primmers, just something that goes bang?

[Rum and not the liquid]

so im getting serious about long range and im shooting 300rum im just use winchester large rifle primers because they were there and to me primers are primers but is it a little more complicated than that i see alot of ppl when they list what the shoot mention primers make and model should i b using sumthing a bit better and really how crucial is it?

thanks

lucas

 

[bassin93]

For a case that large of capacity, I would be using Large Rifle Magnum primers. I tried regular large rifle primers and my velocity was on average 60fps slower and quite erractic. This was with Retumbo powder. I have also real where not using a mag primer in this large of capacity case can cause pressure spikes. Can't remember where I read that. Anyone else ?

 

[Rum and not the liquid]

oh yeah ive only just seen that ther is such a thing as mag primers

 

[winmag]

oh yeah ive only just seen that ther is such a thing as mag primers

Winchester Mag primers are as light as Id go on that big of a cartrige. I only use Federal 215 Mag primers (cause theyre as hot as I can find) on my 300wby, and yours has a bit more case capacity if Im not mistaken.
There can be a BIG difference in the way the powder burns (or doesnt). Primers are definately not just primers. There are some cartriges that can cross over between the lg, and the lg mag such as the wsm family etc, but yours aint one of em. Youve got a big column of powder to set off with an insufficient primer.
You may want to back off your load just a tic and swich to the proper primers, and work back up. There may be a bit of a pressure issue if your loaded heavy on the powder and trying to light it off with a large rifle primer( designed for 308,30-06,270 etc) vs the Mag primers(designed for large case capacity 300wby, 300rum, 338 win etc). Be carefull, but Im guessing youll like the results alot more with the right primer.

 

[boomtube]

"...how crucial is it?"

It varies, depending on your rifle and your load. None of us can tell you anything useful that isn't obvious. Try other types and see how they do for your rig.

 

[Rum and not the liquid]

thanks mite get sum magnum primers

 

[Mikecr]

Here is a good disscussion on it:
Hottest Rifle Primer - Primers, powders, bullets and brass - Metallic cartridge reloading - The Handloaders Bench

There is a linked test showing flash from various primers.
But I've seen other pressure testing where no real world affect prediction could be made with ANY particular primer across the gamut of cartridge capacities & powders. In fact in some cases magnum primers reduce pressure/velocities. So IMO, it is trial & error, regardless of what a vendor says.

I can say that every gun of mine preferred a particular primer with it's best load. That is, one primer for some unknown reason produces better results than all others, -given all the other components in a load(brass, bullet, powder, seating depth, temps, neck tension, etc). Both primer changes alone, or load adjusted for same velocity with primer changes, still resulted in one better than the others.
Another cartridge, another load, different preferred primer brand/type for some reason...
So I keep most on hand for testing.

It is so abstract.
I've spent the last month testing one primer at different firing pin strike speeds, pin penetration depths, spring forces, and seating crushes. With the test gun I could repeatedly vary MOA of grouping from +1 to -1/4(from a 1/2moa standard) with these adjustments. One primer type though..
Now I need to do it with several primer types, and every action of mine, to try and actually learn something!!

 

[Rum and not the liquid]

pin striking speeds wow thats pretty indepth i had always thought that a cases like the rums needed a hotter burning primer to ignite the powder at the top of the cases as quickly as posiable instead of a slow burn up the cases

 

[Mikecr]

I don't know if you can ignite powder at the top with primer fire. Seems like charge density/case fill would influence this(front firing). I know that chambering a lower case-fill shot with the barrel pointed straight up, and easing the barrel downward slowly to target, will produce higher velocities.

Gibbs front ignition testing concluded benefits to front firing with his cartridges. He extended the flash holes with tubes. Without this(what we have), relatively long cartridges like a 30-06 recoil more because a percentage of the yet unburned powder adds to bullet mass pushed down the bore. And 30-06 based cartridges(25-06, 270, etc) are really perfect examples of the very worst in cartridge design. So Gibbs didn'y have any problem fixing many 06 issues..

You know, the powder is going to burn. All primers will ignite it. But you will never predict the best combination.
I learn moreso everyday -don't assume anything, don't pay any mind to rules of thumb, and only the truth passes all tests.

 

[Rum and not the liquid]

yeh i no i no what i mean in my head just cnt put it dwn on paper