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Posted: 12/23/2002 5:21:16 PM EDT
Anybody have a Colt M4? I am curious about those fabled feed ramps and their value. Can someone post a picture of what they look like so I can get a better feel for what they do? Especially if it's worth the difference between me paying $900 for a Bushmaster or $1100 for the Colt.
Link Posted: 12/23/2002 6:26:57 PM EDT
[#1]
If you search the AR15 board for "feedramp", I'm sure you'll find pictures.  There were several posted her in the last two months or so.
Link Posted: 12/23/2002 6:44:26 PM EDT
[#2]
Did the search and found a couple threads ...but either the pic server isn't working, or the people have removed the posted pics from their albums.

PS:  search for "m4 feed"
Link Posted: 12/23/2002 7:31:31 PM EDT
[#3]
Is this what you are looking for??

[img]http://www.bobshuntingpage.com/feedramps.jpg[/img]
Link Posted: 12/23/2002 10:48:02 PM EDT
[#4]
Geez... looks like 15 minutes with a good die grinder could save someone a few hundred bucks.

Anyone ever done it this way?

Just curious.

Noface
Link Posted: 12/24/2002 6:46:47 AM EDT
[#5]
I put a standard barrel in my M4 upper and the bullets occasional catch on the edge. I'll be using a grinder shortly!
Link Posted: 12/24/2002 8:17:09 AM EDT
[#6]
I used a felt bob on the end of a dremel tool with some diamond lapping compound.The feed ramps on my bushmaster and part of the upper polished up very nice.
[^]
Link Posted: 12/24/2002 8:40:39 AM EDT
[#7]
Save your bucks....Kurt's Kustom will grind them in for less then 200 bucks I think.  
Link Posted: 12/24/2002 9:47:47 AM EDT
[#8]
Unless you are shooting full-auto, I wouldn't waste the money. [:(]
Link Posted: 12/26/2002 2:38:30 PM EDT
[#9]
Exactly what I was looking for. I had a lot of trouble understanding what folks were talking about. I don't have ANY problems feeding my Bushy Shorty, almost 1,000 rounds through her now. Thanks for the pics!
Link Posted: 12/26/2002 7:13:33 PM EDT
[#10]
glock23c,
Good quality Colt fit and finish I see (second photo).....

Link Posted: 12/26/2002 9:48:20 PM EDT
[#11]
If your not shooting the variety of ammo some spec ops guys get, its of no use. Even these are cleaned up via grinder. BTW I just got a RRA upper and they did grind in some nice looking extended feed ramps.
Link Posted: 12/27/2002 7:40:15 AM EDT
[#12]
According to the discussion forum on Kurt's Kustom Firearms website, he will do ramp jobs for $35 +S&H, but they really only benefit select fire rifles.
Link Posted: 12/27/2002 9:06:09 AM EDT
[#13]
Quoted:
glock23c,
Good quality Colt fit and finish I see (second photo).....

View Quote


Yeah, I think the same thing every time I see that picture as well.  Makes me glad that I'm not willing to spend the big bucks for Colt "quality" on a post-ban rifle.
Link Posted: 12/27/2002 9:12:10 AM EDT
[#14]
These magical feed ramps are not only found on the mysterious M4 that everyone drools over.  My Sporter has them, my Match HBAR has them, in fact I think every one of my Colt rifles has the teeny weeny little grooves that gets everyone so excited!  Some of these rifles were made long before Colt made the first M4, so they really have nothing to do with the M4, just the M16 family of rifle.
Link Posted: 12/27/2002 9:32:19 AM EDT
[#15]
Quoted:
I think every one of my Colt rifles has the teeny weeny little grooves that gets everyone so excited!  Some of these rifles were made long before Colt made the first M4, so they really have nothing to do with the M4, just the M16 family of rifle.
View Quote


