M4 feedramp thread

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Posted: 5/18/2005 11:18:36 PM EDT

Does anyone have the link to the M4 feedramp thread with pic showing what REAL M4 feedramps look like and what combinations of extensions and uppers work and do not work?

Posted: 5/18/2005 11:28:26 PM EDT

[#1]

www.ar15.com/forums/topic.html?b=3&f=118&t=191733

Posted: 5/18/2005 11:31:55 PM EDT

[#2]

THANKS!

Posted: 5/18/2005 11:45:17 PM EDT

[#3]

Damn, now i'm confused.

Okay, so is it OKAY to use the M4 extension with the "feedramps" in an upper that DOES NOT have the corresponding "cuts" to go with it?

Posted: 5/19/2005 5:25:59 AM EDT

[#4]

Quoted:
Damn, now i'm confused.

Okay, so is it OKAY to use the M4 extension with the "feedramps" in an upper that DOES NOT have the corresponding "cuts" to go with it?

That combo will probably work but if you really want to be sure get a upper receiver with the factory ramps. IMHO, it will be worth it especially if you're getting a new barrel.

Posted: 5/19/2005 5:54:18 AM EDT

[#5]

I think the easiest way to look at this is match your feedramp (barrel extension) to your upper. M4 upper M4 barrel extension. Regular upper (no M4 cuts) goes with rifle barrel extension.

Posted: 5/19/2005 12:05:29 PM EDT

[#6]

I use a Colt M4 barrel that has the true M4 ramps in a upper receiver without the little M4 cuts, and it works perfectly well. No change in feeding reliability from my experiences.

However, it would not be a good idea to use non-M4 ramped extension in an upper receiver that does have the little M4 cuts in it, because that creates a little edge that could conceivably catch a bullet nose on feeding.

Posted: 5/19/2005 12:18:11 PM EDT

[#7]

So what is the big deal about the M4 ramps? I mean, the AR has been around a long time and hasn't had any major feeding problems, has it? Is it (M4 ramps) a solution to no problem? Thanks.

Posted: 5/19/2005 12:34:53 PM EDT

[#8]

Quoted:
So what is the big deal about the M4 ramps? I mean, the AR has been around a long time and hasn't had any major feeding problems, has it? Is it (M4 ramps) a solution to no problem? Thanks.

for short rifles like the M4, it has improved.

Posted: 5/19/2005 8:49:41 PM EDT

[#9]

Quoted:
Damn, now i'm confused.

Okay, so is it OKAY to use the M4 extension with the "feedramps" in an upper that DOES NOT have the corresponding "cuts" to go with it?

You will probably be OK. What you would NOT want to do, is use a barrel extension WITHOUT the cuts in a receiver WITH the cuts. This leaves a lip where the two meet that CAN cause a feeding malfunction.

Lonny

Posted: 5/20/2005 9:50:03 AM EDT

[#10]

You will probably be OK. What you would NOT want to do, is use a barrel extension WITHOUT the cuts in a receiver WITH the cuts. This leaves a lip where the two meet that CAN cause a feeding malfunction.

No. There is no disadvantage to using an M4 cut receiver with a standard rifle extension, you just won't get the benefit of the M4 cuts, it will be just as reliable as a standard receiver with a standard extension. Adding the M4 cuts cannot lower reliability. Let's say the rounds are feeding low and you didn't have the M4 cuts, they would just slam into the receiver = jam. A properly functioning rifle never puts those rounds anywhere but straight into the barrel extension.

Posted: 5/20/2005 6:17:38 PM EDT

[#11]

Quoted:
You will probably be OK. What you would NOT want to do, is use a barrel extension WITHOUT the cuts in a receiver WITH the cuts. This leaves a lip where the two meet that CAN cause a feeding malfunction.

No. There is no disadvantage to using an M4 cut receiver with a standard rifle extension, you just won't get the benefit of the M4 cuts, it will be just as reliable as a standard receiver with a standard extension. Adding the M4 cuts cannot lower reliability. Let's say the rounds are feeding low and you didn't have the M4 cuts, they would just slam into the receiver = jam. A properly functioning rifle never puts those rounds anywhere but straight into the barrel extension.

Umm, negative.

I should know, I have an M&A Parts M4 upper assembly that has an A2 upper (has the cuts in the reciever) and they put a 16" M4 barrel in it that had a rifle barrel extension. I will admit that it went 1800rds, or so, without giving me much trouble, but it turned into a jamm-o-matic one day while shooting. I got to looking at it, noticed what the morons did wrong, whipped out the dremel and blend the barrel extension into the reciever feed ramps, and VIOLA! instant reliability.

Some people might not have any problems, but an M4-ramp reciever and a rifle barrel extension is NOT a good thing.

WIZZO

Posted: 5/20/2005 10:33:09 PM EDT

[#12]

what I'm saying is that it still would have been a jamomatic if you had used a standard receiver... how could it not be? You are feeding rounds into the receiver, if there aren't any ramps there, then BAM! a round gets smashed head on into the receiver and probably seats the bullet back in the case. M4 cuts: You're jammed if you do, and jammed if you don't.

Posted: 5/20/2005 11:12:15 PM EDT

[#13]

I understand where you're coming from, and completely understand what you're talking about.

But my experince has lead me to believe that ideally, the correct barrel extension SHOULD without a doubt be matched with the corresponding upper receiver.

Do I think that an M4 cut upper/barrel extension assembly is necesary for a carbine to run right?

No. Carbines were(and are still) made for years without the M4 cuts in the barrel extension/upper receiver and they don't suffer from decreased reliability.

WIZZO

Posted: 5/21/2005 11:39:27 AM EDT

[#14]

Thanks, guys.

M4 extension needs M4 upper; however it may work if you use a standard upper with no cuts.

Rifle extension with M4 upper is a big negative.

Posted: 5/21/2005 2:00:54 PM EDT

[#15]

That's pretty much the jist of it.

WIZZO

[ARCHIVED THREAD] - M4 feedramp thread

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