Low Pro Gas Block Compatibility. 5.56 vs. 5.45

[MikeL417 33]

Hey guys. I'm about to undergo some mods on a 5.45 upper. I want to get a low profile gas block for it but I can make my own using the original one. Just wondering if the Yankee Hill Machinery low pro gas block which looks like it's meant for a 5.56 application would also work for a 5.45 application. Kinda just asking are the gas blocks the same??? Many thanks for any help in advance!!!

Mike

[T Bill 649]

Use the original one. Already pinned in place. Cut off "A" frame, Dremel remaining block and cold blue. Simple and easy way to do it. Can you install a new gas block, sure. There are no gas block sizes relative to bore diameter, just barrel OD, in this platform. Gas hole in barrel determines flow/volume. Positioning of block is very important. I would take the first option and use the saving towards rail purchase, etc. Low profile blocks are usually hidden by rails.

[DargZ 5]

The gas blocks can be the same. What you need to do is find out the diameter of your barrel where the replacement gas block will be sitting on.

 

Most likely your barrel is using a .750 or .625 gas block. I built an AR15 for my brother in law and it used a .750 gas block. My 308 AR also uses a .750 gas block but there are other 308 AR barrels that use .936 gas blocks as the barrel is even thicker.

 

Keep in mind that you would need to knock out the existing taper pins (a big PITA) and align the new gas block. If you do not align it right, you may turn your rifle into a single shot AR. Now you can go with either a gas block with set screws or taper pins to secure it to the barrel. Taper pins are generally viewed to be more secure than set screws. Loctite will help with keeping set screws in place. You can also dimple the barrel so that the set screws will bite into the barrel.

 

I would probably go with the route that T Bill suggested by cutting the "A" off the existing front sight gas block and get a free float handrail that would cover it. You can also cover up the area you cut with a bluing solution so that it looks like you did not cut it.

[MikeL417 33]

Sweet! Thanks for the help guys!

Mike