I have been reloading for about 10 years and have always followed the information found in published reloading manuals. I have also trusted info collected from individuals from this site once compared with the manuals to be relatively safe. My dilemma is, I want to try a new cartridge, new to me that is, but there is no published data available and I don't have a QuickLoads program. One individual was kind enough to give me a powder to start with. I would like to know when looking at a burn rate chart how to determine which powder would increase or decrease my velocity, faster burning or slower burning powders. For example Ramshot X-terminator is my starting powder and I want to increase my velocity, with a 100% fill in my case my velocity is 2850 fps but I am trying to achieve 3000 fps, would I use a faster or slower powder? I'm not trying to "hot rod" a cartridge, but trying to advance to the next step to understanding reloading safely.
Powder burn rate
- Thread starter RonS
- Start date
CatShooter
RonS said:
IF the case is full, and the charge is compressed, and you see no pressure signs, then go down to the next faster powder, drop 10% and work up.
It's difficult if not impossible to answer your question. You're asking advice on a move, but without knowing the cartridge details it's like asking for directions to Paris without knowing where you are now and even whether it's directions to Paris, France or Paris, Texas. It may be that the cartridge with whatever bullet you're using will never safely produce 3,000 fps anyway, but one simply can't say 'faster' or 'slower' without knowing how well X-Terminator suits the application. If it's a relatively fast-burner for the application, a slower burning grade might give higher MVs, but only if there is room in the case to accept a sufficiently large charge. Or as CatShooter says, if you're running a case-full now with low pressures, go the other way.
There are other problems too:
Burning rates are not fixed across all applications. Two powders' positions can be effectively reversed when used in different cartridges and/or with different bullet weights. The comparative rates listed are only approximate anyway - that's why manufacturers stress they're simply a guide not carved in tablets of stone, so should never be used lightly for substitutions without further and more reliable data.
Second, burning rate is only one of several key factors that determine use, applications, and results. At the end of the day, a cartridge / firearm is a heat machine. Outputs (MV and ME) are determined by energy inputs (charge weight * specific energy) and thermal efficiency. The burning rate affects the latter to a considerable extent, but only the former insofar as it affects the maximum charge weight that can be used, not the amount of energy the powder manufacturer provides. Specific energy values vary considerably across powder makes and grades. They're quoted as KJ (K-Joules) per Kg powder weight and handloaders' rifle powders vary from as low as 3,500 KJ/Kg to a top figure of 4,100.
So, changing powder to one with a different burning speed in your application might allow a heavier charge to be used safely as it suits the cartridge and bullet weight better, but may also see an overall decrease in the charge energy content, for instance by moving from X-Terminator, a double-base ball powder rated at 3,950 KJ/Kg to a marginally heavier charge of slightly slower burning single-base Viht N133 rated at 3,630 KJ/Kg. But if the move were to a say 1gn or 2gn heavier charge of Viht N530 also slightly slower burning than X-Terminator, the energy input and hence MV/ME could leap as that's a 'high-energy' propellant (base nitrocellulose kernels infused with nitroglycerin during manufacture) rated at 4,100 KJ/Kg.
But then again .... X-Terminator might see 100% charge burn early in the bullet travel along the barrel and give say 38-39% thermal efficiency, whilst only 95% of the N530 charge burns in this application and your barrel length and overall thermal efficiency is poorer. .............Ouch!
At the end of the day, burning rate is a single and often not very helpful bit of information that informs which other powders might be worth considering as an alternative, not what will be better than your existing choice.
So .... ask on these forums what other people load in this cartridge with this bullet. Tell them whether the chamber is long or short throated. Ask for help from QuickLOAD users. Google every source of information on the Internet and look at the bullet and powder manufacturers' data sections on their websites to see if they cover it. Use this forum's search facility. The cartridge may be new to you but have dozens of users here who'll happily help with advice. Or then again, it may be very esoteric, rare, and (obsolete) like you're the only shooter on the planet who wants to experiment with 90gn VLDs loaded in the .22 Velo-Dog .... in which case you have a REAL problem
There are other problems too:
Burning rates are not fixed across all applications. Two powders' positions can be effectively reversed when used in different cartridges and/or with different bullet weights. The comparative rates listed are only approximate anyway - that's why manufacturers stress they're simply a guide not carved in tablets of stone, so should never be used lightly for substitutions without further and more reliable data.
Second, burning rate is only one of several key factors that determine use, applications, and results. At the end of the day, a cartridge / firearm is a heat machine. Outputs (MV and ME) are determined by energy inputs (charge weight * specific energy) and thermal efficiency. The burning rate affects the latter to a considerable extent, but only the former insofar as it affects the maximum charge weight that can be used, not the amount of energy the powder manufacturer provides. Specific energy values vary considerably across powder makes and grades. They're quoted as KJ (K-Joules) per Kg powder weight and handloaders' rifle powders vary from as low as 3,500 KJ/Kg to a top figure of 4,100.
