"M4 feed ramps"?
In answer to aap2's question just prior to the previous thread being locked...
Standard M16/AR type feed ramps are machined into the barrel extension only, but M4 ramps continue well down into the upper receiver. This idea behind this is to more readily guide rounds from both sides of the magazine and increase feeding reliability with the heavier (longer) 62 gr. bullets of the M855 load, particularly in full-auto fire.
Here's the M4:
Note that no 'step' or alignment issues should exist in the area where the lower receiver and barrel extension meet. This is sometimes a problem area with lower quality rifles.
Standard M16/AR type feed ramps are machined into the barrel extension only, but M4 ramps continue well down into the upper receiver. This idea behind this is to more readily guide rounds from both sides of the magazine and increase feeding reliability with the heavier (longer) 62 gr. bullets of the M855 load, particularly in full-auto fire.
Here's the M4:
Note that no 'step' or alignment issues should exist in the area where the lower receiver and barrel extension meet. This is sometimes a problem area with lower quality rifles.
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Clearly an improvement but a challenging Dremel job. 0 -
If you Dremel the grooves, you will cut through the anodizing and create a wear point in a place you don't want. 0 -
hello. i also had to die gring my feed ramps on my m-16. i had a dpms kitty kat upper on it. it wouldnt feed all the time on just one side, especially with my drums. after die grinding it ran 100%. you dont have to worry about wearing through the anodising and causing problems. i shot many thousands of rds through it with no problems at all, and its still going strong. 0 -
Do you have dimensions on feed ramp widening and the cuts in the aluminum upper?
After some jams, I polished all my feed ramps with Cratex wheels to a very bright finish but didn't widen any.
My 6mmx45 upper will feed hollow points but not soft points.
I don't recall any jams from bullets striking below the barrel nut.
All mags were converted to green non tilting followers.0 -
Thanks everyone; I'm getting an education on the finer points of building the AR15. I appreciate all of the info. 0 -
quote:Originally posted by aap2
Thanks everyone; I'm getting an education on the finer points of building the AR15. I appreciate all of the info.
If you would like to see how to retro fit a rifle with a CMMG micro piston, go to brownell's they have a free video download that is very infromative.0
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