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jtaylor996
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Regaj
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Re: What should I load based on this data?

Post by Regaj »

Quickload analysis of your 19.2gr., 19.6gr., and 20gr., of H110 behind a Barnes 110gr TAC-TX...

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A few comments...
As you can see, the 19.2 load is nearly at maximum. 19.6 is already above maximum. And 20.0 is well above.

Notwithstanding that Barnes own load data goes to 20.2 of H110, I would proceed with caution.

Anything that reduces case capacity - thicker brass, bullet seated deeper, etc. - will increase pressure. So the maximum case capacity in water becomes a critical measurement. For these analytics I used 24.3 grn, which just happens to be the exact average I see in the Barnes brass I have on hand (and which presumably Barnes themselves use in their own testing). I have no idea what your LC brass capacity is. Given that you're heading out to where the ice gets very thin, I'd strongly encourage you to actually measure it. All you need is a child's medicine syringe, or an eye dropper. First weigh a fired case (with spent primer still in place), zero/tare that on your scale to subtract it... then slowly fill the fired case with water until it's dead-even with the case neck... with neither a concave dimple or a convex bubble at the end of the neck. Weigh it and you have the maximum case capacity. Do it for five pieces of brass and average the results.

I'm guessing, since you're not seeing pressure signs, that your LC brass has greater capacity than 24.3. But QL, like any software, is no better than the numbers and assumptions that you input. Case capacity is not something I'd want to guess at when running near maximum loads.

Good luck!
jtaylor996
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Regaj
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Re: What should I load based on this data?

Post by Regaj »

Roger that on the flare (rather than flattening) on the bottom center case. It's kind of hard to see in the picture, but from what I can tell, those cases don't look awful. Not great, either, but that may be simply because of oxidation and carbon.

The thing to bear in mind is that evidence of excess pressure on brass is a gross indicator. There's not a lot of precision to it... and by the time you can visually see anything, you're already over the line.

The weapon system matters, too. With a bolt gun or a revolver, you have the benefit of being able to feel how heavy the bolt lift is, or if there's any stickiness in the extraction. Not so much with a semi-auto.

If you're truly interested, and you have a high-resolution micrometer (not calipers), you can measure the amount of case expansion - before and after - at the web of the cartridge case. Even that method leaves a lot to be desired, though, both because it requires a very precise set of measurements and because the difference in case expansion (between a "good" load within pressure spec and a "bad" load over it) isn't large enough to be precise or obvious.

Having said all that, I certainly wouldn't belabor the pressure thing. Guns are like children... they're all a little bit different, even when they come from the same parents. There are lots of reasons why one gun runs hot and the next, not so much. One of the beauties of handloading is being able to tailor ammunition to those individual traits.
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dellet
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Re: What should I load based on this data?

Post by dellet »

What did the lot to lot variation show in Quickload?

Probably in the 55,000-75,000 range.

Then look at the difference between predicted and actual velocity, lower velocity generally means lower pressure.

Case volume needs to be adjusted with trim length.

Quickload does not adjust for neck tension or crimp.

Most importantly reading primers is like reading tea leaves, there is a certain amount of voodoo involved.
300 Blackout, not just for sub-sonics.
jtaylor996
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jtaylor996
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dellet
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Re: What should I load based on this data?

Post by dellet »

If Regaj will adjust the barrel length to 16”, it could then be compared to Barnes data.

As far as chamber dimension with Quickload, that is why they use case capacity of a fired round. There are predictable expansion/shrinkage factors.

The pressures and velocities generated are basically mid range. Lot to lot variation is +/- 10%.

If I load 20.2 grains of H110 into a fired case, set a bullet resting on top of the powder, the COL is 2.220” That same piece of brass after sizing and expanding the neck to seat the bullet has a COL of 2.227

LC converted
Case weighs 87.5 with primer trim length 1.362
Fired the case holds 25.4 grains water
Sized case 23.9.

Remington
Case weight 85.3 with primer trim length 1.357”
Fired case 25.5 grains water
20.2 grains H110 fired case 2.210”, Sized case 2.218

When entered into Quickload a COL of 2.220” would require a case capacity of 26.2. So this implies that either their numbers ore off for powder density, their water is lighter, I don’t get as good of pour when I drop my powder or other variables. This is why you can adjust parameters for more accuracy.

When I use the LC case above 20.2 grains @ 2.250”, density is 101.7, pressure 58,905 velocity 2412,16” 2226 in a 10.5”
When I adjust case capacity so that 2.220” is 100%, pressure is 56,588, velocity is 2396 fps. 16” Or 2209 in a10.5”

Lots of numbers that don’t mean much until you put them on target and have enough data points to adjust your inputs.
300 Blackout, not just for sub-sonics.
Regaj
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Re: What should I load based on this data?

Post by Regaj »

A long, long time ago we'd spread out our various loading manuals on the bench, pages open to the caliber and bullet weight we were interested in, and extrapolate what we'd get - adjusting mentally between the different test platform they each used compared to our own gun. My old paper handload logs from that era had a column called "EV," for estimated velocity, which I would dutifully record.

Day before yesterday, while my wife was in the kitchen preparing our Thanksgiving meal, I went outside and shot the 25-round ladder series I had loaded the day before. Sitting there at the bench with a rifle pulled into my shoulder, smiling at the dual pleasures of the ascending numbers on the chronograph and the tidy little groups on paper, downrange.

There were no surprises.

As dellet mentioned, you can tweak Quickload. Once you've got it dialed in, you can sit in the comfort of your living room, while your wife watches some sappy romance on the Hallmark Channel, and run virtual loads long before you ever head out to the loading bench and actually begin weighing charges and pulling the press handle.

Nowadays, my handload log lives on my laptop, inside an Excel Workbook. And instead of "EV," it now has columns for "Predicted Velocity - 16" Barrel," "Predicted Pressure," and "Predicted Velocity - 7" Barrel" (Because, in 300BLK I have a 16" RARR and a 7" DDM4 PDW). When the load then gets shot, the numbers from the LabRadar go into the "Actual Velocity" column. And when that actual velocity sidles up to within kissing distance of the predicted velocity - which it usually does - you know you're on to something.

Pressure has always been the elephant in the room, the shadow behind everything we do. We could guess at it, based upon what the load manuals said. We could estimate how far from max we were. But we could never really know, until it was too late. And because the list of things that affect pressure is nearly endless - some of which will change from day to day and shooting session to shooting session - it shouldn't surprise us that so many shooters still come a cropper with those handloads they cooked up over the weekend.

Quickload, used in conjunction with an accurate chronograph, for the first time gives us the opportunity to see what pressures we're actually lighting off in that chamber just in front of our nose. I heartily recommend it.

Here is the Barnes max load of 20.2 gr., of H110, out of a 16" barrel.

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jtaylor996
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