Starting loads for large capacity cases?

[efm77]

I'm somewhat new to reloading (only been doing it a few years and not in large quantities), and have always read a general rule of thumb to start 10% below the listed max load and work up from there. However, I've read a few pieces that state for cases with capacities above 40 grains, to only reduce by 5%. Some manuals I see the starting loads for larger cases seem to fall in that area as well. What's your experience? Is that considered safe to start 5% below instead of 10%, especially on something like a RUM or Lapua case?

[MikeT124]

For bottle neck rifle cases and some (44, 45C, 454 etc) pistol cases I never go less than the Minimum (starting) load in a reliable up to date loading manual. I generally use a manual from a bullet mfg or powder mfg if they identify the bullet and it's the one I'm using.

Mike

[yobuck]

I'm somewhat new to reloading (only been doing it a few years and not in large quantities), and have always read a general rule of thumb to start 10% below the listed max load and work up from there. However, I've read a few pieces that state for cases with capacities above 40 grains, to only reduce by 5%. Some manuals I see the starting loads for larger cases seem to fall in that area as well. What's your experience? Is that considered safe to start 5% below instead of 10%, especially on something like a RUM or Lapua case?
Finding a place to start is much easier than finding the place to stop.
And if your going to be loading the large capacity cases, why wouldnt you be wanting to know where to stop asap?

[efm77]

I understand the tell tale signs of when to stop and I haven't pushed my luck in that regard, at least not that I can tell. I've yet to load all the way to what the manuals say as max. I value my equipment, face, and appendages too much. Just wanted some clarification as it seems the large capacity cases have starting loads much closer to max from a percentage standpoint than the smaller ones. Most of them being around 5% below the listed max. I just wondered if anyone else had noticed this too. I guess I'm also wondering if most people just go by the listed starting load in the book, or if they look at the max and do the math, and say, "ok max load is 100 grains, so I'm going to start at 90 (10% below max) and work up from there."

[yobuck]

I understand the tell tale signs of when to stop and I haven't pushed my luck in that regard, at least not that I can tell. I've yet to load all the way to what the manuals say as max. I value my equipment, face, and appendages too much. Just wanted some clarification as it seems the large capacity cases have starting loads much closer to max from a percentage standpoint than the smaller ones. Most of them being around 5% below the listed max. I just wondered if anyone else had noticed this too. I guess I'm also wondering if most people just go by the listed starting load in the book, or if they look at the max and do the math, and say, "ok max load is 100 grains, so I'm going to start at 90 (10% below max) and work up from there."
Well ive never met anyone who isnt concerned about their face when loading ammo.
Especially those who have young family members who use the same equipment.
Loading for the larger cases is no more dangerous than loading for smaller ones anyway, its simply mind over matter..
Check the chamber pressures on 243s for example
Point is there is no advantage to owning a 300 Rum if your not getting max use from it.
And you need to get there before you know what it is.
100 or more rounds down the barrel is totally unnecessary in order to find that out.
Im personally more concerned over the yahoo who builds my guns than the one who loads my ammo.
But obviously not all agree on that either.

[efm77]

Except that I've read that larger cases are more prone to problems like pressure spikes with too low of a powder charge and are more sensitive to that than smaller cases. Probably why I've read what I've read about reducing by 5% from max instead of 10% in some instances. Chamber pressure is not the be all, tell all either. The 243 operating at the same pressure as a larger diameter case, will have far less bolt thrust because it's applying that pressure over a smaller area. Anyway, thanks for the replies, but my question still hasn't been answered. I don't know if I'm just not wording it well enough. Maybe that's my fault.

[efm77]

Here's an example of what I'm asking about.

