads are goin on. one is a 190 vld on top of 35.6 of n135. 208 amax on top of 36gr RL 17. gonna start working on 175 Nosler BTHP with n135. just looking to see what I can get out of it.
 
I actually don't load for a .308 ( yet, I just bought one). I load several other calibers and have tried magnum primers with mixed results. I always back well off from and max loads I had developed with a standard primer and work up from there.

I don't believe a magnum primer is necessary in a 308 but no harm in trying it safely.
 
"...what path I should be taking..." Nothing special. You will, or should, work up the load again whenever you change any one component. Nothing bad will happen to you or your rifle if you don't though.
Magnum primers are about the powders used. They burn a bit hotter for a bit longer than standard primers and are for igniting hard to light powders and cold weather shooting. Otherwise there's nothing different about 'em as far as using 'em goes. The term 'magnum' is just a marketing term. It has nothing to do with the cartridge or the cartridge name.
 
glockgrouptherapy said:
Hey guys, im looking at using magnum primers to try something new, now I have a few decent loads that I cooked up but still tweaking and I wanted to know what path I should be taking to avoid injury to my self and rifle.
using Federal Gold medal match magnum primers No. GM215M
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When I'm loading for rifles, I never use Standard primers. I always use Magnum primers. The accuracy and velocities are far more consistent during weather changes etc. Never had a pressure issue once. Mind you, maximum loads need to be approached carefully no matter which primer you use. Use the big head and all will be well.
 
It's rare that you would need magnum primers for .308 Win, even for extreme temperatures. All of the accuracy loadings I've seen for .308 Win actually focus on using as mild a primer as possible.

I don't recall ever seeing a magnum primer recommended in reloading manuals for .308 Win either.

Magnum primers are typically used with tall columns of powder or harder to ignite powders (Ball or Spherical).

The one exception I've seen (in .223 Rem) is the CCI Magnum Small Rifle primer.
Those have thicker cups (than the "regular" CCI small rifle primers) which are more appropriate for the pressures developed in .223 Rem.
 
sunray said:
Nothing bad will happen to you or your rifle if you don't though.
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Testing done by Handloader magazine a few years ago has shown some cases using a load developed with mild large rifle primers can show up to a 10,000 psi increase in peak chamber pressures when a magnum primer is substituted . Your advice will kill someone eventually.
 
rodregier said:
It's rare that you would need magnum primers for .308 Win, even for extreme temperatures. All of the accuracy loadings I've seen for .308 Win actually focus on using as mild a primer as possible.

I don't recall ever seeing a magnum primer recommended in reloading manuals for .308 Win either.

Magnum primers are typically used with tall columns of powder or harder to ignite powders (Ball or Spherical).

The one exception I've seen (in .223 Rem) is the CCI Magnum Small Rifle primer.
Those have thicker cups (than the "regular" CCI small rifle primers) which are more appropriate for the pressures developed in .223 Rem.
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Really, have you ever used Bench Rest Primers?????

They are much hotter than Standard primers and maybe even as hot as Magnum primers. I can't see any velocity difference between BR and LRM primers over a Chrony. Velocity deviation from shot to shot is about equal as well.

This is just IMHO. It's worked well for me and a lot of others for a long time, especially with Ball type powders, where it's a standard rule of thumb for consistent velocities and cleaner burns.
 
glockgrouptherapy said:
the load Im building off of is 35gr of N135 with 190vlds. I backed it off 5grs and building back up. the original load is no where near a full case but am I being over cautious?
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N135 is a fantastic powder. I don't use it for the plain simple reality it is so hard to get on a regular basis. Very consistent burn from shot to shot.

IMHO, it is a bit on the fast side for the bullet weights you are shooting but if you're having good results, stick with it. Just be CAREFUL, N135 develops extreme pressures very quickly when it's pushed to hard. It's best used with bullets in the 165gr range.

You may even get better results with a slower powder.

My personal choice would be in the N150, H414,W760 range, with magnum primers.

This depends on bbl length as well. If your bbl is 22in(45cm) or shorter, you will need the faster powder to get velocities required for good performance.

When trying to do what it sounds like you are, I like to use slower burning powders for two reasons, one is consistent velocities, two is throat life. Hotter burns are not better.
 
bearhunter said:
Really, have you ever used Bench Rest Primers?????

They are much hotter than Standard primers and maybe even as hot as Magnum primers.
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That's not the case, actually. CCI BR2 and Federal 210M primers are in every respect identical to the standard rifle primers (CCI 200 and Federal 210) in terms of components and ingredients. The only difference is that the match primers are made in newer machines, at a slower speed, by the most experienced employees. This is done to maintain absolute consistency throughout the lot, and this is why the price tag is slightly higher because it takes more man-hours to produce them than the standard primers. That's all there is to it.

As far as magnum primers go, the accepted rule for serious competitive accuracy is to use the lightest primer you can get away with and achieve uniform ignition in the conditions that you will be experiencing. This is why the top international Palma shooters in the U.S. are using Russian primers and a number of Canadian Palma shooters are switching to RWS primers in their .308 loads. Their lighter ignition gives more uniform results under match conditions. The ultimate example of this thinking is the Lapua small primer .308 case, which takes only small rifle primers for seriously mild ignition. Lapua and the top competitors would not be going in this direction unless there was a fundamental truth to the notion that best accuracy is achieved with the mildest ignition you can get away with under the conditions where you will be shooting.

I don't know of a single TR, F-Class or Palma shooter who would use magnum primers in their .308 loads.

Magnum primers are used with large charges of slow powders and/or in conditions of extreme cold (like many hunting situations in Canada). If you use magnum primers in standard cartridges, the accepted rule of thumb is that you must work up your loads carefully. Sometimes, magnum primers can create higher pressures, and sometimes they don't.
 
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