M4 feed ramps and Soft Point Ammo

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Deer Hunter

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After buliding up my lower, I've been trying to decide between M4 feed ramps or normal feed ramps. The rifle is going to be a 16" midlength. I've heard that M4 feed ramps help when shooting SP ammo.

I'd like some first-hand reports from people who have used SP ammo with and without M4 feed ramp cuts. How is feed reliability?
 
I have had no issues feeding SP ammo in regular AR barrels. However, M4 cuts keep the nose deformity down and in general do no harm.

I see no reason to NOT specify M4 cuts for all my AR barrels, and so I do.
 
I ask this because right now I am contemplating either buying parts seperate or a complete upper for my lower AR. I have no vise and I'll need to buy a multi-tool for putting the barrel on.

Plus I was getting opinions on its usefulness.
 
I saw your other thread about pulling the parts together for a build.

M4 type extended feed ramp cuts on an upper receiver will do absolutely no good if the barrel you bought does not include the feed cuts on the barrel extension.
As a matter of fact, it may end up causing you some feed issues.

Get yourself a good vise and a block for holding the upper receiver.
I know people can half azz a barrel into an upper receiver and screw everything together "and I didn't need a vice, blah,blah."
I know this because I end up fixing some of these rifles for these master builders.

If you want a visual then try actually shooting the rifle on target at 300 meters and noting the difference in the groupability of a specific cartridge
using a barrel and upper that did not have the extension modification and noting the difference after modifying the feed ramps.
My test rifle was a 20" Bushmaster 1-7" government profile barrel using Black Hills 77 grain Sierra Match load without cannalure.
 
Well that's wonderful. I ordered a barrel that might cause me feed-problems. Great. :uhoh:

If the parts come in by next weekend (ordered today) I'll be home for father's day and I have a vice at home.
 
deer_hunter, where did you get the upper? i'm still looking for a "complete upper half" bolt, barrel, sights.... and the cheapest price is 450 or 500 shipped...yeah i'm looking for a m4 look too ;)
 
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