You’ll get erratic carrier speeds with these using lower action masses and systems with more drag. Using the A5H4ish in a low drag system, the carrier velocities get more consistent. Besides, with lower masses you can end up distorting the round from stripping the round from the magazine to chambering. You want to keep the carrier velocity in check.
As for the “muzzle dip”, you’d have to accept that to run the A5H4, Tubb .308 spring combination. You can gain in operational span range of function going this route, but there are pros and cons.
It can help to reduce drag when using these to alter some buffer dimensions. The spring seat area of the buffer can improve by slight reduction in diameter, seating diameter length, and a shallower transition angle with a radius to that. The combination can have drag induced from the spring OD and ID areas. Changing the buffer dimensions is not a requirement, but you can reduce drag by doing so before the buffer body gets anodized.
There’s more we can discuss on these if anybody is interested.
Gentlemen,
Long time lurker. I’m interested to see where this topic goes, if the handful of individuals that have a handle on this (or similar) type of setup have the time. I’ve started down this same road myself due to the information passed here on similar threads.
Semper Fi
Ryan
I recently assembled an AR with an 18” Ballistic Advantage heavy barrel with rifle length gas system.
It is only been out on two range trips so far, however I had several failure to feeds which I attribute to the buffer and or spring. As soon as I put that upper on my A4 (with A2 stock); clone lower, the problems went away.
Since than I got a Superior Shooting Systems (David Tubb) flat wire buffer spring.
I may make it out to the range this coming weekend or two weeks from now.
I’ll post here whatever results.
So which buffer system was in in the problem lower and has that lower been verified with another upper?
I’m interested. What does it look like and does it reduce drag between the buffer and the spring?
If you are talking about the buffer body, it looks very similar to a normal one. Not like some of the other stuff out there, like HK using something unique to help deal with their carrier tilt issues.
Is this something that is commercially available or one off skunk works stuff?
I am also interested in how you ended up with the A5H4/Tubbs 308 combo. I went as far as the Tubbs 308 and A5H2. I found this combo to be extremely violent in comparison to both the tubbs car/A5H2, and a carbine RE w/ an H2 and the Tubbs spring. The latter honestly having the best feel of all of them.
Rifle:
Nov gen III
Nov 14.5 Mid CHF w/SF brake
SLR Sentry 7
LMT E-BCG
64gr GDSP as function baseline
Semper Fi
Ryan
You can’t keep the carrier velocity down low enough with the Tubb .308 spring with an A5H2. You would really want to use an A5H4.
Again, this setup is not for all by any means, but it can be used by some to get some gains.
That makes sense. Right now with the Tubbs car spring and A5H2 I am in between gas settings with the SLR block. One down and I have failures to lock back consistently. At the current setting there is enough gas drive that the buffer is impacting the RE with some force. This same setting with the car RE was perfect. I believe that changing the installed length of the spring with the A5 RE has lowered the L1/L2 values. I think a 39ish coil spring would be ideal if one didn’t want to commit to the .308 spring, however I don’t like the idea of cutting springs. I would like to do so to test my theory, but I would not keep it long term. I currently have an A5H3 to test. I’m hoping this solves the velocity issue enough to minimize the buffer bottoming out without going another click open on the block.
S/F
Ryan
I presuppose that’s with the LMT-E carrier? That being, carrier velocity increases with the LMT-E carrier?
I believe so.
S/F
Ryan
It was a milspec 6-position receiver extension, carbine buffer and spring.
When I put on the lower from my A4 rifle clone, no problems.
That A4 clone long ago started off with that very same carbine lower and it had no problems what so ever.
It made me wonder if perhaps an 18” barrel with rifle gas system could be more susceptible to short stroking because of the shorter dwell time than a 20” barrel.
Also, that carbine lower worked fine with my son’s 16” faxon mid-length gunner upper.
Everything pointed to that Ballistic Advantage 18” barrel.
I’m running the Tubbs 308 flat wire spring in a suppressed build, and I’m overall pleased with how it runs. I compared the Tubbs 308 flat wire to a green Sprinco spring, and the Tubbs had less felt recoil, less gas to the face, and less violent ejection of the casing. Felt recoil is about the same (if not slightly better) than my KAC SR15 mod 1 with a muzzle brake on it.
I did a fairly high round count course with the rifle back in June and it did well outside of 2 failures to extract that required light mortaring of the rifle. The failures were during heavy tempo shooting and the casing was stuck in the barrel extension. I added a black o-ring over the BCM extractor spring and then it was good to go for the rest of the course without another hickup.
Overall the rifle runs incredibly clean for a suppressed gun and there is virtually no gas to the face when shooting.
Rifle setup:
Centurion Arms 12.5" barrel
Silencerco Saker K
Hodge Defense upper receiver, rail, and gas block
LMT e-carrier with BCM bolt
Geissele Airborne charging handle
BCM lower ordered from Grant with the A-5 Buffer system
A5H4 buffer and Tubb’s flat wire spring.
Has anyone done testing on the Geissele Super 42 buffer & buffer spring kit?
If sticking with the A5H2 and A5 system, would there be an advantage to running the Tubbs flat wire spring over the Springco Green?
There isn’t any real overall gain with either for the A5H2, too many negatives compared to a Colt rifle action spring. The gains from either the Tubb flat wire or the green spring don’t really come into play until the action mass increases. If we want to keep the timing of events to our advantage for function overall, we need to not limit timing in places where we don’t have much of a margin to begin with.
Best source for Colt rifle springs?
OP,
I suppose that I’m the one to blame for this entire thread. But, you’ll like what I have to say.
Like Tom12.7, my findings in real world testing essentially mirror his. Literally. I found that the Tubbs SS 308 flatwire spring, coupled with the Vltor A5H4 buffer, and an LMT enhanced carrier…has permitted me to run the same lower on two different uppers; a 16" BRT Intermediate (Optimum) gas upper usually without a can (my duty upper) and a Sionics RGP 11.5" upper that is 100% suppressed with a SiCo SpecWar 556.
As Tom noted, friction is the cause of many observed inconsistencies and certainly in these applications. A conservative application of an NLGI #2 grease to the outer and inner diameter of the spring coils can assist greatly in break-in of the rough surface of the spring over the first several hundred rounds.
morpheus562, your findings mirror my own as well. Less gas to face…virtually none, in fact. I have to shoot multiple rounds in quick succession with no breeze, nor gun movement, and no eye pro to even begin to get a whisp of that ole Gas-to-Face feeling. And even then it is very slight. My brass, like yours, comes out so clean that it’s impossible to tell it from another gun until you put it side by side with the same ammo from one of our agency std 16" carbine gas patrol rifles. And, if the sun isn’t out, you still might not be able to tell at a casual glance.
No other spring/buffer/carrier combo have has ever done this. Ever. And across barrel lengths and gas system types, too.
I’m not saying it’s “the best” as that’s a deceptive and amorphous phrase…but I’m not changing my setup until something comes along that is better. Might be a while.
BTJ-You’re certainly a contributing factor! I knew of your experience, coupled with little bits of knowledge I had picked up along the way reading other people’s post and I didn’t want to derail anyone else’s thread. As they say, a little bit of knowledge is a dangerous thing, although in this case it’s more of a desire to make well informed choices. Do you feel much muzzle dip with the A5H4?
I honestly don’t unless I truly limp grip the gun. I also do a lot of shooting from unconventional positions. It’s no worse than my agency’s std patrol rifles which are much heavier (16" LMT carbine gas with non free float quad rails, FSB,H buffers, aimpoint PRO, streamlight TLR-1, and sling).
I hope that helps.
Sent from my iPhone using Tapatalk