How much does the 15 Sport Buffer Weight

Hey all. I want to replace my Spring & Buffer, but would like to know how much it weighs.
My LGS weighed it and he could only weigh it in Grains. He got 1273.6 grain which came out to 2.91oz.

Seems light to me. Is that what you guys are getting? Roughly 3oz?

Standard carbine buffer, ~3 oz. Here's a chart:
Slash's Heavy Buffers | Reference

You may want to go to a H or H2, I usually use an H for more reliable ejection.

I have a M&P/Magpul middies. I changed out the carbine buffer and spring, for a Tubbs spring and H2 buffer. The H2 was too heavy and the cases kind of "fell" out. I switched to an "H" buffer and it functions perfectly. You have a carbine length gas system, so an H2 buffer would probably work fine.

Why do you want to replace the spring and buffer? How many rounds do you have through the gun, and what problem are you trying to correct?

All M&P rifles come with the cheapest buffer there is (CAR). I generally recommend folks run AT LEAST an H buffer and prefer an H2 buffer.


BCM Buffers at G and R Tactical



C4

Dragon88 said:

Why do you want to replace the spring and buffer? How many rounds do you have through the gun, and what problem are you trying to correct?

Click to expand...

S&W AR's are over gassed so a heavier buffer reduced felt recoil.



C4

OMG! Here we go again.

In the world according to C4I, ALL S&W's are over gassed because, well they just are. In his world, they are over gassed because the average S&W buyer will, of course be shooting cheap underpowered ammo because they have a cheap rifle. Colts, on the other hand, are not over gassed and will choke on the cheap stuff, but of course the Colt owner would never shoot the cheap stuff.

I think I have that about right.

Stebo said:

OMG! Here we go again.

In the world according to C4I, ALL S&W's are over gassed because, well they just are. In his world, they are over gassed because the average S&W buyer will, of course be shooting cheap underpowered ammo because they have a cheap rifle. Colts, on the other hand, are not over gassed and will choke on the cheap stuff, but of course the Colt owner would never shoot the cheap stuff.

I think I have that about right.

Click to expand...

Spot on. I've always wondered how a buffer can reduce recoil, a claim I see on a regular basis.

All my AR's, regardless of manufacturer have reliable ejection straight from the factory. Never could understand why anyone would buy a rifle that was not reliable and change parts instead of sending it back to the manufacturer as many times as necessary until it was.

I have to admit I put a little bit heavier buffer in my Cybersport and the other day when I was shooting I was shooting it and the new Sport with the stock buffer. They both ejected fine but the new one jumped more than my older one with the same ammo. I do not think that I will replace the buffer though, it did calm down the recoil but the recoil is not that bad and I have had second thoughts about the necessity of it.

C4IGrant said:

S&W AR's are over gassed so a heavier buffer reduced felt recoil.

C4

Click to expand...

I know with my 15-Sport, your statement is true. Given that I know of a few 15-Sport owners that have installed a heavier buffer, I feel comfortable generalizing your statement to the 15-Sport.

Stebo said:

OMG! Here we go again.

In the world according to C4I, ALL S&W's are over gassed because, well they just are. In his world, they are over gassed because the average S&W buyer will, of course be shooting cheap underpowered ammo because they have a cheap rifle. Colts, on the other hand, are not over gassed and will choke on the cheap stuff, but of course the Colt owner would never shoot the cheap stuff.

I think I have that about right.

Click to expand...

Stebo... breathe man... breathe...

The Colt vs everything else in the world thing does get me riled up. C4IGrant does rub me the wrong way at times (and vice-versa), but:

Many civilian AR15 rifles are over gassed. Over gassing provides more pressure to act upon the BCG, ensuring that the rifle cycles most ammo. A rifle that cycles most commonly available ammo reduces the vendor's customer service call center workload. Most AR owners won't ever realize their rifle is over gassed because they'll never bother to learn more about the AR platform other than "it shoots".

So the Colt is gassed at whatever is considered "normal"and gets to use a semi-auto BCG with a carbine buffer. Who cares? Say the Colt owner decides to avail himself of inexpensive ammo. The carbine buffer is the lightest buffer (that I am aware of). They would have to then use a reduced power buffer spring.

The point being that there are so many combinations to get your rifle running exactly the way you want. Semi-Auto BCG v.s. the heavier Full Auto BCG. Carbine, H, H1, H2 buffers. Regular, reduced, increased power buffer springs. Part of the fun of AR15 ownership, at least for me, is trying to get my rifle just right for me.

MichiganScott said:

Spot on. I've always wondered how a buffer can reduce recoil, a claim I see on a regular basis.

