Sierra reloading manual 6th edition - app for your phone

[borbal]

The app seems to have an internal ballistics engine of some sort, where you can slide the muzzle velocity slider up and down and the load for a quite large selection of powders changes to give a load that will achieve the current muzzle velocity.

Not free - but for under £6 for a year's use, I was happy to pay to see how it works out.

I tried it with a 308 Win and a 150 grain MK bullet and ran the loads given for the various powders for a 2730 ft/sec velocity through P-Max internal ballistics. Of the 16 powders listed, 11 of them are listed in P-Max and the P-Max velocities were consistently about 50 to 100 ft/sec up on the given velocity - all except RL15 which was a 100 ft/sec down on the given velocity.

Anybody tried it or have any information on what is going on under the hood?

 

[muddy42]

It was free when I downloaded it last week.

 

[borbal]

The download is free - but you only get the 204 calibres for free. If you want anything (everything) else, you have to pay.

 

[25 Sharps]

The app seems to have an internal ballistics engine of some sort, where you can slide the muzzle velocity slider up and down and the load for a quite large selection of powders changes to give a load that will achieve the current muzzle velocity.

Not free - but for under £6 for a year's use, I was happy to pay to see how it works out.

I tried it with a 308 Win and a 150 grain MK bullet and ran the loads given for the various powders for a 2730 ft/sec velocity through P-Max internal ballistics. Of the 16 powders listed, 11 of them are listed in P-Max and the P-Max velocities were consistently about 50 to 100 ft/sec up on the given velocity - all except RL15 which was a 100 ft/sec down on the given velocity.

Anybody tried it or have any information on what is going on under the hood?

Not really sure what you are asking.

I have used the app for quite a while as Sierra are pretty much the only source of published data for 25-45 Sharps (even Sharps rifle company took their data down).

The data given changes as you slide the slide and at the high end loads are denoted as high pressure with 2 red asterisks. This is actual tested load data that they have tested. The p-max calculator is just a mathematical simulation so won’t necessarily reflect the data.

Looking at it the p max calculator is not even specific to bullet. A 150 boat tail bullet will differ to a flat base or a lead free.

 

[Dr. Strangelove]

Looking at it the p max calculator is not even specific to bullet. A 150 boat tail bullet will differ to a flat base or a lead free.

That’s why you need to calculate usable case capacity with the bullet you’ll be using. Once I’d done that accurately, PMax was 44fps off my actual data.

 

[borbal]

Not really sure what you are asking.

Well, I don't suppose Sierra recorded the muzzle velocity for powder increments of a tenth of a grain between minimum and maximum charges, then stored that as a look-up table in the app. That would be an awful lot of work.

I would suppose they would have some algorithm which gives an estimate of the muzzle velocity for charges between the known velocities at minimum and maximum charge.

One would be tempted just to draw a straight line between the two points of minimum and maximum velocity as a function of charge weight, but that would not do as powder energy goes as the charge weight, whereas muzzle energy goes as the square of the muzzle velocity, and you would expect muzzle energy to be some function of charge weight.

I could go digging at the numbers the Sierra app produced and see what sort of power law I can fit to them, but I had hoped to save myself the energy by somebody putting up their hand and saying, "Ah yes, it is quite simple really and it goes like this..."

 

[Dr. Strangelove]

I could go digging at the numbers the Sierra app produced and see what sort of power law I can fit to them, but I had hoped to save myself the energy by somebody putting up their hand and saying, "Ah yes, it is quite simple really and it goes like this..."

It’s probably a long shot but have you thought about contacting Sierra to ask? By explaining your background you might get more traction than the average customer.

 

[25 Sharps]

Well, I don't suppose Sierra recorded the muzzle velocity for powder increments of a tenth of a grain between minimum and maximum charges, then stored that as a look-up table in the app. That would be an awful lot of work.

I would suppose they would have some algorithm which gives an estimate of the muzzle velocity for charges between the known velocities at minimum and maximum charge.

One would be tempted just to draw a straight line between the two points of minimum and maximum velocity as a function of charge weight, but that would not do as powder energy goes as the charge weight, whereas muzzle energy goes as the square of the muzzle velocity, and you would expect muzzle energy to be some function of charge weight.

I could go digging at the numbers the Sierra app produced and see what sort of power law I can fit to them, but I had hoped to save myself the energy by somebody putting up their hand and saying, "Ah yes, it is quite simple really and it goes like this..."

Ah I see now.

I personally would just use the data and test with the bullet and powder of choice

 

[25 Sharps]

That’s why you need to calculate usable case capacity with the bullet you’ll be using. Once I’d done that accurately, PMax was 44fps off my actual data.

How do you accurately calculate the volume of a boat tail bullet? Either way the bearing surface will vary between a boat tail, flat base and lead free of the same weight so friction will vary which will change pressure and velocity.

