Discussion in 'Handloading and Reloading' started by solman, Nov 30, 2016.
In rifle loading I usually end up one or two grns under max for best accuracy. At that point another 25-50 fps loses out to smaller groups. I still fire through the full load so long as pressure signs don't develope but usually see a consistent closing in group size around mid charge followed by widening. A more experienced loader taught me to check 3 sources for load data due to variances and start with the average of the three.
I wouldn't say I go over book max often but I've done it. Generally with hunting loads for example I go as close to max as accuracy will allow and if accuracy isn't there at the top end of the data I'll switch to a powder/bullet combo that will get me there. There's a time and a place. Sometimes I want the maximum a cartridge will get me. The point of hand loading is tayloring loads to YOUR needs.
When I'm looking at economic range loads then yeah, close to min as possible.
The only way I would load a max load is if it were the most accurate load in that particular gun.
As for a safety net, that is built in when a company is determining the max load. They build in a buffer.
With that being said, you should always work up to a max load, not just start there.
As mentioned, if the Max load is the most accurate, use it. There's no inherent danger.
"...at a starting load and work DOWN..." Below minimum loads can be as dangerous as above max loads.
Where guys get into trouble is playing too close to the edge with no chronograph. The loading manual may say 47 gr = 2880 fps. But I stop when I get to 2880 fps regardless of the powder charge. It might hit 2880 at 47 gr, it might hit that speed at 46 gr.
A lot of hand loaders err so much on the side of caution that their loads may not even break 2600 fps. There is no sense in that.
What load is that?
I'm asking because according to the Hornady manual #4, a max load for 55gr jacketed bullets is 21.1 grains, but Hornady manual #8 lists a maximum of 20.0. Neither edition of the Hornady manual lists pressures, but Hodgdon's manual #25 says 20.5 grains yields a pressure of 48,600 psi while Hodgdon's current on-line data says 20.4 grains produced 53,600 psi. I load a lot of .223 with 4198 and just wanted to know where your maximum loads fell with respect to the various published "maximums".
The load I use: 21.5 gr of IMR4198 is listed as max with a 55gr FMJbt in Lyman's 45th, and Lees Modern Reloading, as well as the "real world, in my rifle" data I inherited from my dad.
I haven't had any problems with this load cycling, or with pressure signs, in either a 20" rifle, or 16" carbine (AR)
Primers flatten a bit, but ...meh. It is slightly more accurate in the rifle than the carbine.
So I treat it as a "max" load. However;
In my Speer #8 & #10, max is listed at 22.0 (both of these have some HOT hot loads in them)
And on the other end,
In Hornadys 7th edition, max is listed at 20.0. I've found this book to be full of powder puffs (relatively speaking).
When I refer to published data, I tend to throw out the highs and lows, average what's left, drop down .5-1.0 grains, and start from there to work up. That way, I shouldn't blow anything up, and it won't take me a week to run through test loads. (10-20 rounds each, in .2gr increments can take a while)
Because of the extreme variance found within the published manuals, it's good to have as much data as you can get your hands on to work with- said Captain Obvious
For reason I can't quite put my finger on, I like IMR3031 in the AR a little better.
Have to look at the details.
However, when shooting long range (~1,000yards) I aim for a good, decent velocity with a low extreme spread. For example, with my 6.5x47 Lapua I aim for a velocity of 2,900fps with 123gr projectiles which just so happens to be just below the max published load. I have a decent ES of 14fps which works well for me.
Keep in mind that some of the published maximum loads are anemic. I don't think any powder manufacturer would publish load data where the firearm would have a catastrophic failure 0.1gr above the maximum load. I still don't think it's a good idea to go over the published load though, the companies that produce load data have done the hard work for you by creating a window for you to work in.
Like bullet shape and how deep it is in the case vs the other load. The Hornady 230 Gr TrFP isn't appreciably deeper in the case than the Speer 230 Gr RN in .45 ACP. It is often just listed as 230 Gr and we assume it is a RN cause it's .45.
starting loads in my Rem 700 .223 with 30" bbl and 12" twist, if I'm using anything heavier than 55 grain bullets. But with 55 grainers I've been getting close to maximum with Varget. This for target shooting only.
PapaG,KingMt, ArchAngelCD, Dog Soldier. have good comments. Approach incrementally.
Bart B. has some good thoughts, too. The gist is (and what I think they are saying) is that max loads are tuned to the particular firearm in which it was developed.
When the loads in the manuals were developed, they were tested in particular firearms and the min/max range was based on SAAMI pressure specifications (however the testing lab figured that out) to be safe in the average firearm in good condition chambered for that round.
You firearm may have lower pressures or higher pressures due to its particular dimenstions;.\
The manuals strive to stay safe in any firearm. But, as reloaders, we take our own responsibility to work up loads safe in whatever firearm we are using. Even if our firearm's chamber produces pressures above max (watch for the tell-tales) by below minimum published data. WE ARE OUR OWN BALLISTICS TESTING LAB!
Each firearm has its own rule.
In general - I never worry about working up to the hottest load a gun will stand. If you by chance inherited or found a deal on one single gun and you wanted to make it something it's not (ie, loading up a hot .243 or something), then sure. However if I'm loading for .257 Roberts for example - I have no motive to try and load it hot, mess with AI chamberings, etc. The whole reason for owning that rifle is to have something more mild powered. If I want to shoot something more powerful I'd just grab the .30-06 or something else.
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