SPORT Buffer upgrades and Spring Questions....

Lock back check tests whether or not the rifle locks back on the last round. Place one round in the mag, load the rifle and shoot it. If it doesn't lock back, it's short stroking. When tuning with an adjustable gas block, close down the gas until the rifle ejects but does not lock back. Then open it one click at a time until it ejects and locks back.

If the carrier is moving too far, the buffer will hit the back of the RE and recoil will feel sharp. Sometimes it will sting the face of the shooter.
 
Thanks for the info.

I know it doesn't fix the actual core issue, but I just want it to run as if it were gassed properly, or better yet, run as smoothly as possible with an H or H2 and possibly use the 7% power spring combo if the setup will still run PMC- 55gr 223 minimum, but be much smoother than it currently is.

Some people with properly gassed Carbines even add heavier buffers, so just want to make it a Cadillac basically.

Also, I indeed was wrong, an M16 Carrier is 14 GRAMS heavier, not Ounces... which is ONLY a half of an OUNCE heavier, a tad less than 1 Tungsten weight in a buffer is.

With that being said, if the sweet spot on a SPORT from archived threads was said to be an "H2 Buffer, M16 Carrier, and factory Spring"... If so, me using an H2, Semi-Auto Carrier, and JP +7% power Chrome Silicon Spring may equate to that extra half an OZ that an M16 Carrier would provide, or, it may be a tad more.

I'll try both springs out though.

Again, just want it to run as smooth as possible and already have the Buffers and Springs needed (even have a Nitride M16 Carrier with 158C bolt, but was told the M&P BCGs are such good quality to not swap it out unless it ever craps out one day as their proven to be great as made by "Microbest" supposedly).

With that said, I will not be buying anything to adjust the gas system, although I appreciate that info greatly, but will proceed going this route and was just curious if any active members have achieved this on an Actual SPORT with a JP Spring and Buffers, opposed to seeing the threads about this all over this forum archived on Google.
 
For an entirely different reason (I don't like the twang sound), I just today installed the JP Enterprises Silent Captured Spring assembly in my Sport II. I used the optional Tungsten weight to give the buffer the equivalent of an H-1 weight.

I already like the smoothness and the noise reduction when racking the bolt, it sounds like a solid gun now. I will get to the range next week to see how it performs.

I'll post again after I shoot it.
 
MistWolf said:
Lock back check tests whether or not the rifle locks back on the last round. Place one round in the mag, load the rifle and shoot it. If it doesn't lock back, it's short stroking. When tuning with an adjustable gas block, close down the gas until the rifle ejects but does not lock back. Then open it one click at a time until it ejects and locks back.

If the carrier is moving too far, the buffer will hit the back of the RE and recoil will feel sharp. Sometimes it will sting the face of the shooter.
Click to expand...
Thanks for this instruction.

As I sated earlier, I have over 3K rounds through one gun and never an issue. So, I never thought of tuning the gas system. It may be a little over gassed, but is it really a problem? So far it hasn't been.

I guess guns will come from the factory a little over gassed to ensure reliability. The Mini-14 must be hugely over gassed because it throws shells like it's trying to win the javelin at the Olympics.
 
Rastoff, ejection pattern is not an indication of over gassing. A rifle can throw an empty two zip codes over without being over gassed. Maybe your Mini is over gassed, maybe it isn't.

If your AR or your Mini isn't giving you any trouble and you're happy with their function, don't worry about it. Enjoy shooting them often. I began learning about over gassing when I built a 10.5" pistol with an overly large gas port and exacerbated the problem by screwing on a suppressor. When I started, the pistol stung with every shot. Now, it's one of smoothest, softest shooting ARs out there.
 
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MistWolf said:
Rastoff, ejection pattern is not an indication of over gassing.
Click to expand...
You clearly know more about this than I do, but I'm not convinced that ejection and gassing are not related at all.

If a gun is over gassed, will it not eject the round with more authority? Understand, I'm not talking about where the round lands or if it lands in a small pile vs scattered all over the place. What I'm talking about is shear force of ejection. They have to be related at least a little.

Look at it slightly differently. If the gas system is set perfectly, it will throw the shells in one manner. Open it up to allow more gas and it will throw them differently. Is that not true?

So, yes, I agree that one gun properly gassed and another, also properly gassed, may not throw the shells in the same place. However, the same gun will throw them differently based on how the gas system is set. Don't you think?
 