So, changing powder to one with a different burning speed in your application might allow a heavier charge to be used safely as it suits the cartridge and bullet weight better, but may also see an overall decrease in the charge energy content, for instance by moving from X-Terminator, a double-base ball powder rated at 3,950 KJ/Kg to a marginally heavier charge of slightly slower burning single-base Viht N133 rated at 3,630 KJ/Kg. But if the move were to a say 1gn or 2gn heavier charge of Viht N530 also slightly slower burning than X-Terminator, the energy input and hence MV/ME could leap as that's a 'high-energy' propellant (base nitrocellulose kernels infused with nitroglycerin during manufacture) rated at 4,100 KJ/Kg.
But then again .... X-Terminator might see 100% charge burn early in the bullet travel along the barrel and give say 38-39% thermal efficiency, whilst only 95% of the N530 charge burns in this application and your barrel length and overall thermal efficiency is poorer. .............Ouch!
At the end of the day, burning rate is a single and often not very helpful bit of information that informs which other powders might be worth considering as an alternative, not what will be better than your existing choice.
So .... ask on these forums what other people load in this cartridge with this bullet. Tell them whether the chamber is long or short throated. Ask for help from QuickLOAD users. Google every source of information on the Internet and look at the bullet and powder manufacturers' data sections on their websites to see if they cover it. Use this forum's search facility. The cartridge may be new to you but have dozens of users here who'll happily help with advice. Or then again, it may be very esoteric, rare, and (obsolete) like you're the only shooter on the planet who wants to experiment with 90gn VLDs loaded in the .22 Velo-Dog .... in which case you have a REAL problem
CatShooter
RonS said:
Why is it that you don't mention the cartridge... or if it is a new wildcat, why not mention the weight of water that fills the case, and the caliber, and bullet weight you are/want to use - why the big secret??
[br]Laurie said:
You saying they have one in France, too? [br]
Don't forget Paris in Arkansas, Idaho, Illinois, Kentucky, Maine, Michigan, Mississippi, Missouri, New York, Ohio, Pennsylvania, Tennessee, Virginia, and last, but not least, the two in Wisconsin.
Attachments
My parents' summer home was five miles from Lynchville, where the sign is located. I bicycled past it to shoot rats at the town dump. [br]
Yes, the old country is just that. My first ancestors arrived from England in 1639 and settled at Plimoth Plantation. But that is only recent history for Brittania.
Yes, the old country is just that. My first ancestors arrived from England in 1639 and settled at Plimoth Plantation. But that is only recent history for Brittania.
from his previous post im guessing hes referring to the 25-223
Yes the 25-233 is the cartridge. Gentlemen please excuse me for not mentioning that at first I was trying to get a sense of how to read or use the burn rate chart, not deceive anyone. But after reading everyone's post I agree that I should have revealed my new project. It's an AR chambered in 25-223 with a 20" 9T barrel, I'll be using 75 & 87gr bullets. So far I have some 87gr Speer TNT's, they are .920" long with a .310 BC and .188 sectional density. The powder I was told to start with was Reloder 15 and after brief phone call today I was also told to try X-terminator. The case length is 1.750" and OAL is 2.260". The case is once fired Wolf Gold, I have about 300 pieces. I don't know the H2O case capacity but hope this is enough info to get started. I also have a set of RCBS small base dies. Thanks in advance with your help and comments.
Most 223 water capacity is ~29.0gr. Is the shoulder pushed forward or back? Safer to assume less case capacity and find that you are below pressure, than the reverse of this. Here is an "easy" way to get close to your case volume:
Borrowed from other forum:
"My method is pretty simple in that I measure full length resized cases that have a primer in them. I fill them with water, and let them stand a couple minutes (maybe tapping the side of the case a couple times to make sure there's no air bubbles). Then I add enough water to reach the very top, and measure. I've also done the samething by first measuring the weight of the case, and then filling it and weighing again. "
Finally, Hodgdon keeps a nice burn rate chart for most powders. Be careful reading the chart, as faster may be either up or down (to bottom of next left-most column).
The suggestion to start with Reloader 15 was a good one as that is a great powder for bullets in .224 that are near your bullet weights. The force to propel the bullet is mostly mass dependent, so the 77gr Sierra Matchking in 2.260 would be a good place to start. The larger diameter will mean a shorter bearing length for same weight, so I expect your loads to be a little more than what is listed for the 77 .224, but please work up slowly and carefully. I would also go as far as to estimate that your 75gr load could be started with 77gr Sierra .224 cal starting loads for reference on the faster powders. What charge of Reloader 15 did you get to, and how does that compare to what is listed for for a 77gr Sierra MK, or 75gr Hornady BTHP?
