Volunteers needed for research study


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Shrinkmd
July 17, 2009, 06:32 PM
I want to design a reloading study to see if we can discover the difference in case life based on how strong the load is. I figure we could pick a cartridge, standardize the powder, primer, bullet weight and configuration, seating depth. If we really wanted to be scientific, we would also standardize what gun it is being shot out of, exact same bullet brand, and same dies/reloading press. This may be too much to ask, but if we can find a handful of people who all have the same stuff we could do it. It would be cool to get rid of as many confounders as possible and get some good data. Obviously one person could do this on their own, but with the people on this board, we could probably generate a lot more data and get better results faster.

For example, it would be cool to load 45ACP in 230 gr LRN from 4.0 to 5.0 of Bullseye in 0.2 gr increments, and construct a survival curve. I haven't designed a study or worked with a statistician for a while, but we have lots of collective experience around here.

Please PM if you are a reloader and interested in making up batches and seeing how many times you can reload till they crack or are otherwise unsafe to reload again. Also, people interested in designing the study or helping crunch/graph the numbers.

Does American Rifleman accept submissions? Since we're all shooting anyway it's not like someone would be doing something they wouldn't do anyway, just keeping track a little more meticulously and submitting the data.

So, any thoughts? Wouldn't it be cool to scientifically study how many loads you can really get out of a cartridge, especially examining how hot the load is?

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fireflyfather
July 17, 2009, 08:20 PM
hm, just off the top of my head, I can think of MANY sources of error that would have to be controlled for:
1. Humidity, altitude, temperature when loading and firing (some people participating in the study live in Alaska vs Miami...)

2. Method of powder measurement (weight, volume, every charge weighed?)

3. Amount of belling/crimping and measurement of belling/crimping

4. Same lots of powder? (powder for reloaders can vary quite a bit in terms of burn rate from one jug to the next, not to mention age of powders/year of manufacture can make a difference) Same lots of bullets? Same lots of brass? Primers?

5. How about the guns themselves? Even if it's the same model, some will headspace better than others, depending on the condition of the gun, year of manufacture, repairs made to the weapon, other gunsmithing, etc.

Need I go on? Most of these variables would be relatively minor, but a few of them (powder lots, headspace, crimping) might make a big difference.

D. Manley
July 17, 2009, 09:04 PM
To have any meaningful value the results must be quantifyable and in this case, I don't think it's possible. There are too many variables other than, the pressure of the loaded rounds. Brand to brand variation, metallurgy differences between lots, different chamber dimensions in different guns, etc., etc. It's well documented that reduced loads extends brass life...by how much, I suspect there's really no answer.

Shrinkmd
July 17, 2009, 09:15 PM
Excellent points. It would be interesting to do, but I suppose the findings would therefore be quite limited.

I wonder if you could get something from such a study, given the limitations.

D. Manley
July 17, 2009, 09:47 PM
I wonder if you could get something from such a study, given the limitations.

My philosophy is, "easy on the brass, easy on the gun, easy on the shooter". I got overy my "flash & awe" phase in the 70's and now pursue soft, accurate loads that are comfortable to shoot during extended periods. I guess extended brass life is a bonus for me.

Sport45
July 17, 2009, 10:01 PM
For example, it would be cool to load 45ACP in 230 gr LRN from 4.0 to 5.0 of Bullseye in 0.2 gr increments, and construct a survival curve. I haven't designed a study or worked with a statistician for a while, but we have lots of collective experience around here.

You might want to pick a different cartridge to test. I don't know about the experience of others, but I usually loose .45acp brass before I wear it out.

Walkalong
July 17, 2009, 10:16 PM
I got over my "flash & awe" phase .......... and now pursue soft, accurate loads that are comfortable to shoot during extended periods. I guess extended brass life is a bonus for me.

Me too. Well....mostly anyway. I still like to make the .44 Mag go boom a few times here and there. :)


Case life. Yep, big boom = less case life. Little boom = more case life. No figures though.

The Bushmaster
July 17, 2009, 11:44 PM
Why..?..I've alrady have a good enough idea how many reloads I can get from a particular case, powder, primer and bullet...

ranger335v
July 18, 2009, 09:36 AM
"If we really wanted to be scientific, we would also standardize what gun it is being shot out of, exact same bullet brand, and same dies/reloading press."

I think your view is much to simplistic. Case life for each of us is what it is. Any differences are going to be tiny, variable and the final results would be overlapping. It's really not worth even trying to qualify. There just is not that much consistancy in guns or anything else we use in reloading. Even if we could "standardize", as you suggest, the manufactoring variables and tolerances between individual guns, chambers, dies, etc. are such that it would mean nothing.

Attempting to find a magic load that equals "best case life" for a .45ACP, etc, is easy; "Load to the lowest possible level that will function."

Efforts to hot-rod any handgun load is virtually pointless. it beats up the gun for little gain. The bullet ballistcs are such that small differences in muzzle velocities will be very small down range. No matter how hard you throw a ping-pong ball, it won't go far. Ditto the short, blunt-nose bullets we use in handguns.

Shoot a rational load. You will lose nothing useful but your brass - and gun - will last longer.

Varmonter
July 20, 2009, 09:42 PM
Agreed case life should be roughly the same if you take away all the variables.
Which it seems to me you are doing.
You need 2-3 maybe 4 different participants sticking to the same (yet different ) load variables.Showing the coralltion between hot loads and mild loads and thier subsequent effect on case life.

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