It isn't that there is no co-relation, it's just that the co-relation is not consistent enough for an accurate analysis. There are too many variables to account for, such as ejector, ejector spring, extractor, extractor spring, action spring, reciprocating mass and burn rate of the powder in the ammunition.

For example, if an AR has a weak ejector spring, ejection distance will be short, even if the AR is over gassed. If the AR ejector spring is strong, ejection distant will be greater.

The most common malfunction attributed to over gassing has nothing to do with over gassing at all. That is when an empty fails to eject from the action, preventing the feeding of the next round from the magazine. There will be an empty in the action and the next round will be partially stripped from the magazine, the bolt over riding the base of the fresh round. Many believe this malfunction is due to excessive carrier speeds due to over gassing. They believe the excessive speed has the carrier out-running the magazine. Nothing could be further from the truth. This malfunction is caused by a weak extractor spring and/or an out of spec extractor. Trying to use ejection angle to diagnose how an AR is gassed in this case is the ultimate exercise in futility.

That isn't to say ejection angle and distance should be ignored. The angle and distance of ejection from a well running AR will be consistent. Any change in the ejection pattern should be investigated.
 
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OK, now I'm tracking. My critical thinking was not too critical for a moment there, but I'm back now.

I mean, duh, the ejection of the spent casing from an AR has almost nothing to do with the gas or the action of the BCG. In fact, it's all about the ejector and ejector spring. I don't know why I didn't make that connection before. I guess I was thinking of how the pistols work.

You see, in a pistol the ejection is directly proportional to the strength of the movement of the slide. This is because the ejector is fixed and it's the moving casing hitting the fixed ejector that kicks the shell out. In an AR it's completely different. The ejector is under spring pressure/tension and the ejector moves in relation to the bolt face. It's that movement that kicks the casing out.

Of course the speed of the BCG will affect the landing pattern because it will dictate when the casing hits the deflector. Though it isn't a significant indicator of BCG speed, it is a factor.

The Mini-14 is a poor example because it has a fixed ejector. It works just like the pistol in that respect. In the case of the Mini, the ejection pattern/distance IS directly proportional to the action of the bolt and therefore, is an indicator of how the gas system is working. Of course the Mini is a piston system and that's also different.
 
It's a misconception that the AR is a direct impingement system. If you compare the gas system of the AR to the direct impingement used in the Ljungman rifle, you'll see there are significant differences. In the original patent got the gas system used in the AR, it makes it clear it's not direct impingement.

Another misconception is that somehow the AR doesn't have a piston. The fact is, the AR does have a piston. The tail of the bolt is a piston and where it fits inside the carrier is a cylinder.
 
I've been down this road. There's an old thread somewhere on this sub forum where I purchased and tested a few buffers. If the goal is to smooth out the perceived recoil impulse + get that ejection pattern closer to that chart that floats around the internet...

Damage Industries Chrome Silicone Spring + Kyntec Corp AR-15 hydraulic buffer + lightened/lightweight BCG (exotic coating if desired).

Decrease spring noise, progressive buffer dampening, lightened reciprocating mass.

Please Note: It's been my experience that while this setup output exactly as desired, it's true function is to drastically lighten your wallet. Money better spent on a better trigger, optic, or more ammo. I'm not saying you shouldn't do it, because I'm subject to my own inclinations towards "ooo that's cool" stupidity that overrides my common sense. I just thought I'd put out the warning out of good conscience.
 
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MistWolf said:
It's a misconception that the AR is a direct impingement system.
Click to expand...
Now you're just going off the rails. First, there is no reason to even bring this up. Everyone in the AR world, who cares, knows the difference between gas piston and direct impingement. Second, trying to say that direct impingement is really a gas piston system is splitting the finest of hairs.

No one doubts or even tries to suggest that the AR doesn't have a piston or cylinder. All direct impingement means is the gas is brought back to and used directly at the BCG.

Comparing it to the rare, or at least extremely uncommon, Ljungman rifle is pointless. Yes, they're different, but both use the gas directly at the BCG. In the Ljungman the gas pushed directly on the BCG. In the AR, the gas pushes on the bolt and the bolt pushes the BCG back.

In a piston driven rifle, the gas is used away from the BCG. It pushes on a rod which then acts on the BCG or directly on the bolt as in the Mini or M14.
 
Rastoff said:
In the AR, the gas pushes on the bolt and the bolt pushes the BCG back.
Click to expand...

