rifle length gas on carbine lower

[outlaw45]

I'm planning to build a 20" barrelled upper to put on my carbine lower. Will I have any problems with the rifle length gas system on a lower with a CAR buffer. What do I need to do?

[tomchang01]

wish others can help you.

[ricsmall]

probably get an H3 buffer, to keep the weight of buffer close to a rifle setup.

[LRRPF52]

You basically have to trouble-shoot it yourself. Each blaster has its own nuances, especially when you start chambering the AR15 in alternate calibers. I like to have 3 different buffer weights on-hand when I go to the range on a new configuration. I evaluate the cycling first, then the brass to see if anything crazy is going on.

During the process of the gas operation, a certain amount of resistance is necessary to build-up enough pressure to get the bolt carrier moving. Oddly, that can mean that the bolt carrier and buffer need to be heavier than you would think. There is a balancing act that needs to be performed in this whole equation, and the charge weight/burn characteristics and bullet weight play a huge part in it. The rest of the system is tailored around those factors.

Most Grendel owners with 20" barrels that I know use a heavier buffer in a carbine lower. Keep in mind that a standard rifle buffer is around 5.1oz-5.2oz, while most factory buffers on civilian carbines are 2.9 oz. I measured one yesterday that was 2.7 oz., and it will be getting a tungsten weight or 2 added to it.

[outlaw45]

So with a rifle length system there would be more or too much gas going back to the carrier and buffer? Would an adjustable gas block help?

I saw this rifle on here. I don't know who's it is, so pardon me for using it, but I love your gun and plan to build about the same thing. I remember is being a 20" barrel from the discription. If its your gun, can you tell me the details on buffer weights and how it runs?

[VASCAR2]

Adjustable gas block will allow you to meter the amount of gas to control recoil but mostly ejection pattern and timing.

[outlaw45]

So the only problem would be is finding out which buffer weight works best?

[LRRPF52]

So the only problem would be is finding out which buffer weight works best?

Yup. It might work with every one you try. Probably will, but one will be more ideal for the system. I would just start off with an H2.

[bronco_buster]

My 18" Satern uses a heavy buffer, M16 carrier, and still needs an adjustable gas block to prevent beating brass to death.

My 24" Lothar Walther doesn't care whether its using an AR15 or M16 carrier, but it will not lock back on an empty mag with a rifle buffer (5.2 oz) or heavy buffer (4.5 oz). I actually had to put a spacer in the rifle buffer to lighten it to 3.5 oz and gain reliable function.

[outlaw45]

M16 carriers are heavier than AR15 carriers I take it?

[leopard6.5]

outlaw45: That is correct.

If you saw the two side-by-side you would be able to see where the AR15 carriers are cut out which makes them lighter.

Lee

[outlaw45]

I have a Young Manufactering national match carrier, that I plan to use. It is definatley heavier.