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K.L. Davis
06-15-06, 01:46
Here is another fun debate... Rather than take sides, I will try to do the Fox News "you decide" sort of thing. And now, for your viewing pleasure, the M4 Feed Ramp.

So what are they? Well, all ARs have feedramps cut in the barrel extension... the bottom two lug cuts in the barrel extension are widened and ramped to guide the round into the chamber during loading.

So what is different about the M4 ramps? Well, on a regular AR type platform, the ramps are cut into the barrel extension only -- the M4 style ramps are cut so that the cut "breaks through" the barrel extension and cuts slightly into the upper receiver. To be honest, an M4 feedramp is really a two piece arrangement... part of it is in the barrel extension and part is in the upper receiver.

Here is a great picture that shows the difference, shamelessly stolen from bigbore (thanks Steve).
http://img156.imageshack.us/img156/407/m4cuts0xk.jpg

As you can see, the feed ramps on the regular rifle barrel are cut just to the edge of the barrel extension... but do not extend beyond that edge; while the M4 ramps continue slightly "outside" of the barrel extension.

As stated, the rest of a properly cut M4 feedramp is in the upper receiver... while the cut in the receiver is small, it matches up with the cut in the barrel extension and makes for a smooth, continuous ramp.
http://img140.imageshack.us/img140/5797/installed5tq.jpg

So why are they there? Ughhhh... here are both sides, the extremes at that:

1. "M4 feedramps serve no purpose at all, they are nothing more than an attempt by Colt to get a patent continuation based on redesign."

2. "M4 feedramps are the greatest thing since canned beer... in order to have a reliable rifle, you must have them. It is a miracle that the platform has functioned this long without them."

Here are some of the facts that lie between those two arguments. With the proliferation of the the carbine gas system (https://www.m4carbine.net/showthread.php?t=94), there did come some unique problems -- it is believed that with the M4, there are times when a cartridge being loaded is more "tip down" than normal, and that the bullet tip could strike the flat surface of the upper receiver, just below the standard rifle feedramp.

So, the ramps were extended down slightly, in order to catch these.

There is a suggestion that the use of heavier bullets also exacerbates any potential problem... this idea seems to have some weight (get it) -- and of course the use of soft or open tip ammunition can help make things snag.

So... Do I need them? Being married has taught me that there are varying degrees of need. The honest answer would be that unless you have a select fire carbine... no, you can get by fine without them. Truth is, everyone that really "needs" them has been given a rifle that has them... I certainly would not run out and replace an upper, just because it does not have M4 feedramps. Note: With the increased use of larger diameter cased cartridges (6.8 SPC, etc), the M4 feed ramps are proving to be of value when using these cartridges... the magazine lips can not move, so with these larger diameter cartridges, the tip of the bullet sits lower in relation to the centerline of the bore (half of the diameter increase to be exact) -- this puts the cartridge in a position where feeding is improved by the extended feed ramp.

Okay, but do I want them? Well, sure, why not. As they are becoming more and more the standard and they certainly do not do any harm -- why not look for them on your next purchase. Again, I wouldn't consider them a deal breaker and would not pass up a good deal on an upper only because it did not have them. Our military is doing just fine with a whole lot of rifles that do not have them...

And all of this is in a perfect world. Feed problems can be caused by several things... the fact that magazine quality is all over the map is most often the first suspect and there is more than one lower receiver in the wild that has an out of spec mag well.

My gun has an M4 barrel, but it looks like someone cut the ramps in the upper receiver with a dremel tool! That is most likely exactly what happened. There are a lot of uppers out there that do not have the cuts... hand cutting the upper receiver with a dremel is a quick way to make the conversion.

Granted, it may not look so great, but odds are (if they are actually doing anything) they will work fine. The most obvious fault with this method is that the cuts are not refinished and you see bare aluminum -- while there may be some surface hardness that is not there... you will wear out a lot of other things on the gun before you have to worry about any problems with "wearing" on the hand cut ramps.

If you are the kind of person that lays awake at night and obsesses over the dire thought that your feedramps were not refinished... well, hit one of the dealers on the site up for a new upper so you can relax. :rolleyes:

Can I run a M4 barrel in a regular upper receiver? Sure, there seems to be no issues with this... or you could just dremel in the receiver cuts. :p

Can I use a regular barrel in an upper receiver with M4 cuts? I don't recommend it... there is a chance that the round can jam on the little "lip" that is caused by the barrel extension extending into the cut; however, there are guns out there that have this setup and work fine -- this tends to go towards the thought that the ramps really do very little? Again, it is not a setup that I would feel all warm and fuzzy about. Here is why...

http://img149.imageshack.us/img149/2064/snags9kb.jpg

SinnFéinM1911
06-15-06, 07:22
Dude - Great info, I hope alot more poeple read this - I run into a lot of Agencies or Departments that have a firearms intructor's that always knows more than everyone and they "need" for them. When they dont even know what - or how they even work.

Boom
06-15-06, 08:17
Excellent post. ;)

BravoCompanyUSA
06-15-06, 09:05
Outstanding summary!

