Smoking Barrels - LTT's Unnofficial Gun Club!

[Jito463]

6 minutes ago, Drak3 said:

That'd take care of the feeding issues.

 

But I stand with what I said.

Thanks for the feedback.  I've got a month to decide, so I'll keep accumulating information until then.  Appreciate it.

[Guest]

1 hour ago, knightslugger said:

well they are just stamped sheet metal with a spring and some injection molded plastic. They are pumped out by the thousands daily.

 

fun fact: the M249/FN249S can also use STANAG magazines in place of disintegrating links.

Yeah the west point guys showed me the M249 can do that. I think I heard the stanag fitting was inspiration for the "LMG" M27 IAR. (It doesn't look like a machine gun to me. Just slightly different AR15.)

Side question:
What makes the HK 416 (or m27 IAR) ANY different from the M16/M4 Carbine? 
They all look the same and seem to use all the same parts. 
It's kind of like the AK rifles are all basically the same. Some use different calibers and some have different barrel winding but that's kinda it. 
As far as I know the only significant difference between the M16 and M4 is M16 has 3 round burst and M4 has full auto. And the barrels are different lengths. 

[Drak3]

28 minutes ago, fpo said:

What makes the HK 416 (or m27 IAR) ANY different from the M16/M4 Carbine? 

Gas piston system

Heavy profile barrel

Free float hand guard

Adjustable gas block

Slower maximum fire rate

28 minutes ago, fpo said:

M16 and M4 is M16 has 3 round burst and M4 has full auto. And the barrels are different lengths. 

The only difference between the M16 designated rifles and M4 designated rifles is the barrel length. Fire modes changed between the variations.

 

The M16A2 and A4 was/is a burst fire, the E1,A1, and A3 are fully automatic.

 

Both A3 and A4 are in current service.

Edited May 12, 2018 by Drak3
Turns out the Colt A4 is also a burst fire PoS

[george357]

2 hours ago, Jito463 said:

I'm mostly curious if any of you have tried it before or not, and/or what your experience is working with Century Arms rifles.

I had one of these a few tears ago and loved mine. Only had one issue with it, the factory sights would not line up windage @ 100yds. Rear sight all the way to the right and it still shot 3-4 inches to the left. I used one of the cheap scope mounts you can get for these and a decent 3-9x32 scope (don't remember which one  now but it wasn't anything special) and never had any further issues. Mine ate anything I fed it, .308 Win and 7.62 Nato,  with no issues. Only reason I got rid of mine was needed  money at the time.

[Jito463]

8 minutes ago, george357 said:

I had one of these a few years ago and loved mine. Only had one issue with it, the factory sights would not line up windage @ 100yds. Rear sight all the way to the right and it still shot 3-4 inches to the left. I used one of the cheap scope mounts you can get for these and a decent 3-9x32 scope (don't remember which one  now but it wasn't anything special) and never had any further issues. Mine ate anything I fed it, .308 Win and 7.62 Nato,  with no issues. Only reason I got rid of mine was needed  money at the time.

So, one for and one against.  That seems to be on par with what I've been seeing from reviews online.  People apparently either love it or hate it.  I've yet to see a review that's ambivalent about this rifle.  I suppose what I'll need to do is test fire it before buying.

[george357]

8 minutes ago, Jito463 said:

I suppose what I'll need to do is test fire it before buying.

Always do this if it an option. The seller could have many reasons for getting rid of it and I am not saying they are just trying to unload a dud, but I would test fire anything used given the option.

[Jito463]

2 minutes ago, george357 said:

Always do this if it an option. The seller could have many reasons for getting rid of it and I am not saying they are just trying to unload a dud, but I would test fire anything used given the option.

True.  This is my first time purchasing from an individual as opposed to a gun store, so I haven't really thought out all the logistics, yet.

[Guest]

3 hours ago, Drak3 said:

Gas piston system

Heavy profile barrel

Free float hand guard

Adjustable gas block

Slower maximum fire rate

The only difference between the M16 designated rifles and M4 designated rifles is the barrel length. Fire modes changed between the variations.

