Mid Length vs Carbine Gas System

[Indy60]

This is a newbie AR platform question, please educate me. On the 5.56 NATO round 16" upper assemblies, what is the difference between the Government mid length gas system and the M4 barrel Carbine gas system?

Other than the fore grip/hand guard lengths do the two differ and is there consensus or preference of one style over the other?

Mid length Govt.: Spikes Tactical 16" Midlength Upper - 5.56MM


Carbine Upper: Spikes Tactical M4 16" Carbine Upper - 5.56MM#

 

[45calibre]

yes the midlength is longer and provides a slightly less recoil impulse. more people seem to prefer the midlength gas system.

 

[Principal Skinr]

yes the midlength is longer and provides a slightly less recoil impulse. more people seem to prefer the midlength gas system.

I've got both, and I can't tell a difference. I also had a rifle length, and other than the additional weight out front, which helped a little, I couldn't tell more than a micro difference there, either. I guess it's like Coke and Pepsi. I can't tell an appreciable difference between the two, but others seem to be able to distinguish them.

 

[Indy60]

I've got both, and I can't tell a difference. I also had a rifle length, and other than the additional weight out front, which helped a little, I couldn't tell more than a micro difference there, either. I guess it's like Coke and Pepsi. I can't tell an appreciable difference between the two, but others seem to be able to distinguish them.

So I would guess this is more an ergonomics issue with individual users. Placing your support hand further out on the barrel vs closer in to the center of mass. Also somewhat an aesthetics consideration I would imagine. Personally I like the look of the shorter carbine style hand guard. Kind of like how tall do you like your field boots, ankle high for light hiking or mid calf for hunting in winter.

 

[sgreen3]

If your wanting to get it to dial down the recoil impulse just go with a different buffer like a Spkes SP-2. I will say the SP-2 I used in my last build made a noticable difference compaired to stock.

 

[Vlad the Impaler]

Midlength will have softer impulse on the bolt carrier than the Carbine. With both barrels being 16" the bullet spends more time beyond the gas block and pressurizes earlier in the carbine barrel, therefore the bolt carrier tends to move more quickly (all else remaining the same). This is why the carbines have heavy buffers, to slow things down with the extra mass to move.
Midlength will have a longer sight radius which theoretically adds accuracy when using your irons.
Midlength has a longer standard handguards, so if you're inclined to hold your left hand further down the barrel, you'll be more comfortable with the middy. Same goes for rails. If you want to add lights, lasers, accossory sling attachments, etc, you'll have more surface to configure with and more places to put your hands afterward with the middy.

Things get even more interesting with dissys, carbines with low-pro gass blocks and long handguards, etc. There's many ways to skin the sight radius and hanguard area cat, even with the carbine gas system.

 

[Indy60]

If your wanting to get it to dial down the recoil impulse just go with a different buffer like a Spkes SP-2. I will say the SP-2 I used in my last build made a noticable difference compaired to stock.

Considering I have never shot a 5.6 or a .223 the fine tuning issues are way down the road. I am still in the process of assembling the necessary components so I can participate in the MCF&G AR15 build meet next month. Better to start from the ground up to know what you are doing.