Thanks,
Paul

Razoreye
06-15-06, 11:46
I love this site already! :D

Stickman
06-15-06, 22:05
Anyone know the angle difference between the two feedramps?


As someone who has had a real world failure to feed, I take great interest in this topic. I'm more than happy to agree that most people won't need them. However, if its for a duty weapon, and you are shooting soft point or hollow point ammo, I think its well worth having. My experience was with SP ammo.

That being said, if your mags are out of spec, don't blame the weapon for feed issues.

teltec01
06-15-06, 23:12
Very interesting post, with good information!

CapnCrunch
06-16-06, 05:16
KD, great post!

Something I've noticed (that echoes Stickman's experience) is that it seems like the problems are associated more with SP or HP ammo (62 grain Trophy Bonded Bear Claws are the worst!) than FMJ. When you take an 11.5" barreled rifle w/o extended ramps and start trying to push the TBBCs through aging mags you'll probably notice failures to feed sooner or later.

My extended thoughts on the matter are pretty simple... Why chance it? Both uppers cost the same amount and most quality barrels come with extended ramps either as standard or an option. If you're building up something a fighting gun, you might as well opt for the ramp as a no-cost upgrade.

K.L. Davis
06-16-06, 19:11
C'nC

The use of SP or HP ammo introduces a variable that changes things... in fact some people make that scrunchy face like they just stepped in dog poo at the mere mention of SP ammo in autoloading rifles.

The carbine gas system and short barrels also change things, and I am in the "why take any chances" camp when given all of the considerations that are brought up in some of the above posts... like I said, most people do not need them, but if you have the choice, why not. :D

ArchAngel
06-16-06, 23:19
Great info and post.

I am in the agreement that if you're building a new rifle then go ahead and get it. If the manufacturer that you're buying from already includes that on the rifle it's ok too.

I know some people freak out about "dremmel" cuts.

I wouldn't lie awake at night and worry about it either if you didn't have the M4 feed ramps and wouldn't change a working set up just to get them.

As Colt tried to maintain an "exclusivity" on the M4 I'm sure this was a tool used to try and retain that "unique-ness" and secure the title of M4.

Those that have a true M4 already have them and need not worry about it.

It will probably become "the" standard as years continue to pass. Is it necessary? - the jury is probably still out.

Any of the CAR-15s that I've handled never seemed to have a feed problem.

A lot of people haven't even been aware of the M4 cuts until recently.

Nice post, nice info. Glad to see a sticky on it.

Ice Cream Man
06-17-06, 08:13
Great post very informative.

KyBlaster
06-17-06, 08:29
Thanks for the info.
Great post.

Stickman
06-17-06, 11:18
C'nC

The use of SP or HP ammo introduces a variable that changes things... in fact some people make that scrunchy face like they just stepped in dog poo at the mere mention of SP ammo in autoloading rifles.



I agree, but some of us poor bastards are stuck with SP and HP 5.56 for most occasions. I can't help but wonder how the 77 grain OTMs would do as a general issue round in weapons that did not have the enhanced feedramps. I don't have an answer, and I can't help but wonder if someone hasn't already done the testing....

C4IGrant
06-17-06, 12:00
I agree, but some of us poor bastards are stuck with SP and HP 5.56 for most occasions. I can't help but wonder how the 77 grain OTMs would do as a general issue round in weapons that did not have the enhanced feedramps. I don't have an answer, and I can't help but wonder if someone hasn't already done the testing....


I shoot 77gr ammo in a weapon with rifle feedramps. No issues.


C4

Stickman
06-18-06, 20:17
I shoot 77gr ammo in a weapon with rifle feedramps. No issues.


C4


Good info to know.

Robb Jensen
06-30-06, 04:33
Anyone know the angle difference between the two feedramps?



Rifle = 45 degrees
M4 = 52 degrees

GETSUM
07-28-06, 14:58
MY 1st POST -----

HERE IS A LINK TO MY HOME MADE M-4 FEEDRAMPS...

Hope this adds to the info.

http://www.ar15.com/forums/topic.html?b=3&f=118&t=288581



















-

M193 BALL
08-25-06, 13:06
My Defender 2000 LMT has the M4 ramps
When I shoot the Ranger 64gr PP the nose still gets smash up a bit, but feed 100% make sure you clean the build up
I feel it better to have them! since it wont make the AR15 any less reliable

SuicideHz
08-25-06, 13:56
I agree, but some of us poor bastards are stuck with SP and HP 5.56 for most occasions. I can't help but wonder how the 77 grain OTMs would do as a general issue round in weapons that did not have the enhanced feedramps. I don't have an answer, and I can't help but wonder if someone hasn't already done the testing....

I think Travis has done quite a bit of informal field testing on live targets...

Robb Jensen
08-25-06, 14:54
I think Travis has done quite a bit of informal field testing on live targets...


Yes Travis' shooting was with MK262 in a Bushmaster Gov't profile A2 20" bbl w/o M4 feedramps IIRC.

AR15barrels
09-04-06, 00:24
Rifle = 45 degrees
M4 = 52 degrees

I took some specific measurements on ramp angle a while back and came up with 37-38 degrees on rifle ramps and 45 degrees on M4 ramps.

