M&P15 OR ST-T2 SPikes tactical Buffer

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christcorp

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Question for anyone out there who is familiar with the ST-T2 Spikes tactical buffer. I recently purchased an ST-T2 buffer. Not that i was having issues with my 2 month old M&P15 OR; just that I like to tweak and make things better if possible. Haven't shot the gun yet with the new buffer. In the 2 months I've owned the gun, I've put about 800 rounds through it. About 500 rounds of Russian steel case and about 300 rounds of PMC bronze.

Now; I've heard that the M&P15's are "Over-Gassed", so I figured the ST-T2 buffer would be a good addition. Heavier than an "H" buffer, but lighter than an "H2" buffer.

My question is: Has anyone had any issues with short stroking their M&P15? Especially anyone who has used the ST-T2 buffer, and/or if you shoot Russian Steel case ammo? Thanks
 
Good move upgrading from the standard weight buffer.

I know a guy that has an H2 buffer in his S&W and shoots Wolf with no real problems. So the odds are very high that you won't have shortstroking with the lighter ST-T2. His extractor does mar the rim a little indicating a timing issue but so far hasn't caused reliability problems. Have you noticed this issue on yours? I would think this issue would be worse with a lighter buffer that doesn't slow down extraction slightly. If so I'd be curious if the ST-T2 makes an improvement.

Also I'm running an H2 in my midlength and no shortstroking or extractor marks on the casings. It should be a piece of cake for a carbine length gas system. Good luck and definitely let us know how it goes...
 
I looked at about 100 empty brass. Some steel and some brass. Haven't seen any bad extractor marks on the rims. I will shoot about 4 magazines with 1 round in each, to make sure that there's still enough gas pressure to have the bolt go all the way back. "If there is, then the bolt should lock open on the last round".

Most people say the M&P15's are "Over-gassed". So the ST-T2 should be a good addition. Easier on the bolt, and a little smoother operation. With the original buffer, I've shot tula, MFS, and PMC ammo. I just picked up a case of barnaul ammo at a gun show, so I'll give that a try. Hopefully this weekend, if we don't get much snow. $4 a box, no tax or shipping (Bought at gun show). Have had a lot of good luck with steel case ammo in many of my guns. Hopefully this batch will work good. If not; I'll use it in my Saiga .223 and buy some more tula or MFS. We'll let you know how it goes. mike...
 
Good news that your new S&W doesn't mar the rims, Mike. My buddy's is about 3 years old and I've heard there have been improvements since S&W has moved much of their production in-house. Still he's been very happy with his.

Anyway I doubt you'll have issues, the rims were the only thing I could think of because of his. Bet you'll notice smoother cycling.
 
Hoping so on the smoother cycling. It's not that a .223/5.56 kicks much. And it's not like after 21 years in the military and owning AR's, that I haven't gotten use to the "TWANG" of the buffer/spring. And it dumps ALL the empty cases in a nice neat pile at 4:00 about 7-8 feet away. But if it can "Feel" a little better; and possible put a little less wear/tear on the BCG; then that's a plus. I've always considered buffers in the same category as sights, optics, laser, slings, etc... It's obviously required; but the original that it comes with usually works fine. Replacing it is strictly for personal preference.
 
The real H2 buffer should work better than the Spikes. The "dead blow" effect of the three weights in the H2 are more effective than the powder used in the Spikes. If you go to M4carbine website there are high speed photos showing the bolt bounce of several buffer designs.
 
DBR: I'm aware of bolt bounce. But to be honest with you, that is primarily an issue that is only significant with full auto weapons. A semi-auto really doesn't have an issue with bolt bounce.
 
Not only do I run an STT2 in my M&P15, I also use an extea power buffer spring. No probs at all,even with Tula ammo, and rifle is noticably smoother.

ETA: A Sprinco Red Buffer spring will also get rid of the "twang"!
 
christcorp: I don't agree with you re bolt bounce. A machine either works as designed or it doesn't. Rifle systems have virtually no bolt bounce. It "may" not matter in a semi auto but it still is a compromise to the original design that can be prevented.

