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.1 vs .02 digital scales
#6321067
06/03/16 12:52 PM
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Joined: May 2014
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TackDriver
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I have the old RCBS digital powder scale that I have been using for years and it measures .1 grain, would a .02 scale help in accuracy at long range? There are scales that cost thousands of dollars that measures by the kernal, but its outrageously high in value and not looking to spend that kind of money. $200 to $300 is my budget. Is the GemPro 250 a great scale? Pros and cons of buying a .02 scale?
Last edited by Big Stan; 06/03/16 12:53 PM.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321121
06/03/16 01:25 PM
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Joined: Jun 2015
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rickym
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For a long range shooter more than likely yes, it would allow you to fine tune a load as opposed to guessing where you are in the tenths. Your current scale is fine, but if you want the ability to consistently produce a duplicate load I would make the switch.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321183
06/03/16 01:51 PM
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Joined: Oct 2004
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redchevy
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I'm not going to say it will or wont help you, but I do know there are countless long range shooters that do well that do not measure to .02.
Some of the well known guys on this forum use chargemasters, which are only accurate to .1.
It's hell eatin em live
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321245
06/03/16 02:34 PM
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Dien
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I use a chargemaster and with the .1 resolution it shouldn't make that big of a difference if you're just trying to hit BIG steel targets out to 1,000 yards. I'm trying to get better at shooting bullet holes at 100 yards though so I am waiting for my auto trickler for a .02 resolution scale. http://www.autotrickler.com/index.html
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321271
06/03/16 02:52 PM
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Joined: May 2007
Posts: 1,225
papa45
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My thoughts: I have an RCBS Chargemaster and have wondered the same thing. When I find high SD's on my loads, I always suspect the Chargemaster, but I have checked it against my beam balance scale and have even pulled bullets on loaded ammo to weigh the charge. It's always within "half a tenth" (0.05 gr) of the desired weight. The powder I use for many of my loads typically gives me a velocity difference of about 50 fps per grain. Keeping things simple, that means 0.1 gr gives me a velocity difference of about 5 fps. Given all the other variables that can affect velocity and accuracy, I'm not worried about 5 fps.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321505
06/03/16 06:04 PM
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Joined: Sep 2009
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ChadTRG42
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Beginning of this week, I made a video to post on line to show how I load my ammo with the powder charge accurate to within .02 grains. (I'll be uploading it shortly).
Take the RCBS chargemaster. It states that it is accurate to within +/- .1 grains. So, that's accurate to within about .2 grains of powder (or more), which is a legitimate swing with the RCBS CM. Now, I use a Sartorious high end digital scale that is accurate to within +/- .02 grains. That's accurate to within .04 grains technically. Most extruded kernels of gun powder are about .02 to .03 grains in weight. So, the .02 grain scale is accurate to within 1 kernel of powder.
Now, what is the real world difference between .2 and .04 grains? From my testing, .1 grains of powder is about 10 fps increase/decrease. So a .2 grain spread is already equal to about a 20 fps extreme spread, just in the powder charge! That's without accounting for any deviation in the load itself, the rifle, environmental conditions and all the other factors.
Now to tighten up those numbers, getting your powder charge consistent to within .02 grains is to the kernel accuracy. This will give you the most consistent powder charge to keep your extreme spread (ES) and standard deviation (SD) as tight as possible. This becomes a HUGE factor at longer ranges where a high ES will cause vertical stringing and groups to open up. Sure, you may or may not see it at 100 yards from a hunting rifle. But for precision shooting, the .02 grains consistency is extremely important to me and my customers!
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321513
06/03/16 06:14 PM
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Joined: Sep 2009
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ChadTRG42
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Also, if the scale is a strain gauge (like the RCBS CM and most low end scales), these will "wonder" with their weight readings. So frequently re-zeroing and calibrating are important. The higher end scales will use a magnetic method to weigh, which is much more consistent and repeatable. Also, look at the settle or stabilization time, which is how fast the scale reads the weight. My Sartorious is the magnetic type, and stabilization time in 1 second.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321548
06/03/16 06:51 PM
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Joined: Oct 2004
Posts: 39,549
redchevy
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How many people loading on a scale accurate to +/- 0.1 grains have a load that is under 20 fps ES?
I don't even have a chronograph, just curious to know.
