Shooters Forum banner

Status
Not open for further replies.
61 - 70 of 70 Posts

·
Registered
Joined
·
18 Posts
Also, something for everyone to consider. I am loading my COAL at 2.915" and suggested is 2.84". This alone will create more velocity with the same pressure in each Cartridge is loaded with the same primers and powder. Bryan Litz explains this in an article he posted. Yes, I'm still going to do pressure testing, but I wanted to share.

Also, because of something that another person posted I feel I need to make this very clear:

THE INFORMATION AND DATA I POST IS NOT TO BE TAKEN AND USED FOR ANOTHER RIFLE. THIS DATA IS LOADED AND TUNED FOR MY CHAMBER AND BARREL ONLY. IF YOU CHOOSE TO USE THIS DATA, YOU ARE ASSUMING YOUR RIFLE IS THE SAME AS MINE AND THAT WOULD BE A MISTAKE.

I hope I made that excessively clear. If anyone else thinks that I am posting "generic" load data, feel free to message me.
 

·
Registered
Joined
·
7,712 Posts
Please pardon me for intruding on this good thread.

We need to be responsible for what we do (I think so anyway). I explore "unknown territory" now and then. Have learned from experience to NOT DO SO NAKED! Socks at least! Helmet and jock-strap preferred.

I would feel horrible if I learned about some idiot using reload data I had posted for my rifle that cause harm to another firearm enthusiast. Is mostly why I don't do that.

Careful is better than careless (I think).
 

·
Registered
Joined
·
13,290 Posts
To err is human...to err on the side of caution is wisdom.

I load for several wildcat cartridges, or cartridges in load configurations that are not otherwise published data. I am always hesitant to mention the specifics of loads used in those cartridges, and preface any such mention with the standard, boilerplate warnings.

This is particularly true if the load I am using is obtaining performance not usually attributed to a given cartridge/bullet combination. YMMV
 
  • Like
Reactions: Darkker

·
The Shadow
Joined
·
7,948 Posts
Also, something for everyone to consider. I am loading my COAL at 2.915" and suggested is 2.84". This alone will create more velocity with the same pressure in each Cartridge is loaded with the same primers and powder.
.
For the sake of discussion and consideration of things.

Is the "Suggested" COAL actually a suggestion, is it as tested, or is is SAAMI minimum? They are and mean different things to the results.

It isn't as easy as simply "getting more velocity with the same pressure", simply because of a COL change. But I'm excited for you to actually record some pressures.


This example may (hopefully) help visualize things a bit for you. Things aren't this simple, and don't happen exactly this way; but for very oversimplified explanation sake...

Lets say that a loaded cartridge in a rifle has a starting "case" pressure of 65,000 psi. There will be some amount of gas that blows around the bullet prior to it engaging the rifling and sealing things off. So the "starting" pressure in the case is 65K, but due to the by-passing of gas, the system operational pressure that the rifle experiences(the building pressure behind the bullet), will be less; for argument sake, lets say that the operational pressure is 58,000 psi.

If you then used that "same" load, but seated the bullet out of the case further, the gas bypass will be less. So now the operational pressure of the rifle with that load, is 63,000 psi. This is because there is less gas escaping around the bullet before rifling engagement.

So is the pressure "The same"? From a technical argument standpoint, the beginning case pressure may NOT have changed(althought bullet seating depth, or case capacity, can change burning rates). However the system operational pressure that the rifle experiences when the shot is fired, in fact DOES change.

When you cast your chamber, you can compare the dimensions to the SAAMI reference chamber dimensions and see how "sloppy" your chamber may or may not be. If the min spec universal reciever was used, you can "see" how much extra gas bypass you may have with a looser chamber. Thus requiring more pressure in your rifle, to match the velocities stated in the book.

If you have a minute, jump over to the SAAMI.org.
Read about MAP, MPLM, and MPSM. That is also where you can find and purchase reference ammo for calibration of your Pressure Trace system.


Cheers
 

·
Registered
Joined
·
18 Posts
Also, something for everyone to consider. I am loading my COAL at 2.915" and suggested is 2.84". This alone will create more velocity with the same pressure in each Cartridge is loaded with the same primers and powder.
.
For the sake of discussion and consideration of things.

Is the "Suggested" COAL actually a suggestion, is it as tested, or is is SAAMI minimum? They are and mean different things to the results.