Depending on which side you were measuring from, we may both be right...

Here's how I was measuring:

http://www.ar15barrels.com/tech/feedramp-angle.jpg

Robb Jensen
09-04-06, 02:45
I read it in 'The Black Rifle II' page 69-70 (Designing the New M4 Receiver), they credited the data from Copyright 2002-2003 Colt Archive Properties LLC Used w/permission, all rights reserved. I'm sure the angles vary slightly from manufacturer to manufacturer. Colt also may have since changed angles I'm not sure. I've never checked one myself.

smith m4
09-08-06, 13:49
Great Post !

Thanks for taking the time to put it together.

ashooter
02-27-07, 21:33
I've always subscribed to the belief that M4 ramps probably don't help much, but don't hurt anything either... But I have a "frankengun" carbine that has an M4 ramped barrel extension and no ramps on the receiver. Shot maybe 1000-1500rds through it with at least 2-3 times every 100 rds where a bullet tip would hang up on the upper receiver just short of the barrel extension, causing me to get a little extra practice with transitions and the "rack and roll" drill.

After seeing some pics c4igrant posted here of Rock River's dremel jobs, I thought "hell, I can do better than that" and gave it a shot.

Roughly 500 rds since my dremel job, I've had zero function problems. So maybe those M4 ramps do help a little. They sure seem to have helped in my beater carbine.

Greenbean
03-08-07, 09:19
the M4 style ramps are cut so that the cut "breaks through" the barrel extension and cuts slightly into the upper receiver.

Man this site it awesome, About 2 months ago when I really got intrigued and started to research my first AR purchase and I started narrowing it down to an M4gery...lol...
I asked almost 5-6 guys that sounded like they had a handle on what they were talking about in two different shops, One was a salesman who was pushing the S&W M&P AR to me and he didn't have a clue.

Thanks again M4carbine...:cool:

SHIVAN
08-18-07, 15:55
bump...

Armati
09-03-07, 16:02
It seems that the M4 feed problem is related to a fast moving bolt and a slow moving magazine. It would stand to reason that long heavy grain ammo would also add to this problem.

Would a mid length gas system help here? I am beginning to believe that the 16" mid-length system may be the best of all possible worlds.

With all of the hype on 'M4 cuts' I wonder if we will see regular uppers selling at a discount.

docsherm
09-05-07, 15:56
This is some of the best M4 info I have read in a very long time. Thanks.

hags
09-05-07, 22:16
I shoot 77gr ammo in a weapon with rifle feedramps. No issues.


C4

I also shoot, 75gr, 77gr and 80gr, HP and match grade ammo with a rifle feedramp configuration. Absolutely zero issues.

Iraqgunz
02-27-08, 05:35
That was a very informative and descriptive post. When I worked as a civilian armorer with the Marines and we converted some M16A4's to M4 configuration we did a complete mod to include the receivers. That was the way they directed it to be done.

SilverEagle
03-03-08, 16:43
Roughly 500 rds since my dremel job, I've had zero function problems. So maybe those M4 ramps do help a little. They sure seem to have helped in my beater carbine.




Full auto aside, is the issue here the length of the gas tube? I understand that a miss-matched receiver and barrel will cause problems feeding, but in a stock "rifle cut feed ramp"- M4 Length system will there be problems? Does anyone have operating experience about that? Do these beasties even exist?

Additionally, is there an increase in problems if you run a true SBR M4 verses a 16" with carbine length tubes?

austinN4
03-04-08, 06:26
Great post! Thanks for taking the time to put it together.

Robb Jensen
03-04-08, 07:08
Full auto aside, is the issue here the length of the gas tube? I understand that a miss-matched receiver and barrel will cause problems feeding, but in a stock "rifle cut feed ramp"- M4 Length system will there be problems? Does anyone have operating experience about that? Do these beasties even exist?

Additionally, is there an increase in problems if you run a true SBR M4 verses a 16" with carbine length tubes?

In theory the 14.5" guns are cycling a little faster than 16" guns (as most 14.5" bbls have bigger gas ports) BUT they usually don't since many people who have 16" guns are running lighter bolt carriers (semi-auto) which then places the cyclic rates closer to the same. This is why I recommend running M16 carriers. The XM177/CAR/M4 wasn't designed around using a semi auto carrier.......why dick with what we know works? There are still some people out there with very tight tinfoil that think that semi auto carriers somehow then define your rifle as a machinegun.

The length of the gas tube protruding in to the upper receiver is the same whether it's CAR, ARmaLite midlength, KAC midlength, intermediate, or rifle.

What do you mean by a 'true SBR M4' ? Do you mean a 14.5" M4? If so yes, rifle ramps in a rifle ramped receiver works for most people, most don't have full auto.

The ramps cure rare problems, most of the time they aren't needed BUT if you have M4 ramped receiver you should have a M4 ramped barrel. The ramps help with weak mags, fast cyclic rate guns and rounds with odd projectile ogives.

I recommend having M4 ramps for anything that cycles faster then a midlength.