It's hell eatin em live
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321550
06/03/16 06:53 PM
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Joined: Sep 2009
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ChadTRG42
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My 6.5x47 Lapua was running 6 and 7 ES on 5-6 shots during load work up. When practicing and putting 20+ rounds down it, my ES was 18, which is about 5 to 6 SD, which is freakin' awesome.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321570
06/03/16 07:07 PM
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ChadTRG42
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Sartorius ENTRIS 423-1S is the scale I run. It offers the best overall performance I am looking for in the precision, weight area and speed I need.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321642
06/03/16 08:06 PM
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Joined: Mar 2012
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Cleric
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Its the old need versus want...
I don't need it, but its nice knowing for sure that when the bullet doesn't go where i thought it would, it was not the ammo.
If you are shooting deer to 300 yards, .1 is more then enough.
If you are shooting matches at to 1200 yards and 10-30k is on the prize table than i want EVERY advantage i could get
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321653
06/03/16 08:11 PM
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Joined: Mar 2012
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I did a class with NTPR a few years ago. We were loading 308 and i wanted to try his Prometheus for grins. We did the same charge on an RCBS CM and it. The SD was half on the Prometheus. Now it was a small sample size so i never did put it through my statistical tool to determine if there was a spastically significant difference in variation. But I would put money i could get one with a sample size of 30 each.
for the record i have a CM and just got a gem pro to measure how good it actually is. I am debating buying a higher end scale. The biggest issue i have had with the gem pro so far is its slow to respond after adding powder.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321795
06/03/16 09:49 PM
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Joined: Sep 2009
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ChadTRG42
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Yes, Jay's Prometheus is to within the kernel, which is .02 grains.
Powder is the sheer driving force behind the bullet. If it's the same each time, you get the same pressure and speed each time. If it varies, so will your speeds.
Like I said, for general hunting, within .1 or so is perfectly fine. I load my personal hunting ammo quickly on the Chargemaster when I need ammo in a hurry. And it does perfectly fine. But when I am wanting to tag something far away, .02 accuracy is how I roll.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321858
06/03/16 10:40 PM
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Joined: Jan 2016
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glocker17
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For general use .1 is fine, I shot F class for some time and with a good load in an accuracy node .1 will get it done out to 600 yards. I would imagine that past that distance the difference would be more apparent. Inside 600 environmental conditions usually played a much bigger role, much less the ability of the shooter, for that matter your average low volume shooter might not be competent enough to realize any performance increase.
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Re: .1 vs .02 digital scales
[Re: ChadTRG42]
#6321916
06/03/16 11:44 PM
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Joined: Nov 2007
Posts: 9,523
RiverRider
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Powder is the sheer driving force behind the bullet. If it's the same each time, you get the same pressure and speed each time. If it varies, so will your speeds. Not that simple. Case volume plays every bit as much a role in velocity consistency as charge weight does. But the real wild card is neck tension.
"Arguing with you always makes me thirsty." -Augustus McRae
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321948
06/04/16 12:20 AM
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Joined: Sep 2006
Posts: 32,515
kmon11
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Going to the more accurate scale does remove one more variable from the loading for accuracy equation. Still have case volume, bullet weight, neck tension, runout and ... for other things that can effect accuracy.
How much the reloader/shooter wants to chase that ultimate accuracy is up to them. Unless one is a very good shot going for better than half MOA or even MOA consistently is often beyond the shooters skillset.
lf the saying "Liar, Liar your pants on fire" were true Mainstream news might be fun to watch
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Re: .1 vs .02 digital scales
[Re: ChadTRG42]
#6321958
06/04/16 12:35 AM
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TackDriver
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Sartorius ENTRIS 423-1S is the scale I run. It offers the best overall performance I am looking for in the precision, weight area and speed I need. And burns a big hole in my pocket.
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Re: .1 vs .02 digital scales
[Re: Cleric]
#6321962
06/04/16 12:39 AM
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Posts: 1,100
TackDriver
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for the record i have a CM and just got a gem pro to measure how good it actually is. I am debating buying a higher end scale. The biggest issue i have had with the gem pro so far is its slow to respond after adding powder. How did the GemPro 250 work for you? Did it keep the ES and SD down over the CM?
