View Full Version : What type reamer to use on barrel gas port

February 13, 2009, 14:39
Doing some searching and trying to figure out what reamer to use on my gas port. I have one of the US made DSA G1 barrels that won't fully cycle with the factory gas port. I plan on drilling it to open it up, but in reading I see that reaming is a "preferred" method.

That being said, and since I want to do the job as cleanly as I can since it is a $300 barrel. What style reamer is appropriate, straight flute, spiral?

What if one drills with a standard bit, and then uses a hand reamer to dress it?

What will produce the cleanest cut?



February 13, 2009, 14:43
.o1o per side

February 13, 2009, 14:48
Ok, so drill .010 undersize and then ream?

Do you recommend a hand reamer?

February 13, 2009, 15:02
ACTUALLY ,020 TO REMOVE TEN PERSIDE OF HOLIO..makes the best RMS (smoothness of profile rating) ...be honest with ya man reaming the hole is gonna be like putting a pair of lacy panties on a sow .......great if your drunk but youll be un happy in the morning ..hehe ..
if you dont use a mill with a rigid reamer ..it may walk on ya trying to go into the radiused barrel ...got a good chance of chewing up the top of the hole ////
plus if ya put a standard .125 screamer thru ...ya might be a bit large ...custom ground reamers are not gonna be cheap ...ive got a 125 ream here if ya need it ...but the gasses wont know the diff between the two .first shot with corrosive will negate your finish anyhoo ..........id just drill it personally ....hope this helps ....

Ron Walker
February 13, 2009, 15:12
Last one I altered, I used a TiN coated dril and it cleaned up just fine. No flange at all. Just be sure to use a new sharp drill. Ron

February 13, 2009, 16:28
Just drill it. You don't need to ream it. That's bullsh*t!

If it's a standard 21" barrel, I'd try a 3/32" first as that's the factory size and you may just have crap in the hole, then step it up with numbered drills (i.e. 41, 40, 39) until it functions.

If it's a 16" bbl, just drill it to 1/8".

L Haney
February 13, 2009, 18:35
Originally posted by idsubgun
Just drill it. You don't need to ream it. That's bullsh*t!

Agreed. Reaming is prep for additional machine operations. Waaay overkill for this application. The gas don't know, 'ya know?


February 14, 2009, 10:50
ggiilliiee, thanks for the offer, and all for the advice.


February 14, 2009, 11:14
ben ..my pleasure ....just thinkin are ya (losing) any gas in the system ...G1 and all ......G1's are kinda like MG's ....pesky little foreign cars ...leakin oil all the dang time ...hehehe ....maybe just needs some sealing up ,,,or a larger gas piston head on your system ....just a thought ...

...but if not +100 on what ron says on the ti coated drill ........makes a sweet hole ....
oh yeah ...just for S&G look in the original buttstock for goodies ....found a hand written note on a peice of cloth in one of mine from .....MEHMET GIRIGULU from SAN SUMLU ,TURKEY .....black sea ..home addy and everything .kinda cool

...wonder if he has a sister...??? ......hehehe lalalalalalalalalalalalalalalalalaalla ...hey baby ........hehehe:)