Someone mentioned H335, I'd toss in Benchmark, and H322 as well, IMR 3031 might be worth trying too.
As for the 87gr .25 cal load, I'd look at 6x45 load data for a similar weight bullet loaded to 2.260" for starting load reference material.
-Mac
Borrowed from other forum:
"My method is pretty simple in that I measure full length resized cases that have a primer in them. I fill them with water, and let them stand a couple minutes (maybe tapping the side of the case a couple times to make sure there's no air bubbles). Then I add enough water to reach the very top, and measure. I've also done the samething by first measuring the weight of the case, and then filling it and weighing again. "
Finally, Hodgdon keeps a nice burn rate chart for most powders. Be careful reading the chart, as faster may be either up or down (to bottom of next left-most column).
The suggestion to start with Reloader 15 was a good one as that is a great powder for bullets in .224 that are near your bullet weights. The force to propel the bullet is mostly mass dependent, so the 77gr Sierra Matchking in 2.260 would be a good place to start. The larger diameter will mean a shorter bearing length for same weight, so I expect your loads to be a little more than what is listed for the 77 .224, but please work up slowly and carefully. I would also go as far as to estimate that your 75gr load could be started with 77gr Sierra .224 cal starting loads for reference on the faster powders. What charge of Reloader 15 did you get to, and how does that compare to what is listed for for a 77gr Sierra MK, or 75gr Hornady BTHP?
Someone mentioned H335, I'd toss in Benchmark, and H322 as well, IMR 3031 might be worth trying too.
As for the 87gr .25 cal load, I'd look at 6x45 load data for a similar weight bullet loaded to 2.260" for starting load reference material.
-Mac
[br]mac86951 said:
My Lapua .223 brass, fired in a .223 Rem bolt gun match chamber, measures 31.0 grains when measured as QuickLOAD instructions advise. They recommend measuring fired brass with primer and filling to case mouth. So, regardless of where you read it or obtained your data regarding case capacity, the three lots of Lapua .223 I've used indicate otherwise.
QUOTE
It is imperative to accurately determine the average capacity for a given group of cases (brand and lot) because case capacity differs substantially from lot-to-lot and brand-to-brand. This measurement is easily done using a dry, empty fired case (with fired primer in place).
[font=verdana, arial, helvetica, sans-serif]After obtaining the weight of a dry empty case (with used primer in place), fill the case with cold [/font]water. Eliminate any air bubbles and bring water even to end of case neck. Reweigh water-filled case. Subtract dry weight from water-filled weight. This gives case capacity in grains of water, which is the standard unit of measure. [br]
[font=verdana, arial, helvetica, sans-serif]UNQUOTE[/font]
Steve Blair said:
Funny, I got my data from this site... Try that link above and to the left. It might also explain the Lapua result you posted too.
As mentioned previously.
Safer to assume less case capacity and find that you are below pressure, than the reverse of this.
-Mac
[br]mac86951 said:
No, safer to correctly obtain accurate data and follow appropriate development procedures, not to make unwarranted and inaccurate assumptions. As an engineer, even an EE, you should know better. I sincerely hope you apply more rigor to your professional pursuits.
I never thought of using data from the 6x45 but I will look into that. I have about 300 pieces of once fired Wolf Gold 223 Rem brass to use with this build. As stated I have a set of small base FL dies for this, so I will FL size a couple pieces and replace the primers with used ones so I can check the case capacity. I'll keep you'll posted.
Brians356
Silver $$ Contributor
mac86951 said:
Hmmm, I just measured four different brands of 223 Rem, and posted in another thread:
Water capacity (grains, level w/ mouth) of 223 Rem:
(Empty case w/ fired primer; case not tumble cleaned; all fired in same standard Rem 700)
Mfgr. Empty H2O
----------------------
RWS 101.5 30.6
Win 94.7 31.1
Rem 95.0 30.7
L.C. 94.5 31.3
Also, chuckhawks.com lists 223 Rem (unknown brand) at 31.4 grains:
http://www.chuckhawks.com/rifle_case_capacity.htm
Brians356
Silver $$ Contributor
RonS said:
Once you weigh the H20 capacity of a few cases (or take a middling value of 31.0) then you have enough variables to plug into QuickLoad, if someone here would be kind enough (I don't have a copy of QL.) I agree 6x47 is a closer comparison, but in such a small case the jump from .243 to .257 is more than just significant.
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