Reloading (Ballistomania)

ALWAYS CONSULT A RELOADING MANUAL. There may be typos. Don't use these numbers without verifying first. Reloader assumes all responsibility.

What is a ladder load? Primarily, a ladder load is methodical approach to determining what amount of a particular powder under a particular bullet shoots best in your gun.

Example. I bought 100 Hornady 168 gr A-MAX^® bullets. The Hornady reloading manual gives me some minimum and maximum amounts for each powder tested by Hornady. See below

10th Edition. Page 478. 165-168 grain bullets. For this bullet, we have this information

C.O.L: 2.800" (Cartridge Overall Length)

G1 B.C.: 0.475 (Ballistic Coefficient, higher is better)

I plan to use IMR 4895 powder. So what can we observe?

The Minimum amount of IMR 4895 powder I need to use is 35.0 grains. The Maximum amount of IMR 4895 powder I should not exceed is 43.3 grains.The Spread for this powder, as listed by Hornady, i s 8.3 grains (43.3 - 35.0 = 8.3 grains).

Each listed grain amount comes with a velocity in feet per second. 35.0 grains should yield around 2100 fps. On page 474, Hornady lists their test cartridge and their test rifle data. Winchester 70 rifle in .308. 22" barrel with a 1 in 12 twist. Case was a Hornady with a Federal 210 (Large Rifle) primer. Generally speaking, the longer the barrel, the greater the velocity.

So, if you have a 20" barrel or an AR-10 with an 18" or 16" barrel, your velocities will most likely be less than those from the Hornady test rifle.  If at all possible, chronograph your ladder loads. 

Look at the increments provided by Hornady for IMR 4895:

35 -> 1.6 grains to 36.6;

36.6 -> 1.7 grains to 38.3 grains; etc. So, really, how much is 1.6 grains in a little brass container with 41.6 grains already in there? A measly 3% more powder.

To go from 2600 fps to 2700 fps, with only 1.7 grains of powder, your projectile is increasing from 1,772.7 miles per hour to 1,840.9. That's 62 miles per hour faster.

Gasoline engines and gun powder are not equivalent as far as I am aware. But as a point point of comparison, think how much more energy is consumed in the difference between driving 55 mph and 117 mph (just shy of terminal velocity) in your '87 Suburban.  Never mind that's a drop in 28% fuel efficiency of your vehicle at just 80 mph.

Pay attention if you are new to reloading. You are dealing with explosives. These are not fire crackers with a creamy, soft, lead filling. The manuals and SAAMI are there to help you stay safe. And these guys test in bunkers. The shed out back that doubles as your hobby hole is not the same as hardened, reinforced concrete.

Now look at the maximum fps listed by Hornady for IMR 4895: 2600 fps. So if you use this recipe, a 168 gr. A-MAX bullet, a Federal Large Rifle Primer #210, and 43.3 grains of IMR 4895, and get 2874 fps, something is wrong. Either you loaded too much powder...dangerously too much. Or your chronograph is off. Or there is something else wrong. Notice that none of the powders provide any fps beyond 2700. Check your case for signs of pressure. Check your face for signs of shrapnel or cratered eye holes (ER docs call them 'orbits'.)

This site will never recommend any powder charge above listed SAAMI specs or those listed in reloading manuals. We have never found a need to do so. If you do so, you did not read that suggestion here. The max pressure of SAAMI specs for .308 is 65,000 psi. 55,000 psi is water pressure used to cut steel. Rarely is more better when loading for accuracy and precision. Don't be that guy.

If you take anything away from this article, please take to heart what every experienced reloader advises: DON'T START AT MAXIMUM. You may not start at the very bottom, though I recommend it, and that is only my opinion, but don't start at the max. You don't know what your rifle will handle.

So, for my ladder load, I will begin at 35 grains of IMR 4895. I will make 5 of these. I will then make 5 of the 38.3. Then 5 of the 40.0. And finally 5 of the 41.6. I will then subtract 0.8 grains from maximum and make 5 of those at 42.5 grains. After each round is fired, I will inspect the case for signs of pressure/deformity/primer cratering. My rifle may have zero issues with max load. But I won't know until I work my way up SAFELY.

Why not just make 3 of each? Because I am not a great shooter. 5 rounds per rung gives me more chances to shoot properly than 3 rounds does. If you are a great shot, do 3 of each. After I load each round, I will use a permanent marker to write the Group  and Round Number on each round. E.g. GAR3, GCR4, etc.

OMG, Rain Man -- is Judge Wapner on? Someone get your baseball cards out of order? Well, I have made my ladder rounds. Put them in the 50 count bullet box. Went to the range with a friend. He opens the box, drops it, and 48 of the rounds fall onto the ground. And I didn't have a chrono or scale. So I hid his body behind the 500 yard backstop.

The grouping is ultimately what we are concerned about. If you shoot a 5 shot group at 100 or 200 meters that can be covered by a dime, you get to use the Porta Potty first before any of the other 30 guys at the job site defile it.

So what to do with the data:

1. Keep it for reference.

2. Use it to determine which group shot the most consistently (grouping) and had the least variation in fps.

3. Then make your next ladder load.

4. E.g. your results may show that 38.3 grains of IMR 4895 with the A-MAX 168 grain bullet gave you amazingly consistent results with a 0.82" group at 100 meters. Since 38.3 is between loads of 36.6 and 40.0, you will need to look at your data. Which grouping was better, 36.3 with a 1.72" grouping  or the 40.0 with a 1.3" grouping? Well, from this made up example, your groupings of note start at 1.72" --> 0.82" --> 1.3". Well between 38.3 and 40.0 will be your next ladder load because your best results are between 38.3 and 40.

5. My next ladder load would be very very Rain Man. You can do 3. I prefer 5 because I am not a great shot.  5 of the 38.3, 5 of 38. 4, 5 of 38.5, 5 of 38.6, 5 of 38.7, 5 of the 38.8, 5 of the 38.9.  But that's 35 round to make. Yes, it is. If you do 3 rounds, then that's only 21 rounds to make. You decide. It's your powder, your time, your money. Personally, my goal is to find the best recipe for my rifle. If my rifle likes this bullet and this powder combo, and I could get consistent 1/2" groups or less at 100 meters, then I would refine further. But that's me. As listed elsewhere on this site, this is Ballistomania... sweet, sweet madness.

Capture your data using a spreadsheet. If you like, go here, copy the file to your desktop. Upload it to your Google drive. Open it there. You will only need to go to the "Data Entry" tab and enter your velocities in column titled "Velocity (fps)." WARNING: don't change data on "Data Manipulation" tab.That's it. If you take the time to fill in the other columns, you will be glad you did. The rest should auto calculate for you. You can see the results on the "Dashboard" tab. The data included is fictitious. The data is representative of what what I might see with my rifle. And, you can't get pretty graphs if everything is "0."  Always double check your manuals.

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