Young manufacturing bolt carrier....

[Grendel-Gene]

I bought one for my grendel and it was sure tight. I could hardly get the bolt in.... i have fired it a few times and all works well.... but i am just wondering if that is normal. Does anyone know about these bolt carriers??? They seem top notch... so i was surprised to find it so tight... extremely tight. Even my new cam pin would not go in.... i wound up using a used one from another gun. Again no problems, just very very tight.

[PumpActionJackson]

I bought one for my grendel and it was sure tight. I could hardly get the bolt in.... i have fired it a few times and all works well.... but i am just wondering if that is normal. Does anyone know about these bolt carriers??? They seem top notch... so i was surprised to find it so tight... extremely tight. Even my new cam pin would not go in.... i wound up using a used one from another gun. Again no problems, just very very tight.

same thing with my carrier from AA, it is very very tight, but works well. i found for me it was the gas rings causing the tight fit.

[RangerRick]

Was the YM carrier chromed? If they take a standard carrier and chrome plate it, it can be very tight because of the extra thickness of chrome.

The gas rings are supposed to be tight to seal in the gasses. After the gas from the gas tube enters the key at the top of the carrier, it flows into a chamber inside the carrier. The bolt plugs the hole in the chamber and the increasing pressure causes the carrier to move to the rear.

The bolt is still locked so the gas rings slide along the hole in the carrier. Eventually the carrier moves enough that it causes the cam pin to slide in the cam slot which rotates and unlocks the bolt.

When the carrier moves far enough back the gas rings slide past one of the holes in the side of the carrier. That lets the gas inside the carrier vent, so the pressure drops.

This happens pretty fast so the carrier already has enough momentum to carry it back the full stroke at this point.

If the gas rings don't seal, pressure can't build up enough in the carrier to operate the action properly.

A rule of thumb is that if you push the bolt into the carrier, then pick up the bolt and let the carrier hang down, if the carrier slides down just from gravity, then the gas rings need to be replaced.

RR

[bwaites]

Make sure you aren't putting it together dry. If you do, it will be very tight feeling.

[Grendel-Gene]

Indeed, the young bolt carrier was chromed. I also did lube it all very well ( i am a industrial mechanic by trade... ). But like i said, it all does all work well, its just much tighter than any bolt carrier i have ever encountered before (and i own 5 ARs and two SR-25s....)

[LRRPF52]

You're not the 1st to report this with YM BCG's. I have a slickside chrome carrier for one of my retro projects, but I don't recall it being that tight. There have been some changes along the way, IIRC. As long as it functions correctly, I wouldn't worry.