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I was fiddling around with the Hornady ballistics calculator, which got me to wondering what the coefficient was on some cast boolits I bought, and some others I was considering. The first is from Falcon bullets, a 30 cal, 165gr, RNFP that is either regular lubed or poly coating. Comparing it to similar things, I'm guessing it to be around .28. The other one is the Badman bullets, a 135gr which also has either plain or a poly coated version.
Knightflyer in CO
Use the search engine and search for cast boolit coefficient. You will get several threads covering this.
The 165 grainer will probably be right around .2, give or take a little.
The 135 grainer, maybe .18 or so.
Go to this link on this site and see what similar boolit may give you for a Coefficient:
http://castboolits.gunloads.com/show...efficent-Table
Btw, my "guesses" are based upon actual tests that I've done with similar designs. So, I'm not basing my estimation off of a chart, but on actual testing.
NOE has BC if you find a similar boolit.
Lee also lists the BC of their cast stuff.
Again, find something similar and go from there.
I've found in actually measuring the BCs via time of flight (M43 Oehler with screens at muzzle and in front of 100 yard target) that most cast bullets have BCs slightly lower than the "calculated" BC we find in mentioned sources. For example a 164 gr cast with a calculated BC of .280 - .290 will actually have a measured BC of .240 to .250 at velocities of 1700 to 2200 fps.
Larry,Quote:
Originally Posted by Larry Gibson
Have you ever checked jacketed bullets? Do they measure close to "spec" or do you see the same degree of deviation?
Sorry for the thread drift!
Thank you! I had tried a search, but I spelled it wrong... :DQuote:
Originally Posted by tazman
Great info ODF! I'm afraid I might like, just a teeny-tiny-bit, to geek out on this stuff.Quote:
Originally Posted by outdoorfan
I had originally thought about casting my own boolits, but honestly, since I can get the Badman plain cast boolits for 8.2 cents if I order a thousand, I'm thinking I'll let them do that part lol. Hard to beat the price once I figured in my time & trouble. Maybe when I get closer to retirement and the kids are really all out of the house. My wife is already squawking about the time I spend with my new toy. I got a Mossberg 464 30-30 at a gun show last month. I really do try not to fondle it in front of her...
Once I've tested the load I'm working on and am sure my reloads work okay, I want to take her to the range. She has arthritis and while she's gone shooting the pistols with me, it's hard on her. But if I can get her to try these Oliver-sneeze* loads, I think she might learn to like my new mistress. :wink:
For the curious, I loaded a 165 grain Falcon poly-coated boolit over ~5 gr of Titegroup last night. I hope to go try these this coming Sunday. The range I use is kinda far away (1 hr) so the only day I can really go is on Sundays.
* Oliver is our huge orange cat. He's very lazy, and Very dumb. We joke that he plays cards with his 'friends' - the mice. Our other two cats leave the mice alone because they don't want to make Oliver cry by eating his Friends.
-Knightflyer
Naw, let it drift! You've got my attention now! I'm guessing the jacketed bullets will be closer due to not having lube channels, but that's just an educated guess.Quote:
Originally Posted by dverna
-KF
I will be more than glad to answer that question on goodsteelforum.com since I have measured the BCs of numerous jacketed bullets of various caliber and make also. Since the answer involves topics that bring out negative responses from several who simply wish to disagree with anything I say I'll not answer on this forum.Quote:
Originally Posted by dverna
I will answer why they measure lower than calculated on the artful bullet forum if anyone is interested.
Larry and Run, I am interested in both. Could you post links if either of you do post on the subject? I just checked both forums and was unable to find either. Thanks!
Hah! I figured out who made the 135 gr bullet mold! It's Magma custom engineering company! Here's their mold catalog. If you look at the 30 cal section, that's the identical bullet. I shot an email to their sales to see what they can tell me about that bullet and a 165 gr that is also definitely their make.
Tracking this is more fun than playing Where's Waldo with kids! Well, maybe not quite, but my kids are too old to fuss with Waldo anymore. I need my oldest daughter and her 'significant other' to get hitched and have some grand-kids. I mean, they've been together for six years...
(tune of Matchmaker from Fiddler on the Roof)
"Mold maker, mold maker, make me a mold! Pour in the lead, bullets to hold! Mold maker mold maker make me a mold! Oh make me the perfect mold!"
-Sincere apologies to Jerry Bock