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Pulse Rifle Ammo; Reality, math and fantasy...
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Author:  scoffman [ Thu Jan 14, 2016 9:31 am ]
Post subject:  Pulse Rifle Ammo; Reality, math and fantasy...
A while ago I was working on an accessory prop to go along with the rest of my Colonial Marine gear; as I had a surplus 7.62mm (.30 cal) ammo can kicking around I decided to create a paint stencil for it and the Pulse Rifle ammo. The problem was figuring out how many rounds it could hold. I have a copy of the CM Tech Manual, but it didn't specify the 'actual' size of the round other than it's 10X24mm caseless (which we already knew.) So I looked up specs on real caseless ammo and looked at images of some of the replica ammo that's been done for the PR (such as Matsuo's) and came up with some of my own numbers. I calculated given a round dimension of 12mm x 12mm x 27mm, one could fit 990 rounds into the ammo can. (For you anal retentive types, here's the math: the interior dimensions of the ammo can are 6.75" x 10" x 3.5" and that's from online specs; my own measurements are slightly smaller but are within .125 (1/8) of an inch - my own measurement of the internal height was 6.625", so not off by too far. So doing some conversion, that's 171.45mm x 254mm x 88.9mm = 3871443.87 mm^3. Divide that by 3888 mm^3 (12mm x 12mm x 27mm) and it comes out to 995.742.)

Image

Then I just recently received Derrick Baena's M41-A manual and his specs of the PR ammo are 14m x 14mm x 30mm. Do the math on that and it takes the amount of rounds that could fit in the ammo can down to 658; quite a bit of difference! Of course this is all speculation (and of course fantasy), but still intriguing (at least to me.)

Which lead me to make some measurements as to the PR magazine itself. As depicted in many images for the Spulse, HCG and Matsuo PR's, the magazine is quite a bit smaller than the well on the PR that it is inserted into. The magazine looks to be around 1.5" x 1" X 7" (and I'm speculating that given that I'm measuring off of an AirSoft PR mag, but I think I'm being fairly generous.) You do the math on this one, and you'll find that the magazine could only hold about 30 rounds using Derrick's ammo specs. Even given the original specs I was using for the M309 rounds, it could only fit about 44 rounds.

Measuring the mag well on my AirSoft PR, I came up with the max dimensions of 2 5/8" x 1 3/4" x 7" - and doing the math on that I calculated that if the well could accommodate a magazine of close dimensions, the max amount of rounds that could be fitted into it (given a round size of Derrick's 14mm x14mm X 30mm) would be 89. Pretty damn close to 95 rounds (or 99 if you think we could stuff that many in there; which is of course pipe dream, but hey - you gave it a try) but no cigar!

-scoff
Author:  retrogarde [ Tue Jan 26, 2016 4:16 pm ]
Post subject: 
I've always wondered about that. 95 always seemed a bit unrealistic, but it's a fun number. I have a few of Matsuo's bullets and also wondered what the true max capacity could be. The problem is that we do see the magazine attached to the butt plate when Hicks instructs Ripley to "slap it in hard", so we're kind of stuck with the narrower dimensions.
Author:  bigbisont [ Tue Jan 26, 2016 5:03 pm ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
Despite the fact the tech manual says 10mm x 24mm, I don't buy it (unless I missed a screen ammo can stating this, anyways).
Why would they need to be that long? 24mm seems excessive.

Consider these points:
-The Pulse rifle fires 'pulses' to activate the round (or activate a process in the chamber to propel the round), likely negating the need for bulky combustible materials built into the cartridge of the bullet.

If we assume the round isnt much longer than it is wide, we have a few more options as it takes up less than half the space of the above calculated 10x24 size and therefore a little over double the previously calculated 44 round capacity. Getting warmer!

-In the novelization, during the training scene Hicks tells Ripley that they like "us" to collect the empty mags and not leave them behind because "They are expensive".

From the magazine comment from Hicks, we can safely assume the magazine itself plays an active roll in the loading and cycling of rounds beyond a simple spring fed system. If they are 'expensive', surely it is because they have moving parts and tech built into them. Perhaps the kind of tech in the over-sized mag base that is able to move rounds not just from the bottom up, but perhaps from the rear of the mag forward into the active feed! I think it is plausible.
(speaking in a "its the future" sense, of course).


