AR Tech Tip – Checking M4 Ramps for overhang

My Dark Storm Industries upper has this problem. Never knew until just now when I checked. Have only fired M193 and Hornady Critical Defense through it. They feed absolutely fine with the Pmags I use. I checked my BCM upper as well and those looked perfect. No sharp edges at all.

Is this worth fixing if there's no feeding issues?

Would it be a problem to have the barrel ramps lower than the receiver ramps….i just checked one of my rifles and the receiver ramps overhang the barrel ramps ever so slightly….almost imperceptible but still it’s there?

This video is old but. I have a question, what if the aluminum feed ramp overhangs the steal one. Is that a problem or no since there is no lip to hang up on in the feed direction?

Noob question, is slight markings on the copper jacket when charging and unloading acceptable?

This is an easy check I can do but if needed, I’ll leave the fix to the pros.

Just checked my un-shot $1200 PSA Sabre M110-A1 and it has this issue. I guess polishing is in order. Thank you SOTAR!

Daniel Defense does this all the time with their uppers.

What would this cost?

Checked this on mine and was lucky enough to not have this issue. When I assembled the rifle I had no idea how much I didn't know about the platform. Love this channel for it's lack of excessive chatter.

Where can we purchase gunsmith tools like the ones you use?

Would this cause the rounds to have chunks of brass shaved off as it feeds ? I just recently got a dd mk18 and it is having trouble feeding more than 3 or 4 rounds in a row and i am seeing lots of brass shaving in my chamber after shooting very little!

What if it goes the other way and the receiver ramps are a tick above the barrel ramps (should be a no factor). I ask because after 40 to 50 rounds (any lube on the ramp is gone) open tip rounds seem to stop right at the receiver ramp, I am thinking due to angle and would like to smooth that area. It is a 6.5 Grendel of course and all the mag issues are visible from E-lander to Dura-mag to others which really are rebranded E-Landers, but this occurs just after the round leaves the mag and just stops at the receiver ramp… Thanks, as I too was breaking out the Dremel, but something told me you better you-tube someone like the School of the American Rifle first. Is there a polishing technique?

Amazing videos thank you so much for your time and expertise especially at no charge! Would love to see a video of how you remedy feed ramp
issues on the M4 when you remove the barrel thank you so much for amazing lessons.

What if it's the opposite, and instead of sticking out just a touch proud it's in a little too deep?

when you go to swap barrels out again wont you have the same issue?

good video!

My PSA receiver has the opposite, the receiver protrudes over the barrel ramps. I assume doesn't 'require' gunsmithing.

I thought Daniel Defense was soooo much better than that😢

Excellent video. Very informative. Thank you.

i have an lmt upper that is chewing up ammo a bit more than my other rifles. is this an issue?

Thank you for the info! Don’t tell my wife I don’t know everything!

Daniel Defense gun?

Hello , I have a M16 retro upper and my BCG and Magpul vise block does not go in barrel ramp. Would like to send you a video. the crazy part is that i have an old colt AR and that BCG fits with no issue.

I’m having the opposite issue and the barrel is all the way back

I was pleasantly surprised, my Aero receiver and Ballistic Advantage barrel mated almost perfectly (even though my neanderthal ass put them together). Never knew to check this, thanks a ton.

Why not put a very this shim between the barrel and the upper receiver under the barrel nut to move the extension forward slightly?

Blending both at the same time also allows microscopic steel particles to become embedded into the aluminum which leads to a corrosion cell. The steel being the anode and aluminum being the cathode will cause the aluminum to be eaten in the presence of an electrolyte rich medium.

Dab of JB Weld and it'll be good to go.

What if it’s the upper receiver partially covering the feed ramps of the barrel extension? I’ve never had feeding issues or anything but your videos have made me a bit obsessive with checking things on my rifles lol

This is such an important channel, thank you for sharing this vital knowledge!

My feed ramps aren’t perfectly centered is this bad ? No over hang

My Aero upper has a slightly twisted barrel, which has the feed ramps are just like yours in the vid, so thanks for the vid. Mine don't have a feed issue but it's digging deep scratches in the projectile, I'm afraid it will damage the rifling.

What happens if your barrel is recessed in the receiver? What is the tolerance?

Do you feel DD are worth there price? I personally feel they are overpriced for what they are.

I haven't fired a shot through my new AR. The first thing I did was polish the barrel. the second thing I'm going to do is Polish the feed ramps . The third thing I'm going to do is lap the receiver. Then the gun will be fit to fire.

I have overhang and it's digging into the bullets, so thanks for the info.

Ever seen the ramp feeds for a gilboa? 😮‍💨

What about the opposite situation where the barrel extension feed ramps are a little bit past the receiver cuts? My BCM upper is like this but I haven't had an issue yet (very few rounds though). I would assume this is not an issue since one cut leads into the other cut and there is no ledge in the way of the bullets path.

I jast want to say thank you for covering that area of the barrel extension and feed ramps very educational topic and actually it made allot of since, plus is a good place to keep an eye on. great content I love your channel

my problem is exactly reversed – where the anodized surface is the one that overhangs. any advice?

M4-style feed ramps always seem like more trouble than they're worth.

For the price of a DD, wouldn't you expect better?

so is it safe to assume that if one does apply a file to the feed ramp while attached to the upper ,that upper should be considered for the scrap pile ?

Good 2 know to maybe mark with sharpie on the barrel extension and only polish the barrel extension to the upper and not the other way around

Excellent information and quality of video!

I wouldn’t have thought that would be present on a Daniel Defense.

Good stuff

Because of this video I avoided having this issue. Your video helped a lot.

as soon as seen this looked at my 8” 300blk n it was over hang but not enough for any malfunction put 50 rounds through it