(Let me know, please, if this is dead-horse material and I'll spare you the 7mm, 8mm, 30-cal, etc results)
I've been keeping this "work" going on my first-love internet reloading site. Figured I'd share with my other favorite place to seek and absorb reloading knowledge.
The following are terminal tests of a number of different bullets in several calibers. The goal being to see what velocity windows a given bullet performs most ideally in. A lot of non-surprises, and a few surprises to boot. The media I'm using is stacked newspaper, soaked overnight to total saturation. It mimics dense tissue quite appropriately, however doesn't offer the "spongy" and/or "woody" aspects that set of lungs and/or rib cage, shoulder, etc. presents. That said, it's a remarkably consistent medium to compare "apples to apples" and I think it's fair to assume any two bullets compared as-such are likely to perform comparably were they to encounter the same denser/lighter obstacles.
This is a work in progress so please feel free to offer your input as to suggestions, predictions, etc.
To start here's the data I gathered for 6mm bullets, tested in the .243 Winchester.
What impact velocity? Approximate penetration depth? Retained weight?
October 9, 2010, 08:36 PM
October 9, 2010, 08:43 PM
Those Barns bullets sure perform well. I've never tried them but have heard of some having accuracy issues. Depolini, any comment on copper accuracy?
I have an ongoing debate in my mind about the trade-off's on a low sectional density bullet in copper - which would be even lighter (even worse SD in copper) - but shot at a higher velocity and a tougher bullet. I'm speaking of a 44 mag bullet, which because of its low SD, may not be that good of a penetrator anyway - what shooting copper would do? Specifically pig armor shot with a Marlin lever action.
I'll take your thoughts whether you think they're qualified or not.
October 10, 2010, 12:04 AM
What impact velocity? Approximate penetration depth? Retained weight?
Who Me? Which ones? Or both? The top ones, the interbonds always were found in the third jug.
Both bullets were right around 3000 fps at the muzzle and the jugs were at 100 yds.
I also did some nosler accu-bond 165's they always were in the forth jug, but expansion was smaller and weight retention was around 65%.
The interbonds expanded to .600, and retained 85% weight. The GMX were nearly 100%, the plastic tip weighing about a grain.
October 10, 2010, 11:42 AM
Nice, I like the info. Thanks!
To answer the one gentleman's question about sectional density, etc... I do believe that there's a trade-off between a "comparable size" all-copper and more traditional leaded bullet. For a given weight the unleaded bullets are always longer and generally thus more aerodynamic than their leaded counterparts, which helps ballistically. They can also be pushed faster given their lighter weight in most cases. The loss of weight (momentum!) is thus made up for balistically by the higher speeds.
Same seems to hold true with penetration. There's no way 80 grains of bullet "should" penetrate as far after impact as a 100-grainer scientifically speaking assuming the same impact speed but, because the lighter ones tend to strike at higher speed, the energy/momentum seems to cancel out.
Long winded story short? That's the main reason I think that the 100 partition and the 80 barnes penetrated similarly despite the weight difference. You can push the 80 TTSX to 3400fps MV out of the 243, good luck pulling that with the 100 partition. Which is better? Check out that wound track... you're probably splitting hairs. Nasty versus nasty. I'm a "TSX" guy now in .243 because, well, they perform right with the partition, are more accurate in my guns usually, and they're cheaper.
Accuracy wise, provided you follow the "copper rules" and seat them .030-.070 off the lands, in most calibers the Barnes bullets and Hor. GMX bullets hang right-in-there or are occasionally superior to others. Haven't tried others yet.
You will get some copper fouling though, more than "average" if you will, when you start screaming these babies out well over 3k fps though :)
October 10, 2010, 01:15 PM
Fired in a custom 98 Mauser, .284 Winchester
Worth saying that I'm not affiliated with any bullet manufacturers. I'm not even in the field for that matter - so nobody's getting special treatment.
That said both Barnes and Sierra deserve thanks. Barnes offered a discount and free shipping for some test runs, and Sierra went and threw 7 boxes of bullets at me. For nothin'. Thanks Carroll!!
Am I killing the forum with all the photos though (size/loading)?
October 10, 2010, 03:42 PM
Depoloni, you just keep this excellent info coming . Very well done. I suspect someone on dial-up may have to wait for the pics to load, but the vast majority of us have cable or satellite hook up.
My main concern is you must be darn tired lugging that soaked newsprint to the range and back home.:D I used it ONCE! Too much work.:mad: Hint,,, It's heavy!:(
People can draw whatever conclusions they want to from expansion and wound cavities. That's the main drawback of my water tests, no feedback on wound cavities. My only conclusions are related to expansion measurements and weight retention. I could draw some data from how bad the jugs were shredded, and where the bullet came to rest.
Ever hear of the "test tube"? It's some sort of re-usable test medium held inside a wound paper tube. Stops bullets quickly, then you melt the medium in a slow cooker to re-cast it in a new tube.
Expensive, labor intensive, and you only get one shot,(maybe 2), per day. Probably closest to ballistic gelatin, without the precise temp requirements and spoilage.
Corbin also makes sim-test, similar to the test tube stuff, you re-melt it to re-use.
October 10, 2010, 08:31 PM
For me it's simple math. Have some open land (gravel/sand pits) in upper-mid michigan here that I can drive the truck right out to the target point, and back to the portable table setup, with no carrying required. The news is "free" and headed for recycling anyhow, whereas the test tubes, gelatins, waxes, etc. are expensive to start with. And to do 20 rounds (or 30?) in one day's testing would thus take some serious remelting time or some serious cash.
I save all my newspapers, as do my folks/folk-in-laws, two friends, and a gun-friendly neighbor. I've since had the friends stop because I didn't get the chance to test for ~6 months and I had four 6' stacks in the garage LOL
It gets shot up quickly in larger calibers. Soaking overnight in a half dozen plastic bins (leave room for swelling!) in the back of the truck makes it simple to transport to "ground zero" and setup, and it goes right back after it's used up. Then straight to the recycling yard. They always give me a funny look that it's wet but they take it anyways.
I think that while the newspaper isn't a "perfect" simulation it's the same as the others - an apples-to-apples comparison between bullets. The wax, or gelatin, does not 'accurately' reproduce bone impacts, spongy lung tissue, or any of the other variables so in that sense they're all relative.
What it does show well is relative things like the 6mm TTSX opening more easily at low velocity than some of the jacketed ones. And eventually I plan to test different alloy hardnesses and/or nose configurations the same way, different twist. End of the day, just fun for me, I shoot a lot of groups and work a lot of loads and dry paper only gets so interesting ;)
October 10, 2010, 11:53 PM
Back in the early 80's my unit bought me a 55 gallon drum of ballistic jel powder to test various loads and bullets for our sniper rifles. I had a great time shootong blocks of the jello; however i was never able to produce results as impressive as your test--great job keep up the good work, and keep blasting away at the Mainstream Media.
October 12, 2010, 11:22 AM
Chiming in a little late here, but another thanks for the info. I've done similar testing with phone books back when they were more common, and was also pleased with the results. The wet pack tends to be a little friendlier to bullets than real critters are, but every attempt to toughen up the media (dry paper, plywood, etc) made the results too erratic to be useful. But again, I appreciate the work and the information. I didn't try much reduced speed testing so that was useful too.
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