How to duplicate a factory cartridge?

[joken]

A guy on another forum asked this question and I responded by telling him to chrono the round and try to match the bullet. Another person said to dump the powder and use a powder that looked the same. I responded that that was a potentially dangerous thing to do and got this brilliant response.
looking at the powder is a great idea, if you have ever relaoded which I take it you haven't or have much experince with as you can tell the type of powder it is, you may not have the actual brand but the style you will be able to see! Then you can match that with a powder that you can use with that round! Example H4350 will be very simular to IMR4350 and if one of those is listed both of them can be used! NOT TOGETHER THOUGH! If it's a stick type poder that is in the factory round then get a stick powder that will work for that round, if it's a small fine powder in the factory round then get that type of powder!!!

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[Mikej]

Why would any sane person want to mess with reloading in this way? So many books available that have proven recipes and there's people out there that would look at a powder to determine IF it MIGHT work?
Ludicrous!

Yeah, let us try making little tiny bombs and see if our guns are strong enough to keep them from blowing our faces off!

 

[deadeye]

A guy on another forum asked this question and I responded by telling him to chrono the round and try to match the bullet. Another person said to dump the powder and use a powder that looked the same. I responded that that was a potentially dangerous thing to do and got this brilliant response.
looking at the powder is a great idea, if you have ever relaoded which I take it you haven't or have much experince with as you can tell the type of powder it is, you may not have the actual brand but the style you will be able to see! Then you can match that with a powder that you can use with that round! Example H4350 will be very simular to IMR4350 and if one of those is listed both of them can be used! NOT TOGETHER THOUGH! If it's a stick type poder that is in the factory round then get a stick powder that will work for that round, if it's a small fine powder in the factory round then get that type of powder!!!

Looking at the factory loaded rounds powder does not mean anything dangerous. What is dangerous about this in your opinion?
Using a bullet puller/hammer to take down a factory round to inspect the type of powder used such as stick, ball, flake etc. just tells you what type they used.

Example would be if you took down a 45/70 round and it contained ball powder I would try something like 335. If it contained stick powder maybe I would use 4198 or 4064. All this would do is get you to use the similar burn rate powder for the bullet weight/type gleaned from taking down the factory load. The next step would be to look at your available recipe's for that bullet/powder combo and try to match your chrono.

I do not see in the OP that the person suggested anything dangerous. Now if he is just guessing what brand and weighing the factory charge based on looks and using a similar powder with out consulting a manual now that would be dangerous.

 

[Mikej]

If it's a stick type powder that is in the factory round then get a stick powder that will work for that round, if it's a small fine powder in the factory round then get that type of powder!!!

I guess if this sentence had soaked in the first time I read it.......
Yeah.

 

[joken]

Maybe I misunderstood him too and if so that's two of us and it's still a problem. Without knowing the velocity of the factory load, it's a moot point.

 

[JRuby]

I have been reloading for most of my life - I cannot imagine guessing at which powder the factory used. The factory powder may not even be available to reloaders. I think the best you can do is try to determine the bullet and then the velocity of the factory round. Personally I would determine what shot best in my rifle before I started trying to duplicate factory rounds unless there was a very good reason to do so. Factory ammunition is created for the average rifle in a specific cartridge. I feel that I can do better than what a factory round can do with a little effort.

 

[Morpheus]

One of my favorite rounds is the Federal Gold Medal Match 762 w/ 175 grain SMK HPBT. I didn't pull apart my FGMM to figure out how to replicate it, I did it base on chronograph and performance at multiple ranges.

For me I like to know that my hand loads are nearly identical to the factory boxes of FGMM. This way if I get lazy and don't have any of my hand loads made up for a competition, I can just grab a few boxes of FGMM and use that instead.

Now, had I been confident I could match the power or been able to do controlled testing of the factory powder to compare it to others, I might have gone this route. Though, I would have had to do a lot more than just look at the powder. You would have to do a burn rate test, gas release test, and a few others. Ones I don't have the time, skill or equipment to do correctly.

 

[mjbskwim]

I have been reloading for most of my life - I cannot imagine guessing at which powder the factory used. The factory powder may not even be available to reloaders. I think the best you can do is try to determine the bullet and then the velocity of the factory round. Personally I would determine what shot best in my rifle before I started trying to duplicate factory rounds unless there was a very good reason to do so. Factory ammunition is created for the average rifle in a specific cartridge. I feel that I can do better than what a factory round can do with a little effort.

