Showoff

[Nolo]

you need to read the last 3 copies of Small Arms Revue; it proves without a doubt the problems of the direct imp. system. Now then, they could be fixed, but do you honestly think the mil is going to retrofit all ar's in inventory? no way. The gas is the problem, it causes rounding of 90 degree corners, which cannot be helped, this is a prob. with sustained , quick fire, or full auto, the gas tube gets up over 800 degrees IIRW, which is the first part of catastrophic failure, which means, cannot be fixed in the field, cannot be fixed without an armorer. the piston drive measured against the m4 , fired 11 beta c mags, all on full auto, without one failure. the m4 variants they used, lasted about 250 or so rounds, before catastrophic failure, same test.
The hottest part of the piston drive, was the piston chamber, which got up to about 400 degrees, plus with it's large chamber, bled off heat extremely fast.
the chamber area of the cartridge itself never got even close to cookoff temps.
Also , the cartridge if marketed for the military , is too heavy.
The 6x45, shooting a 90 grain bullet, is a better idea.

Lastly, the 3 articles have had an extensive interview with james sullivan
who has been with armalite from the beginning of the stoner 62/63 concept, and worked on the ar's, along with several other weapon systems.
He goes into detail of the problems of the ar, that have not been changed in 40 years, and he pretty much says that there are better combat infantry weapons out there, namely the ak-74 and the russian 94, with its counter recoil system. plus he states the 5.45 is a better cart than the 556 by far.
That being said, I do like your weapon, and it could find civilian use,
once you get your degree, you should try to hook up with Mr. sullivan himself.
He says they are allways looking for new designers, there is no school for small arms design, and they try to work outside the system as much as possible, even though it is tough, since our gov. doesn't let you work in another country, and design weapons for u.s., without heavy restriction.

This rifle is really not built for sustained fire, anyway, It's a marksman rifle. However, one could certainly want to use it for sustained fire roles. I don't see why the DI is any hotter, if anything it should be cooler, considering the gas has more room to expand (greater volume=less temperature). And we're not talking about an M4. We're talking about the Talon. Completely different weapon. The M4 has tighter tolerances. The cartridge is not too heavy for the role it is assigned. Though you also assume that it is the only load this weapon will fire. I've kept a 108-grainer in the back of my head for a while, and I think it would do fine at about 2850 f/s.
How in the world is 5.45 a better cartridge? The only advantage I see that round having is ballistic coefficient. The round goes about 200 f/s slower than the M193 (which is the round that I admire, the M855 is a bad European compromise), has a fatter case and a lighter bullet weight. How is that any better?

 

[yesit'sloaded]

My point is that you keep referring to the problem of the M16 as being a DI system with tight tolerances, while this weapon that you have designed uses DI and to get the kind of accuracy you want, must use tight tolerances. You need to do away with the DI or lower the tolerances and forget MOA accuracy past 500 meters. Think of every sniper rifle in use today that is accurate past 500 meters. M14-piston, M40-Bolt, M1a-piston, HK PSG-delayed blowback. None of them use DI. The Barret .50 uses short recoil. I'm sorry, I think a weapon that fires a snazzy new lightweight cartridge in all kinds of environments would be cool, but see the development of the m-16. Just throw on a piston and make yesit'sloaded happy. Then show me CAD prints and a marketing plan and we can talk about getting one built for you.

 

[rangerruck]

I don't know why the 545 is a much better cart, but it is flatter, faster, and curls like a boomerrang after it penetrates something. That I know, but as to why it is better in combat, i am quoteing Mr. Sullivan from his article, it is what he stated.
As far as the di getting hotter, they had timed slow mo pics dropped from video, of the diff weapons being fired. the pics were taken in a very low light condition.
the piston ar glowed a bit, around the muzzle, and the piston chamber.
the Di ar's, glowed red hot at the muzzle, about the same red at the chamber area, and SUPER NOVA, bright led light, red hot, all along the entire length of the gas tube. Mind you , this was with full handguards, the video pics picked up the glowing RIGHT THROUGH the handguards, and it's air gaps.

 

[kfranz]

This rifle is really not built

There you go, fixed it for you. The pretty drawings look nice, and there sure are a lot of words attatched, but you need to make one, ring it out, and THEN report back.

 

[Bartholomew Roberts]

From an ergonomics perspective, your charging handle is poorly placed if those dimensions are anywhere close to AR dimensions.

With optics, you will occasionally end up taking the skin off your hand if you try to manipulate a charging handle in that location under stress.

For an example of this, compare the Magpul Masada prototype with the production version of the Bushmaster ACR.

 

[Illuminaughty]

Looks very well done, but it will never, ever go anywhere unless you translate your skills to CAD or another industry acceptable format.

This is the equivalent of writing a movie script on napkins. Sure, it's possible, but it better be DAMNED good to get someone who can make the decisions on what gets made and what doesn't to push for you.

 

[Bartholomew Roberts]

The gas is the problem, it causes rounding of 90 degree corners, which cannot be helped, this is a prob. with sustained , quick fire, or full auto, the gas tube gets up over 800 degrees IIRW, which is the first part of catastrophic failure, which means, cannot be fixed in the field, cannot be fixed without an armorer. the piston drive measured against the m4 , fired 11 beta c mags, all on full auto, without one failure. the m4 variants they used, lasted about 250 or so rounds, before catastrophic failure, same test.

Hmmm... when the military tested the M16 and the M4 barrels to destruction; both rifles managed over 450 rounds and the barrel failed before the gas tube.