I believe in maintaining fidelity to the original concept/performance unless one can demonstrate an actual improvement.
 
i have not researched buffers as well as i should have so this post as my att. i'm in the process of putting a BCM middy barrel on my carbine (+a BCM bolt) i have a rock river lower i'm not using that has a standard A2 stock and buffer and i'm wondering if it would work better than M4 style w/carbine buffer? not trying to hijack the thread just figured since we are on the subject of buffers i'd ask
 
DBR: How do you know that the dead weight blow of the H2 is better than the soft gradual blow of the ST-T2? You're assuming too much. Part of which, is that all or most semi/auto rifles have bolt bounce. And I've seen those videos before. If you look closely, even the 9mm real heave 5+oz buffer caused bolt bounce. And if you notice, there aren't any high speed videos showing an ST-T2 with bolt bounce. So again, you're assuming.

Unfortunately, without a high speed camera, it's pretty much impossible to recognize bolt bounce. You notice it in full auto, because you can experience slam fires where the firing pin strikes the primer while in the bounce mode. You definitely know it. Sort of like a bad valve in the car. You just know it. You can hear it.

So basically; the bolt bounce is a combination of too week of a spring, with too heavy of a buffer. However; as the video shows, with the right harmonics, even a lighter buffer can bounce. In most of the videos, it's the lightest and heaviest which bounces, and not the middle one. And yet, ALL of them were traditional solid, separate weight, buffers. So unless there's some proof out there that a floating buffer, like the ST-T2 causes bounce, I'm not really buying it. Especially considering most hydraulic buffers are noted for eliminating any possible bounce. And the free floating tungsten powder is closer to a hydraulic than 3 solid weights with spacers between them.

Anyway; we're off on a separate subject. Bolt bounce is not my concern. ST-T2 aren't noted for causing bolt bounce. And without seeing a high speed camera video of an ST-T2, any accusation that is causes bolt bounce is pure speculation.
 
Kwanger said:
Not only do I run an STT2 in my M&P15, I also use an extea power buffer spring. No probs at all,even with Tula ammo, and rifle is noticably smoother.

ETA: A Sprinco Red Buffer spring will also get rid of the "twang"!
Click to expand...
Kwanger; thanks for the info. So with your ST-T2, and an extra power spring, that's physically MORE resistance than the ST-T2 with the stock spring. So if you're doing fine with the russian ammo, that's what I wanted to know. Thanks. I'll be shooting it this weekend. I have a carbine and an H buffer I'll carry along in case I want to experiment.

I actually got rid of the "Twang" by coating the inside of the buffer tube with a dry spray teflon. That's something I've done with all 3 of my AR's over the last 30 years. When I first entered the military in 1978, an old time vietnam vet, who was one of my instructors at the time, taught me to put a little cotton gauze inside the buffer tube before putting the spring in. Then a little dob of the cotton a little way up the spring. (Just inside 1 ring of the spring). Then put the rest of the spring in the buffer tube and the buffer. The spring still functions perfectly, but the cotton absorbs all harmonic vibrations and eliminates the twang and some of the buzz feeling some people mention. I did the cotton on an issued m-16 while I was in the Air Force, but not on one of my own. I don't think the carbines have the same vibration that the full stock 20" rifles did.

Anyway; glad to hear that your ST-T2 works fine in the M&P15. Especially with a heavier spring. It should have no problem short stroking mine with the stock carbine spring. Thanks again.
 
I've read that thread. I probably spend as much time at m4carbine as any other sight. I mainly just read. Definitely a very good thread. But as you can see, there were many variables and combinations. The biggest variable is that those tests were done on midi's. My M&P is a carbine length gas system. Not a midi. Also, they've been experimenting with numerous combinations of springs. Including flats.

Point is; just like will certain ammo or magazines work in my gun, can't truly be known until I try it; there's no way to guarantee bolt bounce on a gun unless you try it. All guns out of the factory don't come with bolt bounce. A particular buffer doesn't automatically create bolt bounce. Anyone who thinks it does, is simply wrong. It's a combination of buffer, spring, gas port size, gas pressure, and ammo. That's why in some of the videos, a lighter and a heavier buffer caused bounce, yet the weighted one in the middle didn't. And all three of those buffers were the same construction. ST-T2 are no different.

Other than that, I really am not concerned about bolt bounce. I'm not firing full auto, and if I have bolt bounce, I'll actually be able to feel it. I shoot way to much .223/5.56 that I can tell when something doesn't "FEEL" right. Most people can if they shoot enough.

But my main question and concern was answered. I am/was concerned more with short stroking than I am with the SLIM possibility of bolt bounce. I didn't think short stroking was too much of a possibility, with M&P15's naturally being a little over-gassed. Just wanted to see if anyone else was running a similar setup using the ST-T2 and shooting russian ammo. Kwanger confirmed what I was hoping and expecting to hear.
 
