AR 40 rounds magazine

[zollen]

Close Up Diagram

Cross-section Diagram

The total upward pressure of a fully loaded magazine is equally distributed between the top first round and the pressure damper.

The total amount of upward pressure of 40 rounds, divided by 2 should be less than the total amount of upward pressure exerted by a 30 rounds magazine.

 

[M-Cameron]

looks like you could run into a jamming issue.......

because that 2nd round in the mag is going to need to shift to the other side because of the pressure damper.....causing a shift in every other round beneath it......so for each shot, the rounds in the mag are going to be switching sides........i could easily see some rounds jamming at an odd angle because of this.

 

[Murphy4570]

That theoretically solves one issue with very large capacity magazines.

However, there remains the issue of length. Firing from a prone position is something to think about.

Have you seen those new quad-stack AR magazines? 60 and 90 round capacity, I think?

 

[steelbird]

Wouldn't a drum-type design be a better choice? Does one exist for AR types?

 

[zollen]

Wouldn't a drum-type design be a better choice? Does one exist for AR types?

The drum type design is for 80+ rounds capacity. The drum type design is also too complex for battle applications and it is way too heavy.

 

[zollen]

That theoretically solves one issue with very large capacity magazines.

However, there remains the issue of length. Firing from a prone position is something to think about.

Have you seen those new quad-stack AR magazines? 60 and 90 round capacity, I think?

I can see that one could simply re-orient his rifle horizontally.

 

[zollen]

This is a initial design and of course there is always room for improvement.

 

[Justin]

There are at least a couple of manufacturers of 40 round magazines. I've got the Tripp Research 42 and 52 round Cobramags, and they run very well.

Nordic components makes a kit that allows you to mod a PMag that will hold 47 rounds.

Magpul's got a 40 round design in the pipeline, though I don't know if they've announced a release date or not.

And, of course, there are the new Surefire magazines that were demoed at SHOT this year. The 60 rounder isn't much longer than a standard 30 rounder, but the 100 round magazine was fairly long. These still haven't been released to the public yet, and the last I heard, they were still working out manufacturing issues.

None of these magazines have the pressure damper shown in the Sketchup renderings in this thread, and I'm not completely sure what the purpose of such an addition to a magazine would be.

However, there remains the issue of length. Firing from a prone position is something to think about.

I've used my Tripp Research 42 and 52 round magazines from prone. For the 42 round magazine, shooting under timed pressure at steel targets at varying distances out to 400 yards wasn't really an issue. Just monopod off of the magazine and go to town.

The 52 round magazine is a little bit more ridiculous to monopod off of, and things can start to get a bit wobbly, but it's not a total impediment to hitting a target.

Where the longer magazines have a definite weakness is when shooting through a low-to-the-ground port. The solution is to either cant the gun and shoot it (rollover prone or the like) or switch to a shorter magazine before shooting through that port.

 

[CYANIDEGENOCIDE]

http://www.midwayusa.com/viewproduct/?productnumber=?saleitemid=197017

somebody beat you too the punch. Honestly I would rather have a beta c-mag because then I can still shoot prone. I am not sure what you mean about drums being too complicated for battle. Don't RPK's run drums? as well as suomi, thompson, RPD, AKM, type 56, G3, SA80? I'm all for innovation, I just don't see what the pressure buffer does, it's not like the 30 and 40 rd mags out now are unreliable.

 

[zollen]

I didn't know 40+ rounds already exist. It would seems these types of magazines utilize specialized designed springs carefully calibrated for various rounds upward pressures. I am very curious to know wherever they are durable and reliable in combat situation. I am trying to come up a design that ensures reliable stripping of the top round regardless of the capacity (< 50 rounds).

 

[gotigers]

Cproduct 40 round mags are usually $22 at the local gunshow.

 

[Ro1911]

I had two sterling AR 180 mags that were 40 rds they dont have any pressure problems, I think this device is not needed and will not function.

 

[kwelz]

Yes the surefire mags are reliable. A number are in people's hands for T&E and they are doing well.

This design has the same problem as your other ideas. A lack of research and a lack of understanding.

 

[Sam Cade]

I didn't know 40+ rounds already exist.

This is where basic knowledge of the subject at hand is good to have.

It would seems these types of magazines utilize specialized designed springs carefully calibrated for various rounds upward pressures.

Yes, virginia, magazines usually have springs of the correct weight and rate in them.

I am very curious to know wherever they are durable and reliable in combat situation.

Dude, the 45 round RPK-74 magazine has been working flawlessly for for decades with no silly do-dads.
http://en.wikipedia.org/wiki/File:Soviet_RPK-74.JPEG

I am trying to come up a design that ensures reliable stripping of the top round regardless of the capacity (< 50 rounds).

....Ok...

Properly designed feed lips and a maximum upward pressure plus friction on the top rounds being less than the forward thrust of the bolt, all under working conditions.
This would involve, like, some actual numbers and stuff.....

 

[zollen]

Are these type of 40+ rounds magazines for AR reliable in combat situations?

 

[kwelz]

The surefire is. The design you are proposing doesn't appear to be.

 

[Maple_City_Woodsman]

I like the 20's.

 

[zollen]

I have been thinking of ways to improve it

 

[Sam Cade]

Are these type of 40+ rounds magazines for AR reliable in combat situations?

What do you mean, "these type"?

There arent any significant engineering challenges to making double collum constant radius draft-STANAG magazines of over 30 round capacity.

 

[Sam Cade]

I have been thinking of ways to improve it

Not successfully.

 

[zollen]

Not successfully.

I agree with other assessments. The initial design would not work. I have been thinking ways to improve it.

 

[Cal-gun Fan]

To be honest, your design isn't necessary-there are already designs that exist and work fine.

 

[Justin]

Are these type of 40+ rounds magazines for AR reliable in combat situations?

I have found them to be reliable under adverse field conditions, including at this year's Texas Multigun Nationals, which had the worst sustained wind and airborne sand that I've ever seen.

Many other shooters used extended magazines from the brands that I've mentioned, as well as the C-Products 40 rounders.

As for whether they're reliable enough for issue troops, I have no idea. You'd have to ask someone who's involved with military testing and evaluation.

Honestly I would rather have a beta c-mag because then I can still shoot prone.

Unless you take meticulous care of them, Beta drums are prone to failure. Those people who use them adhere to a maintenance schedule that includes replacing the feed towers on a regular basis and using graphite lubricant to keep them running.

 

[Owen]

zollen, the rounds that would ordinarily feed from the left hand side won't be able to flip over to the right because of the obstruciton you've placed in the feedway. Look at it this way...the rounds don't flip over the feed lip on the left side. Your damper is bigger than the existing feed lip. The rounds are just going to stop on your damper.

In fact, I don't think the magazine will load correctly.

Also, from a presentation point of view, you should hide the magazines we aren't actually looking at. It took me a while to figure out that the extra lips in the last screen shot were actually on the 30 round mag located behind the 40 rnd mag.

 

[zollen]

zollen, the rounds that would ordinarily feed from the left hand side won't be able to flip over to the right because of the obstruciton you've placed in the feedway. Look at it this way...the rounds don't flip over the feed lip on the left side. Your damper is bigger than the existing feed lip. The rounds are just going to stop on your damper.

In fact, I don't think the magazine will load correctly.

Also, from a presentation point of view, you should hide the magazines we aren't actually looking at. It took me a while to figure out that the extra lips in the last screen shot were actually on the 30 round mag located behind the 40 rnd mag.

I agree. I have been thinking of ways to reliably feed 40+ rounds without the need of the damper.