Click to expand...

You're right. The recoil energy produced by a given round of .223 ammunition is always the same. Regardless of the position where the spent case is thrown, ejection of the case is ejection of the case.

What we're discussing is reducing perceived recoil.

Round of ammunition is fired > hot propellant gasses are bled off down the gas tube > the bled off propellant gas has to overcome resistance of the static mass of the BCG, buffer, and compress buffer spring.

On the return trip, the spring has to provide enough resistance to arrest the rearward motion of the BCG, then use the stored energy in the spring to drive forward the BCG & push a new round into battery.

Too much gas and the BCG cycles faster/harder increasing perceived recoil. Not enough gas and the BCG will not fully cycle, but perceived recoil is greatly reduced.

The different weight buffers is the easiest way for me to increase or decrease the total static mass on which the propellant gasses must overcome.

Finding the right buffer weight puts my rifle in the "Goldilocks" zone. The BCG action is not too fast or slow, felt recoil is reduced, the action reliably cycles, ejection patterns stabilize, and I'm a happy camper.

Thanks, John. Feelin' good now.

It's amusing that our resident lurker/S&W basher should jump in to trash the M&P (once again) and then advertise his website to M&P owners. I'd have to be really, really desperate to ever buy from this guy.

I've attached a chamber pressure chart that visually reinforces your comments. A carbine length gas system is what it is.

Stebo..shouldnt that ammo have been 5.56x45? The listed chamber pressure far exceeds the safe published limit for .223 ammo at least according to SAAMI. The pressure indicated was in the Range listed for 5.56x45, I suppose it is not a big deal it was just one of those things that make me go hmmmmm!

Stebo said:

OMG! Here we go again.

In the world according to C4I, ALL S&W's are over gassed because, well they just are. In his world, they are over gassed because the average S&W buyer will, of course be shooting cheap underpowered ammo because they have a cheap rifle. Colts, on the other hand, are not over gassed and will choke on the cheap stuff, but of course the Colt owner would never shoot the cheap stuff.

I think I have that about right.

Click to expand...

I know it is a hard pill to swallow, but there are SET STANDARDS for two of the three gas systems. The GP size for the 14.5" M4 barrel is .063. This same size is also used for the 16" barrel (though that makes it slightly over gassed IMHO).

With the mid-length gas system, there is no set standard for it and so companies like BCM, DD, Noveske, etc do cyclic rate tests on their GP sizes to establish a baseline of about 700-800 RPM.

The above mentioned companies + LMT, KAC, etc will all shoot lower pressured ammo (like Wolf). These companies also use H buffers in their guns. So if you think about it, if these guns will run lower pressured ammo with a heavier buffer than what S&W uses, what does that say about S&W's GP size????

My earlier post wasn't trying to get anyone to NOT buy a S&W AR or to sell the one they have. It was an effort to educate them that there AR has more felt recoil than other brands (because it is over gassed) and how they can remove some of it. If they don't want to follow my advice, that is fine with me, but at least I shared some technical knowledge in attempt to get their AR's to run better.


C4

Mr Grant. I do appreciate your sharing your knowledge with us. I happen to agree, that the Sport anyway, is slightly overgassed because a slight weight change in the buffer will smooth out the operation. Sir in light of some of your previous posts you do seem to have the ability to put the bulk of us on the defensive, after your derision of our rifles, I am included in that group. But thanks again.

MichiganScott said:

Spot on. I've always wondered how a buffer can reduce recoil, a claim I see on a regular basis.

All my AR's, regardless of manufacturer have reliable ejection straight from the factory. Never could understand why anyone would buy a rifle that was not reliable and change parts instead of sending it back to the manufacturer as many times as necessary until it was.

Click to expand...

Reliable means different things to different manufactures. The Govt says that a 14.5" barrel with a carbine gas system MUST come with an H buffer. This adds cost to the guns price as it issues one Tungsten weight.

So if you think about it, how can a 16" barrel (that has more dwell time than a 14.5" barrel) use a CAR weighted buffer (which is what S&W uses) and achieve optimal reliability???

When we add heavier buffers to guns it is to reduce felt recoil, lower the cyclic rate and slow down the unlock time of the bolt. On top of this, if you are using a Suppressor, you would change that H buffer to an H2 or H3 (depending on barrel length) to help slow down the bolt head speed thusly making the gun more reliable.

Realize that most gun manufacturers (RRA, DPMS, BM, S&W, Oly, etc) DON'T include H buffers in their guns for ONE REASON. Cost! So when you look at people adding H, H2 or H3 buffers and think that they are changing the reliability of their AR (in a negative way), think again.





