Adding feedramps

[SoDak]

I've got a carbine that has a barrel with M4 feedramps put in a rifle upper. Yesterday I had a couple malfunctions where the round went straight ahead and got caught on the receiver rather than feed. I'm now wondering if it would be advisable to cut feedramps into the upper to prevent this. If so, what's the best way of doing this?

[polymorpheous]

Were the malfunctions all from the same magazine?

[Jambi]

best route: buy new stripped upper with M4 feedramps.

good route: mill current stripped upper. Recommend using a gunsmith if you are not comfortable.

poor mans route: Not recommended for the inexpierienced. 600g dremel. Recommend using a gunsmith this route too if you are not comfortable. Remember less is more, little by little. Its also recommended you polish the ramps once youve achieved the appropriate angle. The angle is going to be key, alot of people attempt to mimic the angle of the barrel feed ramps, this is incorrect.
Too much angle and you will cut too deep into the lower part of the upper receiver and jam the rounds into the barrel extension. I have the schematic showing the appropriate angle and tolerance, I believe it was an old Bushmaster schematic. I will see if I can find it.

Again, a gunsmith is highly recommended along with using a mill.

[polymorpheous]

best route: buy new stripped upper with M4 feedramps.

good route: mill current stripped upper. Recommend using a gunsmith if you are not comfortable.

poor mans route: Not recommended for the inexpierienced. 600g dremel. Recommend using a gunsmith this route too if you are not comfortable. Remember less is more, little by little. Its also recommended you polish the ramps once youve achieved the appropriate angle. The angle is going to be key, alot of people attempt to mimic the angle of the barrel feed ramps, this is incorrect.
Too much angle and you will cut too deep into the lower part of the upper receiver and jam the rounds into the barrel extension. I have the schematic showing the appropriate angle and tolerance, I believe it was an old Bushmaster schematic. I will see if I can find it.

Again, a gunsmith is highly recommended along with using a mill.

I would recommend against cutting, milling, or grinding feedramps.
You would lose the anodizing on an area of the receiver.

Typically a rifle upper and a M4 barrel extension, while not optimal, cause no problems.
I would be looking at issues such as magazines, buffer, buffer spring 1st before buying and mounting the barrel to a new upper.

[Jambi]

Agreed

[Iraqgunz]

This topic has been debated to death. It is not recommended. Sell the upper, and get the correct one.