I know I'm not the first to say that theory as I have seen a replica pulse mag that featured a 'triple stack' look of rounds poking out the top. To me, the idea of a triple stacked mag (3 columns and 3 rows, 11 rounds vertical stacked in each = 99 capacity) makes all the sense in the world based on what we know. That oversized base could easily move the back rows forward as the front rounds are expelled.

Short them a few to 95 so as to prevent loading to the max and reduce jams, and you are rolling! All makes perfect sense. You know...if you want it to with it all being fiction and all.
Author:  577_ops [ Tue Jan 26, 2016 7:14 pm ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
Regarding the 99 capacity (3 columns and 3 rows, 11 rounds vertical stacked in each = 99 capacity)

If you look at Spat's Spare Pulse Rifle Magazine you can already see 2x3 per stack giving a good indication of what
size the ammo would actual have with this kind of magazine.

The 99 was for me always a statement that in the future the guns would have significant capacity more than today.
That this is not matching with 10x24 is another story.
Author:  bigbisont [ Tue Jan 26, 2016 9:48 pm ]
Post subject: 
It must have been spats that I was thinking of when I said I had seen one with stacked rounds before.

Personally that is how I like to think it works. The front rounds are loaded and the mag base moves the next column up to take their place after they are fired..
Author:  88reaper88 [ Wed Jan 27, 2016 12:45 am ]
Post subject: 
I've always imagined them as small pastel like things that extend when fired, similar to those collapsible cups:
Image
Author:  scoffman [ Fri Jan 29, 2016 6:22 am ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
Hey guys,

I REALLY appreciate your input on this hypothetical question as to how large the rounds of the PR are.

I really did just start out trying to figure out what would be an appropriate amount of PR ammo that could conceivably be stuffed into a standard ammo can so I could create a paint stencil for it (and that's speculating that an M19A1 ammo can would still be in use in the future - but since it's been around as long as it already has, it almost seems a sort of reverse engineering: "We've got hundreds of thousands of these ammo cans kicking around, what can we develop that will fit into them? Seems a waste to throw them all away..." Retrofitting seems a military pre-occupation.) :)

Think about it: ' The .30 caliber M19 / M19A1 steel ammunition can / box was developed to deliver belts of 250 .30-06 cartridges for the .30 Cal. Browning machine guns and was later used for the NATO equivalent 7.62mm rounds for the M60 machine gun and other weapons.'

I'm glad my post has sparked some amount of debate; bigbisont I must say I'm only using what source material that is available to me, specifically the CM Tech Manual and Derrick's M41-A manual; you have to have a starting point! Other than my own eye-balling of pictures of the size of the PR magazine, Matsuo's rounds, etc. :)

So here's another hypothetical explanation; let's suppose that the 24mm length is totally bogus. I'm still going off the idea that the PR round is encapsulated within a propellant - a "caseless" round. If the round is indeed 10mm, then if it is encased with 2mm of propellant -that'd be 12mm x 12mm x Y per round. So that if they were stacked side by side, it still wouldn't add up. Not to 99 rounds per magazine.

I'm just saying...

scoff
Author:  scoffman [ Fri Jan 29, 2016 6:35 am ]
Post subject:  Re:
88reaper88 wrote:
I've always imagined them as small pastel like things that extend when fired, similar to those collapsible cups:
Image


Pastels are colors having a soft, subdued shade. What are you referring to?

1. a color having a soft, subdued shade.
2. a kind of dried paste made of pigments ground with chalk and compounded with gum water.
3. a chalklike crayon made from such paste.
4. the art of drawing with such crayons.
5. a drawing so made.
6. a short, light prose study or sketch.