C4

Stebo said:

Thanks, John. Feelin' good now.

It's amusing that our resident lurker/S&W basher should jump in to trash the M&P (once again) and then advertise his website to M&P owners. I'd have to be really, really desperate to ever buy from this guy.

I've attached a chamber pressure chart that visually reinforces your comments. A carbine length gas system is what it is.

Click to expand...

You know what is funny is that on other forums, I am known as the S&W "Fanboy!" Imagine that!

We are a S&W Distributor. We make our living selling S&W products. I am a big fan of S&W firearms and many of the AR's you see today is a DIRECT reflection of my input to S&W.

With that said, the TRUTH IS THE TRUTH and I am not the kind of dealer that lies about the products he sells (I know that is a 180 from other dealers that will tell you every firearm is perfect/best).


C4

oneyeopn said:

Mr Grant. I do appreciate your sharing your knowledge with us. I happen to agree, that the Sport anyway, is slightly overgassed because a slight weight change in the buffer will smooth out the operation. Sir in light of some of your previous posts you do seem to have the ability to put the bulk of us on the defensive, after your derision of our rifles, I am included in that group. But thanks again.

Click to expand...

I could walk onto the Colt, Ruger, DPMS, BM, etc dedicated fan website and everyone would tell me that THEIR gun is perfect in every way and nothing is wrong with it. This phenomenon is called "being married to your purchase." If people perceive that there is something wrong or not perfect with their gun, car, house, etc, it is a direct reflection on who they are as a person. This is of course SAD, but is the norm on every gun forum I read.

For instance, Colt doesn't make a mid-length gas system. Why? Their engineers believe that there is no benefit (from a reliability standpoint) to make one. While this quite possibly true, the fact remains that the commercial market LOVES middy gassed guns and to not offer a gun with this gas system in moronic!

If I stated the above on a Colt fanboy forum, they would scream from the hills that I was a Colt "hater." Funny how both the S&W AR owners and Colt AR owners would both equally hate me (even though I sell both brands and am fans of both companies).

I am not trying to put "down" anyones AR choice. I am simply trying to get people to realize that it can be made better with small changes. That is all. At the end of the day though, I would much prefer everyone save their money and attend some training classes so they could actually learn how to properly run their firearms.


C4

I do agree with your last statement. I grew up hunting and fishing. I then had a lot of training in the Marine Corps. And I mean a lot. Everything from cold weather survival to jungle operations training. I didnt buy my Sport to be used as a tactical rifle. I bought it to hunt varmints with it. But people who buy this platform with a tactical intent should take training courses, you tend to do what you practice. In case of a TEOTWAWKI situation, I would hunker down in the mouth of my late 50's early 60's era Nuclear Fallout shelter and pick off the bad guys at a distance. I wouldnt be runnin and gunnin. LOL (to old and fat)

oneyeopn said:

I do agree with your last statement. I grew up hunting and fishing. I then had a lot of training in the Marine Corps. And I mean a lot. Everything from cold weather survival to jungle operations training. I didnt buy my Sport to be used as a tactical rifle. I bought it to hunt varmints with it. But people who by this platform with a tactical intent should take training courses, you tend to do what you practice. In case of a TEOTWAWKI situation, I would hunker down in the mouth of my late 50's early 60's era Nuclear Fallout shelter and pick off the bad guys at a distance. I wouldnt be runnin and gunnin. LOL (to old and fat)

Click to expand...

LOL, your not "old and fat," your wise and husky!


C4

oneyeopn said:

Stebo..shouldnt that ammo have been 5.56x45? The listed chamber pressure far exceeds the safe published limit for .223 ammo at least according to SAAMI. The pressure indicated was in the Range listed for 5.56x45, I suppose it is not a big deal it was just one of those things that make me go hmmmmm!

Click to expand...

Grover,

I offered the chart to visually show the difference in pressure between a rifle length and carbine length gas system. You can see that the carbine approaches twice the rifle.

A statement that "So when you look at people adding H, H2 or H3 buffers and think that they are changing the reliability of their AR (in a negative way), think again" is patently false. I should have my 20" rifle length system up and running within a couple weeks. I am using a carbine weight buffer, not because it's "cheap" but because I expect it to run fine with that weight. Since that is the "cheap" way to go, should I use, say, an H2 (heavier is more expensive=better, right?). Heck no, using an H2 my new system would probably choke, maybe not cycle at all. So can you affect the reliability of your AR by installing too heavy a buffer? The answer is maybe, and as you install heavier buffers, the answer approaches certainly.