Inconclusive load work-up?

[leadchucker]

I just loaded my first batch of Precision Delta 40 S&W 165 gr. FMJ FP bullets. I used W231 and CCI 500 small pistol primers.

I used load data from the Lyman #49 manual for a 165 gr. bullet. I'm at work now, and I don't have the manual handy. I can't recall which bullet it was, but it was close enough for me to feel safe using the data provided. Max load listed was 5.9 gr, and suggested start load was 5.3 gr. I loaded ten each at 5.4, 5.5, 5.6, 5.7, 5.8 gr. I calculated a COAL of 1.117 in..

I fired all fifty rounds, and honestly, they all performed practically identically. They all reliably cycled my S&W Shield. I noticed no real variation in recoil. I inspected each spent shell, and found no evidence of any abnormalities or excessive pressure. If there was any variation in accuracy, I could not detect it, but I'm not the most consistent shot with this gun yet. I suspect that there would be a noticeable difference in velocity, but I don't have a chronograph, so I can't clock the rounds.

Right now, I'm just looking for range/practice ammo, so performance is not that important to me. So should I just load to the minimum and be happy with that, or do I need to experiment further? What would you do?

[Dave P]

I am not a big proponent for putting much effort into pistol loads. Unless you are competing at the highest levels, I can't imagine most of us can find any accuracy improvements.

I say find a cheap lead bullet and start banging away at the targets.

Now rifle loads are a different story ...

[243winxb]

Load the 5.4 gr, avoid the high pressure of the 40. This powder charge should be safe when used with different brands of components. Steve's pages list a range of W-231 From 4.6 grains to 6.3 grains, so your not really at a "starting load"
http://www.stevespages.com/page8a.htm Different Component = Different Pressure.

[Unclenick]

Leadchucker,

I don't know how you arrived at your COL, but if it doesn't interfere with magazine loading and feeding, then you'll probably find that seating out until the head of the case is just flush with the back of the barrel where it meets the breech face (usually a barrel extension), that you will get best accuracy. To set this up, you just remove the barrel and use it as a gauge. When you have this condition you are headspacing on the bullet rather than the case mouth. I've had it cut as much as 40% off group diameters fired from sandbags and reduce leading significantly in the .45 Auto.

As to charge weight, if they all shoot the same, then the lightest load will batter and wear the gun least. It will also let the brass last longer and cost the least to use. The warmest load will exhibit the least drop at longer ranges (like plinking at 100 yard water jugs).

[leadchucker]

All the stuff I've read says that seating depth, which affects internal volume, which affects chamber pressure, is important. I have been trying to keep the seating depth on all my reloads as close as possible the seating depth of another similar documented load.

And yet, the consensus here and on other forums seems to be that getting the bullet as close as possible to the riflings is more important. (and of course making sure the round fits in the mag, and feeds okay.)

So should I forget about trying to get the seating depth so close to a reference, and instead pay more attention to the COAL and rifling clearance? How much difference in pressure would thirty or forty thousandths difference in seating depth make?

[Unclenick]

It's complicated. In a rifle, getting a jacketed bullet close to the lands often sees pressure rise 20% or so, and getting it seated too deep also raises pressure by using up too much powder space, so there is a pressure minimum inbetween. A handgun shooting lead bullets is a little different. The lubricated lead bullets slip out of the cases easily. So while seating too deeply can still raise pressure theoretically, in many short case handgun cartridges the bullets are unseated by primers before the powder pressure really begins to build. Especially with lead. This means your control over pressure by seating depth is less reliable than in the rifle, as the gun may be building pressure with the bullet out in the throat somewhere, regardless of where you seat it. However, it's unsafe to count on that happening, so I advise not seating shorter than the manual says.

As to seating lead bullets long, they don't requires as much force to be push into the rifling as jacketed bullets do, so I've never seen a pressure issue arise from seating them into a throat. The thing you gain is that the bullet starts into the throat straight. The harder jacketed bullets seem to straighten themselves up on their way into the bore under pressure, but with lead bullets, if they start into the throat at a slight angle under pressure, they just swage into the bore at that same angle, making their mass slightly eccentric. The slower speed of chambering doesn't seem to do the same damage primer and propellant pressures do in this regard.

That is what causes the accuracy issue. It's especially bad in guns whose fit is so loose that the chambers are long enough that a standard length case can't reach the end of the chamber before the rim is stopped by the extractor hook. This is called headspacing on the extractor, and it is really common. One gunsmith said he estimated 70% of 1911's he sees are doing this. In this situation the gun fires with the cartridge pivoting on the extractor hook over to the hook side of the chamber. It doesn't seem to bother jacketed bullets, but leading and inaccuracy happen when lead bullet loads are handled this way.