Hello all, Sorry for long post in advance but I need advice and trying to make it as short as possible.

I have an M&P15-Sport and have had for almost 2 years. I dont shoot alot but do when I can and like to make everything as good as it can be.

I have an Aimpoint also and this rifle is great with it.

I originally ran a few hundred rounds with the standard CAR buffer. Then a few months back, I figured I would purchase an H-Buffer and ever since, theres alot less felt recoil which I liked alot until I tried out what I'm about to mention.

I just got a Spike's Midlength Upper for an AR build I just completed and it has an M16 heavy Carrier so I got an H-2 Buffer for the Lower and "Spikes 17-7 stainless electro Polished Buffer Spring" for the lower I have for it. It runs even better with practically NO felt recoil. Not sure if its the fancy polished $10 spring or the H-2 Buffer being the entire Rifle is NEW but it feels Great. Im sure the buffer doesnt go to the back of the buffer tube yet to add recoil being its new and only shot 30 rounds to test it

Now, I really want an "H-2 buffer" for my M&P Sport but worried that it'll be too heavy and the fact I have about 500 rounds through it already and the Buffer spring is worn in properly like it should be, to where when you charge it, it goes all the way back without much tension. Compared to how my New Spikes Middie does have alot more tension when when pulling the charging lever back due to having brand new spring.

Im wondering if I should get a New spring also if I get an H-2 so it doesnt bottom out being spring is 500 rounds worn in.

Do you think its even a good idea to put an "H-2" buffer in a Sport being these don't have "Full auto/Heavy Bolt Carriers"?? Im just looking for OPTIMAL PERFORMANCE in my M&P but it works fine now.

Wouldnt want to run into any problems with the buffer being TOO HEAVY, and if I got the heavier buffer it would only feel right to get a new spring like the one I got for the spikes but then I wouldn't want to have to do a new break in period if thats even necessary (I dont know much about break in period in buffer/buffer spring area if there even is one).

Also, I love the crisp trigger with no creep, its just a little heavy so thinking about getting a Geisselle SSA for better shots with my aimpoint but thats a whole different story.

Summary:

Does H-2 Buffer sound like a good idea for an M&P15-Sport Carbine with around 500+ rounds of strictly 55gr PMC and 62gr 556-Xtac through it? Would a new spring be necessary being I'd need to wear it in again and I wouldn't want it to effect the function or stability of my Aimpoint but I'm just basing the H-2 on the way the Spikes fully MilSpec upper felt responded to the H-2 and spring. The Spike's does have a heavier carrier which may be why I liked it so much but I hear the M&P's are "Overgassed", so that may even the playing field and be a reason to get an H-2 if it would reduce recoil more than the H buffer.

Advice needed...Again, Sorry for the such long post

PS: Maaaaaaybe, I should swap lowers and see how it feels on my M&P. lol. Main issue is wondering about a new Spring on an already broken in rifle though. Not sure if accuracy would be better or if it would take awhile to wear the spring in.

Nighttrainnc,

As you know, the differences you feel between the rifles is due to the different cyclic rates. The full auto M16 bolt carrier in your Spikes + the H2 buffer adds more mass slowing down the cyclic rate of the rifle. The midlength gas system also lessens the perceived recoil impulse. Your 15-Sport has a carbine carrier, a carbine buffer, and a carbine gas length system. The combination of all of this leads to a faster cyclic rate which contributes to a greater perceived recoil impulse.

IMO, most of the affordable range of rifles are a tad over-gassed. This is so that a commercially available consumer rifle will cycle many of the available off the shelf ammo. Increase the gas pressure cycling the action, and the rifle should cycle more different types/brands of ammo. Firearms manufacturer's don't want to deal with endless customer service calls about this or that ammo not cycling.

If you want your 15-Sport to behave more like your mid-length Spikes, you can do a few things to slow down the cyclic rate:

1. Replace the carbine BCG with a full auto BCG to increase the mass the combustion gasses must overcome, slowing down the cyclic rate.

2. Install an H2 or H3 buffer to increase the mass the combustion gasses must overcome, slowing down the cyclic rate.

3. Install a heavier buffer spring to increase the spring resistance the combustion gasses must overcome, slowing down the cyclic rate.

You'll have to experiment with combinations of these to get the lighter recoil impulse you want without the changes inducing malfunctions.

I've installed into my M&P 15-Sport a AR-Restor hydraulic buffer.







Here is a link to the thread about the AR-Restor Hydraulic Buffer. I bought one and passed it around to forum members for testing and impressions.

Hydraulic Buffer?

The other thing you can do to reduce perceived recoil is to change out the muzzle device from the A2 birdcage to a muzzle brake.

