H2 Buffers...anyone using them in MK18 style rifles?

[strider007]

Any of you guys out there using H2 buffers in your short barrel, MK18 style, carbine-length rifles? I know that in the pistol-length PDWs it may be a necessary upgrade, but was wondering if anyone is using them with their carbine-length rifles. Any input, pros & cons, would be appreciated.

 

[Hilo71]

Depends on the ammo and the gas port size.
I use a H2 with my LMT MK18 when shooting 5.56 pressured ammo. Works great, shoots smoother. Hornady TAP tends to double feed with the H2. (LMT uses a smaller gas port tuned for mil type ammo)
The DD mk 18 barrels have larger gas port, which makes it eat just about any commercial ammo. Putting a H2 in it may work fine, and it may change the impulse.

 

[strider007]

Depends on the ammo and the gas port size.
I use a H2 with my LMT MK18 when shooting 5.56 pressured ammo. Works great, shoots smoother. Hornady TAP tends to double feed with the H2. (LMT uses a smaller gas port tuned for mil type ammo)
The DD mk 18 barrels have larger gas port, which makes it eat just about any commercial ammo. Putting a H2 in it may work fine, and it may change the impulse.

Thx Hilo...do you know if the gas port on the 10.3" DD barrels are slightly larger than their longer barrels? If so, this would allow the gas charge to be a bit sharper when making it back to the BCG...shorter barrel, shorter dwell, larger gas port, more positive gas charge to the BCG, guaranteed cycle...I don't know. But in my head, those are the lyrics...

I know how the saying goes, but if it ain't broke and you don't need to fix it, there's always roon to make it even better, right? I guess my curiosity is getting the best of me. Think I'll pick up an H2 and try it out...

 

[TK-Hryciuk]

I picked up a colt H2 buffer for my DD MK18. The recoil impulse to the rear is noticeably less sharp and has a less violent forward slam when the bolt returns to battery, most likely due to it moving slower. I would recommend picking one up and giving it a try.

 

[Dietz]

I run a Colt or LMT H2's in all my AR's, including my 10.5" LMT and I've had no problems over thousands of rounds, 55gr MFS up to 77gr Hornady 5.56, it runs really smooth actually, everybody who shoots it love it. You do feel a noticeable difference in cycling rate when shooting 5.56 compared to .223. That's why I favor LMT barrels for 10.5 builds, they're pretty much the only barrel available in Canada with the correct gas port diameter of .071" for 5.56 ammo, everything else is overgassed.

And it is a well known fact that the short barrels Daniel Defense sells to civilians are grossly overgassed.

 

[strider007]

I picked up a colt H2 buffer for my DD MK18. The recoil impulse to the rear is noticeably less sharp and has a less violent forward slam when the bolt returns to battery, most likely due to it moving slower. I would recommend picking one up and giving it a try.

That's what I figured...so with the slower cycle, how did it affect extraction? Any noticeable differences? Also, are you using 55gr or 62gr with your MK18?

 

[strider007]

I run a Colt or LMT H2's in all my AR's, including my 10.5" LMT and I've had no problems over thousands of rounds, 55gr MFS up to 77gr Hornady 5.56, it runs really smooth actually, everybody who shoots it love it. That's why I favor LMT barrels for 10.5 builds, they're pretty much the only barrel available in Canada with the correct gas port diameter of .071", everything else is overgassed.

And it is a well known fact that the short barrels Daniel Defense sells to civilians are grossly overgassed.

Thx bud...appreciate the info.

So lemme' ask you the same question: Any extraction issues?

 

[Dietz]

Thx bud...appreciate the info.

So lemme' ask you the same question: Any extraction issues?

No, never, even if the gun is so filthy you can smell it from the parking lot, if it were to occur I would be blaming extraction issues on a weak or damaged extractor/spring/insert, or clogged ejector cavity, not on the BCG moving too fast or too slow, you'll have feeding issues before extraction issues if the bolt rides too fast, and it can't really get too slow without running into short stroking country.

This build is sporting a LMT 10.5" barrel and BCM BCG by the way (so I'm not expecting any problems anytime soon), and I removed the overly unecessary o-ring they put in extactors nowdays.

 

[Hilo71]

Heavier buffer will aid in extraction, as it slows the cycle a bit.
DD 10.3 barrels gas ports are .080, compared to LMT's .071 (as Deitz noted)
DD will digest almost ANYTHING. But sharper impulse, and as it beats the crap out the BCG, "may" have extraction issues with some ammo.

 

[Dietz]

Heavier buffer will aid in extraction, as it slows the cycle a bit.
DD 10.3 barrels gas ports are .080, compared to LMT's .071 (as Deitz noted)
DD will digest almost ANYTHING. But sharper impulse, and as it beats the crap out the BCG, "may" have extraction issues with some ammo.

