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250 grain loads for 45 ACP


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Of course, given the standard deviation size of 12, it's way TOO close, and I'll have to load up just a tad higher.

Yeah, really, especially considering the average isn't even making pf.

3.2 gr Clays

708 High

628 Low

681 Average

80 Extreme Spread

15 Std Dev

173,763 Average PF

Still not making it. With a 681 average and a 15 SD, if all three of your rounds over the chrono come in at three SD (highly unlikely but possible) you're going to average 636 fps and a 162.2 pf. Bump it up just a bit more, I'm thinking in the 3.4 to 3.6 grains range, and you should be down the road. I wouldn't be surprised to see your SD tighten up with a slightly heavier load, either.

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I wouldn't be surprised to see your SD tighten up with a slightly heavier load, either.
Did you notice it was just a bit worse with my heavier load? I didn't think much of it because I'm using garbage for bullets, but I'm not sure it'll get better if I don't standardize the lead.

You made me smile with that 'yeah, especially given your average doesn't make PF' comment. I was assuming it DID make PF, or would be close enough, IF the SD was much smaller. What I mean is, I'd be willing to roll the dice.

'Sigma' is standard deviation. Same same. My 'one sigma' value is the standard deviation of the data...the value in fps you can add or substract from the average to get the range of muzzle velocities that, statistically, these loads will fall in 68% of the time. Also, 95% of all these loads should fall within a range that is the average fps plus or minus TWICE the standard deviation value, and 99.7% should fall in a range that is the average plus/minus THREE times the std deviation ('three sigma'). A big standard deviation value (i.e, a big 'sigma') means you have a sloppier process--your stuff is all over the board.

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I knew that, actually. Well, everything except "sigma". :D

My attitude re power factor and SD is that you should always expect the worst. I look at 3 SD as being the lowest I can realistically expect, on average, every one of my rounds to be. So multiple the SD by 3, subtract that from the average fps, then multiply the resulting number by the velocity in fps. Does that combination of velocity and weight make the desired power factor? If yes, cool. If no, you're skating the edge and you have two choices, either do whatever you can to tighten your SD or bump the load to get it up above pf even taking 3 SD into account.

Now, logically, is this exactly the lesson we should take from SD? Is 3 SD below the average vecloity for all three rounds what will always, or even most of the time, happen at the chrono? No. But I'm not interested in rolling the bones, I want a procedure where, if I follow it (and granted my ammo does the same thing on match day it does when I test it myself), I can pretty much forget worrying about the chrono, and focus on more important things.

OTOH, if my ammo didn't even make pf when **I** tested it, and I've got a sloppy SD on top of that, this is not a risk I would be willing to take. That ammo is generally weak, and unpredictable. Statistically are the chances against all three rounds at the chrono station coming out at 3 SD? Sure. Does it occasionally happen? Sure. So you either get Minored or DQed. Would either of those things have happened if the shooter had factored the possibility of all three rounds, however unlikely, all posting 3 SD into their game plan, and refused to settle for ammo that didn't meet that standard? HIGHLY unlikely. A sloppy SD is not a sign we can ignore a load that doesn't make pf because we're counting on the big variation in SD to make up for that.

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OTOH, if my ammo didn't even make pf when **I** tested it, and I've got a sloppy SD on top of that, this is not a risk I would be willing to take. That ammo is generally weak, and unpredictable... A sloppy SD is not a sign we can ignore a load that doesn't make pf because we're counting on the big variation in SD to make up for that.
You're absolutely right, of course, and we're in agreement--what I tried to say is I'd be willing to roll the dice with an average PF of 164,995 (example) IF I had a nice narrow spread of velocities (and a small SD). My thinking was still a bit flawed though--regardless of whether the loads produce super-uniform ballistics or super-sloppy ballistics, your point is you have to load up high enough to ensure that you make PF with a comfortable or acceptable liklihood. And that's not where these loads are at. The velocity spread is a real eye-opener, given the uniformity of the powder charge. When I look at the data in more detail, statistics say the variation is NOT random (that is, not due to a large number of random variables).

Anyway, it's a lot of fun. Sadly, the only practical solution for me at this time is exactly what you suggested: more powder in the case.

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Still, given the basic concept, I don't think you're going to exactly wind up with thunderous recoil. :)
No...recoil won't be much of a factor in my overall shooting performance, I can assure you. I've got so many other issues I'm sure I could get out there with a broomhandle Mauser and see no negative impact.

