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Posted: 11/1/2010 10:30:05 AM EDT
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I'm ashamed to admit I never got around to chronographing my handgun loads until this weekend. I had a few surprises: 1. My own cast 200Grain SWC's in 45ACP with 6.2 Grains of Universal are moving at >1000fps (yikes!) 2. All my other loads are moving at 750fps or LESS (ugh!) (My MOBUCO .380 loads were 500fps, LOL!) The thing that's bugging me is that when I punch all the data into Quickload, it predicts my loads to be much faster (~100 - 200 fps) than the chronograph tells me. For the record, my comparisons of this type with .223 loads were always nearly dead on. Here's an example: I measured H2O capacity of several Winchester .45ACP once-fired brass case at ~27.6 grains. I put in the barrel Length of my Glock 21 (4.6"), The rifling twist, the COAL with 230 grain XTP's (1.230") and the given data for that bullet. I'm using VIHT N340 powder, select .45ACP as the cartridge, and put in 6.2 grains (which is what I loaded at, and no, it's not a typo, 6.2 grains of Universal in the cast load mentioned above, 6.2 grains N340 in the XTP load). Here's what QuickLoad tells me:  So it says 852 fps. This load chrono'd between ~670 and ~750fps (about 10 feet distance between muzzle and chronograph). (And yes, I checked the charges every couple of rounds while loading these...) As a control load, I also chronographed 13 rounds of Hornady 230 grain TAP ammo, they came out in the neighborhood of ~850fps, as expected. So am I doing something wrong? Is there some data I'm not putting in right? What am I missing? Or am I just expecting too much of the tool? All I can think is one of the below: 1. my scale is wrong (RCBS Chargemaster 1500, calibrated and measuring my 2.6 grain "straw" calibration tool perfectly each time). 2. my chronograph is wrong (with my rifle loads it's been dead on, and the Hornady TAP chronograph results looks very normal) 3. I put something wrong into the tool??? 4. The tool just isn't that accurate to a real world model... I'm expecting too much.. EDIT, evidently I only shot 6 Hornady TAP 230gr. Anyway, don't think that changes the end result. |
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You've got an amazing amount of information. However, I think you're missing one thing that could possibly explain some things. That would be ACTUAL chamber pressures. http://www.shootingsoftware.com/pressure.htm I think the software is a good tool to have, but real world is your best answer. You know that your pushing your lead pretty fast, and your chrony told you that. (No leading in the barrel?) At 6.2 you are essentially at the max for your load (6.3 being max). I would say you're doing things right. Your chrony and your eyes are your friend. However, I wouldn't place all my faith in software and what "should" be. As a reloader you have to take your results and evaluate the safety of the cartridge. If they move fast enough for the distance you're shooting, aren't showing the signs of overpressure, and are accurate in your weapons then enjoy! ETA: 500 fps 380??? You shootin' cowboy action with that gun??  |
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I think your chrono results are inaccurate…
You .45 ACP load should have fallen about 800/850 and cannot reach 1,000 fps even going downhill I have loaded 200 Gr SWC’s to that velocity with 7.5 Gr of Unique and you notice it when the hammer falls! I don’t think you can get a .380 ACP to go 500 fps and cycle anything… Maybe some more info about your chrono setup and testing conditions??? |
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Quoted: You've got an amazing amount of information. However, I think you're missing one thing that could possibly explain some things. That would be ACTUAL chamber pressures. http://www.shootingsoftware.com/pressure.htm I think the software is a good tool to have, but real world is your best answer. You know that your pushing your lead pretty fast, and your chrony told you that. (No leading in the barrel?) At 6.2 you are essentially at the max for your load (6.3 being max). I would say you're doing things right. Your chrony and your eyes are your friend. However, I wouldn't place all my faith in software and what "should" be. As a reloader you have to take your results and evaluate the safety of the cartridge. If they move fast enough for the distance you're shooting, aren't showing the signs of overpressure, and are accurate in your weapons then enjoy! ETA: 500 fps 380??? You shootin' cowboy action with that gun?? This was my initial loads with 95 grain RN MOBUCO bullets. There is no load data, so I modeled it in QuickLoad with Red Dot powder. Looks like the data it gave me was sufficient to find a safe starting load at least! Ideally, I'd like to get the lead rounds shooting to a similar POI as my carry ammo for practice at the action range. That's about all the Ruger LCP is good for, I hate shooting it (painful on the hands), but it's a very nice little gun for CCW when you need it to be REALLY inconspicuous... (like summertime in shorts and a T-shirt...) |
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Quoted: I think your chrono results are inaccurate… You .45 ACP load should have fallen about 800/850 and cannot reach 1,000 fps even going downhill I have loaded 200 Gr SWC’s to that velocity with 7.5 Gr of Unique and you notice it when the hammer falls! I don’t think you can get a .380 ACP to go 500 fps and cycle anything… Maybe some more info about your chrono setup and testing conditions??? I'm using an alpha chrony. It was a drizzly day with solid cloud cover, nice and cold (about 50 or 55 degrees) - in other words, ideal western Oregon weather  . I didn't use the plastic covers on the rods because the clouds were very thick and diffusing light very well.I hear what you're saying, but the chrono results for factory loads all look very normal. I have 13 rounds of Lead SWC through the chrony that all registered over 1000 fps, I have no reason to doubt it based on other results that look very normal. Same story with the slow .380's, (they were all ABOVE 500 fps, BTW, nothing under that). I'll post the actual numbers when I get home later (maybe tomorrow, I have a busy evening), but I really don't have any reason to doubt these, I wasn't getting wild variations on anything. ETA: I should also add that I chrono'd MOBUCO lead 200 grain RNFP's in 45ACP with the same load as the SWC's (same gun) on the same day, and got very reasonable results. |
