Things to twist your mind in knots

John Y Cannuck

John Y Cannuck

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This thread is to get people thinking about what they are doing. Investigate that load, study the results on paper, but look beyond that. Look at the case, look at the bore, look at the snow in front of your shooting position. Try to decipher what went wrong, and fix it, understand!.

What goes on in the case when you pull the trigger?

The primer fires, the powder burns, and the bullet moves, simple right?

But there are so many tiny variables that make internal ballistics interesting.

In a big case, is there so much powder room that the powder was well away from the primer?

What happens if I compress this powder?

Why do they have a recommended minimum charge?

Did heat and pressure build enough that the powder burned completely?

Did the bullet move easily, reducing pressure by increasing the volume?

If you are using a plain base lead bullet, was the powder used expanding the bullet base and sealing the bore, or was it pushing
past the bullet deforming it, and causing bad groups and or leading?

Is the cast bullet soft enough? Is it hard enough for the velocity you are trying to reach?

What about OAL? What's that stand for anyway? :)
If your feed will accept it, can you get closer to the lands with that bullet?

How does the bullets ogive design affect OAL with regard to it's proximity to the lands?

When is faster powder better than a slower one, and vice versa.

Why if you go to the range with five different powders loaded under the same bullet, in the same cases, with the same primer are the groups so very different?
 
Additional questions might be:

What benefit is there to a uniform bullet pull weight?

What is the effect of velocity if I anneal my case necks . . . and if I don't?

What effect does crimping have on accuracy?

What effect does the rate of twist have on pressure?

what is the effect on pressure and accuracy if I don't trim my brass?

When is full length resizing more beneficial that neck sizing?

What happens if I shoot cast in a fast twist barrel?

What is the effect of a fast twist barrel on terminal performance?
 
What happens if I use jacketed bullet data for a cast bullet of the same weight?

Is it safe to use cast bullet data for a jacketed bullet of the same weight?

Why is a doesn't a fast powder give better velocity than a slow powder?

Why does a handload that has consistent velocity shot to shot not always shoot better than one that does not?
 
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What difference if any is there from loading for Long Range versus Short Range?

What do they mean by 100% load density?

Effects of flash hole deburring versus not?

Effects of primer pocket uniforming versus not?

Effect of trimming after every firing or not?

Bumping the shoulder back 3 thou versus 1 thou?

How much of an effect does 2 or 3 tenths of a grain make in a magnum size cases versus a smaller case capacity?

Neck tension. Some powders like more neck tension than others?
 
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Why is it ok for OAL to vary slightly with the same bullet that was made in the same mould and reloaded with the same press and seating die 1 minute after the one before it?
 
How can I accurately determine my bullet seating depth when the bullet noses are variable in length like hollow point match bullets?

Is determining a powder charge by weight really more accurate than measuring it by volume?

Why do I get higher velocity from my short barreled revolver than I get from my long one with the same load?

Why do some bullets need sleep time.

How many reloads can I get from a single brass cartridge?

Why doesn't a faster powder give me more velocity in a short barreled rifle with the same bullet weight?

Why doesn't 100% powder density, or 110% for that matter, produce the best accuracy?

Can I tumble loaded rounds?

Why does one standard primer produce better accuracy than another?

Why is a "military primer" better for gas guns?

When I change primers, should I work my load up again?

Should I get a progressive press?

Should I get a turret press?

What's more accurate, a balance beam scale or a digital scale, ?

Does the difference matter?
 
can rjg333 reload in his sleep? Can he answer all the questions? Do the answers to the questions lead to still more questions?


Seriously, This thread is to get you guys thinking. When a load does not perform, don't just grab another can of powder, think it through.
Quite often there are clues that will tell you why you made the wrong choice in component, or methodology.
 
