Tuning without an adjustable gas block

[BoulderE89]

So I’ve never thought about it really before but I’m starting to consider fine tuning my 18” SPR gas gun after realizing all my brass is ejecting at 1 O’clock and some of the LC brass has dents and ejector swipes on it.
The rifle is a mid length gas system with a standard gas block, carbine buffet and spring and nitride BCG. I’m wondering if I can tune it for better recoil and ejection patterns without buying an adjustable gas block? would a heavier/adjustable buffer or stiffer spring do the trick? I’ve also seen adjustable gas keys but that seems iffy.

 

[oldfatguy]

Maybe with heavier buffer and stronger spring you can improve things. But the real fix is to install an AGB.

OFG

 

[Steel head]

A A5A2 or 3 buffer and spring would certainly help.

 

[FishinGuns]

1. http://blackrivertactical.com/ Gas block insert
2. https://www.gemtech.com/gemtech-5-56-suppressed-bolt-carrier.html I have a few of these combined with BRT inserts in my defense guns.

or

If not a defense gun and you like a little more tunability for plinking, games, and/or hunting:

3. https://bootleginc.com/product/full-auto-adjustable-carrier/ Same maker as the above SBC, combine with heavier buffer for the easiest remedy. Could combine with the BRT insert, too, but more involved and I’d just tune to 1. & 2. as noted above, at that point.

 

[rpoL98]

std carbine buffer is about 3.0 oz.
H1 is about 3.4oz
H2 is about 4.8oz
H3 is about 5.4oz
Spike's Tactical ST-T2 is about 4.1oz

with a given spring, you can use these different-weighing buffers to do some fine tuning, provided your gas port diameter is in the right ball-park. When I build a new upper, I find which buffer is the right weight for last-round bolt-hold-open, i.e. what's the max weight I can use and still get reliable LRBHO. If your gas port is too small, you won't get correct cycling action, let along LRBHO with even the 3oz buffer. If your GP is too big, you'll still get LRBHO with a buffer weighing more than 5.4oz. I have a HeavyBuffers 6.5oz and 8.5oz carbine buffer to make a determination how badly I'm overgassed, just for testing.

 

[Yondering]

So I’ve never thought about it really before but I’m starting to consider fine tuning my 18” SPR gas gun after realizing all my brass is ejecting at 1 O’clock and some of the LC brass has dents and ejector swipes on it.
The rifle is a mid length gas system with a standard gas block, carbine buffet and spring and nitride BCG. I’m wondering if I can tune it for better recoil and ejection patterns without buying an adjustable gas block? would a heavier/adjustable buffer or stiffer spring do the trick? I’ve also seen adjustable gas keys but that seems iffy.

I do a lot of work with tuning gas systems, including making my own barrels and tuning the gas port sizes, so take this in the perspective of a guy who feels it's no big deal to pull off a gas block:

If the rifle is so badly overgassed that it's ejecting at 1:00 and leaving swipes in the brass (and probably extractor claw marks on the rim if you look closer), then the only right fix is to restrict the gas somehow. That can be an adjustable gas block, a bushing inside your current gas block, or a few other options like adjustable gas keys as you mentioned. For the time vs money and ease of getting it done though, I suggest the ~$60 Seekins adjustable gas block and be done with it. It's the set and forget style which is perfect for you since it doesn't sound like you want to be clicking back and forth on your gas block for different loads.

Tuning it correctly will definitely smooth out the recoil impulse and make the rifle last longer as well. That alone is worth the $60 for the gas block, IMO.

You can try messing with heavier buffers, but I bet it's still a bit overpowered on an H3, and by the time you buy a couple heavy buffers you've spent as much as a gas block. Proper gas restriction is the better way to tune it anyway, compared to slowing it down with heavy buffers.