Bullpup vs. classic rifle designs? - Page 5




 
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July 31st, 2008  
A Can of Man
 
 
Quote:
Originally Posted by c/Commander
M-16's not very lefty-friendly either - no side-ejecting rifle is going to be very friendly to left-handed shooters, even with a case deflector. Which bullpup rifles eject downward?
Actually I don't see the big deal about the side ejection. It ejects far forward enough not to hit me in the face or anything. Yes I shoot left handed.
July 31st, 2008  
CanadianCombat
 
 
I can't stand the look of bullpup rifles. I guess I'm just used to seeing and using AR-15 type rifles, and I won't be changing my ways anytime soon.
July 31st, 2008  
5.56X45mm
 
 
Until the 40 Watt Phased Plasma Rifle or Lightsaber comes out we're stuck....

The next major evolution in firearms will not be the layout of the rifle. It will be the ammunition. We all talk about cutting edge and ahead of it's time...

The Germans take the cake with the Heckler & Koch G11. Caseless ammunition. It saves weight and completely changes the playing field for you soldier. He can carry far more ammo for less weight.





This rifle was going to be the standard rifle of the West German Army but the Cold War ended, the DDR became no more, and the German State just became broke. So it was scrapped and the G36 (H&K backup design) was approved and issued because of the price of ammo. There were already billions of rounds of 5.56x45mm floating around Europe because of NATO and the USA. The idea of stocking up on billions of 4.73x33mm Caseless rounds was an expensive project.



Right now the USA is looking into LSAT (Lightweight Small Arms Technologies). It's a caseless 5.56x45mm system. They have two designs. A 100% complete caseless system and a stopgap design. Plastic cased-telescoped ammo.





Large Image file
http://www.defensereview.com/stories...4/DSC02547.JPG




Quote:
The Cased Telescoped (CT) ammunition (above) is one of the approaches to meeting LSAT’s weight reduction goals. The most current generation, “Spiral 2” CT, uses specialized polymer formulations for the cartridge case and end cap, but priming is conventional. Six-hundred rounds of 5.56 CT weighs 35 percent less than an equal number of 5.56x45 mm rounds.

National Rifleman, National Rifle Association
http://www.nrapublications.org/tar/LSAT.asp

Quote:
The Caseless Telescoped (CL) cartridges (top), developed by Alliant TechSystems, use the propellant itself for the role of the “case,” which is fully consumed on firing.
National Rifleman, National Rifle Association
http://www.nrapublications.org/tar/LSAT.asp


Quote:
The Lightweight Small Arms Technologies program (LSAT) has been on our radar screen since its inception in 2003. Plastic-cased cartridges are already performing well, and caseless ammunition—a concept dating back to the dawn of firearms—is said to offer the greatest potential. Today, these high-tech cartridges and the innovative lightweight small arms that fire them are showing great promise. What emerges from these experiments is likely to yield benefits not only to the military, but also to law enforcement and to the shooting sports.

It’s real and right now: a dramatically different squad automatic weapon (SAW) that fires radically new ammunition. And this combination is half the combat weight of the M249, the current SAW. We asked the Army’s program manager how soon it could be in the hands of Americas warfighters? That is a tough question, so lets go back a few years.

For further information read the NRA national Rifleman Article.
http://www.nrapublications.org/tar/LSAT.asp
Quote:
The reason AAI is starting with plastic cased-telescoped ammo is that caseless ammo is a higher-risk proposition involving greater technical and physical challenges than cased telescoped ammo. One of the primary challenges with caseless telescoped ammo (CL ammo) is how to continuously and consistently seal the chamber as the weapon is fired (i.e. provide for a repeatable seal), especially on full-auto under high round count. According to legendary infantry small arms designer (a.k.a. firearms designer a.k.a. gun designer) Jim Sullivan (L. James Sullvian), CEO of small arms development firm Arm West, LLC, "if you can't seal that breach, you've gotta' go back to a muzzle-loading single shot. You have to seal the breach, and you've gotta' seal it with every shot. And, you can't have something that wears out. So, you've gotta' replace the seal with every shot." With cased ammo, the case itself acts as the renewable chamber-sealing device a.k.a. "replaceable seal" [replaceable breach seal], as Sullivan calls it, and a brass case seams to work the best at this. "Cartridge brass is unique stuff", Sullivan says. With caseless ammo (caseless telescoped ammo), you lose this replaceable seal.

