View Full Version : So, if you want a rifle length gas system with a carbine buffer tube...
...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?
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.
William B.
09-01-13, 13:59
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.
Does anyone have any performance data on the h6?
I've got a 20" rifle that needs a collapsible stock. I'd buy an a5 emod kit in a heartbeat if I could find one in stock. Been looking for over 6 months and no luck.
If the h6 works I'll buy one today.An H3 with green Springco spring will work. You also don't need an A5 kit. Tubes are available and the buffers are slowly trickling out. You can use any stock.
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.
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.
The A5 uses a slightly longer receiver extension combined with extended length buffers and a rifle length spring. It was developed specifically to convert the M16 to a collapsible stock.
As I recall, the Canadian C7s with telescoping stocks use the H3.
As I recall, the Canadian C7s with telescoping stocks use the H3.
With an extra power spring?
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.
Djstorm100
09-02-13, 01:23
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.
vicious_cb
09-02-13, 05:25
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.
Did I miss the new trend of putting experimental potentially self disassembling parts into fighting rifles? So can we please stop recommending race gun parts in fighting guns, we already went over this in the low mass carrier thread.
Did I miss the new trend of putting experimental potentially self disassembling parts into fighting rifles? So can we please stop recommending race gun parts in fighting guns, we already went over this in the low mass carrier thread.
You just missed "I would not recommend to use it on duty rifles".
OP did not mention that it is duty/combat/HD rifle. There are people here who use their rifles for other things than combat.
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.
Actually, you originally mentioned a green Sprinco spring. See above.
The gas port is .085".
So you have a 20" barrel with a small .085" gas port.
What brand is it?
That port size should be very soft shooting, like a very popular 14.5" mid length.
I'd try something like an H buffer and standard spring to start.
Yeah, it's a 20" barrel.
The gas port is .085".
So you have a 20" barrel with a small .085" gas port.
What brand is it?
That port size should be very soft shooting, like a very popular 14.5" mid length.
I'd try something like an H buffer and standard spring to start.
Don't know. Bought it from McKay Enterprises. It is marked as follows: C MP B
1:7 twist (I checked it myself), chrome lined, A1 profile.
Actually I mentioned the green one for use with the A5 set up. Springco doesn't make a green carbine spring to my knowledge.
Actually, you originally mentioned a green Sprinco spring. See above.
The gas port is .085".
That is a Colt A1 barrel.
Don't know. Bought it from McKay Enterprises. It is marked as follows: C MP B
1:7 twist (I checked it myself), chrome lined, A1 profile.
Actually I mentioned the green one for use with the A5 set up. Springco doesn't make a green carbine spring to my knowledge.
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.
William B.
09-02-13, 15:28
Actually I mentioned the green one for use with the A5 set up. Springco doesn't make a green carbine spring to my knowledge.
Sorry for the misquote then, IG.
Seriously? Please do me a favor and read. The green spring is rifle length and for use with the A5 or rifles. Rifle springs are longer than carbine springs. The blue spring I mentioned is for carbines.
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.
Seriously? Please do me a favor and read. The green spring is rifle length and for use with the A5 or rifles. Rifle springs are longer than carbine springs. The blue spring I mentioned is for carbines.
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").
The .625" gas block seat is supposed to flow a little better than the .750", but I'm not sure it makes that much difference.
I think it will be soft shooting. See below.
Try it out and let us know how it went.
So you have a 20" barrel with a small .085" gas port.
That port size should be very soft shooting, like a very popular 14.5" mid length.
I'd try something like an H buffer and standard spring to start.
How do you think the .085" gas port will affect things? It's a little smaller than the one you mentioned (.093").
vicious_cb
09-02-13, 19:40
You just missed "I would not recommend to use it on duty rifles".
OP did not mention that it is duty/combat/HD rifle. There are people here who use their rifles for other things than combat.
This is M4C, not TOS. Here we consider the AR to be a fighting tool first and a competition/varmint/junk yard shooter second.
theblackknight
09-02-13, 21:39
This is M4C, not TOS. Here we consider the AR to be a fighting tool first and a competition/varmint/junk yard shooter second.
Could you be anymore pretentious?
sent from mah gun,using my sights
dookie1481
09-02-13, 21:44
This is M4C, not TOS. Here we consider the AR to be a fighting tool first and a competition/varmint/junk yard shooter second.
Holy crap, just regurgitate other people's shit some more. There is no "we". There may be a party line, but many people here do NOT use their rifles for "fighting".
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.
Don't know. Bought it from McKay Enterprises. It is marked as follows: C MP B
1:7 twist (I checked it myself), chrome lined, A1 profile.
Are you sure about that?
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.
Are you sure about that?
Are you sure about that?
Which part are you referring to? But yes to all of them: it is marked as mentioned, it is chrome lined, and it is 1:7 twist which I checked myself.
did you try the H2/std CAR spring combo?
... 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.
did you try the H2/std CAR spring combo?
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.
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