Modern Sporter Build - Input Needed

Zee705

Zee705

CGN Regular
Rating - 100%
69   0   0
Location
Northern Ontario
I'm currently running a 14.5" AR with a standard carbine buffer and Ares Armor HPT/MPI BCG. I plan on migrating most of the parts from this rifle over to my rifle length gas 18.6" Modern Sporter with exception of the handguard, gas block/tube and barrel (obviously).

I'm going to run a MRA pencil barrel with a 0.625" adjustable gas block. Should I pickup a heavier buffer or will the carbine buffer and adjustable gas block be the best combination? The rifle's primary use will be action shooting.

Cheers
 
If you get a mid length gas system I would get an adjustable gas block. If you get a rifle length a standard block should be fine. You can try my geissele 42 buffer (stronger spring and H buffer)
 
Sudbury shooter said:
If you get a mid length gas system I would get an adjustable gas block. If you get a rifle length a standard block should be fine. You can try my geissele 42 buffer (stronger spring and H buffer)
Click to expand...

The only adjustable gas block in the 0.625" profile is like $120 from Brownells. If would be nice to re-use the non-adjustable gas block from my 14.5" pencil barrel.

I've been trying to read up on gas system tuning and it's kind of confusing.
 
If you're going as with an adjustable gas block then gas system length isn't going to matter as you're deciding how much gas is returning to the BCG. Also, if you're running adjustable gas, use the lightest buffer you can. A standard spring or even a stiffer spring (braided or flatwire) would be better to give some force going into battery to pick up the next round as lightweight buffers and BCGs don't have as much inertia then. I use adjustable gas, titanium BCG and Taccom lightweight buffer (1.2oz vs the standard 3oz) with flatwire spring. Very smooth and fast.
 
Djb1 said:
If you're going as with an adjustable gas block then gas system length isn't going to matter as you're deciding how much gas is returning to the BCG. Also, if you're running adjustable gas, use the lightest buffer you can. A standard spring or even a stiffer spring (braided or flatwire) would be better to give some force going into battery to pick up the next round as lightweight buffers and BCGs don't have as much inertia then. I use adjustable gas, titanium BCG and Taccom lightweight buffer (1.2oz vs the standard 3oz) with flatwire spring. Very smooth and fast.
Click to expand...
How do a person know when the gas is set just right?
 
I use an Odin adjustable gas block, Brownells low mass BCG and Taccom buffers and spring.
I start at the low end of the gas adjustment, shoot 1 round at a time with more gas each time until the bolt locks back and then I open the gas 1 more click. Has worked well for me using surplus/bulk 55 grain 5.56 ammo.
If you plan on changing ammo often you may need to adjust. Like in my Stag I initially gave it enough gas for Hirtenberger 7.62 but will tone it down for my load development of 168 grain and 208 grain 308 if need be. Once I have a load established that is what I will run and will adjust the gas accordingly.
My goal is to have a reliably functioning firearm with the least amount of gas and reciprocating mass going to the rear.
 
Brianma65 said:
How do a person know when the gas is set just right?
Click to expand...

Load some mags with one round and start with small gas and adjust up until the bolt locks back on empty mag, thats the min amount of gas needed to cycle the BCG. Then fine tune based on what direction you brass is ejecting, brass should eject between 3 and 4 o'clock.
 
You must log in or register to reply here.
Back
Top Bottom