I was kinda wondering why you would want to duplicate a factory round also,when you can do better at home.
BTW,even if you weigh the powder,it may not be the same in every cartridge from the factory(that's why we hand load)

 

[Otter]

Been so long I've shot a factory round I had to think about this. I suppose if you found a good factory load you wanted to duplicate, you could take one apart and try to identify the powder. Some powders is pretty distinctive, like H322, but most powder you would have a hell of a time accurately identifying. If you thought it was powder X, provided it is a powder suggested in the manuals, it wouldn't be a bad place to start.

The odds of doing this successfully would be against you though and I personally would not waste my time on it.

 

[orygun]

Grab a Lyman manual. That will tell you what is a factory duplication load...

 

[2ndtimer]

I don't think it is a dumb idea, as long as it is supported by published loading data and double checked with a chronograph (or pressure measuring equipment, if one has access). A couple decades ago, I was having trouble getting my then New 30-06 to shoot decent groups. Adding insult to injury, it shot it's best groups with inexpensive PMC 150 gr soft point factory ammo! In desperation, I pulled the bullet from a factory round and dumped out the powder. It was a short cut extruded powder that looked similar to H-4895, and the charge weighed about 49 grains on my scale. I checked 4 or 5 of my loading manuals and found very similar charges listed for the 4895 powders. I then worked up to 49.5 gr of 4895 (don't recall if it was H or IMR) and with a Nosler 150gr Solid Base bullet and found my first decently accurate 150 gr handload for that rifle.

 

[joken]

Maybe I misunderstood him too and if so that's two of us and it's still a problem. Without knowing the velocity of the factory load, it's a moot point.

I was kinda wondering why you would want to duplicate a factory round also,when you can do better at home.
BTW,even if you weigh the powder,it may not be the same in every cartridge from the factory(that's why we hand load)

I don't think it is a dumb idea, as long as it is supported by published loading data and double checked with a chronograph (or pressure measuring equipment, if one has access). A couple decades ago, I was having trouble getting my then New 30-06 to shoot decent groups. Adding insult to injury, it shot it's best groups with inexpensive PMC 150 gr soft point factory ammo! In desperation, I pulled the bullet from a factory round and dumped out the powder. It was a short cut extruded powder that looked similar to H-4895, and the charge weighed about 49 grains on my scale. I checked 4 or 5 of my loading manuals and found very similar charges listed for the 4895 powders. I then worked up to 49.5 gr of 4895 (don't recall if it was H or IMR) and with a Nosler 150gr Solid Base bullet and found my first decently accurate 150 gr handload for that rifle.

I suspect this is what the guy was trying to say.

 

[Spitpatch]

1) Trying to guess (or match) a factory powder by appearance alone is not only a fool's errand, it is one from which you might not return.

2) If you believe that you can easily switch back and forth between such powders as "H4350 and IMR4350", or "H4831 and IMR4831", you are once more embarking on the above-mentioned errand. Kiss your kids and make sure your life insurance is current before you depart. These are NOT merely "brand names of the same burning rate powder". They are markedly different powders.

3) If you subscribe to the old adage that "handloads are always better than factory loads", or "I can always do better than factory", then you simply have not explored very many of the new factory offerings. As a devoted handloader (NOT reloader) for 45 years, I am increasingly stunned by the quality and performance of many recent factory loads, and am often challenged (and occasionally defeated) in trying to better them... It is a fun challenge.

4) As Orygun brought to light, Lyman has always offered Factory Duplication Loads in its manuals. Another good source for such is Ken Waters' Pet Loads. I believe the older Sierra manuals made these submissions as well.

 

[AMProducts]

So, since I do load development for ammo factories... I can tell you, nearly all of them are starting with the same loading data published by hodgdon, sierra, western, and everyone else. The question is, what characteristics do we select for? Velocity? Accuracy? Standard Deviation?

As you said, start with the bullet, and velocity, while looking at the powder inside can be useful, if you know what the velocity and bullet are, cross-referencing the weight of the powder inside with those two factors will likely tell you what the load is, or at least what it's close to. The only thing you have to look out for, is factories often have access to powders that are not commercially available, so I load tons of .223 with SMP735, now after having more than a few years experience with that powder I can tell you it's nearly the same as H335 grain for grain in all the lots I've tried. However that's no guarantee you will be able to pull open a round I make and tell whether it's H335, SMP735, WC-844, D073-04 or BLC2, because they're all spherical ball powders.

Generally, I would say duplicating a factory load is kinda pointless, getting close to a factory load and selecting for the properties you want is a much better way to load ammo. There are more than a few loads that are fantastically accurate that never got loaded, because the customer wanted maximum velocity. And there are more than a few loads that generate maximum velocity, that were never produced because they had poor accuracy or consistency.