It isn't as easy as simply "getting more velocity with the same pressure", simply because of a COL change. But I'm excited for you to actually record some pressures.


This example may (hopefully) help visualize things a bit for you. Things aren't this simple, and don't happen exactly this way; but for very oversimplified explanation sake...

Lets say that a loaded cartridge in a rifle has a starting "case" pressure of 65,000 psi. There will be some amount of gas that blows around the bullet prior to it engaging the rifling and sealing things off. So the "starting" pressure in the case is 65K, but due to the by-passing of gas, the system operational pressure that the rifle experiences(the building pressure behind the bullet), will be less; for argument sake, lets say that the operational pressure is 58,000 psi.

If you then used that "same" load, but seated the bullet out of the case further, the gas bypass will be less. So now the operational pressure of the rifle with that load, is 63,000 psi. This is because there is less gas escaping around the bullet before rifling engagement.

So is the pressure "The same"? From a technical argument standpoint, the beginning case pressure may NOT have changed(althought bullet seating depth, or case capacity, can change burning rates). However the system operational pressure that the rifle experiences when the shot is fired, in fact DOES change.

When you cast your chamber, you can compare the dimensions to the SAAMI reference chamber dimensions and see how "sloppy" your chamber may or may not be. If the min spec universal reciever was used, you can "see" how much extra gas bypass you may have with a looser chamber. Thus requiring more pressure in your rifle, to match the velocities stated in the book.

If you have a minute, jump over to the SAAMI.org.
Read about MAP, MPLM, and MPSM. That is also where you can find and purchase reference ammo for calibration of your Pressure Trace system.


Cheers

Thank you, I'll definitely get over there and take a read on that. I understand what you are talking about with the gas blow by and its affects on pressure. If you havent read this yet, take a minute to read through it.

http://www.bergerbullets.com/effect...coal-and-cartridge-base-to-ogive-cbto-part-1/

I'm not arguing that you are incorrect with you're statement, I'm just letting you know what I have learned on a couple of different articles written by people with a background in ballistics.
 

·
Registered
Joined
·
18 Posts
I apologize for putting any load data on here, for everyone concerned. I tried to delete the posts, but was unable to. It wont happen again.
 

·
The Shadow
Joined
·
7,948 Posts
Yes, but there are some things to consider.
I'm not sure of the current M.O. but Berger WAS calculating pressures with software, not measuring; in another forum Eric Streckler said that Walt (at least at one time) was using QuickLoad.
Unless there has been an update to Hartmut's system, my understanding was there was a formula in there that unilaterally had pressures increase as seating depth increased; which isn't quite right.

That does happen, but isn't simple and the same in every case. UncleNick has a graph from IIRC Dr. Brownell floating around here somewhere(or I can get it when I get home) which shows testing in the 30-06. From the lands, pressures are high, and decrease the deeper you seat things; until a point when the curve goes the other way.
You can't say they do rise with increased seating depth, but you can't say that they don't; it depends.

That's the trouble in life, no free lunches, and it always depends.



Second page has the chart referenced and posted:

https://www.shootersforum.com/handloading-procedures-practices/220648-bullet-seating-depth-2.html
 

·
Registered
Joined
·
46 Posts
I have never understood why people would move up to the 8mm diameter and yet continue to use bullet weights that have worse Ballistic Coefficients and sectional densities than the same weights in the .308 diameter. It seems to me that below 200 grains, you are better off with a .30 cal. cartridge. Any of the .300 magnums do things with a 200 grain bullet that cannot be matched by any 8mm of the same weight.

If I was to use a .325WSM, I would want to use heavier bullets than I could shoot in a .300 Win.
I stumbled on this old post and it made me laugh.Plenty of folks not concerned about ballistic coefficient and sectional density shoot very accurately and harvest tons of game. Always have and always will. Better yet let me phrase it as the person that posted did.” I have never understood why people move up “ to technical aspects when it is not necessary- LMAO. Must make them feel smart.
 

·
The Shadow
Joined
·
7,948 Posts
I stumbled on this old post..
We know... You stumbled upon it right after you joined. Now you appear to be bored and trolling.
Replying back to back, with nothing substantive to add either time. This isn't the first time you've been warned about old threads or snarky responses.

Take some time off and decide if you are capable of acting like the rest of the boys and girls here, or if you need to find somewhere else to play.

Thread closed
 
61 - 70 of 70 Posts
Status
Not open for further replies.
Top