You hear about it? What do they do? Why would you want/need them?

Short version:

The high-speed-low-drag crowd uses them because they're supposed to be more reliable. (I say "supposed to be" because I have no personal experience with them)

The wannabe high-speed-low-drag crowd wants them because the real HSLD uses them.  Same reason they want a M4-look-alike with 10lbs of extra stuff hanging off the rifle.  Mostly bragging rights.

The rest of us don't give a rat's behind one way or another because the "old" way is working fine and we don't see the need to dump $$ into fixing a problem that hasn't affected us.  

So, they are supposed to make it more reliable? How?

I guess they are saposta feed m855 and the new black hills 75 gr stuff.  M-4 ramps and longer and give the bullet a little ramp to feed up into the chamber.  I have no experience with them either.  Im sure if you do a search you will find plenty of info on this subject.

They're supposed to enhance feeding on short full auto jobs I think.

Totally unnecessary for 99 percent of the Fat bodies here.

its suppose to aid feeding of the bullets.




hence "extended" feedramps  


i have never had a rifle extension barrel give me any problems nor have i had any problems the "m4" feedramps.


to me its a precautionary item added to the rifle. i guess a fix before a problem.



to me if i have a rifle without it, you wont see me rushing to swap over my barrel for it but if im building a new one and the feedramps are offered at no additional cost and they are properly done so that they will match a properly done upper reciever,,, hey why not

M4 ramps came as a result of the M4 cycling too fast. The magazine spring had trouble keeping up with the cyclic rate, especially on the last couple of rounds when the spring has the least tension on it. The follower would have moved up far enough for the bolt to start pushing the round, but not far enough so that the bullet would hit the feed ramps.

High cyclic rates have caused the need for H2 buffers, and have caused increased bolt breakage.

Edit: this will only be noticable in full auto.

Quoted: They're supposed to enhance feeding on short full auto jobs I think. Totally unnecessary for 99 percent of the Fat bodies here.

You saying my ARs have a weight problem?

the cartridge may nose dive and hit slightly below the feed ramp. The shorter the barrel ist, the more likely it will occur. I've seen pics on this board, whe the anodizing below the barrel extension was worn off due to this. M4 feedraps should eliminate this problem. The only disadvantage is $$$.

Here's a scenario where extended ramps would come in handy.  Let's say you've got a high round M4, a real M4, not these toys that everybody posts pictures of here, but the real deal.  Due to it's high round count, the gas port has eroded open a little and this M4 cycles pretty fast.  Additionally , this M4 has had hundreds, if not thousands of magazines that have been inserted and ejected out of it and this has worn the top of the mag catch a little, which drops the magazine down in the magwell.  On top of this, you are using an old, worn USGI mag which has a weak spring.  The worn mag allows the mag to sit even lower in the magwell, due to wear at the mag catch area.  The weak spring cannot push rounds up as fast as it used to.

This combo will give you a super fast cycling carbine, with magazines sitting very low in the magwell, which puts the bullet tips farther down in relation to the feed ramps.  Add a weak spring that cannot push up rounds fast enough to keep up with the cycling rate and you have a possible need for an extended ramp to increase the odds of a bullet feeding.

If you fall into the above situation, you need extended feed ramps.  If you don't, extended ramps will certainly not hurt you, but you shouldn't pay any more to get them, as they probably aren't needed.  If you choose to get extended ramps, I recommend you get the proper equipment to get them, rather than hacking them into existing equipment.  YMMV.

Mongo and I will be marketing AR uppers with Ma Deuce feed ramps soon.  Of course there will be a hefty premium for such reliability!

Quoted: Mongo and I will be marketing AR uppers with Ma Deuce feed ramps soon.  Of course there will be a hefty premium for such reliability!

Put me first in line, after all the SF guys, of course.

Quoted: It simply eases feeding during loading with a high bolt velocity (which also happens in semi in short barreled large gas ported weapons) * any 14.5" or shorter * anyone shooting 69gr+ ammo * any full auto * anyone with a suppressor It will never hurt (if done properly).

Kevin, just to make sure I'm clear, are you saying that regardless of the gas system length, a rifle shooting 69gr+ should have M4 feedramps?

Quoted: Quoted: It simply eases feeding during loading with a high bolt velocity (which also happens in semi in short barreled large gas ported weapons) * any 14.5" or shorter * anyone shooting 69gr+ ammo * any full auto * anyone with a suppressor It will never hurt (if done properly). Kevin, just to make sure I'm clear, are you saying that regardless of the gas system length, a rifle shooting 69gr+ should have M4 feedramps?