Perhaps that is the difference in the perspective of a mechanical engineer and an electronics/computer engineer in how mechanical things should work. If you are happy with the results of your inquiry then I am happy. Enough said.
 
Well, if you read the thread from the beginning, you'd know that I haven't fired the rifle with the new buffer in it yet. And while I may not be a mechanical engineer, I've built/rebuilt enough cars to understand the basic concept of physics. But unfortunately, where we tend to disagree, is that you believe the physics of rifles to be finite. In other words, you tend to believe that buffer "X" will perform identical in all AR's imaginable. Even the thread you quoted, admitted the variables to their testing.

Guns as in life are not finite. I know you don't honestly believe that 100 rifles from the same manufacturer are all going to perform equally. Mechanics are not that precise. Just like you can't believe that each rifle has come out of the factory performing at it's optimum capabilities. I've been chatting with others who all own M&P15's, and will all stock parts, and using the same ammo, have ejection patterns ranging from the 2:00 position to almost 5:00.

Anyway; maybe there will be bolt bounce, maybe not. maybe we'll find out. Does your rifle have bolt bounce? You probably don't know. Not unless you filmed it with a high speed video camera. Which you very may have. Point is; you probably don't know. There's no way to guarantee that if you take "X" buffer spring; "Y" buffer; and "Z" BCG, that you are guaranteed not to have bolt bounce. The objective would obviously to have exactly the same exact force against the buffer, that the spring will push back on. This would hopefully create a balance. But getting that exact, when ammo, gas port size, pressure, spring tension, and buffer weight are all factors, is pretty difficult. And as time goes on, and springs start to wear, the variables continue to change. Either way; your link to a post looking for the bolt bounce of an ST-T2 had variables in it that aren't equal to my gun. Therefor, it's difficult to say what will be the result.
 
This response does not relate to "bolt bounce" but it does expand on my earlier comments:

I believe in statistical probabilities. When I have reviewed what I think are the relevant tests or performance reports then I choose the combination of parts that are most likely to produce the results I want.

Reducing this exchange to its essence: I have only tried to inform you and we don't have any disagreement with respect to basic principles.

I think the Spikes Tactical buffer is a gimmick and not equal to the standard parts. I have also seen tests that show them to be inconsistent in both weight and quality of the powder they contain.

Buffers in ARs tend to get wear on the face of the buffer from contact with the bolt carrier. If steel shows significant wear (it does) I would not want to bet on aluminum being equal or better.

Only you can decide what compromises are acceptable. I have made my choices.
 
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All other things aside, you do bring up a couple of concerns I had. That is the inconsistent weight and the aluminum. But after some deeper research, I believe the weight issue was a QC issue in the beginning stages of production. But within 3 minutes of receiving the ST-T2, that was the very first thing I did. I weighed it. I also weighed my standard carbine buffer. The carbine was almost dead on 3.0 oz. It was like 2.9+ oz. I also know that an "H" buffer is around 3.8 oz and an "H2" is around 4.6 oz. Upon the best research i could do, the ST-T2 was said to be between 4.2-4.3 oz. And 3 minutes after i received it, I weighed it, and it came in right at the 4.2-4.3 oz. Practically dead on at 4.3 oz. Part of the reason I wanted the ST-T2 buffer was because I believed the "H" buffer at 3.8 was going to be a bit light for what I wanted to accomplish. But an H2 seemed a little heavy. I own both the standard carbine and an H3. Between the two, I can mix and match the weights to get an H, H2, or H3 if I want. I wanted in better the H and H2. Thus, the ST-T2.

The other concern was the aluminum. But after some wear tests on my other AR, having many 10's of thousands of rounds through it; I determined that even if the ST-T2 lasted only have the lifecycle of a steel, it was made from Billet aluminum instead of forged. So that alone would make it much stronger than if it was forged or cast. Anyway; I wasn't too concerned about it being made from aluminum. Technology has changed a lot over the years. And being made from a block of aluminum (Billet) is quite acceptable.

