I assume the TDP on gas port is carbine length in a 14.5" carbine barrel. Wouldn’t “the ideal” be different for different barrel lengths as well as for gas port locations? I’m thinking mainly about the port on 14.5" carbines vs. 16" carbines vs. 16" middys…
great thread. as a new AR buyer, this site has been an incredible and indispensable resource! have a few questions about the fighting weapon spec list above in regards to M4 feed ramps.
colt, lmt for example, nice deep ramps. noveske has very shallow ramps in the upper receiver portion of the feed ramp. no issue as far as i’ve been told, even by noveske. is there a reason they are spec’ing their uppers with shallow ramps on a fighting weapon? on the noveske website they are listed as “extended” ramps not M4.
maybe a rookie question but, how necessary it to have deep M4 ramps in a semi auto carbine or for the lower cycling rate of a middy? especially seeing that a brand like noveske is not having any issues.
i recall reading a reply by a gentleman from AR15 Barrels who had said that you really only need the first 1/16 of the upper receiver portion of the ramp, in addition to the barrel extention ramp.
thx.
The Hornady T2 rounds are also correct pressure. You are correct, they all work well with the .063 gas ports.
The lowest pressured rounds I have seen are the wolf, PMC (bronze) and winchester white box.
C4
Glad I could help.
C4
The barrel length of course has a lot to do with the gas port size. So a 16" middy will be different from a 16" M4, etc etc.
C4
I really would not be overly concerned about how deep the cuts are in the upper receiver. What is more important is how the cuts line up with the M4 barrel extensions. This smooth transition is what is most important I think.
C4
Since we are all interested in gas port size, let’s continue on down this road. One of the problems facing gas ports is erosion. As you fire your weapon, the gas port slowly (over thousands and thousands of rounds) grows bigger and bigger (allowing more gas to go down the tube). So that means that if you already have a large gas port, it will only get bigger!
The next question is, what can we do to help bleed off some of the excess gas and slow things down a bit? One of the things I like to do is switch out the bolt carrier to the LMT enhanced carrier (notice I did not say enhanced BCG). The LMT enhanced carriers have 3 gas vent holes. This seems to help get rid of some of the extra gas. The other thing you can do is try an H2/H3 buffer and a CS buffer spring (one or the other or combination of the two). You should also make sure that you are running a stiff extractor spring and a Crane O-Ring to help with extraction.
C4
I think you are the first I’ve seen to recommend the LMT enhanced BC, I’ve wondered if the longer dwell time would not be easier on carbines but all the advice I’ve seen before was to stay away from the enhanced products. I’ve got a complete LMT with the standard BCG and it has performed as expected (100%) I also have a BM M4 "16 that I’ve stacked myself but wonder what other mods I should make, by the sounds of it I may need to start using Wolf in the BM:rolleyes:
A big thank you to C4 and Rob_S, you guys have been godsends for running a civilian M4, keep up the good work.
You are welcome. I don’t think you only have to shoot under pressured ammo through your BM, but just be aware of what is going on inside your AR and that there are some things you can do to help the situation.
C4
Are you sure about this? I was told that the Noveske bolts were individually MP tested and not batch tested. I even called Noveske and asked them about that when I was looking for a MP bolt for my 6.8. They told me that all of their bolts for both 6.8 and 5.56 were mp inspected
That’s what I thought as well, I was just going off of rob_s’ chart. Maybe I was referencing an old chart (rob_s spread-sheet), as I do recall hearing that Noveske’s bolts were MP tested. I just didn’t want to make an unsupported statement (this way I get to pass blame onto rob_s :p).
Could you have Josh check to see if his extractor has a blue or black buffer and check for the MP etch? Just want to confirm. If those two are present then it would be hard not to give top billing to the Noveske.
EDIT- Crossed wires here- meant to note HPT, but MP stuck in my head. Noveske DOES MP their bolts by all accounts.
Grant,
Speaking of gas port erosion. Are you saying that the LMT enhanced carrier should be used when issues occur or to mitigate the problems from the beginning? Thanks.
I know that my extractor insert was blue on the bolt which came with my N4 Light Recce. I don’t recall whether there was a MP on the bolt. I will have to check.
I screwed up on my post re: MP tested bolts. I should have said HPT (hight pressure test), but MPI stuck in my head instead.
By all accounts Noveske’s bolts ARE MPI’d, but batch HPT’d. Apologies to everyone that runs back to disassemble their Noveskes to check their bolts for MP.
I’m still blaming rob_s though.
Any idea on the gas port size in the ADS rifles?? Jeff
so i put together a parts gun with a bunch of stuff around.
RRA Upper/Lower
CMT LPK
LMT BCG
VLTOR Clubfoot/ RE / spring / buffer
M4 handguards
and a Sabre Defense Barrel.
it runs fine, the recoil doesn’t seem better or worse than my LMT’s. but does anyone know what port size is used in a Sabre barrel?
I think it should be used from day one and especially if you are running a Suppressor!
C4
I do not know.
C4
If you have a carbine gas system on the SD, it is most likely .063.
C4
I thought it might be good to bump this thread after reading some silly crap on TOS about BCG’s.
As I stated in my opening post, Mil-Spec does NOT mean that it is the “best” it simply means that it follows a set of guidelines set forth by the US Govt. Typically speaking, the Govt does not spec out gear on the high end, but the lowest quality that will get the job done. So if you are not meeting this LOW standard, then what standard are you meeting???
You cannot say you gear is Mil-Spec (meaning that you are using the term in order to convince people that it is quality) and then say that a part of what the TDP calls for is utterly useless or not needed!
C4