I have a VLTOR MUR upper receiver (with M4 ramps) on my 3gun rifle and I 'Dremeled/WECSOG'd/Hack-Fu'd' the ramps myself on its midlength RRA barrel extension. It still works even with the new JP LMOS 6.25oz carrier and the damn thing shoots like my 10/22 now with the light carrier and muzzle brake combo. It feeds even 50gr American Eagle hollowpoint and the PMAGs have no problem keeping up with the increased bolt speed. To ensure that it works ALL the time I may still add Wolff +10% mag springs to my dedicated PMAGs for this rifle. Sunday I did find out that I do need to lube my Geissele trigger more often than I have been (which was never ;) ). I relubed it after it failed to reset a few times and all was good.

AR15barrels
03-05-08, 01:04
In theory the 14.5" guns are cycling a little faster than 16" guns (as most 14.5" bbls have bigger gas ports)

I disagree on most 14.5" barrels having bigger gas ports.
Having measured 100's of gas port diameters, I can tell you that there is more variance from manufacturer to manufacturer than there is from 14.5" to 16" barrels within any single manufacturer, or even amongst every major maker averaged together.

Iraqgunz
03-05-08, 01:35
My understanding for the reason of faster cycling is due to the shorter distance that gas travels through the gas tube (faster) therefore causing a more violent extraction. I have examined some barrels that were 14.5, 16, and 20 inch. with a bore scope and my Mk1 Mod0 eyeball couldn't see a difference in the sizes.


I disagree on most 14.5" barrels having bigger gas ports.
Having measured 100's of gas port diameters, I can tell you that there is more variance from manufacturer to manufacturer than there is from 14.5" to 16" barrels within any single manufacturer, or even amongst every major maker averaged together.

Robb Jensen
03-05-08, 05:32
I disagree on most 14.5" barrels having bigger gas ports.
Having measured 100's of gas port diameters, I can tell you that there is more variance from manufacturer to manufacturer than there is from 14.5" to 16" barrels within any single manufacturer, or even amongst every major maker averaged together.

I should start writing down what I've encountered. I'm finding differences of about .003-.004" between 16" and 14.5"s bbls usually from the same manufacturer......some of it might be the wear of the barrels.

rockm4
03-30-08, 16:23
I also shoot, 75gr, 77gr and 80gr, HP and match grade ammo with a rifle feedramp configuration. Absolutely zero issues.

I hand load 98% of the ammo that i shoot witch, mind you is only about 3oo to 4oo rds at a time every two weeks or so but i load 40gr. sxp, through 77gr. in all types of sp,hp and fmjs. and never had any feeding problems w/ my RRA or old COLT SP1. but i am very anal of specs. on my cases and conditions of the wear on my mags and wear on my mag release catch.:confused:

opticalc
04-02-08, 10:33
so for "rifle feedramps", the barrel cuts are not extended, and the upper receiver has no cuts at all?

and assuming that i did want to mod my own upper to have m4 feedramps, what size round file would be needed?

Shihan
04-02-08, 17:58
so for "rifle feedramps", the barrel cuts are not extended, and the upper receiver has no cuts at all?

and assuming that i did want to mod my own upper to have m4 feedramps, what size round file would be needed?

Its best not to mess witht he feedramps unless you are having problems as you will remove the protective hard annodizing.

RallySoob
05-20-08, 08:49
is it possible to swap your standard bbl extension out for a M4 bbl extension? I have m4 ramps on my upper and not my bbl. I have had not 1 hitch in 2500+ rnds but I would feel better with M4 ramps...
Any advice would be most appreciated

Shihan
05-20-08, 12:30
is it possible to swap your standard bbl extension out for a M4 bbl extension? I have m4 ramps on my upper and not my bbl. I have had not 1 hitch in 2500+ rnds but I would feel better with M4 ramps...
Any advice would be most appreciated

Nope.....

Col_Crocs
05-20-08, 19:09
is it possible to swap your standard bbl extension out for a M4 bbl extension? I have m4 ramps on my upper and not my bbl. I have had not 1 hitch in 2500+ rnds but I would feel better with M4 ramps...
Any advice would be most appreciated

If youve never had problems I wouldnt touch it but I understand how the thought bugs you. I get like that too. If you must, I think you can have it ground down. -- By someone who knows what he's doing ofcourse but I think that could be the start of a whole new issue. -- Exposed metal which is probably going to bug you just as much.

scottryan
05-20-08, 22:04
Great info and post.



As Colt tried to maintain an "exclusivity" on the M4 I'm sure this was a tool used to try and retain that "unique-ness" and secure the title of M4.




The problem with this is "M4 ramps" existed well before there was such a thing as an M4 carbine.

scottryan
05-20-08, 22:06
That was a very informative and descriptive post. When I worked as a civilian armorer with the Marines and we converted some M16A4's to M4 configuration we did a complete mod to include the receivers. That was the way they directed it to be done.


Agree and I don't recommend using a rifle upper with carbine feed ramps either.