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-John

Thanks for advice, I dont plan to change the carrier as the rifle was fine out of the box and still fine with an H buffer so maybe I should stop there.

Main concern was if I could put an H-2 in with the original Recoil spring That is already broken in or a New stiffer spring being a better idea for heavier buffer without changing the BCG to a heavy one.

Would you say the "H-Buffer" that I currently have is most likely a good STAYING POINT for my intentions? I was just going to put in an H-2 with hopes that it would reduce recoil even further but definitely not getting a new BCG for this one.

My conclusion is that with a carbine buffer and worn in spring that the "H-Buffer" may be my best bet without running into any issues with ammo. Am I correct??

Just didn't know if any guys on the board run an H-2 with OEM Bolt Carrier (BCG)??




Also, The trigger on my sport has NO CREEP whatsoever which I like, I put a DPMS parts kit in my lower for the Spikes Middie and the trigger is ******. Anyone know where to get Stock M&P triggers?
ALOT of folks have told me to get a "Geisselle SSA (or) SSA-E" and I've yet to read about anyone complaining about the $200+ price tag on the trigger its apparently so good.

The stock M&P trigger is great but its a tad stiff and kind of shifts my POA when my red dot is on something at 50+ yards and I start pulling the trigger. Im Probably jerking the trigger at times. I lubed the little notch on the lower rear of the hammer where that the disconnector does into, and it had a much lighter break weight until the lube wore off :-( (used CLP)...Ill use thick oil next time, just didn't want carbon to stick to the oil in the trigger group but I read its not an issue. I always thught the Trigger and FCG springs weren't supposed to get lubed. Am I right or wrong on that??

Interesting to hear about your stock M&P Sport combat trigger. Mine was the same way. Wherever S&W sourced their standard combat trigger, it is good stuff. You can work on your M&P Sport's trigger. Stone it and give it a quick polish. You can also install JP Enterprises Yellow reduced power trigger spring set. The only drawback is firing some Russian steel case ammo that has hard primers. The light springs sometimes don't have enough in them to ignite a hard primer.

If you want the best single stage combat trigger, check out an ALG Defense ACT trigger. I've shot one, and it beats any polish job and work I've done on a stock trigger.

ALG Defense - where triggers with tradition, value and regulatory concerns are of primary importance

I've also had the chance to try a Geissele Automatics SSA-E trigger and a Timney AR-15 Skeletonized trigger. Both were unbelievably good. Of the two, I prefer the Timney because it's a complete drop in unit. The only thing I couldn't stomach is the price.

I've installed a Rock River Arms 2-Stage Varmint trigger in my 15-Sport. Take up the slack, hit the wall, then the trigger breaks at 3.5 pounds. It helped to tighten up my groups.

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-John

Nighttrainnc, I have an MP15TS that I run an H3 type buffer with a Wolff extra power buffer spring. TS has a different barrel from the Sport, so I'm not sure if this is a good benchmark to weigh your decision. You can purchase the tungsten weights for the buffer separately and use your original buffer. Generally, a standard buffer is 3 steel weights, the H is 1 tungsten and 2 steel, the H2 is 2 tungsten 1 steel and the H3 is 3 tungsten. The weights are removed/installed by removing the roll pin that retains the end pad to the end of the buffer.

When you get your parts, test fire your rifle with 1 round in the magazine. This will allow you to see that the rifle will properly eject a round and then secure the bolt catch automatically with the empty magazine.

To make tuning of your gas system easier, you may want to consider an adjustable gas block. This takes some of the mystery out of balancing the gas system with the weight of the bcg/buffer components installed. And helps especially when your gas port diameter is over-sized for your setup.

The Gieselle SSA-E trigger is a very nice trigger. You feel the difference in quality as soon as you take it out of the package and examine the machine work and coating. If you purchase an SSA-E on e-bay and it does not have a signature "G" on the trigger arm, it is probably fake. I have this trigger on both my MP15TS and my MP10. I have also used the RRA 2 stage trigger in the past. The RRA 2 stage trigger has a longer pull and reset than the Gieselle, but functions reliably for half the price, giving you a 2 stage trigger pull on your AR that is more like that of a hunting rifle with an OEM 2 stage trigger.

Sprinco Blue Spring with H2 buffer and it will run like a dream.

Remember. It's VERY easy to drive yourself nuts over thinking all this "stuff". ...But it is fun.

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THIS WE'LL DEFEND ΜΟΛΩΝ ΛΑΒΕ

It's fun reading about it. I think all AR-15 owners go through this phase. (Some get stuck in it)

__________________
-John

Not all of us John, but I think I am in the minority.