Primer use

Hunterjohnb

Well-Known Member
Hello all, can I have your oponions on the use of magnum primers in non magnum calibers, when loaded with slower burning powders.Thanks in advance.
 

accurate

Well-Known Member
Hello all, can I have your oponions on the use of magnum primers in non magnum calibers, when loaded with slower burning powders.Thanks in advance.
magnum primers will burn hotter and increase pressures in non magnum cases so reduce loads by 10% and work up again. Personally i would only use a magnum primer in a magnum case
 

Brithunter

Well-Known Member
magnum primers will burn hotter and increase pressures in non magnum cases so reduce loads by 10% and work up again. Personally i would only use a magnum primer in a magnum case
Define magnum case ;).

An example:- I brought a tub of Reloader 19 and made up some rounds to try in 25-06 using my normal Rem 9 1/2 or CCI 200 primers and got some hang fires :eek:. I had also loaded up some .270 Winchester with Sierra 140 BTHP bullets from the same tub and using the same primers ........................... shot fine. Repeated the 25-06 recipe and got hang fires again in it :banghead: .................... So tried the load with some CCI250 primers and the load fired fine in the 25-06 using the same tub of Reloader 19.

Now neither the 25-06 not the 270 Winchester are magnum cases yet they use more Reloader 19 than the .240 Weatherby Magnum for instance does and that is a belted magnum case ............................... so define a magnum case :old:.

Now Hunterjohnb really the only thing to do is to try and see which your rifle prefers. Just take it slow and work up as per normal hand loading safe practice ;).
 

palo

Well-Known Member
I have used them with good results in the 6.5x55.
I never found any increase in pressure but I would still reduce loads and work up to be on the safe side.
 

270TOMMY

Well-Known Member
i shoot 270 and from september 1st untill april i always use a mag primer and always remington never had a problem i think the powder burns a lot better/cleaner when the weather is a bit cooler
 

mick b

Well-Known Member
reduce load by 10% and work up with magnum primers.
i use magnum primers with
100gn spbt in 243
150gn spbt in 308
250gn spbt in 338 :D

they burn hotter and longer so they burn most of your powder but do look out for presure signs.
 

Henry Straker

Well-Known Member
reduce load by 10% and work up with magnum primers.
i use magnum primers with
100gn spbt in 243
150gn spbt in 308
250gn spbt in 338 :D

they burn hotter and longer so they burn most of your powder but do look out for presure signs.
So, when you dropped back by 10% to find a load for the magnum primers, I assume you ended up with a lesser powder weight than when you used conventional primers?

If this was the case, did you still achieve the same velocities (more/ same / less)?
 

mick b

Well-Known Member
yes you do end up with less powder and yes velocities are higher,you have to work the load up at .2 at a time and to watch for presure signs.
what cal are you loading?
 

325wsm

Well-Known Member

Primers are as much a variable component as any other in reloading and canalter velocity and trajectory and therefore accuracy quite considerably.

I have long been an advocate of using primers in the same way aspowder to vary a load with great effect.

We dont choose our case because one looks shinier than another but because ofthe chemical composition that is most suitable for our particular load. Neitherdo we choose a Powder just because the local shop has it on the shelf and sowith Primers - choose your primer to do the best job possible for the load youare generating.

A change of primer can in some loads require a drop of 3 grains and thedifference in velocity without any increase in pressure can equally improve by100fps. Use your primers in the same way as your powder and you will besurprised at the difference your loads will provide.

Here is a basic heat chart - from top to bottom drop about 5-6% in powder andwork from there.


http://img.photobucket.com/albums/v356/mry716/Shooting%20-%20other/primerheatchart.jpg


Use it as a guide and add in your own primers when you have assessed them. eg,the Prvi Partizan Primers although burning approximately as hot asthe Winchester range do because of their different construction not seemto require a reduction in powder when changing from say Remington. Try foryourself and let us all know your test results as it will expand the abovechart considerably.

Use of Magnum primers is normally reserved for the Ball Powders but I amfinding I can use them to great effect in the shorter stumpier cases suchas the WSM and WSSM range of cartridges. Logically this should also be validfor the Benchrest PPC cartridges.