Now, a plastic case is better than no case (with regard to providing a fresh breach seal for each shot), of course, but it ain't brass, either. For one thing, plastic, historically, has tended to melt/burn at the high temperatures generated by full-auto weapons (small arms). It's possible that AAI has solved this problem by utilizing some kind of high-tech heat-resistant plastic that can handle these temperatures, but that remains to be seen. Assuming the plastic they're using can handle the high temperatures of full-auto fire at high round count (or even low round count), the plasic case should assist in insulating the chamber so it doesn't heat up to much (unconfirmed/unverified). It's also possible that the LSAT LMG/SAW prototype's swinging/"rotating" chamber reduces the amount of heat transfered to the chamber, and thus to each subsequent plastic case as it's loaded in, but we haven't been able to confirm this, either.

However, this same insulative property keeps the plastic cartridge case from performing another function of a brass cartridge case, and that' removing (i.e. expelling) heat from the weapon upon extraction and ejection. A brass case absorbs heat upon firing the round, and that absorbed heat is immediately removed from the weapon upon extraction and ejection of the case. Plastic doesn't offer this same heat-removal bonus.


Aside from the plastic cartridge casing, it's DefenseReview's understanding that cased telescoped ammo (CT ammo) itself has a few challenges to overcome. According to Sullivan, one of the primary challenges is achieving adequate and consistent projectile velocity, since the round is literally sitting inside the gun powder inside the case. This makes it very difficult to keep enough of the ignited powder (i.e. propellant gases) behind the bullet upon firing/detonation of the cartridge. In other words, you have to prevent too much of the propellant gases (from the burning powder) from escaping around the bullet as it's propelled down the barrel after firing.

The whole reason for going to plastic cased telescoped ammo (plastic CT ammo) and caseless ammo (CL ammo) in the first place is to save weight, i.e. to lighten the infantry warfighter's load, and to perhaps shorten the weapon's action (bolt carrier group's reciprocating distance, for instance) so you can speed up the full-auto-burst time. AAI claims in its LSAT fact sheet that it's achieved an overall weapon/ammo system weight (LSAT prototype weapon plus 600 rounds) of 22.9 lbs (CT ammo system) and 19.1 lbs (CL ammo system). This constitutes a 40-50% weight reduction vs. the FN M249 SAW + 600 rounds of standard 5.56x45mm NATO ammo (38 lbs OA weight). Whether or not AAI can achieve the requisite weapon reliability, accuracy, and lethality (on full-auto at high round count under adverse conditions) required for an infantry combat weapon with plastic CT and CL ammo remains to be seen. Time will tell.

However, what if you could accomplish the specified 35% weight reduction (weapon + 600 rounds), and perhaps even more, while avoiding the incumbent technical and physical challenges of these two ammo technologies (CT and CL)? What if you could cut the weight AND retain all of the advantages of a metallic cartridge case? This will be the subject of a subsequent DefenseReview article on the Arm West "Backbone" Weapon System a.k.a. Backbone Family of Lightweight Machine Guns (including a modular assault rifle/carbine/LMG/SAW) and ammo concepts.



http://www.defensereview.com/modules...ticle&sid=1000
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July 31st, 2008  
senojekips
 
 
Quote:
Originally Posted by CanadianCombat
I can't stand the look of bullpup rifles. I guess I'm just used to seeing and using AR-15 type rifles, and I won't be changing my ways anytime soon.
The day when "Looks" become a consideration, will be the day we just give up all development.

Weapons of war are not designed or adopted for their "looks".
July 31st, 2008  
The Other Guy
 
 
Quote:
Originally Posted by senojekips
Weapons of war are not designed or adopted for their "looks".
If weapons were designed for looks, the M-16 and MiG-21 would have never left the drawing board...
July 31st, 2008  
senojekips
 
 
Quote:
Originally Posted by 5.56X45mm

Right now the USA is looking into LSAT (Lightweight Small Arms Technologies). It's a caseless 5.56x45mm system. They have two designs. A 100% complete caseless system and a stopgap design. Plastic cased-telescoped ammo.



