M4 Feedramps

[Shihan]

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]

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]

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]

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]

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

[RallySoob]

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]

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]

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]

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 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]

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! None of the local Scum WalMarts have it.