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6321975
06/04/16 12:51 AM
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Posts: 3,809
Cleric
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for the record i have a CM and just got a gem pro to measure how good it actually is. I am debating buying a higher end scale. The biggest issue i have had with the gem pro so far is its slow to respond after adding powder. How did the GemPro 250 work for you? Did it keep the ES and SD down over the CM? haven't even really tried it for loading...I got it about a month or two ago, but have been slammed with house renovations and travel. Hopefully next week i will have a chance to use it. From the limited i used it, it does not react well/fast to adding powder. I took some target and was able to add 4-6 kernels before it registered any difference in charge. I think its going to be good for the occasional check of the CM, but it is far from a high end scale.
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Re: .1 vs .02 digital scales
[Re: RiverRider]
#6322568
06/04/16 06:46 PM
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Joined: Sep 2009
Posts: 18,954
ChadTRG42
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Powder is the sheer driving force behind the bullet. If it's the same each time, you get the same pressure and speed each time. If it varies, so will your speeds. Not that simple. Case volume plays every bit as much a role in velocity consistency as charge weight does. But the real wild card is neck tension. Yes and no. It depends on the burn speed of the powder used in the cartridge and bullet combo. This is exactly one of the topics we talked about at the Applied Ballistics seminar. For example, take a 300 Win Mag with a 190 grain bullet. Selecting a powder with near 100% case fill will be something in the 4831, R22 and H1000 burn rate. These 3 powders, or anything in this general burn rate, would be a great choice for this 190 grain bullet to get near 100% case fill and push the 190 grain bullet to it's maximum speeds efficiently with low ES and SD numbers (about 3000 fps). Now, if you were to drop down to a much faster burn rate powder, like H4895, in the same 300 WM and 190 grain bullet, and get 80% case fill, the efficiency is still there, but at a cost of much slower speed. Litz did this testing, and found that with the right powders getting to the max pressure with this 80% case fill, your ES and SD numbers actually stayed the same or improved (lowered the ES and SD). Your velocity will be reduced by about 100-200 fps by using 80% fill and a faster burning powder. This is the same thing I have seen. Whenever I can not dial in a rifle with the usual powders that generally work, I drop down to a faster burn rate powder with the same bullet. This makes the cartridge have a larger sweet spot, and less finicky to find the accuracy node. This is why I select the "optimum" powder for a given cartridge and bullet weight. Each cartridge and bullet combo have a general area where I want to be in when selecting a powder for it. When you see guys that want only 1 powder for about 5 cartridges they shoot, but 1 or 2 (or more) of the rounds are not optimized for that powder and bullet combo. Neck tension, of course, is important. But IMO, the powder charge consistency is much more important than having a slightly varying neck tension (which I have had before in the past, but the rifle still shot well). But like I said, powder is the shear driving force behind the bullet. Nothing else propels the bullet out of the barrel. So it is very important to have a consistent and accurate powder charge from round to round to maintain a consistent velocity, especially at longer ranges.
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6322824
06/04/16 09:45 PM
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Joined: Nov 2007
Posts: 9,523
RiverRider
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I will agree that charge weight consistency is important, and I will also agree that running in the correct pressure range is important---even moreso. But if you can't control neck tension and case volume the benefits of weighing to 0.02 grain are simply going to be out of reach. The very first portion of the pressure curve is influenced by the inertia of the bullet at rest, proximity to the lands, and neck tension. Change up any of those three, and the first portion of the pressure curve is altered which in turn affects the rest of the burn, and the rest of the curve.
"Arguing with you always makes me thirsty." -Augustus McRae
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Re: .1 vs .02 digital scales
[Re: RiverRider]
#6322886
06/04/16 10:37 PM
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Joined: Sep 2006
Posts: 32,515
kmon11
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I will agree that charge weight consistency is important, and I will also agree that running in the correct pressure range is important---even moreso. But if you can't control neck tension and case volume the benefits of weighing to 0.02 grain are simply going to be out of reach. The very first portion of the pressure curve is influenced by the inertia of the bullet at rest, proximity to the lands, and neck tension. Change up any of those three, and the first portion of the pressure curve is altered which in turn affects the rest of the burn, and the rest of the curve. Agree, while consistent powder charges are important they are not the only variable in getting consistent velocity. Powder selection does play a part as do the other things mentioned in this thread
Last edited by kmon1; 06/04/16 10:40 PM.
lf the saying "Liar, Liar your pants on fire" were true Mainstream news might be fun to watch
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6322937
06/04/16 11:20 PM
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Joined: Apr 2011
Posts: 988
okie44
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I've got no dog in this fight. What do you you do with the bench rest boys that load by volume? Page 21 starts the loading process. If you want to fast forward, I've come to the conclusion that all you need is time, money and talent. Lately I've had the time, short on the others that are far more important. http://singleactions.proboards.com/thread/11487/building-benchrest-rifle?page=21
Last edited by okie44; 06/04/16 11:21 PM.