Staind503
05-21-08, 02:02
this is the first time i've seen this post and i realize this thread was started 2 years but i've seen a lot of people talking about feed ramps and i always thought to myself WTF are feed ramps?? well know i know thank you this was a very informative thread:cool:

RallySoob
05-21-08, 13:10
If youve never had problems I wouldnt touch it but I understand how the thought bugs you. I get like that too. If you must, I think you can have it ground down. -- By someone who knows what he's doing ofcourse but I think that could be the start of a whole new issue. -- Exposed metal which is probably going to bug you just as much.

Yes, I seriously question how much it really helps when I absolutely have not had 1 jam or misfire in my AR since I built it. I only use P-mags and black hills or rem umc 55gr. (yes, the rem is crap ammo i know) I'm not exagerating here either guys, not 1 jam, or 1 problem period. I've bump fired a few clips w/o hitch as well...

My factory standard RRA CAR A4 had 1 problem after another until i finaly got rid of that upper. It would jam an unfired round in the chamber every 50 to 100 rounds...

I think you are right though, it would be more risky for me to attempt to fix it since it isn't really broken or causing me any grief. It will always be a semi-auto unless the laws seriously change and we all know they won't so I should be safe

lanceriley
05-21-08, 19:44
very informative thread. when I started the thread I didn't expect a lot of replies.


What do you do if you have an M4 UPPER. Then you buy a barrel with an extension which is not an m4 feed ramp?

do you replace the barrel extension? or do you just dremel the barrel extension to fit the upper reciever?

AR15barrels
05-23-08, 02:15
is it possible to swap your standard bbl extension out for a M4 bbl extension? I have m4 ramps on my upper and not my bbl.

I grind feedramps into the barrel extension in cases like this.
The trick is that you remove the barrel from the receiver so you don't cut through the anodizing.

Fyrwolf
07-31-08, 15:39
Ok, I just got a new Left Hand M4 upper from Stag Arms and shot it yesterday.

After sighting it in and polishing out the chrome lining with 200 rounds of various factory ammo from Win. Q3131 to Hornady 75gr Match HP, I had zero malfunctions of any kind using a 10rnd Bushmaster post-ban magazine. By the way, this 16" 1:9" twist weapon pulled in a .73", 5shot group at 100yds using Black Hills 'Blue Box' 52gr Match HP :D Anyway, in relationship to this thread, after shooting 200 rounds accurately on a bench. I loaded some of the Federal Power Shok 50gr HP you can get at Walmart in a 200 rnd bulk pack. While firing the first 30rnd mag, I had 4 failure to feeds, where the bullet tip caught the feed ramp/receiver transition and the force of the bolt shoved the bullet back in the case until case hit the receiver. :( I had already read this post before I went out to shoot, so I understood what happened. Out of curiosity, I switched to the 10rnd magazine, loaded and fired 10 rnds as fast as I could with the same ammo and had no problem. I then loaded 30rnds of the Black Hills 52gr HP in the 30rnd magazine and fired away, also with no problems.

My Conclusions...

1. Certain Ammo can be a problem without M4 feed ramps...
The Federal 50gr HP are fat, short bullets with big HP holes, that,
when observed feeding into the chamber by slowly hand releasing
the bolt/carrier, can snag on the feed ramp lip. The Black Hills 52gr
bullet is only 2gr heavier but is long and lean with a small HP hole
and did not come as close to the feed ramp lip, as such, not causing
the feeding problem. Therefore, HP ammo can be reliable without
M4 feed ramps, but short, fat ogive bullets need not apply.

2. The magazine can be the issue, but not the way you would think...
I noted that when the 10rnd Bushmaster magazine with the 'GI'
Green follower was used, I didnt have the same problem as when I
used a C-Products 30rnd mag with a MagPul 'enhanced' anti-tilt
follower. Again, when watching the bolt close in slow motion, I
observed that the follower tilting rearward just slightly is an
advantage to helping feed the 50gr HP. When the follower is
restricted from tipping, as in the MagPul, it drives the HP directly
toward the feed ramp lip. This is not to say the MagPul decreases
reliability, just that an anti-tilt follower may not be the best for
trying to feed wide tip ammo without M4 feed ramps.

So, yes, M4 feed ramps would be better, but only for using ammo the M4 was not really intended to fire, IE. lightweight HP. I will be doing further testing but I am only slightly disappointed that my upper does not have this feature since most of my shooting will be done with heavier weight bullets and mostly FMJ. ;)

markm
07-31-08, 16:39
Use a PMAG and it's a non issue. The front of the PMAG body covers the M4 feedramp so the bullet tip couldn't hit that low if it tried.

I wish I could find that damn Power shok ammo bulk around me! :mad: None of the local Scum WalMarts have it.

