determining max cartridge pressure/velocity

[nishon]

Gentlemen I have a question that some may find rather silly but I really need an explanation.Here in RSA we use Somchem powder and the powder I use for my 30-06 and 243 is S365 which is similar to IMR4350.I do know that there is some difference in burn rate etc with the two powders although they similar.let's take the 165gn nosler partition bullet which I intend using on my 30-06.by using our somchem manual the max load gives a max velocity of around 2400fps yet on the american sites you guys are getting close to 2800-2900fps with your powders.
What I'm trying to ask is if I reach our somchem max load data and I do get around 2400fps and I'm not happy with that low velocity,can I go past the max recommended load to achieve higher velocity and use the primer as a guide for pressure signs.is there a max velocity standard for any cartridge or can you just try to gain velocity and just be on the lookout for pressure signs.please educate me on this subject.

 

[pyrotechnic]

Going above maximum recommended loads is an at your own risk endeavor. I have loaded and shot rounds above the published maximum without issue and currently do so in the 30-06. The data on this cartidge is usuw very conservative due to the many old firearms chambered for it.
That being said pressure curves aren't linear and burn rates are effected by pressure so if do you go over max, work up slowly carefully inspect your brass.

 

[SAPenguin]

What I'm trying to ask is if I reach our somchem max load data and I do get around 2400fps and I'm not happy with that low velocity,can I go past the max recommended load to achieve higher velocity and use the primer as a guide for pressure signs.is there a max velocity standard for any cartridge or can you just try to gain velocity and just be on the lookout for pressure signs.please educate me on this subject.

Dagse meneer hoe gaan dit? Lekker!
Yes i think you can increase your powderer charges SLOWLY by very small amounts, and keep a sharp eye out for pressure signs, like flattenend primers, expanded case heads, heavy bolt lifts / sticky bolts. Some pressure signs are not very obvious. Do some searching on the term "ladder test" too. Essentially you increase your grains of powder by 1% each shot and see where the bullets start grouping. So, for example, if your starting charge was 50 grains, then load your next rounds at 50.5, then 51, then 51.5 etc and fire them all at the same target. Some of them will fall into a group - this will be your accuracy "node". Please be moerse careful when doing this! How long is your barrel? You obviously wont get high velocity with a short barrel.

Now i am lus vir biltong...

 

[SAPenguin]

Also... there is a program called "quickload" that one can use to determine what pressures each loading will generate, but i think it is a fairly complex program to use and I am not smart enough to mess with it.

 

[SAPenguin]

also check this out... Long-Range Load Development

 

[pawprint2]

Also... there is a program called "quickload" that one can use to determine what pressures each loading will generate, but i think it is a fairly complex program to use and I am not smart enough to mess with it.

I guess the use of pressure guns/calibrated transducers/ref ammo etc. are a thing of the past! We just need a "quickload" program! I'm callingl BS.
Your chamber pressure has little to do with your velocity, if the powder mfg is calling a given powder/load max pressure, it is because it is at or near max pressure, they [the powder mfg] have a vested interest in publishing data that makes their product look great. To start to- ease past published maximum (and tested) loading data is done all the time, but at very small increments. Based on what you've posted, you'll never get another 400fps with this powder.

 

[4000fps]

One of the surest signs of being over pressure is erratic spread in your velocities (tested over chrono), which usually means poor accuracy too. So it isn't much good to chase 100fps only to have your groups open up. I know in the USA we have more options, but sounds like you need a powder with a different burn rate.

 

[nishon]

Thanks so much for the advise guys,much appreciated!
Gues I'll just go wd manufacturers specs and maybe try another powder,mayb something slightly faster burning than S365

 

[Greg Langelius *]

Thanks so much for the advise guys,much appreciated!
Gues I'll just go wd manufacturers specs and maybe try another powder,mayb something slightly faster burning than S365

I think a lot of good suggestions didn't get made. Knowing the purpose the load needs to serve would help.

It may be that peak velocity, for its own sake, could be counterproductive. As long as the bullet is designed for the desired purpose, and supersonic at the target, it could be adequate for its purpose at muzzle velocities that are less than the maximum attainable. Going for max/over max without a good reason is a classic path to premature bore/throat washout and may have a potential for mishap as well.

Before going into uncharted/inadvisable territory, make sure you have a real need for such a practice. In my humble opinion, a better strategy might be to stay within more conservative range and energy limits, or perhaps try with a more capable chambering.

Greg

 

[nishon]

Point taken guys,I'm just going to stick within specs for now.