338 Lapua Magnum – Hunting HandloadsHandload Data
by ©RGI Media, Inc - Published with permission (https://www.realguns.com/author/wpadmin/)
Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet length will alter net case capacity, pressure and velocity. Primer selection is specific and primer types are not interchangeable. These are maximum loads in my firearms and may be excessive in others. All loads should be reduced by 5% as a starting point for development where cartridges have greater than 40 grains in capacity and 10% for cartridges with less than 40 grain capacity following safe handloading practices as represented in established mainstream reloading manuals. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.
https://www.realguns.com/wp-content/uploads/338lapuarugerprecisionproj-300x57.jpg



Cartridge – 338 Lapua 65kpsi



Firearm
Ruger Precision Rifle



Barrel Length
26.00″


Min – Max Case Length
2.7244″ +0.000″/-0.020″


Min – Max COL
3.6811″ +0.000″/-0.120″



Primer
CCI 250



Bullet Diameter
0.3390″ +0.000″/-0.0030″


Reloading Dies
Redding

[243winxb]

Simply follow published start data from powder manufacturers. I load 1 shell at starting & quickly move up the powder charge. One shell at a time, while watching for pressure signs.

Hodgdon data has 338 LM data. Most are not reduced 10% for a starting load.

In some brands of powder, lot to lot variation, in burn rate, can be 10% Hopefully, the powder manufacture that allows a 10% difference will list a lower start load?

Any change in 1 component or COL, OR bullet hold/neck tension makes a difference.

https://thefiringline.com/forums/showthread.php?t=476535

Strange things can happen.https://www.thehighroad.org/index.php?media/257-weatherby.1262/full

[efm77]

Simply follow published start data from powder manufacturers. I load 1 shell at starting & quickly move up the powder charge. One shell at a time, while watching for pressure signs.

Hodgdon data has 338 LM data. Most are not reduced 10% for a starting load.

In some brands of powder, lot to lot variation, in burn rate, can be 10% Hopefully, the powder manufacture that allows a 10% difference will list a lower start load?

Any change in 1 component or COL, OR bullet hold/neck tension makes a difference.

https://thefiringline.com/forums/showthread.php?t=476535

Strange things can happen.https://www.thehighroad.org/index.php?media/257-weatherby.1262/full


Your practice for starting and working up is the way I've been doing it too. It kind of sucks having to start all over again when one component is changed but I understand it. I was told by Hornady though that if I replace just the case with a new one I don't need to start all the way at the starting loads again, but just back off 2 or 3 grains and start from there. That's with the same brand of brass which should have similar capacity, although that can vary too. Hence the reason for backing off some. Now, switching anything else (primer, powder, bullet, seating depth, crimp, etc), definitely warrants going back to starting loads. I still have a hard time wrapping my head around how it is that the ammo manufacturers can produce factory loads that produce the speeds they do, and yet are supposed to be safe in any firearm chambered for it, but handloading you have to start way below that and hopefully work up to it. I understand the powders they have access to are different from what's available to the hand loader, but still.....

[charlie b]

It's because the mfg's can test everything and buy in large lots. They will buy a large lot of powder and primer compound. Load up test ctgs to get the vel they want and still stay below max press. Then load a 100,000 rounds. Each lot will probably be a slightly different powder charge based on their testing.

I have not loaded a ctg at max pressure for decades. I find the best accuracy at 100-200 fps below max in most cases. It is difficult to judge sometimes due to different book recommendations. Sierra, Hornady and Hodgdon are the ones I use the most, and they rarely agree. Sometimes they are off by a couple grains, sometimes they are very close. Just shows how different barrels, chambers, brass, etc make a difference in a load.

I also realize that 'signs' of excess pressure usually mean I am far over the safe limit. If I am using fairly new brass and the case 'sticks' in the chamber, I stop and pull all those rounds. Same with 'impressed' case head. Primer condition is rarely a good indicator by itself. I've had flattened primers with factory loads in some ctgs and in loads well below max. Same with cratered primers. But, if I am at or over book vel and primers have started to flatten, I back off.

[efm77]

Good points Charlie B and I've heard those before about factory loads. I too have not loaded anything to the max. The closest I've gotten is about 3 grains below the listed max. Velocity was good enough and accuracy was good too. Like I said, I don't want to push my luck in that regard. Thanks for the info.