Fyrwolf
07-31-08, 17:03
Demigod, Where do you live? I'm in Oklahoma...I'm surprised they don't sell Glocks at the f'n convience stores here but, Walmart sells that Power-Shok 200rnd pack for $76. About the same price that you can get similar ammo from any online store, so it's not that awesome of a price, just convenient. I really just got it to blast it all thru the barrel to polish out the lining. Thanx for the suggestion. A P-Mag is on the must try out list.:D

Fyrwolf
07-31-08, 17:47
Demigod, Could you elaborate on the PMag advantages. I have been considering getting these instead of standard alum. or SS mags and using my 5 C-Products mags for training/kicking around. and using the better PMags for duty use. I also have a HK 30rnd super-duper-bitchin-expensive mag that I'm going to try out to correct the problem.

lanceriley
07-31-08, 19:10
somehow the pmags are smoother when loading. hope this helps.

MassMark
07-31-08, 22:06
First, knowing this is not the ammo thread, but waiting for my M4 upper, (complete with ramps), how accurate and reliable is the Federal Power Shok? Secondly, where are the Wal-Marts with this fodder in bulk? There's zero around Western Mass. The only bulk pack 223 I've seen is at Dicks Sporting Goods and it's UMC at $99.99 for 200! :rolleyes:

markm
07-31-08, 22:52
Demigod, Could you elaborate on the PMag advantages.


Yes.

https://www.m4carbine.net/showthread.php?t=9628

And I'm in Tempe, AZ. I've looked in 3 sprawl marts and haven't found anything. I really hate going near walmart so I'm not motivated to check many stores.

Iraqgunz
08-01-08, 03:01
Demi,

I had no idea you are in Arizona. When I go out to Tempe to check out ATF we'll have to do lunch.

markm
08-01-08, 08:35
Demi,

I had no idea you are in Arizona. When I go out to Tempe to check out ATF we'll have to do lunch.

Why not do a shoot? Aren't you moving here?

RallySoob
08-01-08, 10:33
First, knowing this is not the ammo thread, but waiting for my M4 upper, (complete with ramps), how accurate and reliable is the Federal Power Shok? Secondly, where are the Wal-Marts with this fodder in bulk? There's zero around Western Mass. The only bulk pack 223 I've seen is at Dicks Sporting Goods and it's UMC at $99.99 for 200! :rolleyes:

accurate and reliable enough. I love these walmart bulk packs. we have 3 walmarts in town so I generaly can get one whenever I want, lucky I guess...

Its amazing to me people are still unaware of how much better the P-Mag is than any other mag. The added reliability you get from the P-mag should make it the only mag to consider. I gave away all my old GI mags and strictly run P-Mags and always will.

not too mention, they look really nice too. Heres a shot of 1 of my P-Mags with ranger plates and Raineer Arms Grip Kit.
http://i136.photobucket.com/albums/q198/RallySoob/0718080943.jpg
and the 20rnd mags are great too...
http://i136.photobucket.com/albums/q198/RallySoob/20rndPmagpimped.jpg

Iraqgunz
08-01-08, 14:25
Demi,

We'll do a shoot and lunch. How's that? I'll only be home for about 36 days though, but for sure we'll make it happen.


Why not do a shoot? Aren't you moving here?

markm
08-01-08, 16:02
No sweat. Just contact me when it's time.

Fyrwolf
08-01-08, 18:43
The Federal Power-Shok put 10rnds in 1.5" (16" barely broken in barrel) in a sandbag rest at 100yrds, pretty accurate for bulk pack ammo. The interesting thing is I believe it is actually loaded in 5.56mm brass. The brass is all marked Lake City '08 or '07, with a crimped and sealed primer! It's available at all Tulsa area and Muskogee Oklahoma Walmarts.
This begs the question...Is all Lake City Brass 5.56mm? I ask because the Black Hills ammo I have is also marked LC '07 with crimped primers, and If I reload it, I want to know which is which.

Demigod, I fully follow your logic and after looking at my weapon with various GI mags loaded and unloaded as well as your pictures, my reaction is that I ordered 2 P-Mags w/ Windows today. Maybe you should send a resume to MagPul for a sales & advertising position. :p

mattjmcd
08-01-08, 19:01
Informative post. Thanks.

(durka takes a decent pic, I reckon:D)

NVFirefighter
10-06-08, 03:43
Quote:
Originally Posted by RallySoob
is it possible to swap your standard bbl extension out for a M4 bbl extension? I have m4 ramps on my upper and not my bbl. I have had not 1 hitch in 2500+ rnds but I would feel better with M4 ramps...
Any advice would be most appreciated.








Nope.....


Sorry to revive a dead horse, but could you elaborate on why this isn't possible to do??

I have a Oly Pre-Ban XM177 and wanted to keep the barrel as is, but I would like to switch out the A2 receiver to an A3. I was going to use the Vltor MUR but it states that a M4 barrel extension must be used. Hence, I started doing some googling and found many a vendor that sells M4 barrel extensions in the $20 to $25 range, including DPMS and a few other higher end vendors. I know it takes a special tool to remove it, which runs about $60, so I will take it to a local armorer to get it done without the purchase of the tool.

I wanted to just say great site!! I have been a lurker for a bit and now I want to upgrade some things and this place seems fantastic for ideas and info!

Thanks again!

