Powder education

[thefitter]

Where can I learn about powder fundamentals such as appropriate burn rates for specific calibers and bullet weights?

For instance I can see that N550 is a litter slower than N540. They are both listed on the Vihtavuori site as being good for .308 but there is no mention of appropriate bullet weights for either powder.

Thanks

 

[CJ6]

UMM ERR... a loading manual .........Seriously tho, VihtaVuori lists BOTH N540 and N550 starting with 150gr weight bullets in the 308 Win up to the 190gr Sierra HPBT.

 

[Cort]

The powder manufacturer web sites all have tables that recommend specific powder charges for specific calibers and bullet weights. Also, many of the bullet manufacturers have similar tables. I use the Lyman Reloading Handbook as a starting point for my loads. I also compare the tables from more than one source for whatever I reload. Occasionally, there will be typos in the tables.

No matter what a table says, always reduce the charge by a little (10% is often a good amount) and see how your firearm "likes" the load. You can then increase the charge and watch for pressure signs while striving for utmost accuracy. You will often find an accuracy node that is below the maximum pressure level that works well for you. Staying away from the maximum charge your firearm accepts generally increases barrel life.

Cort

 

[bsekf]

Nosler Manual has a good section on BC, bullet drop, energy and velocity. By working from that table you can extrapolate pretty accurate information on bullet drop out to 500 yards. Sierra, Hornady, Berger web sites give the BC of their bullets. Hodgdon Manual has a good section on powder burn rates and identification. AND, you can always do a google search.

Can't be said enough......ALWAYS START LOW AND WORK UP........you usually find an accurate node fairly low and then again just before max.

Bill

 

[liltank]

Good rule of thumb: the heavier the projectile is for a specific caliber, the slower you want the powder burn. Now this isn't law, this is just something I go buy. You want to try and achieve a 90 to 95% load density within the casing for what ever caliber you are reloading. However with say a .308 Winchester, you could use IMR/H4350 for 180 and and up bullets, but due to the lack of case capacity you won't be able to gain that much velocity. The slowest powder I might use for a .308 would be RL17, or Ramshot Big Game. But that would be with 180+ grain bullet to optimize the slower burn rate. I go by the maximum load info and top velocity for a specific weight bullet. The velocity is a tell tail sign as to its ability to be the optimal burn rate for that bullet and caliber. It may not be the most accurate, but gives a starting point in powder selection. Then I pick a medium charge weight in that caliber, that bullet, and work up to the max charge trying to find a node that accuracy is acquired safely. Lapua offers an excellent burn rate chart that gives powder manufactures different powders and compares them against each other. Here's the website: http://www.lapua.com/upload/reloading/reloadingburningratechart2011.pdf

Tank

 

[thefitter]

Good rule of thumb: the heavier the projectile is for a specific caliber, the slower you want the powder burn. Now this isn't law, this is just something I go buy. You want to try and achieve a 90 to 95% load density within the casing for what ever caliber you are reloading. However with say a .308 Winchester, you could use IMR/H4350 for 180 and and up bullets, but due to the lack of case capacity you won't be able to gain that much velocity. The slowest powder I might use for a .308 would be RL17, or Ramshot Big Game. But that would be with 180+ grain bullet to optimize the slower burn rate. I go by the maximum load info and top velocity for a specific weight bullet. The velocity is a tell tail sign as to its ability to be the optimal burn rate for that bullet and caliber. It may not be the most accurate, but gives a starting point in powder selection. Then I pick a medium charge weight in that caliber, that bullet, and work up to the max charge trying to find a node that accuracy is acquired safely. Lapua offers an excellent burn rate chart that gives powder manufactures different powders and compares them against each other. Here's the website: http://www.lapua.com/upload/reloading/reloadingburningratechart2011.pdf

Tank

Thanks that is what I was looking for. I guess I did not make my self clear in my OP, hence the other replies. I'm definitely looking more powder engineering fundamentals and physics.

 

[glo]

My Second Edition (1995) VihtaVuori Oy reloading manual is great source on Smokeless powder, burning rate fundamentals. Its Chapter 2 and goes from page 6 to 29.

