Large rifle primer question

[GeoDudeFlorida]

I posted a note in the Speer manual that called for 30-06 speeds out of a 308 that was not even achievable in their load tables. I have never seen, experience or herd of a problem using a start load from any manual. My normal blurb always includes consider using a starting load first. Now that precaution may be most useful in old guns where reloading might be the only option and rapid disassembly is more likely than say a new glock. The two layers of safety are knowledge and or a strict compliance with the manual. If you don't use or have one you better double down on the other.

I'll add the caveat that misprints happen so check MULTIPLE manuals and make sure you read the addendums put out by the publishers when new editions are released.

 

[Fooey]

Here is my philosophy, unlike most reload data, covers all reloading scenarios. I just ask myself.....is it faster to start over at start load charge than it is to grow new eyeballs then I start at the manual's starting point. If I can grow new eyeballs before I get back to reloading room, then I take a chance! Is this good newby advice or what!

 

[ms6852]

There is quite a disparity between manuals when it comes to loading data. Information from each manufacturer varies because their conditions could be different. There is also a lot of disparity between reading and comprehending what one is reading, so interpretations are varied. Just as has been mentioned above it is a safe bet to always start at lower loads from what is published and is noted in many manuals, Sierra for one mentions it. Also one can not assume that they will get the same results from like velocities because barrels used may be shorter or longer and depending on powder used velocities can vary from 25fps to 50fps per inch of barrel length.

This is why when switching to Magnum Primers from Large Primers it makes a difference what type of powder one uses. Magnum Primers are commonly used in slow burning powders to create a more uniform ignition whereas faster burning powders may use regular size rifle, pistol...etc primers.

 

[JJFitch]

Folks like most reloading supplies are slim pickings right now. Looking to load 30-30 ammo and a friend gave me a pack of magnum large rifle primers. My current load is 150gr bullet with 29.7gr H322. Question is do I need to drop my charge due to magnum primer or roll with current load?

YES!

Using Magnum primers DOES NOT automatically mean an increase in pressure or velocity BUT how many of us have the laboratory equipment to verify PRESSURE?

As mentioned several times above conventional wisdom means reducing the powder charge!

But then there is the number one rule in reloading! "Use only manufacturer's load data"!

Here is a "primer" on primers!
Google:
Primer Info & Chart + Milspec Primers for Semi-Autos & Other Primer Applications

Smiles,

 

[Fishtales]

The standard when changing any component is lower the charge by 10% and work back up if necessary. Don’t go below published minimum.
Not to be offensive, but one can make all kinds of conveluted arguments for, and get any number of Internet opinions about, deviating from this standard, but the fact is, if you’re asking this question, you probably don’t have the expertise and experience to do so.

I agree with bullseye 308 on accuracy and twarr1's last two sentences. If you intend to proceed, as some have suggested, with the magnum primers, make up 3-5 cartridges. After firing one, check the primer and case for signs of pressure. If you don't see any, shoot another two and check for pressure signs again and also check your target to see if you are getting the grouping you are used to-changing any component usually affects accuracy. Without accuracy what's the point of continuing. That being said, if it was me, I would not reload any cartridge using a primer not recommended for it. I would bite the bullet and go on Gunbrokers auction site (or something like it) and see what's available and what the bids are (I know, many think GB is a rip off, but if you need some component it's usually there). Last time I looked the prices have come down considerably from what they were 2 years ago-they will never be what they were 50 years ago (or even 15 years ago). Good luck and, most importantly, be safe.

 

[denton]

Ummmm.... maybe a little controversial, but....

I do have both pressure measuring equipment and a chronograph. I have done tests comparing Federal and CCI standard and magnum primers in a couple of rifle cartridges, and have not found any detectable difference in peak pressure. That is not to say that there is no demon out there, just that I never found where he lives.

If you think you can safely work up a load by watching primers and case head expansion.... you can't.

The best tool commonly available for load work up is a chronograph. If you're using the same powder and bullet as a known good load, load 2 cartridges for each test charge. Control barrel temperature the best you can, and/or if you are feeling frisky, fire the cartridges in random order. Do a scatterplot to ensure that MV advances with increasing charge, and that the load you want to use does not produce more MV than the known good load.

MV is a product of all the area under the pressure curve, but is mostly determined in the region near the peak. For a given powder, MV is a good relative indicator of peak pressure.