There are hundreds, if not thousands, of DCM/CMP shooters out there that may have an issue with that part of the statement.  I had a SAM-R upper built with a Bushmaster DCM barrel that had standard ramps that fed 77gr SMK loads all day long without issue.  YMMV.

Quoted: Quoted: It simply eases feeding during loading with a high bolt velocity (which also happens in semi in short barreled large gas ported weapons) * any 14.5" or shorter * anyone shooting 69gr+ ammo * any full auto * anyone with a suppressor It will never hurt (if done properly). Kevin, just to make sure I'm clear, are you saying that regardless of the gas system length, a rifle shooting 69gr+ should have M4 feedramps?

Not necessary if the bolt velocity is controlled with heavier buffer.  Note, replacing the internal weights with a solid piece of lead is self-defeating because the urethane bumper on the back of the buffer will rebound, causing higher bolt velocity.  What is needed is a low coefficinet of restitution, a fancy term for "low bounce".  The sliding weights/rubber washers in the standard buffer do this well.  Replace the aluminum spacer in the buffer with like weights should be enough for most.  Make sure the weights still move.

Quoted: Quoted: It simply eases feeding during loading with a high bolt velocity (which also happens in semi in short barreled large gas ported weapons) * any 14.5" or shorter * anyone shooting 69gr+ ammo * any full auto * anyone with a suppressor It will never hurt (if done properly). Kevin, just to make sure I'm clear, are you saying that regardless of the gas system length, a rifle shooting 69gr+ should have M4 feedramps?

Hopefully, that is not what he is saying as it is inaccurate.  I have multiple rifles with standard extensions and shoot 69s, 75s, 77s, and 80s all day long with no problems.  As do 99% of the Service Rifle shooters out there.

Every facotry Bushmaster has standard extensions, no enhanced (M4) extensions are even offered by Bushy.  Bushys run well, everyday, with ammo over 69 grains.  

Quoted: Here's a scenario where extended ramps would come in handy.  Let's say you've got a high round M4, a real M4, not these toys that everybody posts pictures of here, but the real deal.  Due to it's high round count, the gas port has eroded open a little and this M4 cycles pretty fast.  Additionally , this M4 has had hundreds, if not thousands of magazines that have been inserted and ejected out of it and this has worn the top of the mag catch a little, which drops the magazine down in the magwell.  On top of this, you are using an old, worn USGI mag which has a weak spring.  The worn mag allows the mag to sit even lower in the magwell, due to wear at the mag catch area.  The weak spring cannot push rounds up as fast as it used to. This combo will give you a super fast cycling carbine, with magazines sitting very low in the magwell, which puts the bullet tips farther down in relation to the feed ramps.  Add a weak spring that cannot push up rounds fast enough to keep up with the cycling rate and you have a possible need for an extended ramp to increase the odds of a bullet feeding. If you fall into the above situation, you need extended feed ramps.  If you don't, extended ramps will certainly not hurt you, but you shouldn't pay any more to get them, as they probably aren't needed.  If you choose to get extended ramps, I recommend you get the proper equipment to get them, rather than hacking them into existing equipment.  YMMV.

+1 with Mongo....again!

I have had one occaision where the mag catch did start to wear and the bullets would hang up on the barrel extension. I "dremeled" M4 Type feed ramps in that upper, and adjusted the Mag Catch. no more problems. Question was...what fixed it? The ramps or the mag catch adjustment?

I agree that 99% of the time M4 ramps aren't needed. The same can be said about "Walking trigger Pins", but I've had that happen too.

IMHO, and FWIW....anything you can do to a "Serious" Defensive Weapon to make it more relaiable...do it! Too many here snub there nose at these types of things like Magpul Followers, Ranger Plates, Anti-Walk Pins, and M4 feed ramps. They are innovations, and at least from my viewpoint...they are solutions to those 1 in a Million problems that can occur.

Eliminate these issues before they make your Weapon go "Click"...when it should go "Bang!"

BTW...My LMT MRP has M4 Feedramps.

Tack

Quoted: Quoted: It simply eases feeding during loading with a high bolt velocity (which also happens in semi in short barreled large gas ported weapons) * any 14.5" or shorter * anyone shooting 69gr+ ammo * any full auto * anyone with a suppressor It will never hurt (if done properly). Kevin, just to make sure I'm clear, are you saying that regardless of the gas system length, a rifle shooting 69gr+ should have M4 feedramps?