How can I accurately determine my bullet seating depth when the bullet noses are variable in length like hollow point match bullets?

seat based on a point further down the bullet


Is determining a powder charge by weight really more accurate than measuring it by volume?

yes, you are getting the same number of pieces of a uniform powder using weight, if you took a volume measure and stacked every piece of a stick powder neatly inside until full, it could weigh alot more and have more energy in it than an unsettled measure of the same size might, some powders will be less effected based on grain shape and size

Why do I get higher velocity from my short barreled revolver than I get from my long one with the same load?

tighter or looser bore on one of the other (long ones too loose and has some blow by or is too tight and has more friction for the bullet) or perhaps its an issue with the long barrel having a large cylinder gap, and finally it could be a chamber dimension issue. or some combo of the above

Why do some bullets need sleep time.

because purple, and a cat is a horse with no tail

How many reloads can I get from a single brass cartridge?

1 to several hundred, some very very tight chambered guns for competition will shoot several matches on the same case, with the shooter reloading it between shots. reducing the effect of different brass. many autoloading pistol cases never fail, but are just lost in the grass after being loaded 10 or more times. i know a guy with a .30 carbine. he buys brass in sets of 100, and reloads them untill he losses most of the batch of 100. loads it again and puts it aside for a rainy day. he kept one set that is down to about 4 rounds now and they are on their 20 something reload

Why doesn't a faster powder give me more velocity in a short barreled rifle with the same bullet weight?

could be that you are burning it all, and the bullet is coasting and slowing down in the barrel, but i doubt it. especially in a sbr.
another possiblity is that the max load for the fast powder does not give the same energy due to a higher but shorter pressure spike as the slow one

Why doesn't 100% powder density, or 110% for that matter, produce the best accuracy?

it may result in the bullet leaving the barrel at a bad point in the guns harmonic, so a bullet leaves just as the barrel is starting its down swing and one that is a few feet per second slower leaves almos at the bottom of the barrels down swing so the angle and velocity difference compound and make the shots fall further appart


Can I tumble loaded rounds?

yes

Why does one standard primer produce better accuracy than another?

could be as simple as how long the batcxh was mixed that day. if you get some that have been mixed for a week and the moisture content is the same and every primer has exactly the same compound it will be better than one that was only mixed for 10 minutes and one primer has more or less of each chemical than the last

Why is a "military primer" better for gas guns?

not sure what you mean, but if you mean crimped, its because they are less likley to come free from the case after firing, so they cant get caught up in the gun, if you mean harder, its due to potential slam fires

When I change primers, should I work my load up again?

depends, if its for your minute of pie plate SKS, no, if you are hunting unicons at 1000 yards and you only want to shoot of the horn without killing them, yes. you choose where you fall in there

Should I get a progressive press?

sure

Should I get a turret press?

sure

What's more accurate, a balance beam scale or a digital scale, ?

accurate? depends which one was zeroed most recently. precise? beam scale

Does the difference matter?

not as far as most people can shoot. if it makes you more confidant to have one or the other, use it. also, consider having your bullets blessed by a witch doctor
 
If we use the same powder and same bullet weight, why would one bullet manufacturer have low and medium velocity loads that are listed as the higher velocity or exceeding maximum loads from the other bullet manufacturer?
** this one I actually need an answer to!!**
 
Sounds like my 3 year old when he comes down to daddys
Loading room! Who/what/when/where/why!?.........WHYYYYY?!
Lol!

So many questions,so little time!

When all of these questions are put on the screen, it helps me realise just how much experience I have and how much I take for granted! It will be a long learning curve for my son, but I look forward to seeing those "AHAAA! I understand now!" moments in his eyes!
 
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hoochie said:
If we use the same powder and same bullet weight, why would one bullet manufacturer have low and medium velocity loads that are listed as the higher velocity or exceeding maximum loads from the other bullet manufacturer?
** this one I actually need an answer to!!**
Click to expand...

This is because not all bullets of the same weight have the same frictional coefficient, there are thicker and thinner jackets, there are homogenous bullets and there are greatly varied bearing surface lengths as well as different jacket materials. All these factors affect the frictional coefficient of the bullet which affects the pressure curve and peak, of the load.
Also each manufacturer uses a different rifle to test loads and pressures and as we all know, there can be as much as 200 fps difference in two rifles of the same caliber, using the same load. Not all barrels are equal, in fact virtually no two barrels are equal.
 
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