A question for Randall Rausch and others:
How short can you cut a 20" barrel and retain reliability? 17", 16.5?
I am considering building/buying a KISS lightweight middy upper, but I have an extra 20" Colt “pencil” barrell (1/12 twist) sitting aorund. I love those barrels with 55 grainers.
I’ll get off a lot cheaper by having you cut it down and open up the ports, but I want it 17" at the most - shorter if possible.
Thanks.
I don’t personally like to go shorter than 17" on the rifle gas system, but I WILL cut to any length you want.
The diameter of the barrel at the gas port has some effect on how much gas flows through the port.
In this respect, If I were going to make a 16" barrel with a rifle gas system, I would SPECIFICALLY CHOOSE a 0.625" diameter at the gas block such as your A1 barrel has.
I have cut many 20" barrels down to 16" and 17" and I don’t remember ever getting a function complaint from the owner of the barrel.
One guy actually won the NY state 3 gun championship with his 16" A1 chopped barrel a couple weeks after getting it back from me.
I have a very good working knowledge of gas ports and I will ask you specific questions about the rest of the rifle, ammo and operating environment before I choose a port diameter.
For instance, someone in Wisconsin or Alaska shooting Wolf ammo is going to get a very different port size than someone in Arizona only shooting M855 with a suppressor mounted.
Thanks Randall. I sent you an email.
I’m in GA and would shoot the barrel in shorter 3 gun matches (one’s with shots 100-150 yards or less) and for plinking.
In shorter 3 gun matches, I usually run XM193, although it’s getting hard to find and my stockpile is down. For plinking/practice, I run anything I can get my hands on including WWB, commercial reloads and Wolf :eek:
So in other words, I need it to run hot XM193 and underpowered Wolf if possible. Thanks.
Email is futile.
My home computer died a few days ago so email is just stacking up right now.
Do you shoot when there’s snow on the ground?
If there’s snow on the gorund, I’m NOT shooting!
So if I’m reading your web site, it’s $55 to cut it back, re-thread and open the gas ports + return shipping? That’s a hell of a deal if correct.
If you are sending just the barrel, that’s correct.
I charge more when I have to tear down and rebuild the upper as well.
Randall,
If I cut a Bushmaster 20" gov’t profile barrel down to 18", would I need to modify the gas port?
Probably.
I open them up to the known-good size for rifle-gassed 18" barrels as a matter of standard practice.
If you are running hot enough ammo in warm weather, it may run just fine without opening the port.
Cooler weather and weaker ammo will likely cause short stroking.
My shorten/thread service INCLUDES opening up the gas port as required.