Hello:

I purchased a new White Oak Armament 16" barrel from Rainier Arms.  I went to slide on a gas block (low profile gas block that I bought from Rock River) and she's too tight.  The gas block hole diameter is just a hair smaller than the gas block shelf.  I know that Rainier sells his own low profile gas block that he claims will fit match grade barrels like the WOA that I have, is there any other way to make the block I own fit?  

I've read where you can freeze the barrel and heat the gas block?  

How would one go about reaming out a gas block to make fit?  Certain size sanding drum?

For those of you that have experienced this, is there any other gas block that will fit a match grade barrel?  

Thanks!!  

I have reamed out various parts using a rod with 1" wide 180grit emery cloth wrapped around the rod.  Tape one end of the emery cloth to the rod and wrap around until it is a tight fit into the hole.  Chuck the rod into a drill and move back and forth while rotating.  You may need to change the cloth depending on what you are reaming and how much needs to be removed.  Wrap the cloth so the trailing edge is facing away from the direction of rotation.  Take your time and check often.

I have had this problem before. I just used some scotch brite on my pinky and basically "finger" the ID of the GB until all the park is gone. Go slowly and check fitment often.

This is often reported here for WOA barrels. I believe they leave them a little large when they machine them. I just used a little sanding in the gas block until it fit on mine. Always best to make changes to the cheapest part.

I had the same issue with my build.   Superior Barrels suggested I use a heat gun on the block before slipping it on.  Worked like a charm.

Had the same issue with a GTS 6.8 barrel and a LaRue Lopro gas block.



I held the gas block with some channel locks, heated it up very well with a torch, then quickly installed it.  You have to be quick and align it fast or it will cool and it's on there for good.

You can place the barrel in a freezer overnight, it should shrink enough to fit.

You can apply heat to the gas block.

Once slip fitted using this method it won't move afterwards. Make sure you line it up right. I much prefer this type of tight fitting gas block to even the slightest amount of play. It will not leak.

The 18" WOA I bought from Rainier had the same problem. I took sandpaper to the inside of the gas block, over and over and over, until it finally fit. Scratched the hell out of the barrel, going slightly further each time, but I was gonna paint it anyway.

This.

I had this issue with a PRI Gas Block and RRA Varmint barrel.

I fired up the gas grill and let it heat up, then tossed the gas block on the grill and closed the lid.  After about 5 minutes (using some heavy ass gloves) I took the gas block off the grill and dropped it on the barrel.  Then I quickly lined up the gas block and let it sit for about 20 minutes.  It's not going anywere any time soon.