Conflicting Reload Data by "Experts"

E

epags

New member
Just got back into reloading the 357 Mag and have run into a interesting issue.
I am interested in reloading 158 gr JHP with Hodgdon's H110.

Hodgdon's online data says: Start with 15.0 gr 1,418 FPS Max 16.7 gr 1,591FPS.

Sierra's Edition V, Edition 6 say: Start with 13.3 gr 1,150 FPS Max 16.3 gr 1,250 FPS

Hornady's 7th Edition says: Start with 12.7 gr 1,000 FPS Max 15.6 gr 1,250 FPS

How does 15.6 gr give you 1,250 FPS while 15.0 gives you 1,418 FPS?

Barrel length? Some sources provide data others don't.

Any comments?
 
It is what it is.

Some ballistics labs shoot universal receivers, some shoot actual firearms.

They show the differences between bullets, primers, and powder lots.

You won't find any load data anywhere that replicates another test lab's work ups. There are just too many variables involved.

You can duplicate their loads using identical components and still have different data.
 
Yep, Dufus nailed it: " There are just too many variables involved."

Those writing the manuals can only tell you how their testing went on that day with that batch of components.

This variables thing is why we always say: Start low and work up.
 
I never use any of Hornady's data. Their data is developed by their wives and mothers which is why it's so low.

As told by others there are always differences because of the equipment used so you have to use an average from all sources.
 
"I never use any of Hornady's data. Their data is developed by their wives and mothers which is why it's so low."

Yupper, just keep adding powder until you blow your face off--that's when you know you should have stopped sooner.
 
Epags,

The issue with H110/296 is that if you load it down too far it can actually extinguish and leave a bullet stuck in the barrel for you to fire the next round into. As near as I can discern this is a matter of percent case fill under the bullet. If it gets much below 90%, it can put you at risk of this happening. Hodgdon used to have a warning up not to reduce the posted minimum by more than 3%. But, understand, this is only going to apply to the components the list. If you use a bullet that is the same weight but a little longer, owing to a lighter alloy or a bigger hollow point, you will have less space under it in the case, so 90% becomes a smaller volume. if you use a brand of case that has thinner side walls or head web, it will have more volume so it will take more powder to reach 90%.

As pointed out by Mehavey's posted image before I had to remove it, the barrel lengths used in the tests are often quite different and that results in substantial velocity difference. SAAMI may have up to three barrel lengths. For .44 Magnum, for example, there is a 4" vented pressure and velocity test barrel with a 0.008" open gap (the vent) at the end of the chamber throat to simulate a revolver. There is also a 8.275" barrel that is closed to simulated a single-shot silhouette barrel. There is also a 20" rifle barrel to simulate a carbine. The velocities will be significantly different for each. Then there are folks, as mentioned earlier, who test in a production gun and get still different numbers.
 
Variables known to affect pressure/velocity:

barrel
barrel length
case capacity
bullet composition
bullet length
cartridge overall length (seating depth)
powder lot #
primer, and probably lot # as well
 
Once you realize that the data is going to be conflicting from one manual to another and you get at a minimum three or four manuals to compare loads with you will see correlation between the different data. Barrel lengths, universal chambers , primers everything can alter the numbers. Average the numbers and use them as a guide. Maximum and starting loads need to be watched .
Load manuals are a guide not necessarily a exact recipe to be followed. If four manuals give starting loads of : 5.0 , 5.2 , 4.9 and 6.0 , average those numbers and you get 5.275.
I would start at 5.2 or 5.3 and work up.

I wish there was one book that had perfect loading data but there isn't, be careful and use common sense when loading.
Gary
 
You mentioned several different bullet makers manuals as well as hodgdon.

Bullet maker reloading manuals use only their own bullets for the most part. Each bullet may have a different bearing surface and profile. no two JHP's are exactly alike ....especially from different bullet makers. base shape, bearing surface, ogive length, nose shape....it all affects case capacity vs OAL and that's taking for granted that primers, chambers, barrel lengths etc all make differences as well.

Some folks say bullet maker "X" has a reloading manual that is too conservative, and I have personally had situations where hodgdons max was over max yielding pierced primers at a middle-range charge.

My point is, manuals are guides, not absolutes in every firearm. Use them as a starting reference and work up for yourself.

FWIW H110 is a powder for when you want to operate at max velocities. it's pretty forgiving near or even over max but not one to try and download.
 
Well, thanks for all the information. I was aware of barrel length but overlooked bullet composition. I always load below max and above min but never thought about averaging. I am looking at H110 for hunting loads so want to be at the higher end. Use AA No. 7 for accuracy.
Thanks again to all of you.
Ed
 
As Unclenick said, you can't use light loads of H110 and W296, and I refuse to use it for just that reason. I will gladly give up 50fps and use either 2400 or 4227. Just MHO.

Don
 
The discrepancy between the different published data is what caused me to develop the practice I use.

Locate as many different data listing as possible using the same components, compare to what the powder manufacturer lists. There are usually outliers for both start and max to which I discount those. Chose a starting point and then only load 5 to 10 of those and fire for effect. I usually fire the first few rounds in my hand guns loaded one at a time just to check function and that the bullet is going to clear the barrel. Then load 3 and repeat, checking for function in auto loaders. Are they going to cycle and lock the slide after the last shot.

Then if they look like they will work successfully I'll load more for further testing or bump up the load to the next increment.
 
Mobuck said:
"I never use any of Hornady's data. Their data is developed by their wives and mothers which is why it's so low."

Yupper, just keep adding powder until you blow your face off--that's when you know you should have stopped sooner.
Click to expand...
Hornady fan? Most of their data is way under everyone else's. Compare all the sources and guess who is at the bottom with the lowest charges.

Nowhere did I say keep adding powder, I said I don't use any Hornady data, wise one.
 
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Yeah, since I was just setting up for 30-06 165s over IMR-4350, I checked a number of manuals' max loads: Sierra 56, Hornady 57, Nosler 57, Speer 58.

Since I had the books out, I checked Hornady against Speer for a number of the rounds I load. They are pretty consistent. A little variation, and sometimes Speer will have a higher charge with one powder, Hornady with another. But never much difference. I don't have a preference for anyone's data other than my own, but to say Hornady is consistently the lowest doesn't hold water.
 
For sure get a good manual. I suggest the Lyman 50th Reloading Handbook.
Read the manual. Then look at the suggested loads for your needs, then go buy components and start loading. Remember: Start low and work up!
 
The thing to always keep in mind is that loading manuals are nothing more than a guide! That's why we back off max loads and learn to look for sign's that mean pressure. I don't trust my ability to see it in handgun's but I load about 99% cast bullet's and I never get to close to max loads. Well within a couple tenth's. Handgun powder's are fast burning powder's and pressure run's up a lot faster than with slow rifle slower powder's in rifle's!
 
I have a better one for you!

300 AAC Blackout

Nosler 110gr bullet; Enforcer 15.5-17.5 gr

Ramshot 110gr bullet; Enforcer 17.4-19.3gr

What gives? That said, my primers look mild compared to factory Armscor at 17.4 gr.
 
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