...what is the optimal buffer weight to use?
Also, how exactly do the two different (rifle gas/carbine recoil assembly) systems interact? i.e. is a rifle going to generate more force to the carrier thereby necessitating a heavier buffer?
...what is the optimal buffer weight to use?
Also, how exactly do the two different (rifle gas/carbine recoil assembly) systems interact? i.e. is a rifle going to generate more force to the carrier thereby necessitating a heavier buffer?
What barrel length?
Assuming you are using a 20" barrel and a rifle length gas system, generally the standard carbine buffer and spring kit have been known to not be as forgiving as other setups, even when using heavier springs and buffers.
Your best option is a Vltor A5 system. This gives you the feel and reliability of the rifle spring and buffer, but with the advantages of a collapsible stock.
OP,
You may want to search Iraqgunz' post history. I want to say I remember him recommending a specific buffer and spring combo for this recently.
ETA: Here it is along with a link to the thread. Hope this helps.
https://www.m4carbine.net/showthread.php?t=92388
My old man has many thousands of rounds through a 20" barrel, rifle gas upper on a carbine RE and standard carbine buffer. The only failures to date were definitively ammo related (couple case deformities). For reference, his firing schedule isn't quite up to M4C style, but he pushes the limits far beyond the average bubba/dirt clod killer.
Not to disregard the A5 guidance... I agree and have suggested it myself as the technically "better" solution for his rifle... but in his case it's a wad of cash for something that wouldn't provide him any benefit.
ETA: Should also mention he has shot everything from XM193 down to Wolf through it.
Yeah, it's a 20" barrel.
So the rifle gas system DOES impart more recoil impulse than a carbine then? I see the A5 recommended and that would lead me to believe that is the case.
Another question: can you use the A5 spring in a regular (non-A5 length) carbine tube? Never mind, just read on Bravo's website to not use it with a standard carbine tube.
As I recall, the Canadian C7s with telescoping stocks use the H3.
I have a Wolff Extra Power carbine spring still in the wrapper. Would that and an H2 or H3 bolt suffice?
Unfortunately, there are just way too many important, but completely minute variables in fine-tuning the AR platform. Fortunately, there aren't too many ways to adjust it, at the user level (and not too many more beyond), so give it a go and see how she's runs is usually a great answer to these questions.
If it was me, I'd put an H3 in there and try it with the Wolff spring with some anemic .223. If it short-strokes, swap the Wolff for a regular spring, and try again.
The gas system length is only a part of the answer.
The gas port size is one other HUGE factor.
The combination of those two things and the ammo determine how much gas drive the upper will produce.
Good advice for 20" rifle gas uppers that were originally ported to use rifle buffers, is to start with a buffer around the same weight.
That means an H3 or H2 CAR buffer.
It's not surprising the standard A5 is also very close to the same weight.
I'm about to build a 18 inch rifle gas system and been doing a great deal of searching for a buffer and spring to get me in the "ball park" of what I want which is a light shooting "combat" rifle. I say combat because it is going to be a MK12 type rifle but with a twist.
I would not recommend to use this on duty rifles, but JP SCS-15 self contained recoil assembly is exactly same for rifle and carbine buffer tubes (to use in rifle tubes drop in included polymer spacer first). I understand that is was designed with rifle length gas system in mind. It is competition part, it costs fortune, but always an option.
As I mentioned before. Assuming you have a rifle with a .093 gas port I would use an H3 buffer and blue Springco spring. It will run just fine.
Believe it or not they DO make a green one (I was looking at their website when I read that post of your's quoted above). And it is for the A5 buffer and tube setup. That's why I asked. So blue it is then for a regular carbine tube?
I kind of feel lucky to have gotten this barrel. Colt made them for the IDF (or so I've heard in the past) at one time with a 1:7 twist so the Izzies could convert and use the heavier bullets like M855. They're supposed to be like hen's teeth.
Yeah, I know rifle ones are longer. Technically the green one can be used on a carbine as long as you have an A5 setup so that is where the misinterpretation of what you said came in on my part.
How do you think the .085" gas port will affect things? It's a little smaller than the one you mentioned (.093").
Enough of the bullshit. Move on or take it up in PM's.
Just to update an old thread: I got the rifle finished utilizing a Sully stock with one inch spacer (which is a carbine length tube) and used a Wolff Extra Power carbine spring and a standard weight carbine buffer. Cycled perfectly, ejected to 4 o'clock about 7 feet out. Pretty smooth too. No marks on the buffer face to indicate a beating.
I had a regular carbine spring, regular buffer, an H2 buffer, and the Wolff spring on hand to mix-and-match if necessary. With the .085" gas port (a tad on the smaller side) I was wondering if both the H2 and Wolff spring were necessary. It turns out they weren't.
As an aside, the Sully stock with 1" spacer makes it 9" in length....just shy of an A1.
I just checked their website and they are claiming the following.
Replacement barrel for M16 A1, new manufacture. Just released from prime military contractor. Perfect for finishing your M16 build project.
- Grey phosphate finish
- 20 inch length
- A1 "pencil" profile
- 1 in 7 twist
- Caliber 5.56 NATO
- Chrome lined
- With gas hole and barrel extension.
No I did not. The Sully stock is a solid chunk for sure, not exactly "light" by polymer stock standards. I was trying to keep from adding any weight at all (even a few ounces) to the ass end if I didn't have to. Of course I had 4 possible combinations if one didn't work.....it did and I stuck with it.