AKsarben
05-09-10, 08:36
It could be that the bolt that you use and that barrel extension is head spaced to the correct dimension. Just putting on another extension would more than likely change a headspace. I believe that the way extensions are put on the barrel is that they are first "tuned" for headspace by the amount of contact to the barrel and then the cuts are made and they put in the index pin to match. I believe the head spacing is done before any drilling of the gas block or the index pin and that once they have the right head space spec, that they can simply unscrew the extension and finish the cutting in of the ramps of the M4 feed where they should be, and re-assemble the extension back onto the barrel.

If I am all wet on this, perhaps someone would correct this, as I was in belief that this is the procedure to head space the AR-15.

B52U
05-09-10, 11:04
As far as M4 feed ramps go, what is the difference between going with anodized ramps vs polished ramps?

rob_s
05-09-10, 11:10
As far as M4 feed ramps go, what is the difference between going with anodized ramps vs polished ramps?

Mostly that calling them "polished" tends to be a BS marketing ploy used to cover up the fact that the ramps were cut in after the fact. In today's market with uppers available from multiple forges there really isn't any reason not to use the extended ramps that are cut in prior to anodizing.

The other issue is that anodizing is not simply a painted-on or cosmetic finish, it actually hardens the surface of the too-soft aluminum. So, if the ramps are actually needed or used and the bullet tips are making contact, having them hit on a soft material like bare aluminum *could* cause problems.

Mike91A
05-09-10, 14:00
First, knowing this is not the ammo thread, but waiting for my M4 upper, (complete with ramps), how accurate and reliable is the Federal Power Shok? Secondly, where are the Wal-Marts with this fodder in bulk? There's zero around Western Mass. The only bulk pack 223 I've seen is at Dicks Sporting Goods and it's UMC at $99.99 for 200! :rolleyes: Went to Dick's yesterday. UMC 79.99 per 200 rds. As for 6.8 needing ramps. Learned that at the range. I ground and polished feed ramps in two uppers. Bought an M4 barrel extension as a guide/jig. Bought all M4 after that. Should't this thread be a sticky?

AR15barrels
05-19-10, 03:53
It could be that the bolt that you use and that barrel extension is head spaced to the correct dimension. Just putting on another extension would more than likely change a headspace. I believe that the way extensions are put on the barrel is that they are first "tuned" for headspace by the amount of contact to the barrel and then the cuts are made and they put in the index pin to match. I believe the head spacing is done before any drilling of the gas block or the index pin and that once they have the right head space spec, that they can simply unscrew the extension and finish the cutting in of the ramps of the M4 feed where they should be, and re-assemble the extension back onto the barrel.

If I am all wet on this, perhaps someone would correct this, as I was in belief that this is the procedure to head space the AR-15.

When an AR barrel is made, the barrel blank is chambered and threaded to accept a barrel extension.
The chamber depth is cut so that the cartridge protrudes 0.750" from the shoulder of the barrel.
This is the nominal spec and specific headspace gauges are used to check that a combination of bolt and barrel are within an acceptable range to be considered safe to fire.

http://ar15barrels.com/tech/ar15bolt-extension.gif

There is NO adjustment of headspace while the barrel extension is installed.
There is also no adjustment of timing or indexing of the extension.
The extension is installed far before the gas port is drilled, the barrel is roll marked or the FSB is installed.
The installation of the barrel extension actually determines where the top of the barrel is located.
The extensions are complete with feedramps and barrel indexing pin hole before they are ever installed on a barrel.
There is no standardization of thread timing so barrel extensions are not interchangable.

halo2304
06-05-10, 08:25
Awesome info! (And nice CAD work too! :D)

AKsarben
06-05-10, 09:37
Thanks for that info, Randall !! So, the barrel is undrilled and the barrel extension, with the M4 feedrams are tightened into place and the opposite of the very bottom of where the feed ramps are, is the very top of the barrle and once they are put into a Jig (I would assume they would always be put into a jig to get correct alignment) then the gas port hole is drilled. That determines the top of the barrel in relation to the feed ramps at the very bottom rear of the barrel.

I can see from this proceedure that there would be no way to assure that the gas port hole is drilled in the middle of a valley in the lands & groves of the barrel. It is drilled according to the ramps and at the distance where it needs to be and how it lines up with the rifling is inconsequential.

arizonaranchman
06-06-10, 01:24
Excellent summary and analysis! Thanks for sharing...

AR15barrels
08-26-10, 14:09
I can see from this proceedure that there would be no way to assure that the gas port hole is drilled in the middle of a valley in the lands & groves of the barrel. It is drilled according to the ramps and at the distance where it needs to be and how it lines up with the rifling is inconsequential.

If it's important to someone that the gas port ends up in the middle of a groove, then the barrel would be threaded for a barrel extension, but not chambered.
Then the barrel extension is torqued on and the gas port location is checked with a borescope.
A determination is made as to how much more rotation is required to center in a land.
Then the shoulder of the barrel is cut, the length of the extension threads cut and finally the barrel is chambered.
When the extension is re-installed, there will be a groove centered where the gas port is to be drilled.
This type of work is only done on a custom basis.
It's far too much work to do in a mass production environment.

RyanB
08-27-10, 00:56
Are M4 cuts necessary on an SPR? Ostensibly they have them to protect the bullet.