I have a like new surplus Colt M-16A1 upper on my RRA lower, no extended feed ramps. I'm looking at my buddies Model 614, no extended feed ramps on it either.
Link Posted: 12/27/2002 11:18:52 AM EDT
[#16]
The ramps have nothing to do with full auto.  They are there because of the carbine buffer and gas system.  When the carrier moves back and ejects a round you will have the carbine bufer move back faster than the rifle buffer due to lower mass and the more violent action of the gas impulse from the closer gas port.  If you have weak mag springs the bullet can fail to come up fast enough and the bolt will be coming back to strip a round faster than the mag spring can get a round up and you will have the bullet jam just below the feed ramp causing a malfunction.  If it hits an extended feed ramp it will just slide up and load normally.
Link Posted: 12/27/2002 12:14:52 PM EDT
[#17]
Link Posted: 12/27/2002 12:58:25 PM EDT
[#18]
RayDBones
You might want to have a closer look.
Link Posted: 12/27/2002 1:02:46 PM EDT
[#19]
Quoted:
Quoted:
glock23c,
Good quality Colt fit and finish I see (second photo).....
View Quote


You're looking at the difference between a brand new upper (right) and one with about 8,000 rounds through it, that isn't particularly clean (left).  I know because I took those pictures.

-Troy
View Quote


Thanks for the info, Troy.  I wondered where those pics came from.

BR
Link Posted: 12/27/2002 1:21:24 PM EDT
[#20]
Quoted:
Quoted:
glock23c,
Good quality Colt fit and finish I see (second photo).....
View Quote


You're looking at the difference between a brand new upper (right) and one with about 8,000 rounds through it, that isn't particularly clean (left).  I know because I took those pictures.

-Troy
View Quote


I believe USNJoe was referring to the new receiver on the right.  The machining of the feedramps does not line up properly with those of the chamber itself.
Link Posted: 12/27/2002 1:27:18 PM EDT
[#21]
That's not what I was commenting about.
The feed ramps that are cut into the upper are off center from the feedramps cut into the barrel big time on the one on the right.


Quoted:
You're looking at the difference between a brand new upper (right) and one with about 8,000 rounds through it, that isn't particularly clean (left).  I know because I took those pictures.
-Troy
View Quote
Link Posted: 12/27/2002 3:26:42 PM EDT
[#22]
Link Posted: 12/27/2002 3:56:15 PM EDT
[#23]
Quoted:
RayDBones
You might want to have a closer look.
View Quote


Now you made me go rooting around in both safes (like I need an excuse!!).  What I found is very interesting.

My Colt Sporter Match HBAR (A2 upper with 20" heavy bbl - large hole) does not have the extended feed ramps milled into the barrel extension or into the receiver.

Both my Colt Sporter Lightweight's (A2 uppers with 16" bbls - small hole) DO HAVE the extended feed ramps milled into BOTH the barrel extension and the receiver as in the photo above.

Both my Colt "M4" uppers (the real deal - 14.5" machine gun uppers - small hole) DO HAVE the extended feed ramps in BOTH the barrel extension and the receiver as in the photo.

As expected, the RRA LAR-15 and the Bushmaster XM15-E2S DO NOT have extended feed ramps.

So now the question becomes - are the feed ramp extensions found only on the Colt small hole uppers as my small sample size would suggest or is there some other explaination???  Or are they only on the small hole 16" and shorter barreled uppers to combat bolt bounce as suggested above??  Or is it some other mystery Colt has added to their guns to make yet another variation??  Large hole/small hole; big pins/small pins; sear block/no sear block; lug/no lug; and now feed ramps/no feed ramps!!!!!  What will they think of next?
Link Posted: 12/27/2002 10:08:06 PM EDT
[#24]
Link Posted: 12/28/2002 4:48:35 AM EDT
[#25]
BTW to the original poster,

You can have Kurt Wala from KKF in the industry section cut Colt style feed ramps for very little $.  I have had him do some work for me in the past and it was excellent.
Link Posted: 12/28/2002 5:41:03 AM EDT
[#26]
My VERY inexpensive DPMS M-4 upper has the deeper M-4 feed ramps which are milled into the receiver... And they match a lot better!
Link Posted: 12/28/2002 6:07:05 AM EDT
[#27]
Link Posted: 12/28/2002 8:12:10 AM EDT
[#28]
Ditto on my DPMS M4 upper. 1 in 7 chrome-lined with the extended feed ramps.
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