 

The M16A2 and A4 was/is a burst fire, the E1,A1, and A3 are fully automatic.

 

Both A3 and A4 are in current service.

Oh. I thought the M16/M4 was gas piston. 
I remember hearing something about the navy seals using M416s so I guess the new Gas system is better for their use case somehow. 

Thanks!! 

[Drak3]

12 minutes ago, fpo said:

Oh. I thought the M16/M4 was gas piston. 
I remember hearing something about the navy seals using M416s so I guess the new Gas system is better for their use case somehow. 

Thanks!! 

Theoretically, pistons are more reliable than DI.

 

Real world, it took 50 years for the US military to decided to replace DI guns, and it'd not even for the cycling system. It's reliable when cleaned (duh), and when using good powder (double duh).

[knightslugger]

3 hours ago, fpo said:

Oh. I thought the M16/M4 was gas piston. 
I remember hearing something about the navy seals using M416s so I guess the new Gas system is better for their use case somehow. 

Thanks!! 

Piston systems are more reliable in general. They just don't suppress as well.

[Drak3]

7 hours ago, fpo said:

I think I heard the stanag fitting was inspiration for the "LMG" M27 IAR. (It doesn't look like a machine gun to me. Just slightly different AR15.)

Something I forgot:

No official documentation explicitly paints the M27 as an LMG. For awhile, it was planned to be a Squad Automatic Weapon or SAW, but that was due to it being an HBAR and open bolt design, which helps keep the barrel cool enough to retain accuracy under suppressive fire and avoid cook offs.

 

But with a Pmag D60, Sunfire 60 or 100 round quad stackers, or X Products X-15 50 round magazine, the M27 could function as a LMG.

[knightslugger]

35 minutes ago, Drak3 said:

But with a Pmag D60, Sunfire 60 or 100 round quad stackers, or X Products X-15 50 round magazine, the M27 could function as a LMG.

except no military in the world would use those magazines.

 

especially the surefire mags (funny name).

[Drak3]

8 minutes ago, knightslugger said:

except no military in the world would use those magazines.

 

especially the surefire mags (funny name).

No, they don't. They're too expensive, too heavy, and can't support a cartridge change should the military decide to pursue .458 SOCOM, .50 Beowolf, or .300 Blackout*. (or 6.5 Grendel, if we were lucky). Reliability with Surefire is a bit of a gamble, I can't speak od the D-60 because it's too new, and the X Products are way expensive.

 

But my point stands. With a high capacity magazine, the M27's functionality as an LMG is damn better than the M4A1 or M16A3.

 

* X Products actually supports 208Gr. and lighter .300BLK, 220Gr. and up causes added stress.

[Real_PhillBert]

On 5/11/2018 at 1:24 PM, kaiju_wars said:

 I don’t mean to get off topic, but I just noticed your location.  You’re in North Dakota also?

Indeed.

On 5/11/2018 at 9:40 PM, fpo said:

Belts are illegal in my state (Even the links for belts... "Magazine with capacity over 10 boolet")

Do you have cloth belts in your state? I couldn't bear to pick up all the stupid links after burning 300~ rounds or something. Reloading that with links must be annoying. 

Here we can have belts of any type, although I dont own any or really have a desire to own any. 

 

As for loading them there are little crank operated machines that make loading them much easier and faster. 

 

[kaiju_wars]

5 hours ago, Real_PhillBert said:

Indeed.

Which part of the state?  Or what town even if you don't mind me asking.

[Real_PhillBert]

2 minutes ago, kaiju_wars said:

Which part of the state?  Or what town even if you don't mind me asking.

I live in Fargo. Yourself?

[kaiju_wars]

1 minute ago, Real_PhillBert said:

I live in Fargo. Yourself?

Stanley.  Small town about an hour from Minot.

[Real_PhillBert]

6 minutes ago, kaiju_wars said:

Stanley.  Small town about an hour from Minot.

Sweet! I know the area.