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tbonifie:
Re: QuickLoad... You can tweak the starting pressure to about anything you want. How strong is the crimp? What about bullet set and case volume? Do you have the QL data precisely correct ie. bullet weight, length, etc.? Have you weighed a known volume of VV to get a bulk density? How does it compare to the powder bulk density data in QL? I think the powder bulk density is listed but only visible in the powder chart, which is not on the main page. 65% load can bring on position sensitivity. I think the 65% is going to be laying away from the primer for level firing, unless you are hand feeding and handling the slide. Are you using magnum primers or regular primers? Does the Glock have rifling that does not work well with lead bullets? Powder flash (still burning after bullet exits according to QL) may be false tripping your chrony. Move the Chrony out a bit more or shoot through a cardboard window. |
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tbonifie I am having similar results here with QuickLoad and my .45 loads. I just got a CED M2 Chronograph and I too was surprised at the difference between what QuickLoad predicted and what the actual recored FPS turned out to be. QuickLoad gave me 905 FPS but they chrono'd at 800 FPS average when I tested them this past weekend. The load I shoot in my .45 is 230 gr Berry's plated RN, 6.0 gr W-231 @1.265 OAL.
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Quoted: tbonifie: Re: QuickLoad... You can tweak the starting pressure to about anything you want. How strong is the crimp? Just barely enough to chamber into my LWD Barrel using LFC die What about bullet set and case volume? See the screenshot above, I put these into the program. Do you have the QL data precisely correct ie. bullet weight, length, etc.? Yes. Have you weighed a known volume of VV to get a bulk density? How would I go about this, and what would I do with it? How does it compare to the powder bulk density data in QL? No idea. I think the powder bulk density is listed but only visible in the powder chart, which is not on the main page. 65% load can bring on position sensitivity. I think the 65% is going to be laying away from the primer for level firing, unless you are hand feeding and handling the slide. Are you using magnum primers or regular primers? I am using Winchester Large Pistol Primers. Does the Glock have rifling that does not work well with lead bullets? I use a Lonewolf Distributors Barrel for lead loads in my Glock. It works great. Powder flash (still burning after bullet exits according to QL) may be false tripping your chrony. Move the Chrony out a bit more or shoot through a cardboard window. I will try this next time, but my experience with the chrono is that I get very erratic results if I'm too close to it and it's being affected by the powder flash and pressure exiting the muzzle, these results were all quite consistent for each given load. If I get a chance tonight, I'll sit down and post the actual chrono results. |
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Bulk Density?: In QL, go to "Data:Add, Change, Load, Save", then "Propellant Data", then "Change records in active file". The propellant data window will open. Then go to bottom of R/H column and see Bulk Density in g/cm3. Changing this parameter to match your actual powder characteristics can tighten the QL model up a bit.
If you have a recording bomb calorimeter, then you can adjust many more parameters, but most folks do not have one handy. 
To experimentally determine bulk density. Find a graduated volume container and fill it with powder to known volume. Don't tamp it down, because you are running loose powder in the 45ACP (not compressed). Pour the known volume in your balance beam scale and record the weight. Now convert grains to grams, and known volume to cubic centimeters. Compute grams / cubic centimeters. Do this several times and use your statistics to get an AVG and SD. When you are confident in the measurement, compare it to the Bulk Density in your QL. Change as you see fit. While you are at it, back on the main page, update the bullet length to actual bullet length, and update case volume in grains of H2O to actual volume in grains of H20. Then make sure the COAL parameteris set per your measurements of actual reloads. As you may have noticed, setting starting pressure on the main page, is a black art, and can significantly affect how the model plays. If you are slightly crimping the lead, then the start pressure, that comes up with the standard main page data may be too high. Having said all that, the QL model in its best condition is probably only accurate to +/- 10%. |
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The first thing I'd do is move your chrono to at least 15' away from the muzzle of your pistol. I think there's a good possibility that your chrono is reading the muzzle blast in addition to the bullet. Because your ammo is subsonic while the blast is supersonic, it's getting to the chrono ahead of your bullet. Conversely, you rifle rounds are supersonic and the bullet gets to the screens before the blast. I was getting really fast readings with my chrono when I first got it and after I moved it farther from the muzzle, things went back to normal. |
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Quoted:
1000 ft/s sounds an awful lot like a muzzle blast shock wave. You end up with something close to the speed of sound (often a little slower since the wave loses speed rather quickly). I think this sounds most like the answer. Always be consistent when setting up test instrumentation like chronographs. If your distances aren't consistent than your data is useless. I always set up using a tape measure. I've been using Chronys for years and I can tell you for sure that this works: 10' for revolvers and pistols (EXCEPT .44 Magnum and more powerful). 15' for rifles and .44 Magnum revolver.
