Bolt ring positions

[Ulysses]

On my Bushmaster M4, the reassembly instructions say the slits in the three bolt rings are to be evenly spaced (120 degrees between each of the splits in the three rings). On my DPMS .308 this is not required. Two questions: What is the reason for the even spacing instruction on the M4, and why is this not required on the .308?

[98Z5V]

5 minutes ago, Ulysses said:

On my Bushmaster M4, the reassembly instructions say the slits in the three bolt rings are to be evenly spaced (120 degrees between each of the splits in the three rings). On my DPMS .308 this is not required. Two questions: What is the reason for the even spacing instruction on the M4, and why is this not required on the .308?

It's just like spacing rings in a piston on an engine build - so you have even compression across all cylinders.  The bolt is your "piston" and it's got rings.  The "cylinder" is the inside of your BCG.  Same rationale.

I will tell you that these things will still fire, when all the gaps are lined up.  Whenever I have my bolts out for cleaning, I space the ring gaps.  I don't take a gun apart to see if the rings are gapped, though. 

[sketch]

kinda gun myth as it turns out over years of manufacturing.. do what the manufacturer says. saves you down the road if there is a problem. yet none here and tested many times on the feild. space them appropriately per manufacturer and see if they rotate on their own? but have confidence it will shoot. 

This just gave me a stupid idea.. remove the rings  and see what happens... dont do this Ul.