For what it's worth, the USGI spring measurement requirements are ONLY applicable to USGI springs.
Unless an aftermarket spring is made to the exact same specifications of numbers of coils, wire thickness, etc., the measurement will not apply and be correct.
No doubt. But as you'll notice in my original question, I was asking what the HK OEM spring length was. Or more specifically, was the USGI length applicable (or was it not). If it's not, totally understandable, but I couldn't find any OEM dimensions.
I've been doing a lot of googling and searching here and just haven't been able to confirm some info to help troubleshoot some gas issues on my 10.4 416 (AH), non-vented. I've found bits and pieces of info that I'm looking for, but still hoping someone can check my work and see if there's anything I'm missing...
- Running 416 upper with OEM buffer spring (red paint on end) and OEM buffer on a BRN-4 lower (HK buffer tube). It works 4.0 unsuppressed, but is over-gassed with SOCOM RC and SOCOM Mini shooting Federal M193 and M3 mags. Extractor will lose its grip on case, causing the case to bounce back into the chamber as the new round is loaded, locking everything up.
- Buffer spring measures 11" on the dot. I haven't been able to definitively determine that a 416 carbine spring should match a M4 spring length, but if that's true, then it's right where it should be. Is the HK stripe spring longer? I seem to remember reading that.
- Tried shooting suppressed with the above setup but put in Colt H3 buffer (new) and same issue.
- For testing only, I tried a Springco Orange spring and it worked suppressed, but I can't remember if that was the correct length to not cause damage. I need to go pull it out to measure.
Given the above, and with the intent to run this with just OEM parts, do I start messing with extractor spring or ejector spring? It's the only thing I can think of that's left.
Anything else I'm missing without getting into new gas block territory?
I Just got an upper with the same date code. running the hk buffer and spring.. It was getting 2 oclock ejection unsuppressed and suppressed with my GemTech HaloT is was more like 1:30 suppressed.. I have it on a post sample lower and had no malfunctions besides needing to shoot with a gas mask on.. lol
Got a vented Gas block and runs great suppressed still 2 oclock ejection but feels like shooting a normal DI gun with my gasbuster charging handle. BUT unsuppressed it would not run.. and it it did it was SLOW.. so they are right when they say the gas port needed to be opened up. But I am thinking I may put on the non vented gasblock and see if i can get it to run with a stiffer spring.. I also have a Orange springco spring that i was thinking of trying.. And it is 11 inches on the dot my HK spring is more like 10 3/8 Did we ever get an asnwer on what the Spec for the HK spring is ?