No.  20" rifles, which is all I have experience with, will feed heavy bullets all day long with normal feed ramps.

I don't even know why heavier (longer) bullets are being brought up as a reason to have M4 ramps.  The extra length of the bullet (compared to M193/M855) goes INSIDE the case, as the cartridge still has to fit inside a magazine (OAL < 2.25").  I load my Hornady 75 reloads to 2.24" and they work just fine in slow and rapid fire.

By far the most common malfunction I have ever had with AR-15 type rifles is a bullet tip stubbing between the barrel extension and the receiver.  Next up would be a primer popping out from a hot load (not using ball powder solved that).  Only other trouble I have ever had involved two bum barrels, an E MP barrel that would have ejection trouble if not cleaned every 1,000 rounds, and a Colt's M4 barrel that was over gassed and had trouble with ejection (actually an extraction issue).  Going to green followers and using ramped barrel extensions has easily halved the malfunctions.  And I found that just a regular ramp job on the extension itself rather then the full blown M4 ramps does wonders, TANKS did the ramp jobs on my match service rifles (back when I dabbled in high power) and it was the extension only.

That said, it is entirely possible to shoot 10,000 round of hollow points with black followers and never have a a bullet tip stub.  Or shoot a short barrel with a weak extractor spring for years on full auto and never have an extraction issue, or etc, etc.  But that don't mean the day ain't coming.

the only time it could have benefitted me is when I was using hollow points with worn mags.the mags had play letting the hollowpoint catch where the feed ramp started.

+1 Mongo, great answer.

You've cleared myself also regarding M4 ramps. Thanks.
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G18 - the best in full-auto...

Quoted: Quoted: ....just to make sure I'm clear, are you saying that regardless of the gas system length, a rifle shooting 69gr+ should have M4 feedramps? No.  20" rifles, which is all I have experience with, will feed heavy bullets all day long with normal feed ramps. I don't even know why heavier (longer) bullets are being brought up as a reason to have M4 ramps.  The extra length of the bullet (compared to M193/M855) goes INSIDE the case, as the cartridge still has to fit inside a magazine (OAL < 2.25").  I load my Hornady 75 reloads to 2.24" and they work just fine in slow and rapid fire.

Thanks for the info SWO_daddy. I should have been more specific and mentioned that right now, my main concern is mid-length and rifle length gas systems. I guess I misread Kevin's statement. My 16" middie and 20" rifle do not have M4 feedramps and I don't plan on trying to change that situation. However, I need to build a good 'old carbine again someday so I might want to get M4 feedramps on that.

My LMT has them. My Bushy doesn't. They are both reliable.

What's the point of M4 feed ramps?

To make the M4 as reliable as possible, so our GI's have the advantage over the other guys they are shooting at.  


Let's not over complicate things around here.

Quoted: What's the point of M4 feed ramps? To make the M4 as reliable as possible, so our GI's have the advantage over the other guys they are shooting at.   Let's not over complicate things around here.

Well, if it makes it more reliable, that's what I was asking. But it poses another question (which it seems may have been answered). HOW? and How much more reliable does it make it?

Quoted: Quoted: What's the point of M4 feed ramps? To make the M4 as reliable as possible, so our GI's have the advantage over the other guys they are shooting at.   Let's not over complicate things around here. Well, if it makes it more reliable, that's what I was asking. But it poses another question (which it seems may have been answered). HOW? and How much more reliable does it make it?

Do you think you got the answer you wanted in the multi above replies?


ETA:

www.ar15.com/forums/topic.html?b=3&f=118&t=244896
www.ar15.com/forums/topic.html?b=3&f=118&t=245071
www.ar15.com/forums/topic.html?b=3&f=4&t=244951
www.ar15.com/forums/topic.html?b=3&f=118&t=244648
www.ar15.com/forums/topic.html?b=3&f=4&t=243709

Quoted: What's the point of M4 feed ramps? To make the M4 as reliable as possible, so our GI's have the advantage over the other guys they are shooting at. Let's not over complicate things around here.

Thanks Spooge. That pretty much answers my question. If I have a carbine length gas system, M4 feedramps aren't a bad thing to have. The longer the gas system, the less important they become.

If feeding is an issue try a dremel toll and polish the feed ramps. I normaly polish the feed ramps of my pistols and have never had a malfunction.

I still never had a jam and its been 53,000 plus rounds and I don't have the ramps. I think if I did get them on my next carbine I might then get a jam.