;)
Author:  Alien1099 [ Fri Jan 29, 2016 11:39 am ]
Post subject:  Re:
88reaper88 wrote:
I've always imagined them as small pastel like things that extend when fired, similar to those collapsible cups:
Image

That would be the opposite of anything close to optimal for a bullet, especially an armor piercing one which relies on a hard/dense spitzer (pointed) tip. Even if you could work out the design, it just wouldn't make any sense at all.
Author:  88reaper88 [ Fri Jan 29, 2016 1:35 pm ]
Post subject: 
It's fucking sci-fi, anything goes
Author:  Russ Krook III [ Fri Feb 05, 2016 1:51 am ]
Post subject: 
I think it was Alex Ko who did a 3D model of the ammunition capacity. The mag was motorized vertically
and I believe the rounds were a shortened, wrap around caseless design like Matsuo made and double
stacked or triple stacked in the magazine.

And... Sci-fi. :)
Author:  scoffman [ Fri Feb 05, 2016 12:06 pm ]
Post subject:  Re:
88reaper88 wrote:
It's fucking sci-fi, anything goes


Sorry if I pissed you off or something, it was just a hypothetical question/proposition. I didn't mean to offend or annoy. I apologize for my attempt to bring a little bit of humor into the discussion.

scoff
Author:  Russ Krook III [ Fri Feb 05, 2016 4:08 pm ]
Post subject: 
No worries mate. :)
Author:  Caramac [ Fri Feb 05, 2016 6:39 pm ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
A few years ago I saw a pistol that used horizontally stacked ammo, the Metal Storm pistol, a similar setup could be in the PR and would be case less ammo.
Author:  88reaper88 [ Fri Feb 05, 2016 8:45 pm ]
Post subject:  Re: Re:
scoffman wrote:
88reaper88 wrote:
It's fucking sci-fi, anything goes


Sorry if I pissed you off or something, it was just a hypothetical question/proposition. I didn't mean to offend or annoy. I apologize for my attempt to bring a little bit of humor into the discussion.

scoff


Wasn't directed at you mate! I liked your post :)
Author:  scoffman [ Tue Feb 09, 2016 3:00 am ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
Ah, thanks guys... I guess I just misread the thread a bit. :oops:

I've pretty much given up on trying to figure out what an individual round's dimension would actually be and have decided just to go with the idea that the mags hold at maximum 99 rounds. bigbisont's comment of "From the magazine comment from Hicks, we can safely assume the magazine itself plays an active roll in the loading and cycling of rounds beyond a simple spring fed system" made sense to me the more I thought about it. From there I then calculated that the ammo can is able to hold 6 magazines, and so that's 594 rounds. Just got to update my stencil and change Cartons to Magazines and I should be good to go with the updated version. :)

Thanks for all your input and suggestions!

-scoff
Author:  Moosh89 [ Tue Mar 15, 2016 12:10 am ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
So I've ripped myself a personal copy of my Alien Anthology Bluray collection so I can get HD screens for reference for a few things I'm working on and I grabbed this. Might add a little fuel to this topic!

Attachment:
Pulse Rifle Ammunition Anthology.png
Pulse Rifle Ammunition Anthology.png [ 874.65 KiB | Viewed 8522 times ]


I'll be making another thread of a few more screens I've found interesting/informative

They've stacked them 3 across ;)
Author:  retrogarde [ Tue Mar 15, 2016 12:38 am ]
Post subject: 
Nice one Moosh! I was all excited about the starmap you see on the BluRay menu, but it was actually cribbed from a fan-made one. No credit given... :(
Author:  Moosh89 [ Tue Mar 15, 2016 1:35 am ]
Post subject:  Re:
retrogarde wrote:
Nice one Moosh! I was all excited about the starmap you see on the BluRay menu, but it was actually cribbed from a fan-made one. No credit given... :(


I saved a screen of that too!

So is the rest of the menu screen info fan theory that Fox likes? Hmmm...
Author:  577_ops [ Tue Mar 15, 2016 11:57 am ]
Post subject:  Re: Pulse Rifle Ammo; Reality, math and fantasy...
Moosh89 wrote:
So I've ripped myself a personal copy of my Alien Anthology Bluray collection so I can get HD screens for reference for a few things I'm working on and I grabbed this. Might add a little fuel to this topic!

Attachment:
Pulse Rifle Ammunition Anthology.png


I'll be making another thread of a few more screens I've found interesting/informative

They've stacked them 3 across ;)


Thanks for sharing.
The graphic shows standard Ammunition where the text speeks of caseless.
The weight information might give a clue on how 99 rounds would be possible.
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