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Discussion Starter #1 (Edited)
I've been using this site as a cross reference to verify loads for quite a while now and have never seen such varying loads between sources until now. I was setting up to use a new powder for the 223 using my Hornady 9th edition and the Hodgdon website for verification and was very surprised at what I found. I guess up until now I just happened to use loads that jived between these two sources for all of my rifle loads.

I had a small amount of Win 748 left over from reloading 308 so decided to see how well it might work for 223 (55gr bullet). Looking at the Hornady manual it gives a starting load of 22.7gr for 2800fps and a max of 26.4gr for 3200fps max C.O.L of 2.260. Then looking at the Hodgdon website there is no starting load and only a max load of 26.3gr for 3150fps? The velocities seem to be in line but why is there no starting load? How are you supposed to work up a safe load without a starting reference? This made me curious about some of my other calibers.

I use H4198 for 7.62x39 (123gr bullet) as it's the Cadillac of x39 powders. I suppose I never really cross referenced this particular load because I've been reloading it for a long time and it worked just fine. The Hornady manual lists 17.2gr for 1900fps and max 25.7gr for 2400fps max C.O.L of 2.190. Now here's where I think it gets crazy. Starting off the Hodgdon sight is using a 125 grain bullet with a max seating depth of 2.150. We already know the heavier bullet and deeper seating depth means more pressure. But then it has a starting load of 24.5gr for 2190fps! The max load is 26.5gr for 2378fps. So not only is Hodgdons starting load approaching Hornadys max load it also registers 110fps slower than Hornadys 24gr load. That just doesn't seem right at all. Hornady is using a 20" 1 in 7 twist barrel and Hodgdon is using 24" 1 in 9 twist.

Shouldn't 7.3 grains of powder produce way more than 190fps? Can 2 grains of weight difference between the the projectiles make that much of a difference in velocity? Shouldn't a longer barrel produce MORE velocity? I don't know maybe I haven't been reloading long enough but something seems wrong here.
 

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Look on your bottle of powder .. my imr and bc2 in fine print say drop by a X% .. for starting load .. i'm in the house now and cant recall the number .. 3 ,5 10 ..
 

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I use published velocities as an estimation. There are too many factors that affect velocity in any specific firearm. I only trust my chrony :D
 

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Discussion Starter #4
It seems only my Hodgdon powders with load data printed right on them have any charge reduction percentages listed. "MAXIMUM LOADS - DO NOT EXCEED - REDUCE BY % TO START". H110 is 3%. Titegroup and 4198 is 10%. My IMRs, Accurates, Vihtavuori, Alliant and Winchester don't. Trailboss doesnt but that is another can of worms. Either way if we started with 10% less it would still leave us at 15.48gr vs 22.05gr starting charge for the x39. I agree load data is more of a starting point estimation but where do you start with that kind of difference? So like if someone only had the website and not the manual then what? I guess the best route would be to start with the lowest data you can find and work up from there. I see my chrony will be getting more of a workout for more than just subsonic loads.
 

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So like if someone only had the website and not the manual then what? I guess the best route would be to start with the lowest data you can find and work up from there. I see my chrony will be getting more of a workout for more than just subsonic loads.
The key to reloading is data. I always try to compare 2-3 sources when checking starting/max loads. I would never recommend a person only use 1 source. Although sometime you may have to roll the dice. Usually there is some obscure forum that you can cross compare loads. I personally subscribe to a "paid" load data database website.

Here is a data dump. Standard use at your own risk disclaimer
Bullet, Powder, Charge (grains), Muzzle Velocity
123 Hornady SST or SP Hodgdon H-4198 17.2 1541
Remarks:
123 Hornady SST or SP Hodgdon H-4198 18.9 1690
Remarks:
123 Hornady SST or SP Hodgdon H-4198 20.6 1861
Remarks:
123 Hornady SST or SP Hodgdon H-4198 22.3 2033
Remarks:
123 Hornady SST or SP Hodgdon H-4198 24.0 2205
Remarks:
123 Hornady SST or SP Hodgdon H-4198 25.7 2361
Remarks: maximum load
 

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Hogden info is what one would call Laywer load data, it tends to be conservative.

You want good load data Sierra has some of the best real world data that you will find, different bullet design may yield different results but if you match the weight and powder to there load data you will find it to be an excellent starting point. If your useing there bullets, its pretty much dead on, give or take depending your barrel length.

Berger data is absolutely terrible But there free ballistics tool has worked very well with there bullets.
 

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If I am working up a load for a new rifle, I take the median load from Hedgdon, Hornady, Nosler and Sierra. I then take the average of that number and start there. Then, up and down by .3 grains and then further narrow it down. The variation is so great, you cannot rely on only one book or chart. It is time consuming and frustration, but it is the best way I can come up with.
 

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I've used Hodgdons published load data in the past and still use it for reference. Over the last several years I have been using Noslers published load data as I use mostly accubonds now. I've used most other published data over the years as a reference. The big take away at least for me has been the published data generally gives you sammi spec pressure load data and it is a good place to start from. Not all actions are created equal and one will vary from another. Invest the time and start low, work up and look for signs. A chronograph will be your friend looking for velocity changes out of the normal.
 

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I'm fine using one source (Hornady, Hodgdon, even Quickload) for STARTING loads, provided that they are well below the published maximum. I completely ignore pulished max loads. As I'm working up from a published starting load, my safe max load is 0.1 grain (or more, if it's a charge that will be dropped rather than weighed each time) below the loading at which pressure signs appear on the primers. I have seen pressure signs well above and below published maximum loads (values which, as noted above, often vary from source to source). I wear gloves and eye+double ear protection as a matter of course for all shooting, which reduces the risk of injury by 90% for most load workup. I am particularly careful with plastic frame handguns (and only own one), but my G19 is a range gun and as long as everything makes Minor power factor and cycles the gun it's fine. Finally, remember that nitrogylerine and nitrocellulose are highly sensitive to pressure, which is a function of the initial case volume. Seating depth has a huge effect on maximum pressure; seating depth is not carved in stone, particularly with semi-autos. Chamber a few dummy rounds and see what your COALs are before and after; if your neck tension is not consistent, they may vary, which will in turn result in variable peak pressures (i..e one bullet gets pushed further back into the case than the next due to variation in neck tension). Changing neck tension or crimping to fix bullet setback will ALSO affect peak pressure. The hardness in the brass at the case mouth will also affect neck tension, which will vary unless you anneal your case necks in a repeatable fashion after every firing (which is unsafe for pistol rounds and time consuming for rifle rounds). A "safe" factory round fired from my LR rifle would generate dangerous pressures because the chamber is reamed with an extremely tight neck made to be used with trimmed case necks.

A load isn't safe unless it's proven safe in your gun with your components and techniques, no matter what a book using brass that may be VERY different from your brass says.

The best reloading advice ever given to me for high power rifles was one of the guys at GA Precision, who has forgotten more about loading and shooting than I will ever know. He said "always work up your load based upon ballistics; look and see what the extra FPS gets you in terms of minutes/mils of come-up, because the extra pressure WILL cost you barrel life but may not get you any tangible gain on the range. If you don't need the extra velocity, back off and get a few hundred more rounds out of your barrel."
 
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