I'd have to have a much closer lok at this, but what strikes me in this cas is the physical size (bulk) of the ammunition. Any gains in weight reduction would be immediately offset by the fewer number of rounds that you have room to carry. Plus, I couldn't see this type of ammo being suitable for standard type magazines because of it's bulk. Anyway it's only an adaptation of the old "Dardick Tround" and no doubt has many of the same problems.

But I'll wait and see.
July 31st, 2008  
c/Commander
 
 
Quote:
Originally Posted by the_13th_redneck
Actually I don't see the big deal about the side ejection. It ejects far forward enough not to hit me in the face or anything. Yes I shoot left handed.
This is true for single shooters, but side ejection has other issues. This is a picture I took of a mid in my Marine Week platoon who unfortunately took a hot casing in the neck from the shooter next to him. This is a worst-case, but obviously not a good thing regardless. Someone needs to design an M-16 variant that ejects to the ground
Attached Images
File Type: jpg IMG_2813.jpg (43.2 KB, 5 views)
July 31st, 2008  
5.56X45mm
 
 
Quote:
Originally Posted by senojekips
I'd have to have a much closer lok at this, but what strikes me in this cas is the physical size (bulk) of the ammunition. Any gains in weight reduction would be immediately offset by the fewer number of rounds that you have room to carry. Plus, I couldn't see this type of ammo being suitable for standard type magazines because of it's bulk. Anyway it's only an adaptation of the old "Dardick Tround" and no doubt has many of the same problems.

But I'll wait and see.
Ahhh... the old Dardick Tround. I haven't heard about one of those in years. Anyways...

From the complete article in National Rifleman. The "Lipstick Round" and the Caseless round are about the same size in diameter as the standard 5.56x45mm cartridge. For a magazine feed weapon system. The only one that got off the ground was the G11 and it's system. The LSAT is designed as a possible future replacement of the FN M249 (FN Minimi). Allowing our GIs to carry a SAW that weighs less, performs the same function, and even fires a projectile with the same ballistics as the 5.56x45mm SS109 62Gr FMJ is a pretty good set up.

Of course this is all in the testing stage and who knows about it's sturdiness out in the field with a bunch of GIs that can destroy a block of wood by simply looking at it. If it works and can be made to be Soldier Proof then we have a fine product.

But that is the future. Caseless ammunition is the next major evolution. Every major advancement in the world of firearms came with the evolution of the ammunition first and then with the mechanics of the firearms themselves. Black Powder went from Match Lock, Wheel Lock, Flint Lock, to Percussion Cap. Then it was cased ammunition. The evolution of that was first from rim fire to center fire and then into rimmed, semi-rimmed, to rimless, and the feeding mechanics. Also the evolution from black powdered cased ammunition to smokeless was also the major advancement within the evolution of firearm design because of of advancement of ammunition.

Trust me.... the future is caseless ammo. When? I can't answer that but I believe it will be at some point within my life time.



Crappy photo.... I know but you can somewhat get an idea.
July 31st, 2008  
senojekips
 
 
Thanks Luis, that's answered that question, the photo with the two different rounds side by side is much better.

Caseless rounds have been in the pipeline for many years, and I have little problem with the idea that they will figure in our future firearms design, no doubt the boffins are making some headway. Previously there has always been a problem of some sort, not the least of which was deterioration of the propellant and lack of mechanical strength (resistance to breakage and chipping etc). There was also a big worry about ignition from flash in the case of an explosion.
July 31st, 2008  
A Can of Man
 
 
Quote:
Originally Posted by c/Commander
This is true for single shooters, but side ejection has other issues. This is a picture I took of a mid in my Marine Week platoon who unfortunately took a hot casing in the neck from the shooter next to him. This is a worst-case, but obviously not a good thing regardless. Someone needs to design an M-16 variant that ejects to the ground
Which is why you should flip up the collar on your flak jacket. At least ours has one.
The issue with downward ejecting cases would be that if you were shooting from some kind of cover, i.e. you have something under your weapon such as a sand bag, hard ground etc., the casing can bounce up back at your face and that will be a surefire way to screw up your day.
The FN P90 has a downward ejecting system but I don't know if there are any real issues with it or not. Then again, it's a real compact PDW so I don't think it's even meant to be fired while prone.
 


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