Anyway; I guess we'll see this weekend how it performs. Just like you don't know if your rifle has bolt bounce, I probably won't know if mine does either. Currently or after the ST-T2 replacement. Sometimes we have to "Use The Force". I work on a lot of car restorations. Mostly old carb type cars. Sometimes you can't really explain good/bad with numbers and test equipment. sometimes you just have to "Feel" it. With older cars, I almost never use a tach or vacuum gauge for adjusting timing. You can hear it and feel it. Feel the hesitation; idle; etc... Well; if you shoot a particular gun enough, you just know what seems out of balance. Sometimes what we learn in school needs to be put aside in place of simply feeling and knowing; and not being able to explain it. I have no intention of filming my rifle and bolt to see if it bounces. And I don't fire full auto, so I can tell by feed/ejection problems. I'll just have to "Feel it".
 
I'll be waiting to hear how your rifle "feels". When I built race cars and motorcycles (before computer controls) I always used vacuum gauges, dwell meters, timing lights and tachs so if I wanted to change something I would know where I started.

Just a small point: Forging generally produces a tougher part than machining from solid. The grain structure in a forged part follows the contour of the part whereas machining from solid (billet) interrupts the grain structure where the contour changes.
 
Well; just got back from the range about a half hour ago. Only got to shoot 240 rounds. There's no time limit; I have a yearly membership - $75; but it's the first real warm day we've had in a long time. There were a few others wanting to get onto some of the 100+yard bays. Just being considerate. I do love that about Wyoming. We don't need as many rules/laws. We're just really into being considerate. (Hell, we don't even have a range officer. Just don't shoot each other). Anyway; I digress.

Anyway; of the 240 rounds, I shot 100 Tula .223 steel case; 100 Barnaul 5.56 steel case; 20 rounds of PMC Bronze .223; and 20 rounds of Military 5.56 I took off the stripper clips. Put the Spikes Tactical Buffer in prior to going out there.

Ran perfectly. Just like I has hoped and expected. FWIW: All cases ejaculated exactly where they had in the past with the stock buffer. At the 4:00 position. Still enough gas pressure, that the bolt locked open after the last round of every magazine. I use 4 USGI Mil Surplus 30 round mags with Magpul Gen III followers; and 5 Thermold LE/Govt use 20 round mags. (I've been using Thermolds for about 10 years. If you get the "LE/Govt use only", I've never had 1 failure. For $3.99 per magazine, I love them).

I do feel that the recoil on the rifle was a little softer. I know that could be just perception, but I don't think so. I've only owned this gun for LESS THAN 2 MONTH. (Got it for Christmas). But I've now put through it about 1000 rounds of ammo. I sort of know how it felt with the original stock carbine buffer. I noticed something else, which I can't really decide on yet. Normally; even with a .223/5.56, while I don't flinch, I usually "BLINK" after the round goes off. That is just normal. At least for me it's normal. Today; even with a pretty windy day; I was able to sight in through the Red-Dot, take the shot, and not blink at all. So I really do believe that the recoil is softer. Not necessarily less; just softer. Maybe smoother is the right word. Is the change DRAMATIC compared to the original Carbine buffer? No, not dramatic. Sort of like the analogy I gave earlier with working on cars. It's a "Feeling" that you get when you tune the motor a certain way. Can't really explain it; just that you know it's better or right.

Anyway; I'm happy with the Spikes Tactical ST-T2 buffer. 2 things I like. 1) My perception/feel is that it's slightly smoother/softer. Again; it's a perception that I can't quite put my finger on. 2) More importantly; the more counter weight that you can add as resistance to the bolt coming back from the gas, and yet still have it go back far enough to eject the rounds, feed properly, and lock the bolt back after the last round; mean less wear/tear and stress on the bolt. That, no matter what, is a good thing. I could probably use an H3 in the rifle, but I'll stay with this for now.

Oh; and DBR. I've been rebuilding cars (Only old carb type without modern electronics), for about the last 30 years. Of course I use vacuum gauges, tachs, etc... My point was, that once I set it for "Book Specs", I would put all those tools away and "Tweak" the rest. Usually by Ear and Feel. I've moved from the Jersey Shore to Texas to the Rockies in Wyoming and New Mexico. "Tweaking" is a necessity with carbs. You simply can't tune such a car strictly by timing and vacuum settings. But that aside; the same with the AR. Without a high speed camera, there's no way to know for sure if there's bolt bounce. It didn't "Feel" out of place. While not select fire, I ran off a half of a magazine with bump firing. No issues there either. Can some rifles with an ST-T2 experience Bolt Bounce? Yes, most definitely. So can a Colt, BCM, DD, or any other with an H, H2, or H3 buffer. And some have. Even in the videos, some did. But there can never be a blanket statement that "X" brand of buffer WILL CAUSE Bolt Bounce. That's simply not accurate. Just like saying "Y" brand buffer will NEVER CAUSE Bolt Bounce. Again; an ignorant assumption. Bolt bounce has as much to do with timing, gas pressure, and spring tension as it does with the buffer. And that's part of the compromise that the M4/Carbine model came up with. Shorter stock; shorter barrel; use a lighter buffer, but a heavier spring. Try and reduce the gas pressure.

