Pet Loads Over Maximum Load Recommendation

2Bad4u

2Bad4u

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I started reloading for my handguns last December and I am now ready to load for my new .308 WIN rifle. I've always read that you should NEVER exceed the maximum load recommendation.

However, when I look at people's pet loads for the popular SMK 175gr HPBT almost all of these loads exceed the recommended maximum powder limit. For example, when using the above SMK bullet and Varget powder, their pet loads are anywhere from 43.0 to 44.8 grains. I checked the Sierra reloading manual and they recommend a maximum loads of 41.7 grains.

BTW, I found a pet load for the above SMK bullet, my exact rifle, and he uses:
  • Varget 44.4 - 44.5 grains
  • Fed 210M primers, and
  • Laupa brass

BTW the barrel is a 24" Kreiger with a 10:1 twist.

What gives - all of these pet loads are over the recommended maximum powder limits? I assume these loads are safe to use.

Thanks in advance.
 
We can go a hundred pages on what constitutes a safe load, but my advice to you as a new reloader is to follow the manuals carefully, including the instructions to start with the low load and working upward, until you are familiar with what constitutes pressure signs in a metallic rifle cartridge.

The handgun cartridges you are used to operate at pressures where the gun is the limiting factor. In a cartidge like the 308 Winchester, the brass case is the limiting factor and you need experience, not peoples pet loads, to find safe levels.
 
rgv said:
We can go a hundred pages on what constitutes a safe load, but my advice to you as a new reloader is to follow the manuals carefully, including the instructions to start with the low load and working upward, until you are familiar with what constitutes pressure signs in a metallic rifle cartridge.

The handgun cartridges you are used to operate at pressures where the gun is the limiting factor. In a cartidge like the 308 Winchester, the brass case is the limiting factor and you need experience, not peoples pet loads, to find safe levels.
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So the quality of the case used influances the range of the powder weight. I check the Sierra manual again and noticed that they used Federal cases when they developed their recipes. Obviously the Laupa brass is more robust.

I am well aware of slowly working up loads to safe levels, and what to look for with respect to overpressure signs. What I was not aware of, was that the brass case plays a more dominate role with respect to rifle cartridges.
 
2Bad4u said:
So the quality of the case used influances the range of the powder weight. I check the Sierra manual again and noticed that they used Federal cases when they developed their recipes. Obviously the Laupa brass is more robust.

I am well aware of slowly working up loads to safe levels, and what to look for with respect to overpressure signs. What I was not aware of, was that the brass case plays a more dominate role with respect to rifle cartridges.
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Its not so much the case strength but rather that the case is built to the sammi spec of 60000psi. Like most things in life some are built to a higher standard than others.

Hodgdon lists winchester cases for its test data. If that helps you at all.
 
The printed data from any source is designed to allow for margin of error and be "lawyer safe". For a new reloader you would be well advised to stick within the printed data until you learn the ins and outs which is part of the fun of reloading. Buy a chony too :) makes it that much more fun and gives you real feedback to compare against the data as well as for you to use to compare loads. I have a few loads that are WELL above any published data that work great but I have also seen pressure signs at the lower end of the spectrum. OAL plays alot into it as well as the bullet used so pay close attention to what the publisher used in developing the load
 
"What I was not aware of, was that the brass case plays a more dominate role with respect to rifle cartridges."


Where is this written in stone?
 
The printed data in the Lyman book specifically states that the loads are not conservative to be lawyer proof, they say this so that they're legally covered.
 
I've overloaded varget all the way up to 46.5gr under a 178gr A-max with CCI 200 primers; the only change was increased recoil and slightly flatter primers, bolt was still easy to open and brass was in good condition.

I obviously don't recommend exceeding maximums but certainly take them with a grain of salt.
 
My load for 208 amax's in my 300win mag is 79.5 gr of h1000. Book max is 77 I think. My 150gr smk is 77 of imr 4831, the book is like 73. Oddly in my friends reloading manual from the 60's, the max limits are way way way higher. I think it's in the 80's of imr 4831 with the 150 gr bullet.
 
It's not a case of what works "for them" as a "pet load", that you need to know about. Their gun is a different gun than yours, and yours is different than the test guns used in the manuals. The 41.7 vs 45 gr loads from Sierra and Hodgdon are a case in point. Two different guns, different brass, two different results. Maybe even two different pressure test methods.
You may hit pressure signs with 42gr in your gun, you may not see them til you get to 46gr plus as one poster stated. Depends on the gun and how it is constructed, brass can have an effect, but, the gun dictates what the brass can handle pressure-wise in your gun. Then you add in variances in primers, bullet construction in your lot, and powder lot variations.
Only way to do it, is to work up the load in YOUR rifle, with YOUR components.
Then you will find out what is fact or fiction about other people's "pet loads".
 
Add in brass that is different in it's internal dimensions and you can get increased pressure easily. Remington brass is heavier than Winchester brass which means that, if the external dimensions are the same (ie you've FL sized and trimmed both) then there will be less case capacity in the Remington case.

It's rarely wise to exceed maximum loads but sometimes it's inevitable. My 9.3x62 needs 3 grains more powder than other guys' rifles to get the same velocity. Why? The chamber is slightly bigger. But feed one of my loads that makes 2350 fps in my rifle to someone's new manufacture Tikka and you could have a serious pressure issue (though the case likely wouldn't chamber due to the fact that I neck size).

Book data should be safe. Someone else's pet load, not so sure.

Caveat Emptor.
 
Start below and work your way up. I've never found the most accurate loads to be near the max, except for one rifle I own.
 
KDX said:
I've never found the most accurate loads to be near the max, except for one rifle I own.
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Really? My experience has been the exact opposite. I find the extreme spread and standard deviation, as well as the group size tend to shrink as I'm getting closer to (or over) max.
 
Differents rifles, differrents results, to each is own devellopement, your performance belong to you and stay safe... JP.
 
agilent_one said:
Really? My experience has been the exact opposite. I find the extreme spread and standard deviation, as well as the group size tend to shrink as I'm getting closer to (or over) max.
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With Savage rifles I've always found the best groups 1/2 - 1gr below max (ex .223). with my one AI I'm using 45gr of powder and the book max is 43gr with the best accuracy results. If my chrony isn't out there is a 275fps difference from the book with that one. If I remember right I went up to 48gr with that one without pressure signs.
 
KDX said:
Start below and work your way up. I've never found the most accurate loads to be near the max, except for one rifle I own.
Click to expand...
Most of my rifles shoot best at or near max. Couple of my pet hunting loads are slightly over max and this way because of development. Load until pressure signs start to appear then back off by half grain or until these disappear. Environmental conditions such as temperature are real important to note as well.

M12
 
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