.22 LR barrel porting.

[Brian Ski]

I want to port a .22 LR barrel to keep high velocity .22LR rounds subsonic. I understand the "it will ruin your gun" "don't do it". Just looking for some good advice. I do not have access to an EDM but I do have access to milling machines.

Has anyone here tried porting before? How many ports and what diameter? I have about a 10"? barrel. (I need to double check length) Subsonic should be around 4-5" IIRC. I guess pull out the Chrony and give it a try a little at a time.

[BWS Arms]

Porting will not ruin your gun. Look at the mp5sd.

[Brian Ski]

Porting will not ruin your gun. Look at the mp5sd.

I meant for the ones that will mention "drilling holes" will damage a barrel. I know porting is fine.

Just trying to see what other have done. Barrel length, port diameter, how many holes and how far from the muzzle, etc Thanks

[BWS Arms]

It’s going to be trial and error to get the correct amount and diameter. You can search the old threads here and probably find a starting point. You could also tap the ports and use allen headed set screws to block them off when not needed.

[BWS Arms]

I would start porting close to the chamber. Again, use the mp5sd as an example.

[Brian Ski]

I would start porting close to the chamber. Again, use the mp5sd as an example.

Wow, Never got to look at one before. Must be 30 holes in that barrel. I will start off slow. Thanks for the help. It may be a while. Will try to post a follow up.

[alordnapa]

What is your overall barrel length? Too long a barrel and ports to close to the chamber can give you squibs ( Which you will probably survive if your gun explodes) Putting ports in four inch barrels is not going to buy you much. There are many interrelated factors to consider.

[Brian Ski]

What is your overall barrel length? Too long a barrel and ports to close to the chamber can give you squibs ( Which you will probably survive if your gun explodes) Putting ports in four inch barrels is not going to buy you much. There are many interrelated factors to consider.

I think my barrel is about 9" (or 10?) I don't have it here right now. Looking to drop the cheaper high velocity down to a subsonic level. I thought High velocity was subsonic around 4" or so.

[Capt. Link.]

I want to port a .22 LR barrel to keep high velocity .22LR rounds subsonic. I understand the "it will ruin your gun" "don't do it". Just looking for some good advice. I do not have access to an EDM but I do have access to milling machines.

Has anyone here tried porting before? How many ports and what diameter? I have about a 10"? barrel. (I need to double check length) Subsonic should be around 4-5" IIRC. I guess pull out the Chrony and give it a try a little at a time.

A pair in the throat for 900-950fps in rimfire using HV ammo.

[Brian Ski]

I want to port a .22 LR barrel to keep high velocity .22LR rounds subsonic. I understand the "it will ruin your gun" "don't do it". Just looking for some good advice. I do not have access to an EDM but I do have access to milling machines.

Has anyone here tried porting before? How many ports and what diameter? I have about a 10"? barrel. (I need to double check length) Subsonic should be around 4-5" IIRC. I guess pull out the Chrony and give it a try a little at a time.

A pair in the throat for 900-950fps in rimfire using HV ammo.

Do you have an idea on what diameter?

[Capt. Link.]

I would start with the smallest size until you reach your desired speed. Nobody can give you an exact size as chambers very as do barrels. The old saying of the devil is in the details apply. Make sure you do not cut into the chamber or the lands center it in the throat.

[Brian Ski]

I know, You cannot undrill it.

[sub-sonic]

Freebore the barrel back to 3.75” and it will make all ammo subsonic then drill ports as you like in the freebored section to let out gas