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Here are the actual Chrono results. These were all shot over the chrono from the same location (about 10' from muzzle). 230 grain XTP bullet, 6.2 Grains VIHT 704 724 769 739 746 749 735 739 721 735 715 Hornady 230 Grain TAP 847 856 835 860 840 834 Cast Lead 200 Grain SWC, 6.2 Grains Universal 1013 988 1025 1032 1046 1059 1052 1036 1052 1059 1059 1015 Cast Lead 200 Grain RNFP (MOBUCO), 6.2 Grains Universal 778 799 820 738 824 817 795 801 781 765 Hornady XTP 380ACP TAP 813 787 777 794 795 Cast Lead 95 Grain RN (MOBUCO), 380ACP, Red Dot
90 Grain XTP bullet, Universal Powder, 380ACP
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Quoted: Quoted: 1000 ft/s sounds an awful lot like a muzzle blast shock wave. You end up with something close to the speed of sound (often a little slower since the wave loses speed rather quickly). I think this sounds most like the answer. Always be consistent when setting up test instrumentation like chronographs. If your distances aren't consistent than your data is useless. I always set up using a tape measure. I've been using Chronys for years and I can tell you for sure that this works: 10' for revolvers and pistols (EXCEPT .44 Magnum and more powerful). 15' for rifles and .44 Magnum revolver. My first thought was that that makes sense except I would expect muzzle blast to give inconsistent readings. But looking back at my data now, I see that group was MORE consistent than the rest... so I'm thinking it's back to the range with that load... I'm tending to agree with you... |
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Quoted: Bulk Density?: In QL, go to "Data:Add, Change, Load, Save", then "Propellant Data", then "Change records in active file". The propellant data window will open. Then go to bottom of R/H column and see Bulk Density in g/cm3. Changing this parameter to match your actual powder characteristics can tighten the QL model up a bit. If you have a recording bomb calorimeter, then you can adjust many more parameters, but most folks do not have one handy. To experimentally determine bulk density. Find a graduated volume container and fill it with powder to known volume. Don't tamp it down, because you are running loose powder in the 45ACP (not compressed). Pour the known volume in your balance beam scale and record the weight. Now convert grains to grams, and known volume to cubic centimeters. Compute grams / cubic centimeters. Do this several times and use your statistics to get an AVG and SD. When you are confident in the measurement, compare it to the Bulk Density in your QL. Change as you see fit. While you are at it, back on the main page, update the bullet length to actual bullet length, and update case volume in grains of H2O to actual volume in grains of H20. Then make sure the COAL parameteris set per your measurements of actual reloads. As you may have noticed, setting starting pressure on the main page, is a black art, and can significantly affect how the model plays. If you are slightly crimping the lead, then the start pressure, that comes up with the standard main page data may be too high. Having said all that, the QL model in its best condition is probably only accurate to +/- 10%. OK, will do... but first have to find a proper measuring container... would a powder dipper be appropriate, or not accurate enough? I've already done the parts in blue above... +/- 10% is pretty reasonable, I guess. that would be +/- 80 to 85 fps on these loads... I'm actually not to far from -10% on the XTP load... |
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Quoted:
Quoted:
Quoted:
1000 ft/s sounds an awful lot like a muzzle blast shock wave. You end up with something close to the speed of sound (often a little slower since the wave loses speed rather quickly). I think this sounds most like the answer. Always be consistent when setting up test instrumentation like chronographs. If your distances aren't consistent than your data is useless. I always set up using a tape measure. I've been using Chronys for years and I can tell you for sure that this works: 10' for revolvers and pistols (EXCEPT .44 Magnum and more powerful). 15' for rifles and .44 Magnum revolver.
My first thought was that that makes sense except I would expect muzzle blast to give inconsistent readings. But looking back at my data now, I see that group was MORE consistent than the rest... so I'm thinking it's back to the range with that load... I'm tending to agree with you... Muzzle blast is usually VERY consistent. The speed of sound and the rate of the shock wave slowing vary lowly. Air temp, density, barometric pressure just do not change very quickly. |
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Had a little more time to dig
Looking at Sierra, .380 ACP ~ 95 Gr FMJ. The Red Dot range is from 2.7 Gr (750 fps) to 3.1 (900 fps) Cast & Jacketed data is pretty much interchangeable… Lyman 45th showing 2.6 to 3.0 for both FMJ and Lead of that weight… So for the .380 your results do seem correct for the anemic loading 
I think I would compare loads against at least 2 other sources before putting a lot of faith into a program that is proving inconsistent. |
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