MarkG
12-21-10, 11:55
Feed ramps only exist in the barrel extension. The other “feed ramps” as they are often referred to in the upper receiver are more accurately defined as clearance cuts. Their purpose is not to guide the ammunition into the chamber but to prevent it from hitting a 90 degree corner and glancing off as the scalloping of the carbine barrel extension causes it to end short of the common edge with the upper receiver. All of the photos used to illustrate what the different ramps look like, rifle (45 deg) vs. carbine (52 deg), typically provide a from the rear chamber view. A side cutaway would clearly illustrate the necessity of the clearance cuts and why they increase reliability in the M4 carbine and its commercial counterparts.

AR15barrels
12-27-10, 16:26
Feed ramps only exist in the barrel extension. The other “feed ramps” as they are often referred to in the upper receiver are more accurately defined as clearance cuts. Their purpose is not to guide the ammunition into the chamber but to prevent it from hitting a 90 degree corner

However in doing so, the "clearance cuts" do indeed help to guide ammunition into the chamber. If you examine a few M4 cut and non M4 cut uppers with high round counts, you will no doubt see the copper deposited both on the 90 degree corner and in the clearance cuts.
This copper deposit is obvious evidence of the usefulness of the M4 cuts.

4thPointOfContact
12-28-10, 17:40
The problem with this is "M4 ramps" existed well before there was such a thing as an M4 carbine.

Now you've got me curious; just when did the "M4 ramps" make their appearance?
In a production model, or in a prototype?

SVT-ROY
12-28-10, 20:16
Very good info! I have been curious about this and didn't know what to look for. My m4gery has both the m4 feed ramps! Cool I guess.

scottryan
12-28-10, 20:56
Now you've got me curious; just when did the "M4 ramps" make their appearance?
In a production model, or in a prototype?



Colt started using extended feedramps around 1990 to 1991 on its carbines.

Dangerousdan
12-29-10, 10:08
This is valurable information, I'm looking forward to more of the same.
Thanks.:cool:

mkmckinley
08-05-11, 05:42
can i use M4 barrel on A1 reciver? please explain it in detail.
It seems to me it's been explained in minute detail earlier in the thread. Did you bother to read it?

usmcvet
08-05-11, 06:44
I assume you found this thread by using the search button. That's good. Now go to the top of this page and hit the tab that will bring you to page one and read the first post and check out the photos.

I am looking at mine now. It is an old Colt SP1 upper and a BCM 11.5" bbl.


https://www.m4carbine.net/picture.php?albumid=374&pictureid=1897

NoveskeFan
08-05-11, 07:01
Please would you help me by directing directly to that place which contains the information. Thanks.

Um...the last two points of the first post, to start.

Iraqgunz
08-05-11, 07:26
Please read the beginning of this thread. The information is there.


Please would you help me by directing directly to that place which contains the information. Thanks.

CLJ94104
04-17-12, 01:55
This should really be made a sticky. I'm just sayin. Thanks for the info guys.

Tweak
04-17-12, 02:54
Rifle = 45 degrees
M4 = 52 degrees


I've got a APR70 extension print that concurs with the 45 deg.
+/- 30' if I'm reading the blurry bastard right.

https://skydrive.live.com/redir.aspx?cid=b6c261153cc0be16&resid=B6C261153CC0BE16!153&parid=B6C261153CC0BE16!132&authkey=!ABayCggLbM69p3k

I'll just leave these here

http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/m16ramps.jpg
http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/m4ramps.jpg
http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/M4STDramps_Troy.jpg
http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/Albalos_M4_feed_ramps.jpg

What to look for.

http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/gregw45M4extstamp2.jpg

How not to do it.

http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/Armaliteramps2gixxerguy.jpg
http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/Armaliteramps1gixxerguy.jpg
http://i13.photobucket.com/albums/a264/artweaker/Troubleshooting/minuteman_coltm4_unmarked.jpg

LongBeach_Patriot
10-27-12, 08:46
I see on Stags website that the 2T comes with M4 feedramps, but everywhere on the web I read that it does NOT. Correct me if I am wrong please but arent these M4 feedramps? Appears to be when comparing pictures of M4 vs. Standard Rifle feedramps.

Thanks

http://i879.photobucket.com/albums/ab355/mperlman1234/photo-2.jpg

jb1911
10-27-12, 17:52
My opinion on this matter is that the M4 feedramps won't hurt, but they might help.

Here's some pix I found on another black rifle forum:

http://i48.photobucket.com/albums/f240/mvician/feedramps2-6.jpg

sinlessorrow
10-27-12, 19:09
My opinion on this matter is that the M4 feedramps won't hurt, but they might help.

Here's some pix I found on another black rifle forum:



I honestly do not see a huge need for M4 feed ramps if you have proper working magazines, They do help for worn magazine springs that are starting to move a little sluggish as they give you that extra space in case the round is not full pushed up in the magazine.

LongBeach_Patriot
10-27-12, 22:36
I'm a PMag whore so it really shouldnt matter with me but I still like having the same amenities as my classmates do.