What buffer/spring combo would work best for a 14.5'' midlength barrel"

With an ar15 bcg... non full auto.

Edit: the rifle is already built.

it has a Spike's fn chf barrel and a bcm gas block... so hopefully no gas port issues..

Currently installed are the standard carbine buffer and spring from Palmetto.

I've probably shot 400 rounds through it, using brass and steel.

I've had about 10 light primer strikes while shooting rapidly, with both brass and some steel cased ammo.

I bought a "heavy"  5 oz buffer from amazon and used it for two range sessions and couldn't tell much of a difference.

Note: when I slam the bcg home it SLAMS forward... I mean mine seems to slam harder then other people's,,, but that's just me comparing mine to people's on utube.

Is there anything I should be worried about?

JPSCS

It's going to depend on the maker and if they have a rep for over gassing.  Personally I would just go with a regular carbine spring and a H buffer and see where I need to go from there.

This /\/\/\/\.... start at the beginning with "known" parts to give yourself a baseline. Once correct function is established you can experiment from there.

I run Slash's HSS buffer(6.5oz) with a standard power carbine action spring with my Noveske Afghan and it runs really nice. A Spikes ST-T2 would also be a good choice. I agree with trying a H, H2 or H3 and see what you get from those.

I'd use a standard spring and a standard buffer to begin with. BCM recommends this, especially if using weak ammo.