Well, correct if I am wrong, and I very well may be, but I always thought that the silver gas tube in the upper receiver just behind the Barrel extension would go inside of the Port on the Gas Key, and assumed that was the MAIN driving force of Gas in a Direct Impingment AR.

If I am wrong, and as somewhat of a novice of Direct Impingments, I very well may be, but what necessarily allows the gas to push directly into the Bolt?

Or am I assuming you mean the Bolt Face and really you mean the method I described, yet once in the gas key what it does?

Where exactly does that pressure make full contact with the Bolt to provide the needed force?

Does it go from the Receiver's gas tube, into the gas key, into the 3 gas ring openings, and out of the rear portion of the bolt, or is there an area it actually pushes once inside?

If so, does it provide pressure on the firing pin or just blow gas out if the rear or the bolt tail, in which the carrier is wide open..?.?.?

Not as simple as AKs which I am used to, I admit.
 
Rastoff said:
Now you're just going off the rails. First, there is no reason to even bring this up.
Click to expand...
Perhaps. But it was brought up that the Mini-14 is different (from the AR) because it has a piston. This ignores the fact the AR has a piston.

The AR does NOT use a direct impingment system. The AR uses an expansion chamber inside the carrier. The direct impingement system does not. In the direct impingement system, the gas flows from the gas tube directly a small piston fixed externally to the carrier. This pushes the carrier rearward to unlock the bolt.

In the AR gas system, the gas flows through the gas tube to the gas key. From the gas key, it flows into what Stoner calls an expansion chamber. Inside the expansion chamber (cylinder) is the piston, the tail of the bolt. When the gas in the expansion chamber reaches operating pressure, the carrier is pushed to the rear. The piston (bolt) remains fixed in place until it is unlocked then pulled back with the carrier.

There are exhaust ports in the right side of the AR carrier. You can see them if you look into the ejection port. When the carrier moves enough, the exhaust ports are open and the gas vents through them.

If you look up the original patent covering the gas system, Eugene Stoner states it is not a direct impingement system because his system uses an expansion chamber. The US Patent Office agreed when they approved the patent.

If you check Colt's literature describing their AR, you will see they describe the gas system as a "direct gas" system, not direct impingement.

It is not pointless to compare the AR gas system to the Ljungman because the Ljungman is the prime example of a direct impingement system. If you study the Ljungman, you can see the difference betwen it's DI system and the direct gas system of the AR.

The AR is a piston system. The difference between it and the Mini-14 or the AK is that the piston in the AR is located in the carrier inside the receiver, not the gas block.

If we were just splitting hairs, I would point out that the AK is more like a direct impingement system than the AR. The AK has a piston fixed externally to the carrier, just like the Ljungman. The only difference is, the AK piston is longer and its gas tube shorter.
 
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I'm changing this post because we're just talking semantics. What's important is to know how the system works and you do. What we call it is really irrelevant as long as we know what it means.

The term organic is all the rage in produce. Aren't all tomatoes organic regardless of what chemicals are used to control insects? Yet we use that term to denote that the tomato was grown without harsh chemicals (whatever that means). Isn't water a chemical?

So, any disagreement over calling the gas system one thing or another serves no purpose. I'll defer to you.
 
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As I mentioned earlier, I installed the JP Silent captured spring assembly in my Sport II and finally got to the range to check it out.

I fired about 300 rounds through the rifle of all types except steel, and didn't have a single issue. When I ordered the assembly I asked the good folks at J.P. to install a single tungsten weight giving the buffer a H (H-1) equivalent.

The rifle seems to have a bit less recoil and ejects the shells at 3:00 with lots of energy (There was a wall next to me at the range).

Absolutely NO Twang noise. I am delighted with the addition to my Sport. I was just notified that the LaRue MBT trigger I ordered several months ago (I had plenty of time), has shipped today. Once I get the trigger installed My Rifle is done!! The only S&W parts left are the BCG, Stripped Lower and Upper, and the barrel with flash hider. I did shave down the front sight to clear my free floated hand guard. I have had a lot of fun and learned lots with this rifle. I built (assembled) a second AR-15 over the past year from parts I hand selected based on weight and quality for the most part.

This BRD is a lot of fun!
 
This reminds me of calibrated washer packs to index your spark plugs for optimal orientation to get 2 more horsepower on a 500 hp engine. Is it real? Yes. Does it REALLY matter? No.
 
Ricrock, when I shot competitively I figured that if I heard the twang I wasn't concentrating hard enough on my target. And yes, I can afford it.

I'm glad that you are now happy with your rifle.
 
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