The same is true for the H4831 SC powder in 243 - A Federal Magnumprimer seems to provide anything up to 120 fps higher velocities thanstandard primers yet seemingly without additional pressure.
BUT
do drop the powder weight and build up again.



Please remember to drop powder weights when changing primers and do alsoremember that with hot summer weather you need to reconsider all those maxloads and take out a little powder.

A 10 degree rise in temp requires a 5% decrease in powder. If we are going toget such varied weather in coming years it may be best to have a min, intermediateand max load to use dependant on weather temperature.

 

Henry Straker

Well-Known Member
yes you do end up with less powder and yes velocities are higher,you have to work the load up at .2 at a time and to watch for presure signs.
what cal are you loading?
I am loading for a .270, for long range. The problem is my chrony reckons I have a high ES (approx. 70 fps) and SD. My groups are 3/4 MOA @ 700m with VLDs but there is obvious room for improvement according to my chrony. I am thorough with the brass prep (same brand and shot-life of brass, redding dies, primer pocket uniforming, flash hole uniforming, case trimming, case weighing, chamfering etc.) and so having come across someone's post of using magnums in non-magnum rounds to reduce ES / SD, I thought it was worth exploring. Plus, if what I hear is true, there may be a saving in powder as I can reduce the charge?

However, my real headache is my cold-bore shot. My very first shot is always way out (MOA high) at the very beginning of every session, and of course in a stalking situation that is the shot of paramount importance. Can anyone offer me experienced / informed (rather than stab in the dark) suggestions as to why this is? If it is of any importance, my barrel is a factory finnlight barrel which is decarboned properly and decoppered dubiously approximately every 50 rounds and has a bore snake only when taken out in the damp.

Thanks 325wsm for background on pressure signs
 

325wsm

Well-Known Member
""However, my real headache is my cold-bore shot. My very first shot is always way out (MOA high) at the very beginning of every session, and of course in a stalking situation that is the shot of paramount importance. Can anyone offer me experienced / informed (rather than stab in the dark) suggestions as to why this is? If it is of any importance, my barrel is a factory finnlight barrel which is decarboned properly and decoppered dubiously approximately every 50 rounds and has a bore snake only when taken out in the damp. ""


....................if you email me at mry716@hotmail.com I will forward you an article on just that subject but I cannot put it on a public site or send it via Forum channels. Sorry
 

sharkey

Well-Known Member
I have seven different cals in belted magnums from 270 wby up & don't use magnum primers in any,& never had an issue.
I like to keep it simple.
My smallest centerfires are 22 250's, so they also have a large rifle primer.
One primer for everything.

Cheers Sharkey
 

325wsm

Well-Known Member
.....and I suppose if you had 3 cars and one was diesel you would put petrol in all of them?
:lol:
 

ndt man

Well-Known Member
Hello all, can I have your oponions on the use of magnum primers in non magnum calibers, when loaded with slower burning powders.Thanks in advance.
use whats in the loading manual. speer recomends a magnum primer for imr 4350 in its 243 data and 243 is not a magnum load.if you use a magnum primer with this data it reduces group size by 25mm some powders need a hotter primer for good ignition.
 

Sinistral

Well-Known Member
Well, that's news to me. IMR 4350 needs Magnum primers.

In that case so should Vihtavuouri N160 which is the nearest to it.

Are you sure that you're quoting from the latest Edition (#14)?
 

ndt man

Well-Known Member
its edition 13 and more than one powder is marked up as using a magnum primer in the 100 grain data
 

Brithunter

Well-Known Member
Speer 14th Ed on page 250 list Magnum primers with 100 grain bullets for only two powders:-

H414
Ramshot Magnum

Now the Speer 13th only lists IMR 4350 with a magnum primer for the Boat tailed 100 grain bulllet #1220 on page 173. over the page (P-174) IMR 4350 is listed with normal primers for use with the 100 grain Grand Slam bullet #1222 and the 105 grain Spitzer # 1229. One must carefully read these manuals as there are little trips ups like this in a lot of them.
 

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