Now, I did a bit more data gathering (in my continued effort to avoid building some powerpoint decks for work) and discovered that my powder charges aren't as uniform as I'd thought. In fact, they have at least a .1 gr spread. Also, the bullets, cast from the same pot at the same time, show more than a 10 gr spread (from 248 gr to over 259 gr). While these variances might make a bench rest guy cringe, I'm just going to accept them and move on.

What I'm going to do now is spend far less time measuring things and far more time reloading and shooting. I found this kind of approach worked very well in my beer making endeavors, and should pay off well here, too. Cartridge quality just can't make up for procedural errors, panic or poor form. :)

Edited by Bongo Boy
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I'm still interested to see what sort of velocity/pf/SD performance you get when you up the powder charge, what you load you finally settle on that predicably meets pf, and your impressions of the recoil level, and quality of recoil, you get when you do.
Oh, of course. Jeeeezzz...I talk real big but I'm far too analytical to let it go. I've been doing a lot of powder charge drops just to see what a particular, fixed setting gives me (Lee thingy) and it looks like an average of 3.15...no kidding, +/- .05 gr. I took some care with the mold, too, and I think the problem is that aluminum tends to 'wet' or 'tin' just a tad, and picks up small amounts of lead that gets in between the mold and really makes a mess of everything downstream. I've always dislike aluminum, and now I just have one more reason to.
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Sounds like the bullets are the real cause of the sloppy SD. If you can tighten up the SD with more consistent bullet weights, you might be able to make the 3.2-grain load work for you. Of course you could always just bump the powder charge a few tenths and call it good, too.

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  • 3 weeks later...

Well, about all I can say with some confidence is that, at least when working down at charges this small, it sure is hard to get consistent results.

Today I lit up a bunch of stuff I loaded last night with the only primers I have...CCI Magnums. Here's what I have, once I stopped using bullets that were too fat when they went into the sizer and wouldn't feed:

Charge: in the general range of 3.14 to 3.24 gr, give or take. If I fart in the garage, the scale will have a completely different reading.

Primers: CCI 350 Magnum Large Pistol

Bullet: Same old 255 gr RNFP

Lube: White Label 'BAC'

Max fps: 712

Min fps: 660

Avg: 689

SD: 9

So, 689 + (3*9) = 716 and 689 - (3*9) = 662

716*255 = 182,580

662*255 = 168,810

So, I should be okay 99% of the time, all variables being random (which I already know they aren't, of course).

Anyway, I've reached a load I can live with, like it, and I'll just have to see what standard primers do to the performance. Casting good bullets is now the key to consistent results...if I drop some soft lead in the pot eveything seems to go to hell in a handbasket.

The only other change I've made that hasn't been tested is to move to a hard lube vs. the room temp BAC. I've made about 1,200 of the 255 gr bullets with the new stuff and it's worth its weight in gold AFA I'm concerned. The new bullets are also very uniform, are sizing perfectly (just getting kissed by the sizer) and most importantly, look great.

Edited by Bongo Boy
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So, what is your impression of the recoil level? Regale us with tales of the thunderous recoil of the heavy metal .45 ACP Major load. :D
It's astonishing...there simply isn't any. :) I just go 'bang, bang, bang-bang-bang' all day long, the sights are literally sucked back down on target by an invisible force, and I can recover 1/2 of my own lead with a pooper scooper. I guess there was just no improving on your magic load of 3.2gr...I LIKE it! I suppose I should see if they'll cycle the 1911, but they're doing fine in the 220.

I have a pound of WST on the way, and will see if that has any benefits over the Clays. Hard to imagine anything burning cleaner though--but I guess that's not too surprising given how fast it is and the pressure we must be getting behind those big lead punkins.

Edited by Bongo Boy
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  • 4 weeks later...
  • 2 years later...

Thread reasurection!

Stumbled across this thread in search of the lowest powder charge to make major. More economical on powder with vvn310 than my current 9mm minor load!

Allways thought i was "tracking my sights", i was not. Slower impulse let me trully track my sights for the first time. Dropped .45 seconds off of my el pres in one practice session. I am enjoying this.

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I just tried 4 loads of 250 Lead truncated cone semi wadcutter (not sure the manufacturer as I got them from a friend of a friend of...). Loaded them at 1.120 and shot out of a 4" 625.

250gr.jpg

Good to see closet revo shooters come out of the closet every now and then :lol:

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  • 2 years later...

Anyone willing to share a 45 ACP load using an Extreme 255gr FP? I will be using the load in a 625JM and I am not worried about making a specific power factor. The load will be used for bowling pins. I have Universal Clays, 231 and WST to work with. Thanks in advance.

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