AR bolt -- normal movement/resistance "feel"

M

mehavey

New member
I've had my Colt HBAR for about five years and got used to very smooth movement of the bolt/gas rings assembly within the bolt carrier upon cleaning.

`Couple days ago I got YoungSon a Colt M4-style sporter for XMas which functions just fine. But I noticed a significant difference in the feel/resistance when reseating the bolt past the gas rings into the bolt carrier, and when moving the bolt back and forth when assembled.

The gas rings/setup otherwise appear normal, and the weapon had no stoppages over 50 rounds yesterday with either commercial bulk reloads or my own (69SMK/Varget/25.3/WWcase/CCI400).... But that bolt sure feels like things need to lap themselves in.

`Other's experiences with new/Colt bolt assemblies?

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I have two Bravo Company bolt assemblies and on both of them the bolt is a snug fit to the carrier even when they are oiled well. One is brand new and the other has over 1,000 rounds through it. I carry spare rings in my kit so that when the day comes that the rings need replacing I have them handy but as long as your AR cycles correctly I doubt there is any worry. Someone else with more experience will chime in to answer you better than I can at this time.
 
Give it a squirt of CLP through the vent holes in the side of the bolt and work it a few times. That usually helps smooth things out.
 
A bolthead with rings in a bore is exactly the same as a piston in a cylinder. It will break in and each will lap the other to an appropriate finish. Keep it well lubed. The TM specifically prohibits swapping bolts precisely for the same reason an engine builder always puts a used piston and rings back in the same bore. Same for a lifter on a cam lobe - they're broken in to each other.

ANY lubricant is better than none, CLP is adequate for military use and those weapons see tens of thousands of rounds.

As long as the bolt carrier won't collapse onto the bolt head when stood on end, the rings are working. The carrier bore is tapered, the ring gap closes up as it's inserted, so different bolts will feel different regardless.
 
My Smith is pretty lose and from what I remember never was very tight, I just bought a PSA that is very tight compared to the Smith both shoot fine so I am happy......
 
Newer BCG's can have a fairly stiff feeling bolt until several hundred rounds have been fired..

The corrct testing from the 23&P.

Check bolt assembly for proper fit with bolt
cam pin removed. Turn key and bolt carrier
assembly and suspend so the bolt assembly
is pointed down.

The bolt assembly must not drop out. If
weight of bolt assembly allows it to drop
out of the bolt carrier assembly,
replace bolt rings (p 3-21)
Click to expand...

There are some after market AR books that tell you the bolt rings should support the weight of the bolt carrier, that is incorrect. They only need to support the weight of the bolt.

You can down load a free copy of the ARMY TM 9-1005-319-23&P manual. It contains all the info you well ever need for maintenance on the AR15.
 
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