If you really want to compare powders and bullet weight affect then get Load from a Disk or the more popular QuickLoad software programs. Then you will be able to compare interior ballistics.

 

[jonbearman]

I own at least 35 loading manuals and use them to cross check load imformation to avoid an overcharge. I have found many small mistakes in bullet manufactures manuals the most. There is a book for sale right on this sight in the bookstore all about gun powder and its use.

 

[BoydAllen]

My view of reloading manuals is that, given that current ones show ample evidence of massive concern about liability issues, they are mostly to be used as sources for safe starting loads from which to start my own load workup.
Boyd

 

[Outrider27]

Regardless of how much of it is liability issues and how much is improved ability to measure pressure accurately (like you, I believe most of it is the former, and the ambulance chasers that make their living off it), it sure is a good laugh to take my first reloading manuals, a Speer #8 and a Lyman #45, and compare the loads in them to the ones in the Speer #14 and Lyman #49 for the same powders in most any cartridges covered in both age groups. There's some big differences out there....

 

[BoydAllen]

Exactly

 

[artbosco]

Where can I learn about powder fundamentals such as appropriate burn rates for specific calibers and bullet weights? For instance I can see that N550 is a litter slower than N540. They are both listed on the Vihtavuori site as being good for .308 but there is no mention of appropriate bullet weights for either powder.

I have found it very helpful to work from the opposite direction.

Find a bullet you like or want to try. Then call the bullet company's ballisticians and ask them to send you the loading data for the specific bullet(s) you're interested in. I usually receive an email within five minutes. The accuracy load is usually highlighted at the bottom of each list. And is a good starting point. Other powders on the list shouldn't be overlooked.

 

[necchi]

Some of the guy's are missing the point here fitter,

Look around your local library for loading books, not bullet or powder makers but ones like
The ABC's of Reloading by Bill Chevaleir and other books like it, most will give a rundown of various powders and why,,

But the bottom line best for me was just buying a few powders of varying burn rates listed for common calibers and trying them like;
Varget, Benchmark and H4895 for the 223, then use the same bullet in seperate load developments.

It doesn't take too long for the realities to sink in, then with that background you can look at powder burnrate charts and understand the uses,

 

[jonbearman]

I agree that the reloading manuals are starting points to be worked up from to the best node,however to not own a book or two is foolish as there is good advice for beginners and novice reloaders.Safety first and later you can start to experiment with hotter loads.

 

[louielouie]

From this generic example QuickLoad sorted thru the powders I have and developed loads based on the 'Optimum Barrel Time' (the B_Time of 1.022) I chose for my particular gun. As you can see some powders are physically difficult to put into the case and/or too hot (the "P max" column). H4831sc or IMR 7828ssc *may* fit but at 92~93%, they're still burning a lot of powder out the end of the barrel judging from the 'Prop.Burnt' column. In this example I would probably choose RL-17 or H4350 or go to a lower accuracy node where more suitable powders will work.
This is the 'art' that jonbearman is talking about and you can't have too much info otherwise it's a crapshoot...

Predicted Data for Indicated Charges of the Following Powders.
Matching Barrel Time: 1.022 milliseconds
USE ONLY FOR COMPARISON !
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Accurate 4350                      105.1     48.2     3.12    3558    99.6    61038   12604   1.023  !DANGEROUS LOAD-DO NOT USE!
Accurate 3100 Old                  114.1     51.7     3.35    3525    99.3    61738   12269   1.022  !DANGEROUS LOAD-DO NOT USE!
IMR 7828 SSC                       105.5     52.0     3.37    3520    93.3    56612   13384   1.022  ! Near Maximum !
IMR 4895                            90.4     43.4     2.81    3509    99.9    59607   12038   1.023  !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-17                  91.5     46.0     2.98    3504    99.7    56720   12284   1.023  ! Near Maximum !
Hodgdon H4895                       88.0     42.2     2.73    3481   100.0    59518   11633   1.022  !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4831 SC                   105.3     51.0     3.31    3456    92.8    57471   12465   1.022  ! Near Maximum !
Hodgdon H4350                      101.8     47.8     3.10    3451    96.7    58442   12021   1.022  ! Near Maximum !

 

[Terry]

http://www.reloadersnest.com/