[yobuck]

Your practice for starting and working up is the way I've been doing it too. It kind of sucks having to start all over again when one component is changed but I understand it. I was told by Hornady though that if I replace just the case with a new one I don't need to start all the way at the starting loads again, but just back off 2 or 3 grains and start from there. That's with the same brand of brass which should have similar capacity, although that can vary too. Hence the reason for backing off some. Now, switching anything else (primer, powder, bullet, seating depth, crimp, etc), definitely warrants going back to starting loads. I still have a hard time wrapping my head around how it is that the ammo manufacturers can produce factory loads that produce the speeds they do, and yet are supposed to be safe in any firearm chambered for it, but handloading you have to start way below that and hopefully work up to it. I understand the powders they have access to are different from what's available to the hand loader, but still.....
Strange things dont or at least shouldnt happen.
Take a look at the case in the picture, and that should tell the story.
By and large the cases, especially of the large capacity ones should be more carefully scrutinized before loading again and tossed at the least sign of a problem.
The dent might well have been caused by excess build up in a die that dosent get cleaned very often.
One more firing from a borderline case is quite often where those type issues develop.
Another issue not discussed often is case weld developing in ammo that has been sitting around awhile.
Especially the large cases that only get used for hunting and might be several years old.
If your not familiar with it it would behoove you to find out about it.

[efm77]

I didn't say anything about not examining cases carefully, nor did I say anything about trying to get too many firings out of a case.

[Czy_Horse]

Is that considered safe to start 5% below instead of 10%, especially on something like a RUM or Lapua case?

IMO, a 10% reduction is not safe, 10% more often than not, puts you below the Published Min Start Load.

Below is Data for one of my rifles, a 25-06Rem. In this example, if you reduced the Max loads by 10%, every load is below the Published Min. Start load.

https://i.imgur.com/hwL8z8Ll.jpg



Below is Data for a 338Lapua Mag. With a 10% reduction in Max load, only 1 load is above the Published Start Load.

https://i.imgur.com/jEEoB8Gl.jpg



If I'm not doing a load ladder, I just pick a powder weight between Min & Max, why screw around with percentages?

[PhilC]

I always start with bullet manufacturer's recommendation. If that is not available, then I default to powder manufacturer's data for specific bullet and go from there. Follow those, forget what you read on the internet, and you'll be safe. Unless you are actually loading for a large volume rifle case (I do not consider 40gr "large volume") I don't know why it would matter.

[yobuck]

I always start with bullet manufacturer's recommendation. If that is not available, then I default to powder manufacturer's data for specific bullet and go from there. Follow those, forget what you read on the internet, and you'll be safe. Unless you are actually loading for a large volume rifle case (I do not consider 40gr "large volume") I don't know why it would matter.
Well he is talking about large capacity cases Phil, and his first post stated that.
And that no doubt is at least part of the issue.

[PhilC]

I read his original post several times and sounded, to me, to be more an academic question about powder reduction when using large volume cases vs him actually loading for them. If I missed it my apologies for responding.

[yobuck]

I read his original post several times and sounded, to me, to be more an academic question about powder reduction when using large volume cases vs him actually loading for them. If I missed it my apologies for responding.
Well you could be correct as he wasent very specific, but i interpeted it as if he were.
Problem with the larger capacity rounds is that there is only so much life in the barrel.
How much of it do you want to use up developing loads?

[Robinhood]

I always start with bullet manufacturer's recommendation. If that is not available, then I default to powder manufacturer's data for specific bullet and go from there. Follow those, forget what you read on the internet, and you'll be safe. Unless you are actually loading for a large volume rifle case (I do not consider 40gr "large volume") I don't know why it would matter.

I was that guy that pushed the limits. Now I am the guy that follows this advice. The differenc in large volume cases is the spread between charges when working up a load.

For conversation sake, I wonder the difference between max charge by volume and max charge by weight is if you looked at altering loads by 1 percent.

[efm77]

I always start with bullet manufacturer's recommendation. If that is not available, then I default to powder manufacturer's data for specific bullet and go from there. Follow those, forget what you read on the internet, and you'll be safe. Unless you are actually loading for a large volume rifle case (I do not consider 40gr "large volume") I don't know why it would matter.

I am going by what the manufacturers say and not what the internet says. That's where I get the "start 10% below max load" from. Some published load data only shows max loads for that particular arm, hence why they say to reduce by 10% and start from there. But I've also seen the "reduce by 5% for cases that hold more than 40 grains" as well. See the reference site I copied above from Real Guns. I've also read in Hornady's manuals that large capacity cases do not respond well to being reduced much below max. IIRC they said it can cause dangerous pressure spikes from too small a charge.