Anyway; I don't know if my M&P15 has any bolt bounce. I've never filmed it, and probably won't. It's not full auto, so I know that I won't have any operational problems. I also know that it's virtually impossible for a semi-auto with bolt bounce to hurt the rifle/bolt at all. (Not considering the amount of stress on the "Bounce" isn't even a fraction of the stress on the initial slam forward when it's chambering the next round). So it's really a non-issue. I understand the concerns in a select fire situation. But in a semi-auto situation, which 99.9999% of all of our are, I think we're discussing a solution to a problem that does not exist.

But for me, the ST-T2 seems to be smoother. I like my physical body reaction to the firing and recoil. I like even my perception. And it's ALWAYS a good thing if you can add more resistance to the bolt blow back, if it continues to eject, feed, and lock back properly. So for me; it's good-to-go.
 
christcorp:

Sounds like we have very similar interests/backgrounds except I've doing it for 50 years (hate to admit it). Yes, the sweet spot is often subjective.

If you like the gun the way you have it setup you are good to go in my opinion. I have only one other suggestion: test at the limits of performance like weak ammo, dirty, hot, cold etc.

I used to "detune" my street race cars so they always ran well. I beat many hotter cars that only ran well for a 100 miles after a tuneup (before electronic ignition).
 
Thanks for the suggestions. Actually; I've probably covered all those. This is wyoming. The weather is never the same. Today; it was 50 degrees. When I shot last weekend, it was 20. The week after christmas, when I shot it the first time, it was 5 degrees with a -10 windchill. Gotta love the high plains. I mainly shoot 3-4 different Steel-Case russian ammo. MFS, Tula, Barnaul, and Silver bear. I also have about 500 rounds remaining of PMC bronze that I shoot at least 1 magazine each outing. I've also shot a lot of mil-surplus as well as some defense ammo like TAP. So I think I cover every possible scenario with my shooting habits.

With the ST-T2, obviously this was my first time shooting it. I doubt it will change much in colder or warmer temperatures. The M&P15 seems to shoot anything I feed it, in any type of weather.

The only real tweaking I have left, is to determine if I want to keep the red-dot, or swap it out for one of my reflex sights.

As for the cars; they are definitely fun. I'm very good with engines, but can't do body work worth a crap. I work on other's engines and trannies in trade for other services. Every car I've rebuilt for myself, I wind up selling. Then get another one for a project. There is one however that I'll never get rid of. Then again; I'll NEVER stop tweaking it either. That's my 1966 Mustang coupe with a 289. Of course, I don't believe in OEM or original spec. (Not trying for 100% OEM restoration. I rebuild them to drive. So of course, the first thing that had to go was the distributor and ignition. Points and condensers just make no sense. So I took a modified GM HEI that's mounted on a Ford 289 shaft. Excellent electronic ignition. Starts right up, even on the coldest days. But with the mechanical fuel pump, if it's sat for a few weeks, I usually have to turn it over a bit to get gas into the carb. That's ok though, cause it give the motor a chance to cycle some oil. Maybe I'll go electric fuel on it. I've been playing with this car for almost 20 years.

Anyway; I digress. As for the ST-T2; i definitely can tell the difference between the stagger of a standard weighted buffer and the more fluid shift of the T2. So, if anyone is interested in trying it, it's definitely a cheap tweak. If you don't like it, take the T2 to the next gun show and trade it for something else. It's only $29. But for me, I'll stay with it for now. Anyway; with the three day weekend, I think the wife and I are going to go up to the casinos in colorado tomorrow. Maybe I'll win some money and buy some more toys to tinker with. LOL!!!!
 
Life's too short to not have some humor. Especially with how serious some people are with their guns. Hopefully I didn't offend anyone. Then again; the type of person who would get offended over that, deserves to be offended. LOL!!!
 
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