The case for M4 Feed Ramps

[C4IGrant]

Huh. Okay, folks familiar with the M16's, which to my knowledge don't have M4 feed ramps, how do they fare running M855 through them? Generally better or worse than M193? I'm wondering if any Marines have found the same thing you have, Grant.


-B

M855 is much like the M193 in that it is not a hollow point. Remember what I wrote in my post about the heavier grain ammo being hollow points and that is one of the major reasons for the higher chance of a malfunction in guns without feed ramps.

I would guestimate though, that if you had a worn out USGI mag and were shooting the two ammo that the M855 would most likely exhibit a higher malfunction rate. This is of course just my opinion.



C4

[C4IGrant]

Grant,

Any idea how far down the face of the receiver the rounds contacted? I'm curious, because as we know, there are ramps, and then, there are R-A-M-P-S. Is there a standard regarding how deep the ramps need to extend to catch any nose-down rounds?

We saw that the rounds were impacting JUST below the barrel extension. So IMHO, the ramps do not need to be all that deep and long. What is of MUCH greater importance is how smoothly the M4 cuts interface into the M4 barrel extension.

If there is ANY kind of lip here, the rounds tend to bounce off and run directly up into the receiver.


C4

[C4IGrant]

Does "captured" mean they were somehow video taping the events? In slow motion perhaps??
I would like to see some video of tests like this. Would be interesting. Thanks for posting Grant..

They did have high speed video and logged every malfunction in a graph (which they showed me).



C4

[GLOCKMASTER]

We have had problems with some of our Armalites since day one because most of them did not have feed ramps. They had serious feeding problems when we used 77 grn. for duty ammo and still had the same problem when we switched to a 55 grn. load. The folks prior to me taking over were misdiagnosing the issue. I had to cut feed ramps into right many of them to get them to run reliably with 55 grn. ammo. Since then the rifles have been reliable.

[JBnTX]

Thanks Grant,

I understand the need for M4 ramps better now.

[bkb0000]

So now I've been honest. bkb0000, where did you first hear of them?

years ago, dude.. they aren't that new.

I don't appreciate being called un-informed just because I question the
need for something.

i thought i said that pretty diplomatically... and it wasn't your questioning the need for something that i was responding to- it was you stating you'd only recently been made aware of their existence followed by you dissing on them that made me comment.

the platform has been evolving for the last 50 years, and will continue to. there's nothign wrong with coming up with ways to improve it, and M4s are an improvement. they don't hurt anything, and can prevent problems. in the years that they've been around, they've absolutely been proven to, overall, improve the platform, even if the exact level of improvement is debatable.

[Robb Jensen]

Having M4 ramps helps with a number of things. The first thing they help with is with ammo other than 55gr FMJ.

The other things M4 ramps help with are very fast cycling rifles, mags with weak springs and dirty magazines. If you ever get a chance to see really slow motion of an M4 or M16 cycling in full auto it's very interesting. The rounds are bouncing up and down in the magazines and sliding fore and aft. This is why it's critical where the top round is going to be as the bolt strips off the top round in the magazine. If it's not high enough in the magazine the round will run into the receiver and cause a stoppage. Since the M4 ramp continues into the upper receiver it has a higher probability of feeding the top round even if the round isn't all the way up in the magazine.

[RD62]

Grant,

Thanks for sharing the feed ramp info. I learn something new every day!

-RD62

[Eric]

We have had problems with some of our Armalites since day one because most of them did not have feed ramps. They had serious feeding problems when we used 77 grn. for duty ammo and still had the same problem when we switched to a 55 grn. load. The folks prior to me taking over were misdiagnosing the issue. I had to cut feed ramps into right many of them to get them to run reliably with 55 grn. ammo. Since then the rifles have been reliable.

Interesting. Current Armalite carbines have M4 type ramps.

[Iraqgunz]

Here is a question for the anti-M4 feed ramp crowd. Since I have zero background in production maybe someone else can answer this.

How much of a time and cost difference is there between manufacturing an upper receiver with feedramps as opposed to without? Are they really saving that much money? If not, why do it?

When ones considers that in addition to no feedramps the usual suspects also often times use crappy end plates, have improper or non-staked BC keys, extractor springs, improper or non-staked end plates/ castle nuts, inferior barrels assy, etc...what is the whole point? Is it to produce a weapon purely to make money w/o regard to its' performance or is it because they don't know better or to increase their profits?

How can some companies which are smaller produce a better weapon for a few hundred dollars more?