Bullet Length and Case Capacity [Archive] - Glock Talk

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preventec47
06-07-2010, 02:49
Myself and a friend have been hypothesizing about various potential loadings with some
different powders but for the sake of discussion
we have picked AA#9 as an example.

Following are our measured case capacities
using Federal 10mm cases using a few different
powders we want to play with.

Below are calculated maximum volumes of AA#9
powder using various different length bullets.

1.26" (OAL) - .99" (case length) = 0.27" max bullet protrusion
assume .8” case internal depth

MAX of AA#9 grains w/o compression:

bullet .512 length = percent case capacity 70 - 15.89gr
bullet .55 length = percent case capacity 65 - 14.76gr
bullet .600 length = percent case capacity 59 - 13.39gr
bullet .650 length = percent case capacity 53 - 12.03gr
bullet .700 length = percent case capacity 46 -10.44gr

Weight of a full case of the following powders (Federal Case); without compression
AA 9 =22.7gr
AA 7 =23.6gr
800X =13.6 gr
VV 3N37 =18.5gr

LET ME REPEAT. the above powder weights
are simply the weight of the respective powders
that are poured into an empty case till full
and with the top leveled by scraping off sideways
with a straight edge. This is simply to show
the different powder densities without compression and also provides a basis for
calculations of case capacity remaining after
bullets are inserted.

In the above calculations, I simply calculated the
seating depth of each bullet and subtracted that
from the total case capacity to get a percentage
and then applied that percentage to the
measured full case volume for that particular
powder. I use an assumed internal depth of .8
inches.

I would like to see this msg made a sticky so
more bullet length data can be contributed for
each of the various manufacturers.

10mm Bullet Lengths---------------
( Definitions: solid = non-hollow )

Nosler 135 JHP .494 Inch
Nosler 150 JHP .535 “
Nosler 180 JHP .620 “
Barnes 140gr HP pure copper bullet .682"
Barnes 155gr HP pure copper bullet .732"
Hornady 155 XTP .555 “
Hornady 180 HAP .624 “
Hornady 180 XTP .624 “
Hornady 200 XTP .685 “
Precision Delta 165 FMJ .547"
Precision Delta's Solid 180gr bullet .595 "
Speer #4399 155gr TMJ .538"
Speer #4400 155gr GDHP .540"
Speer #4410 165gr TMJ .555"
Speer #4397 165gr GDHP .580"
Speer #4402 180gr TMJ .600"
Speer #4406 180gr GDHP .630"
Speer #4401 180gr GDHP Short Barrel .630"
( slower velocities for expansion)
XTREME 155gr 512 inch
Remington 155Grn Silvertip, .550 in length
GoldDot HP 155gr .546 in length

_The_Shadow
06-07-2010, 09:58
While that is good in therory it is not practical to actual loading and pressure development!

preventec47
06-07-2010, 16:19
Huh ? Not Practical ?
Well I agree "practical" could have a lot of different
meanings.
Shadow, please do explain what you think.

Let me pick a worst case example.
Lets say two 155gr bullets. You dont think it is "practical"
to know that one gives you 70 percent of case capacity
to work with and the other only 50 percent in your load
development ? ? ?

Or how bought another iteration. Suppose you are
contemplating a load. Wouldnt you like to know
if one has very little to no compression verses
one that might be impossible to compress as necessary
to make work ?

_The_Shadow
06-07-2010, 17:04
Sure the bullets total lenght is what determines what space is left...but that is not the total picture by no means.

The burn rate of powders is different from light loads to compressed loads. Therefore as they become compressed the characteristics changed, usually the powder burns cleaner closer to 100% comsumed and total pressure generated. If this doesn't remain within the proper pressure range then the results vary. The differences in the chambers, bullet jump to rifling and the bore/rifling itself of the various guns alone are enough to skew the results of the test.

Not all bullets are the same...FMJ's being shorter than HP's of the same weight and total copper being lighter than the same length of either.

Then the actual cases themselves that hold tension on the bullet for proper ignition, the case capacity for powder, primers used, tempature which the ammunition is being tested at, all affect the data to some point.

This is why person with gun "A" was able to go with this much of Powder "A" and get the results he/she got vs. what you or I get using the exact same recipe in our test.

What we see in print these days have been "LAWYERED" so much, that this is why we are left to fend for ourselves looking for our best performance (we know that the sweet spot exist) even though the published data falls short.

The data your posting can be very misleading to those reading what you are posting vs. what you're trying to say!

preventec47
06-07-2010, 17:43
Shadow,
I agree there are a dozen (maybe two) factors
influencing total performance. I just singled out two
that are directly intertwined irrespective of all the rest.

