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1/12/2026 4:55:01 PM EDT
I recently built an 11.5" ARP using a DD RIS III upper and Aero lower. I am using a DD M16 BCG. I wanted to ask for some recommendations and learn about the different setups for an 11.5".

I was testing out Sprinco's White/Hot White/Blue springs, along with H1, H2, and H3 buffers. I was able to rule out H1 across all springs. H2 performed well, but H3 definitely reduces felt recoil by some amount.



One question I have with ejection patterns, are they measured after they hit the deflector or is it measured before it hits it? For example, with Sprinco Blue/H2, it looks like the brass is ejected at almost 5 before hitting the deflector and then moving towards 330/4. I seen videos online of brass being ejected consistently at 300 without even touching the deflector on 11.5" setups. I am sure AGB's play a role, but some folks comment that they have nothing more than a Sprinco spring and an H2 buffer.

I am mainly looking to learn and experiment with setups to reduce recoil, gas, and run a reliable setup both suppressed and unsuppressed. Is there anything else worth experimenting with? I am going to order a G$ S42 spring to test, as I've also read it performs pretty well in 11.5" uppers.

I have close to 1000 rounds combined testing through these setups and so far I think Sprinco White/H3 seems to be the best. However, I'd love to continue learning, I've even heard of people running the green or red springs.
1/13/2026 10:36:48 AM EDT
[#1]
Simple milspec carbine spring w/ H2.
1/13/2026 10:49:36 AM EDT
[#2]
Brass should be measured where it hits the ground. I dont even know how youre measuring brass before it hits the deflector. About 430 is the sweet spot, but being over gassed isn't necessarily a problem
1/13/2026 3:54:15 PM EDT
[#3]
Quote History
Originally Posted By Phiers:
Brass should be measured where it hits the ground. I dont even know how youre measuring brass before it hits the deflector. About 430 is the sweet spot, but being over gassed isn't necessarily a problem
View Quote


I took slow motion videos to review the ejection pattern each spring/buffer was generating. At the same time, there's a lot of inconsistency online regarding the Sprinco springs. Some run blue, some run white, some run green, etc., which was the point of testing all across 700+ or so rounds.

In those videos, I've seen the casings do all sorts of things. They either slam into the deflector, or hit the top of it, or it'll hit closer to the ejection port and then hit 4.

I mainly started testing to reduce gas to the face and smoothen the recoil a little, but now I'd like to understand the mechanics around ejection to get closer to 3 consistently.
1/13/2026 4:22:31 PM EDT
[#4]
Sprinco equivalent would be green right?
1/13/2026 4:59:38 PM EDT
[#5]
Green is rifle length, and or VLTOR A5.

I run Geissele Super 42 and H3 in my 10.3-12.5 length rifles/pistols.

Work perfectly for both suppressed and non.
1/13/2026 7:19:49 PM EDT
[#6]
Do you have consistent ejection? What ejection do you see on your build?

1/13/2026 9:28:52 PM EDT
[#7]
Yes, around 3 suppressed and 4ish unsuppresed.
Colt 10.3 .070
Super Duty 10.3 .070
BCM 11.5 with .070 BRT gas tube
Super Duty 12.5 (whatever they gas it)

1/14/2026 12:36:33 PM EDT
[#8]
Quote History
Originally Posted By BULLDAWG_556:
Yes, around 3 suppressed and 4ish unsuppresed.
Colt 10.3 .070
Super Duty 10.3 .070
BCM 11.5 with .070 BRT gas tube
Super Duty 12.5 (whatever they gas it)

View Quote


I bought the S42 H3 combo. Will update once it arrives and I can test it out.

1/28/2026 4:49:51 PM EDT
[#9]
Quote History
Originally Posted By BULLDAWG_556:

I run Geissele Super 42 and H3 in my 10.3-12.5 length rifles/pistols.

Work perfectly for both suppressed and non.
View Quote


I've experienced the same out of my 10.3". Functional reliability with reduced recoil.

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