Too much maths for me, I'd rather just spend the money on quickload!

 

[Dr. Strangelove]

How do you accurately calculate the volume of a boat tail bullet? Either way the bearing surface will vary between a boat tail, flat base and lead free of the same weight so friction will vary which will change pressure and velocity.

Too much maths for me, I'd rather just spend the money on quickload!

You don’t! You seat your chosen bullet to your chosen seating depth in a case with no primer. Put the case without water on your scales using some putty etc then tare/zero them. Then use a syringe to fill the case with water and you’ll get the usable case capacity in grains of water.

If you want a syringe PM your address and I’ll pop one in the post - got more than I’ll ever use!

 

[25 Sharps]

You don’t! You seat your chosen bullet to your chosen seating depth in a case with no primer. Put the case without water on your scales using some putty etc then tare/zero them. Then use a syringe to fill the case with water and you’ll get the usable case capacity in grains of water.

If you want a syringe PM your address and I’ll pop one in the post - got more than I’ll ever use!

Nice.

Thanks for the offer but I have 2 kids so plenty from Calpol. Quick load is much simpler, fill the case with water so the meniscus is at the case mouth. Input that figure and the bullet and the programme works it all out for you

 

[borbal]

You know, it is just as easy to measure the *usable* case capacity as it is to measure the case capacity to overflowing. Here is a youtube video showing you how to do this.

Once you have the usable case capacity, you don't need the extra measurement of the COAL and the exact make and product number of the bullet.

Since you need to measure some sort of case capacity for whatever program or app you use, why don't just measure the usable case capacity? Then you can use a program that is free to use on anything that has a browser, whatever the operating system.....

Simples!

 

[25 Sharps]

You know, it is just as easy to measure the *usable* case capacity as it is to measure the case capacity to overflowing. Here is a youtube video showing you how to do this.

Once you have the usable case capacity, you don't need the extra measurement of the COAL and the exact make and product number of the bullet.

Since you need to measure some sort of case capacity for whatever program or app you use, why don't just measure the usable case capacity? Then you can use a program that is free to use on anything that has a browser, whatever the operating system.....

Simples!

The exact make and model of bullet still has a bearing due to friction, for what it costs of take quick load any day of the week

 

[borbal]

The exact make and model of billet still has a baring due to friction, for what it costs of take quick load any day of the week

And how does QL adjust the bearing friction according to the bullet model....?

 

[25 Sharps]

And how does QL adjust the bearing friction according to the bullet model....?

By adjusting for the bearing surface of the bullet?

 

[borbal]

By adjusting for the bearing surface of the bullet?

That would be a reasonable approach.

But QL does not have a separate function for bullet friction. It uses the 'Sebert factor' which accounts for losses in a general way. This from the manual:

QuickLOAD accounts for energy losses by use of a weighing factor (also known as Sebert's factor). A portion of the propellant charge is added to the bullet mass. By adding a part of the charge mass to the projectile mass, Sebert's factor accounts for losses from bullet, barrel and ammunition heating, flowing propellant gas kinetic energy and friction - as is often the case in physics, this calculation uses an "effective mass".

P-Max, on the other hand, does have bullet friction in the barrel as a separate variable. If you think about it, bullets are much the same shape and so for a given bullet density, the bearing area will depend on the calibre and the bullet weight. P-Max has a function to account for bullet friction in this way.

 

[25 Sharps]

That would be a reasonable approach.

But QL does not have a separate function for bullet friction. It uses the 'Sebert factor' which accounts for losses in a general way. This from the manual:

QuickLOAD accounts for energy losses by use of a weighing factor (also known as Sebert's factor). A portion of the propellant charge is added to the bullet mass. By adding a part of the charge mass to the projectile mass, Sebert's factor accounts for losses from bullet, barrel and ammunition heating, flowing propellant gas kinetic energy and friction - as is often the case in physics, this calculation uses an "effective mass".

P-Max, on the other hand, does have bullet friction in the barrel as a separate variable. If you think about it, bullets are much the same shape and so for a given bullet density, the bearing area will depend on the calibre and the bullet weight. P-Max has a function to account for bullet friction in this way.

Not really as a flat bullet will generally have a different bearing surface to a boat tail of the same calibre and weight.

As for not accounting for friction the ‘friction-proofed’ check box does nothing then?

I get it you’re a pmax fan, I’m a QL fan, we can probably leave it there as I’m not really into cock measuring, I usually lose....

 

[Dr. Strangelove]

I get it you’re a pmax fan, I’m a QL fan, we can probably leave it there as I’m not really into cock measuring, I usually lose....

I suspect one of the reasons that @borbal is a PMax fan is because he created it!

I also suspect that he will forget more about internal ballistics than many on SD will ever know, myself included!