Personally, I do not know that it isn't a wise idea to have a $0.50 gas tube fail before you can destroy your $250 barrel with sustained fire. As far as "repairable" only by an armorer, it is repairable by anyone with a pin punch, new gas tube and common sense.

 

[kingjoey]

Nolo, you can get TurboCAD v14 Deluxe at OfficeMax for probably $100. We use v15 Pro here but that runs about $1200 which might be a bigger chunk of change then you want to pony up. TurboCAD works better than SW or AC (and is fully compatible with both) for stuff like this and is fairly easy to learn if you have some CAD saavy. Going through the work of drawing up something like that on any non-CAD program is pretty much wasted time since you'd have to redraw it on CAD to get any machining done. Check your local Staples/OfficeMax/wherever for TurboCAD, we've been running it since v.9 and won't be using anything else for the forseeable future.

 

[CWL]

You can usually order S/W at a significant discount online if you are a student. All you need is student ID. Shipping is free.

http://www.academicsuperstore.com/s...ode=0D5S004B&gclid=CNeDxO_ZppMCFSQqagodgWZZng

 

[Nolo]

My point is that you keep referring to the problem of the M16 as being a DI system with tight tolerances, while this weapon that you have designed uses DI and to get the kind of accuracy you want, must use tight tolerances. You need to do away with the DI or lower the tolerances and forget MOA accuracy past 500 meters. Think of every sniper rifle in use today that is accurate past 500 meters. M14-piston, M40-Bolt, M1a-piston, HK PSG-delayed blowback. None of them use DI. The Barret .50 uses short recoil. I'm sorry, I think a weapon that fires a snazzy new lightweight cartridge in all kinds of environments would be cool, but see the development of the m-16. Just throw on a piston and make yesit'sloaded happy. Then show me CAD prints and a marketing plan and we can talk about getting one built for you.

You forgot the M110. It's DI. And it outdoes the M14/M1A/M21 rifles by a good margin. They were only supposed to the DMR weapons, anyway, which has looser accuracy tolerances.
I must use tight tolerances only in certain areas. Think of it this way:
I can have a rod with a "T" cross section inside of a form-fitting sleeve.
The rod can have a millimeter of space between the sleeve and the rod, making for very loose tolerances.
Or it can have a micrometer of space between the sleeve and the rod, making for tight tolerances.
OR it can have a micrometer of space only at the top and ends of the "T", and a millimeter of space everywhere else. You get a lot of the benefit of loose tolerances with near-tight tolerance accuracy.

There you go, fixed it for you. The pretty drawings look nice, and there sure are a lot of words attatched, but you need to make one, ring it out, and THEN report back.

I'm seventeen, I'm going to college for Mechanical Engineering. Give me a break, I just want to share my ideas with someone, and nobody around my house and areas wants to hear about guns. Apparently, neither do you.
From an ergonomics perspective, your charging handle is poorly placed if those dimensions are anywhere close to AR dimensions.

With optics, you will occasionally end up taking the skin off your hand if you try to manipulate a charging handle in that location under stress.
For an example of this, compare the Magpul Masada prototype with the production version of the Bushmaster ACR.

I did think about that, so I made the charging handles longer, which you unfortunately can't see in this render. A head-on is kind of a biotch, though, so I'm waiting to do that. Where'd the ACR move them to? Do they have any demonstrators out for that weapon?

Nolo, you can get TurboCAD v14 Deluxe at OfficeMax for probably $100. We use v15 Pro here but that runs about $1200 which might be a bigger chunk of change then you want to pony up. TurboCAD works better than SW or AC (and is fully compatible with both) for stuff like this and is fairly easy to learn if you have some CAD saavy. Going through the work of drawing up something like that on any non-CAD program is pretty much wasted time since you'd have to redraw it on CAD to get any machining done. Check your local Staples/OfficeMax/wherever for TurboCAD, we've been running it since v.9 and won't be using anything else for the forseeable future.

I don't have $100 to spend...

 

[kingjoey]

Another upside to using CAD for designing stuff like that is that you can design it in 3D. Sometimes when you do design work on complicated parts in 2D you'll find that there are tolerance problems or places where material is thin which can cause failures. We usually do the rough dimensioning and layout sketch-up on a C-sheet grid then generate a 3D model on TurboCAD. We will add our needed machining operations to that model then examine it in 3D and do cross-section checks to ensure that there is no places where we have potential weaknesses in the structure. It also allows us to assemble complicated mechanisms virtually on a computer before committing to making actual hard parts. We can even check tolerances between parts, check alignment, and see where parts are going to be at various degrees of movement. Just for example I took pic of our actual KA-1222, a basic hidden line drawing of the KA-1222, then slice it diagonally on CAD to show the interior structure. We go through this sort of process several times before building prototypes to check for potential interferences or weaknesses.

 

[Owen]

its not designed without tolerances.

Get yourself a copy of ANSI/ASME Y14.5

 

[Bartholomew Roberts]

Where'd the ACR move them to? Do they have any demonstrators out for that weapon?

The ACR moved them forward on the handguard (similar to the position for the G3 and MP5). Personally I like the ergonomics of that position (as long as you aren't too short armed). There are a few pre-production versions of this ACR out and about. You can probably find pictures from SHOT.

A longer charging handle will probably work; but the other side of that is with MOLLE vests, armor, etc. you may see an increased tendency for the charging handle to snag the gear and even partially cycle.