 

Last spring I had a few machines out in Antler and Mohall area that I was overseeing. 

 

EDIT: In fact one of the other guy's has a machine or two just outside of Donnybrook right now. 

[Guest]

7 hours ago, Real_PhillBert said:

I live in Fargo. Yourself?

https://en.wikipedia.org/wiki/Brian_Fargo
You live at the creator of Fallout?!?!

Sorry. 

[Jito463]

9 hours ago, Real_PhillBert said:

I live in Fargo.

1 hour ago, fpo said:

https://en.wikipedia.org/wiki/Brian_Fargo
You live at the creator of Fallout?!?!

Sorry. 

In, not at.  IN Fargo.  Sheesh, get your words straight.  

 

Also, wrong Fargo.

 

[Marinatall_Ironside]

Anybody good with some math here who can help me do some calculations with a custom rifle cartridge I made? Would be helpful

[Guest]

4 hours ago, JurunceNK said:

Anybody good with some math here who can help me do some calculations with a custom rifle cartridge I made? Would be helpful

Maybe a professor here? (In link below) I remember seeing a flyer for a gunsmithing school in Pennsylvania USA but I'm not sure if this was it. 
https://pagunsmith.edu

[Marinatall_Ironside]

12 minutes ago, fpo said:

Maybe a professor here? (In link below) I remember seeing a flyer for a gunsmithing school in Pennsylvania USA but I'm not sure if this was it. 
https://pagunsmith.edu

Not able to go there, that's way too far. Plus I don't see an email which would be helpful.

 

I'm sure someone here knows the math needed to do some calculations. Here's some parameters that may be of help.

 

This is a concept projectile that I made and mocked up in Blender.

• 10.4x99mm
• Parent case is a .50 BMG (12.7x99mm NATO)
• Case has been necked down to accept the 10.4mm projectile, and shoulder moved closer to the base to maintain 15º shoulder angle
• Bullet is longer than the .50 BMG.
• Loaded round is as long as the .50 BMG.

Now let's try and make some estimated calculations as simple as possible (picture 2 for reference).

• Cases are loaded to their appropriate maximums (see cross-section for an idea)
• Bullets are seated to meet the case shoulder.
• Bullet is a monolithic copper bullet weighting 570gr (a 720gr monolithic copper .50 BMG bullet was used for reference. See picture 2 for volume loss. If you want to correct me, feel free to do so.)
• Barrel length is 29 inches.
• Shooting platforms are two McMillan Tac-50's, with one of them outfitted with a custom .41-caliber barrel and same muzzle brake with the difference being the bore being smaller for the .41-caliber projectile, while the other is standard .50 BMG)
• Let's set up the location at the Phoenix Rod & Gun Club, Phoenix, AZ, with a 84ºF ambient temperature, desert weather with clear skies, 710m above sea level, and atmospheric pressure set at 29.76 inches of Mercury.
• Targets are set up at 500 yards for point of reference.

All I need primarily is the velocity of this projectile. Ballistics can really only be tested by actually making and shooting these in real life to see how they can behave, but we can discuss some theories on their characteristics, which is okay as long as it's in the realm of reality.

 

Here's some pictures for reference. Right is the .50 BMG. Left is the projectile I made using Blender.

Picture 1

 

Picture 2 (all the cross-sections)

[Guest]

@JurunceNK I meant you could email. I forgot to type that. I don’t know where you live but there may be gunsmithing or engineering schools or universities nearby. If the teachers are passionate enough, they may actually get back to you. Some are too busy to even reply. 

I’m not mathematically acquainted with these concepts but if you don’t email I hope someone here gets back to you. 

[knightslugger]

What exactly are you looking to understand? speed? Bullet stability? pressure? case volume?

 

I can fire up QuickLOAD tonight and see about creating a custom cartridge. see what it spits out for MV of varying powders. might need more info from you to get an accurate calculation.

 

I will need details on the bullet profile. base diameter, boat-tail length to body, OAL, tip to Ogive. If this is a bullet already in production, the model number would be extremely helpful.