In trying to share some (what I thought would
be) some helpful FACTUAL info,
I laid out the facts purely as there is no
concept that could be more simple.

The longer the bullet the more space it takes up
in the case.
I also gave a specific example powder to
work with to show the direct relevance.

If you see ANYTHING that could be misleading
then by all means mention exactly what it is
so we can clear it up or restate
it in a more non-misleading manner.

I came here to learn from guys like you
but I am not purely a taker and can share some
analytical methods from my rifle days that may
not be required for success. I hope however at
a minimum, it makes for a better understanding.

_The_Shadow
06-07-2010, 19:04
preventec47 (http://glocktalk.com/forums/member.php?u=144152) wrote
Weight of a full case of the following powders (Federal Case);
without compression
AA 9 =22.7gr
AA 7 =23.6gr
800X =13.6 gr
VV 3N37 =18.5gr


I'm not trying to flame you or demean what you are trying to show, just to point out that people sometimes don't read and comprehend what they think they read. They could overlook very important keys, if not being scientific about their quest interpreting what is being shown.

Some unsuspecting person might take this to mean that you are loading to these levels instead of taking it to mean that this is what the case holds without a bullet on the casing, powder not packed, shaken or stirred from your test, on your scale.

I my quest to study data people have written needs to be scrutinized with a fine tooth comb, magnifying glass looking to see if all the pertinent data is there to start with. Then trying to compare that, to other known variables or reference data to quantify what I’m seeing. I do this looking to see if there was a typo, any missing data or substituted component or some other mistake, that throws up a flag.

Bottom Line, we are responsible for our own use of this information in every shape or form. But in this hobby, a simple mistake might be a person’s last! After well over thirty years of working in the hobby...I'm still trying to learn also!

Good luck, carry on...

ctkelly
06-07-2010, 20:51
Hmm....where did you get your data for length? Just curious because the Nosler 180 JHP I have measure in at .612". And did you debur the flash hole....I've seen some wicked burrs on winchester brass before (never played with federal pistol brass) and since AA#9 is so fine it could result in a slightly lower capacity if left alone.

preventec47
06-08-2010, 03:10
Hmm....where did you get your data for length? Just curious because the Nosler 180 JHP I have measure in at .612". And did you debur the flash hole....I've seen some wicked burrs on winchester brass before (never played with federal pistol brass) and since AA#9 is so fine it could result in a slightly lower capacity if left alone.

All of the bullet lengths were obtained from
tech support reps at the bullet manufacturers.
They all readily agree however that the data
provided is subject to manufacturing tolerances
and the the measurements provided are their
manufacturing objectives. The exception is
the XTREME bullet. Since I had some, I measured
directly with a micrometer and did not query the
manufacturer.

The lengths of all the Montana Bullets have
been promised and I should receive an email
any day now.

Regarding potential burrs.... I have no idea.

ctkelly
06-08-2010, 19:52
.547" for a Precision Delta 165 FMJ.

By the way....I see you referring to FMJ's, Rainers, and other various flat points as "solid" bullets. Since you say you are familiar with reloading magnum rifle rounds, I would hope you are well aware of the difference between a solid bullet and a Full metal jacket, Complete metal jacket, Plated flat point and so forth and so on.....a solid bullet is a mono-metal bullet, in rifles typically machined from brass or copper and used for deep penetration as there is no jacket or plating to sheer off/fragment/etc. Any jacketed (full or complete) or plated bullet is simply that..copper/bronze/brass/aluminum jacket or plating over a lead core..even if it does not have a hollow point, that does not make it a solid bullet.

Referencing another thread you commented on 135 grain bullets and noslers being noted for fragmentation....there is a simple reason for this, the 135's were never meant to be driven at 10mm velocity. It is a simple problem of over driving the bullet beyond its design. Take a GDHP short barrel bullet and launch it out of a 357 magnum 6" barrel and it will also fragment, typically on impact. Speer is well aware of this and offers loading data for varmint control. More than likely, a berrys/extreme/rainer or whoever plated 135 will do the same if it can even withstand the velocity....if it were a true solid, you would have a huge problem of over penetration.

Probably the only true solid bullet out there would be the barnes XPB bullet which is completely copper alloy, but has a large hollow point cavity so not a true solid bullet.

For someone who likes to play around with various loads, variables, etc I would suggest looking into Quickload. I have an outdated copy I have not upgraded but find it quite useful for toying around with different variables. I find it to be fairly accurate but there are some bugs in my old version that were hopefully fixed in the newest set. It is pretty customizable, so if you start getting all the little details put together that you are collecting you could have a fairly accurate setup for quickload.

Good luck.