�The trouble ain't that there is too many fools, but that the lightning ain't distributed right.� Mark Twain
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Re: .1 vs .02 digital scales
[Re: TackDriver]
#6323018
06/05/16 12:36 AM
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Joined: Nov 2007
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RiverRider
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Here are the results that QuickLOAD predicts for a .270 Winchester load using a 130-grain Partition. The case capacity difference is 0.5 grains of water: Cartridge : .270 Win. (SAAMI)
Bullet : .277, 130, Nosler PART SP 16322
Useable Case Capaci: 61.884 grain H2O = 4.018 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Alliant Reloder-17
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-10.0 83 49.68 2889 2409 46212 10621 99.5 1.230
-09.0 84 50.23 2918 2458 47675 10704 99.6 1.212
-08.0 85 50.78 2947 2507 49181 10782 99.8 1.195
-07.0 86 51.34 2976 2557 50737 10855 99.9 1.178
-06.0 87 51.89 3005 2606 52341 10923 99.9 1.161
-05.0 88 52.44 3033 2656 53995 10985 100.0 1.145
-04.0 89 52.99 3062 2706 55703 11042 100.0 1.129 ! Near Maximum !
-03.0 89 53.54 3090 2756 57465 11097 100.0 1.113 ! Near Maximum !
-02.0 90 54.10 3118 2806 59281 11150 100.0 1.098 ! Near Maximum !
-01.0 91 54.65 3146 2857 61161 11202 100.0 1.083 ! Near Maximum !
+00.0 92 55.20 3174 2908 63102 11254 100.0 1.068 ! Near Maximum !
+01.0 93 55.75 3201 2958 65104 11305 100.0 1.054 !DANGEROUS LOAD-DO NOT USE! Cartridge : .270 Win. (SAAMI)
Bullet : .277, 130, Nosler PART SP 16322
Useable Case Capaci: 62.388 grain H2O = 4.051 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Alliant Reloder-17
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-10.0 82 49.68 2879 2393 45556 10630 99.4 1.238
-09.0 83 50.23 2908 2441 46990 10715 99.6 1.221
-08.0 84 50.78 2937 2490 48467 10795 99.7 1.204
-07.0 85 51.34 2966 2539 49989 10870 99.8 1.187
-06.0 86 51.89 2994 2588 51557 10940 99.9 1.170
-05.0 87 52.44 3023 2637 53177 11004 100.0 1.154
-04.0 88 52.99 3051 2687 54843 11064 100.0 1.138
-03.0 89 53.54 3079 2737 56569 11119 100.0 1.122 ! Near Maximum !
-02.0 90 54.10 3107 2787 58346 11173 100.0 1.107 ! Near Maximum !
-01.0 91 54.65 3135 2837 60179 11226 100.0 1.092 ! Near Maximum !
+00.0 91 55.20 3163 2887 62073 11278 100.0 1.077 ! Near Maximum !
+01.0 92 55.75 3190 2938 64026 11330 100.0 1.062 ! Near Maximum !
+02.0 93 56.30 3217 2988 66045 11381 100.0 1.048 !DANGEROUS LOAD-DO NOT USE!
+03.0 94 56.86 3245 3039 68129 11432 100.0 1.034 !DANGEROUS LOAD-DO NOT USE!
+04.0 95 57.41 3272 3090 70280 11481 100.0 1.020 !DANGEROUS LOAD-DO NOT USE!
+05.0 96 57.96 3299 3141 72504 11530 100.0 1.006 !DANGEROUS LOAD-DO NOT USE!
"Arguing with you always makes me thirsty." -Augustus McRae
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Re: .1 vs .02 digital scales
[Re: RiverRider]
#6323042
06/05/16 12:50 AM
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Joined: Jan 2012
Posts: 9,273
blackcoal
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Powder is the sheer driving force behind the bullet. If it's the same each time, you get the same pressure and speed each time. If it varies, so will your speeds. Not that simple. Case volume plays every bit as much a role in velocity consistency as charge weight does. But the real wild card is neck tension. How is neck tension measured and how does one control it from cartridge to cartridge?
The Greatest Enemy of knowledge is not ignorance, it is the illusion of knowledge.--Stephen Hawking
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