I got some better calipers and got 0.061, then some pins and got 0.061 which still comes off as small. Why wouldnt 0.062 surprise you? Is that what they use on a different length?
it’s a standard port size… incorrect for your barrel, but the drill is in the pile. .058 would be some kind of custom size drill that wouldn’t correlate with any gas ports in use that i’m aware of.
My bad, it’s just that I see a lot of people trying to squeeze the tips of their calipers in there to measure and a good set of gauge pins can be too spendy for some people to justify.
no worries, the first caliper I used was so-so, I wasnt going to ship it without using A) more than one method, and B) a better set of calipers (couldnt find the “good set” my first run).
I am guessing the 0.062 has to be it, measuring with pins I doubled the 0.061, but I was also missing a couple pins :rolleyes: so I probably could have gone up one.
Although it was a PITA breaking it all down and troubleshooting just to shoot some .223, it did feel good to go through and see that I did not do a crappy install, for awhile I was going on and on with “how could I have messed this up” going in my head, but all the way down things looked good, good ring around the port with good alignment, etc.
the holes usually run smallish… drill bit wear, elasticity of the steel, perhaps even custom slightly-undersized drills, maybe even just inherent irregularities in drill manufacture. i find .061 holes frequently… LMT, for instance, is almost always a perfect .0610. a couple thousandths wont make much difference, and being on the tight side allows for longer use before port erosion over-gasses you.
fiocchi i has a bad history. i know for certain 1 p.d. had to return it all as defective
there is a common thread here.
fiocchi = bad function
p/p = good function
t.a.p. = good function
all my 10.5’s & 11.5’s work with p/p and t.a.p. and an h-2 buffer 100%. i have 4 of them
cops call that a clue, and no i am not.
Grant turned me on to p/p 3-4 years ago and t.a.p. has known results
go back to basics and start again.
p/p?
The Fiocchi functioned fine in all my other SBRs, it is definitely a little weaker than the other stuff, but there is no reason why this carbine should not have been able to function properly with it, especially with a carbine buffer and spring. I miss the days of cheap S&B…
Well I will challenge that claim as I have shot alot of Fiocchi ammo in the past when I was in Europe and there was never a problem. Having said that any maker can put out bad ammo. Lake City and other top military suppliers have issues all the time and just about everyday NAR’s are sent out regarding various issues.
Now that you have posted this…
It appears your gun doesn’t like the weak ammo because it holds the bolt open on the rounds that are loaded to spec (prvi and hornady). It is not getting enough gas to function with the slightly downloaded ammo.
Have you tried Federal or Winchester M193 (55 gr FMJ 5.56 NATO)?
A LMT enhanced carrier is going in the opposite direction you need to be going. It bleeds off gas, you need more gas, not getting rid of it.
Have you tried a Colt bolt and carrier yet?
I tried the LMT after reading the “Best Suppressed SBR” thread, I thought the same thing and it proved to make no difference. The gun didnt like 90% of .223 nor did it like anything heavier than a carbine buffer.
Not sure if you are serious about the Colt BCG, but I consider my BCM, LMT, and RR bcgs that I tested to be sufficient. No keys were loose, all were staked above and beyond sufficient, and there was evidence that the gas block was perfectly aligned. I will wait to hear from Noveske, but it seems that the issue lies in the port.
his gas port is too small… until that’s addressed, i dont see how a colt BCG is likely to make a difference.
Well, got the barrel back from Noveske today along with a nice pint glass. Apparently the gas port was one of around 10 that had a switchblock gas port 
Regardless, its back, functions and locks bolt with Fiocchi 62gr .223 and a Spikes T2 buffer, so I am happy. Noveske was extremely helpful and they resolved the issue and shipped it out the same day.
Happy endings are awesome.
Who makes decent gauge pins? This is the first I have heard of them. I pretty much figured out their use, but are holes that accept a pin typically larger or is there some standard, like 1/1000th larger? I’m not a machinist, so any tricks or tips that aren’t intuitive to using them?
calipers actually work fine for port measuring. unless you put out the bucks for a comprehensive pin gage set ($300ish), you’re not going to get any better than that. its too bad nobody makes an adjustable hole gage in the appropriate size for gas ports… that’d be ideal.
my father has a set of pins that I use, but any decent calipers can work so long as they are held completely parallel to the barrel.
ETA, im picturing a quarter with different pins sticking out along the rim
that would be pretty cool, something like a feeler guage for spark plugs