So what does Mil-Spec mean???

[carbinero]

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...

[mat10x]

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.

[C4IGrant]

Regarding ammo, Mk262, M855 and XM193 are NATO-pressure level, so those loads should work hand-in-glove with the .063 sized port. But they beat the crap out of BMs/RRAs since they run larger ports.

Wolf is down on the pressure scale and it may have problems with these ports, but because BM/RRA/et al drill their ports larger, this ammo will work in those barrels.

Where does other ammo fall in line pressure wise? BH ball, Win White Box, Amer Eagle, TAP? Are those loaded to SAAMI spec, in which case that would be a better match for a BM/RRA than a NATO-spec load?

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

[C4IGrant]

I have been looking for that specific info for quite awhile.

Thank you!

Glad I could help.


C4

[C4IGrant]

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...

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

[C4IGrant]

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.

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

[C4IGrant]

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

[jhs1969]

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

A big thank you to C4 and Rob_S, you guys have been godsends for running a civilian M4, keep up the good work.

[C4IGrant]

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

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

[Abraxas]

probably right along with the Noveske N4 (due to blue buffer and batch tested bolts).

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