Conflicting Load Data


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leadchucker
March 14, 2013, 06:38 PM
I'm trying to work up a load, and I was looking at the data in two of my load manuals. Both manuals provide load data for the exact same bullet, at the exact same OL, but the powder charges differ significantly.

I'm looking at a 40 S&W 165 gr. bullet. The bullet used in both manuals is a Speer TMJ FN, Speer part # 4410. The OL in both manuals is 1.120".

The Lyman #49 manual, page 363, says that the maximum charge weight for Winchester 231 is 5.8 gr, for 1050 fps, and the suggested start charge is 5.2 gr.

The Speer #14 manual, page 918, says that the maximum charge weight for Winchester 231 is 6.3 gr, for 1031 fps, and the suggested start charge is 5.8 gr.

The start charge in the Speer manual is the same as the MAX charge in the Lyman manual. I realize that different primers, different cases, maybe minor barrel differences, etc., could cause variations, but this much?

If it helps here's what I'm trying to find a decent load for:
40 S&W Precision Delta 165 gr. FMJ FP, Winchester 231, Winchester WSP primers. S&W Shield.

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gamestalker
March 14, 2013, 06:45 PM
They used different test barrels, or one may have a more conservative lawyer? If they are both using the same exact bullet part number, I would add the two starting charges together, divide by 2, and then use that average from that to use as your starting point.

GS

DanTheFarmer
March 14, 2013, 07:21 PM
My method is to cross reference a lot of data. Usually most will agree, more or less, and 1 source will be a real outlier. When I find that I go with the data that is in general agreement.

For sources you've got your manual, sites like Hodgdon/Alliant/Ramshot on-line load data, and data posted by individuals on forums. This last source is the most suspect but can be useful if you intelligently cross reference. If a bunch of people say they are getting good accuracy, velocity, and cycling of their pistols with (EXAMPLE FOR THE SAKE OF ARGUMENT ONLY!) 5.5 grains you would feel more confident in the Lyman data vs. the Speer. If people can't get 5.5 to cycle and are happy with 6.0 then you may want to use the Speer data instead of the Lyman.

Good Luck.

Dan

readyeddy
March 14, 2013, 07:43 PM
This does seem to happen a bit frequently. What I do is start at the middle, the max of the low range/start of the high range. In this case, 5.8 grains of W231. So long as gun and components are in good order you should be safe. As always, look for signs of pressure.

Give this thread some time to grow. Others like rcmodel may have very different ideas that you will want to read.

BYJO4
March 14, 2013, 07:55 PM
This is not unusual to see when looking in several different manuals. I personally will use the lighter load and work up as needed.

leadchucker
March 14, 2013, 08:00 PM
I sat down with several manuals and compared some similar loads. I have discovered some minor variations from one manual to another, but for the most part, they all agree, within one to two percent or so, except for the Lyman manual. It almost always has the most conservative loads, by a significant margin, of up to ten percent or more.

Jesse Heywood
March 14, 2013, 08:06 PM
except for the Lyman manual. It almost always has the most conservative loads, by a significant margin, of up to ten percent or more.

And in the past Speer has been on the opposite end of the spectrum. If you wanted to find the hottest loads, Speer was the first book to look at.

jstein650
March 14, 2013, 08:39 PM
I can second that, Jesse

Quote:
And in the past Speer has been on the opposite end of the spectrum. If you wanted to find the hottest loads, Speer was the first book to look at.

I got a few of the 'Load Books' from Midway a long time ago, before so much was available on-line, before there was an on-line in fact. They were each dedicated to a single caliber. Anyway I thought they were good, and a good way to get a feel for how different bullet and powder makers list their loads. Some were notoriously light while others were significantly hotter!

bds
March 14, 2013, 10:03 PM
I'm looking at a 40 S&W 165 gr. bullet. The bullet used in both manuals is a Speer TMJ FN, Speer part # 4410. The OL in both manuals is 1.120".

The Lyman #49 manual, page 363, says that the maximum charge weight for Winchester 231 is 5.8 gr, for 1050 fps, and the suggested start charge is 5.2 gr.

The Speer #14 manual, page 918, says that the maximum charge weight for Winchester 231 is 6.3 gr, for 1031 fps, and the suggested start charge is 5.8 gr.

The start charge in the Speer manual is the same as the MAX charge in the Lyman manual. I realize that different primers, different cases, maybe minor barrel differences, etc., could cause variations, but this much?
Yes. I can't speak for test barrel Speer used but Lyman used .401" groove diameter test barrel instead of more typical .400" for 40S&W chamber pressure testing and Lyman #49 loads have been significantly higher than Hodgdon/Winchester load data.

Slug your barrel and see what the groove diameter is. If it is .401", go ahead and use the lower of Lyman/Speer load data. If it is .400", I would use Hodgdon's current load data (http://data.hodgdon.com/cartridge_load.asp).

165 GR. BERB FP W231/HP-38 OAL 1.125" Start 4.7 gr (933 fps) 25,200 PSI - Max 5.4 gr (1049 fps) 33,400 PSI

165 GR. SIE JHP W231/HP-38 OAL 1.125" Start 4.8 gr (946 fps) 28,100 PSI - Max 5.3 gr (1001 fps) 32,500 PSI
I'm trying to work up a load ...
FWIW, I use Montana Gold 165 gr FMJ/JHP bullets with 5.0 gr of W231/HP-38 at 1.125" for milder recoil target loads and WSF/AutoComp for higher velocity full-power loads.

SlamFire1
March 14, 2013, 10:06 PM
I would use the lower charge and chronograph during load development. I do not have a 40 cal but I have shot kegs of W231 in 45 ACP and some in 9mm. W231 will likely function the pistol at low loadings and actually does well in light charges, unlike some other powders.

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