Yeah and I think it's a shame they drill those gas ports so large (I've read reports of gas ports being even larger than that, one case was a 12.5 that had it insanely large), because all things considered, Daniel Defense makes a hell of a good barrel, if it wasn't for their gas port mentality of "people run cheap underpowered crap so we should size the gas port accordingly" I would be buying their barrels over LMT, but the LMT guys don't cut corners to accomodate for crap ammo, so they get my money.

 

[Movado]

I use a Spike T2 buffer in my MK18 build with a DD barrel. After more than 8000+ rounds of Norinco ammo, I never had any extraction problem.

 

[strider007]

Thanks Dietz and Hilo...appreciate the replies. That's exactly what I wanted to know. Especially the fact that you removed the o-ring, Dietz...that's what I was getting to. I was hoping that extraction wouldn't be compromised, and that I wouldn't have to upgrade any of the extractor components. I guess that with the slightly slower clycle, the extractor has a bit more of a methodical approach to performing its task. Even with the overgassed DD port, I should be good to go. Perfect...thanks guys.

 

[Dietz]

Thanks Dietz and Hilo...appreciate the replies. That's exactly what I wanted to know. Especially the fact that you removed the o-ring, Dietz...that's what I was getting to. I was hoping that extraction wouldn't be compromised, and that I wouldn't have to upgrade any of the extractor components. I guess that with the slightly slower clycle, the extractor has a bit more of a methodical approach to performing its task. Even with the overgassed DD port, I should be good to go. Perfect...thanks guys.

Yeah all things considered, those o-rings sometimes put so much pressure on the case rims they cause more feeding/extraction problems than they theorically solve, if your bolt is from a known trusted manufacturer, it will have a propper extractor spring and insert. The cheap #### is often fitted with too small or weak springs, even the wrong insert.

I carry spare extractor spring/inserts in my range kit (I get some Stag ones from Arms East or DD from Wolverine), along with every small part that could fail in an AR, gas rings, cam pin, extractor, etc, etc...

Generally speaking, I tell people to run the heaviest buffer they can get their hands on, I'd be running an H3 if I had one, I have considered cannibalizing an H buffer and put the tungsten weight in an H2 to make it an H3, but the H2's run well and I abide by the "don't fix it if it ain't broken" rule.

 

[Ix]

H2 in mine also, I never tried it with the factory H so I can't say for sure what difference it makes on the DDMK18. It smoothed out my 11.5" well enough for me to switch it to my 10.3" without any doubt in my mind. I've been thinking of going H3 for a while too, but I just keep buying other parts It's on my next brownells order tho.

 

[-[Crosshair]-]

I use a Spike T2 buffer in my MK18 build with a DD barrel. After more than 8000+ rounds of Norinco ammo, I never had any extraction problem.

Are those the buffers with the tungsten powder? How does the recoil feel compared to a regular buffer with weights? I've always been curious about them.

 

[Island_Craig]

In for the opinions as well.

Have a off the shelf MK18, never really thought about modifying but if its beneficial.

So running m855/m193 a heavy buffet is 100% reliable?

 

[strider007]

Are those the buffers with the tungsten powder? How does the recoil feel compared to a regular buffer with weights? I've always been curious about them.

I was looking into the Spike's buffer also, but their T2 buffer weighs in at 4.1oz, whereas the Colt H2 buffer that I ordered weighs in at 4.6oz. I know it's only 0.5oz, but figured it would be better than stepping up to the Spike's T3, which may be a bit too heavy, weighing in at 5.4oz. I know a few guys running the T2s, and they are happy with them. I'm gonna give the Colt H2 a run and see if there is a noticeable difference...maybe might even swap in a buddy's T2 for comparison.

 

[strider007]

In for the opinions as well.

Have a off the shelf MK18, never really thought about modifying but if its beneficial.

So running m855/m193 a heavy buffet is 100% reliable?

According to everything that I have read over the net, it should be 100% good to go. But honestly, when members are posting from their own experiences, and claiming that they've had nothing but good results with the H2, that's pretty much good enough for me. I'm sure that if issues were had, we'd be made aware...most of the time, anyway. But in this case, I'm pretty confident that it's a positive.

 

[Movado]

Are those the buffers with the tungsten powder? How does the recoil feel compared to a regular buffer with weights? I've always been curious about them.

Yes those are the tungsten powder. The recoil is smoother then the regular H, especially on the MK18 with the hot Norinco ammo. Most of the ammo I shoot are Norinco so my MK18 and DD M4V5 all have the T2, never had any extraction problems. Only for noise reduction of the weight shifting in the regular buffer and the spring, I personally think they are worthed.

 

[Dietz]

In for the opinions as well.

Have a off the shelf MK18, never really thought about modifying but if its beneficial.

So running m855/m193 a heavy buffet is 100% reliable?

You should be running an H2 regardless of barrel lenght if you shoot 5.56 spec ammo, but especially so with the short barrels.

I'm not big on powder buffers, they don't do as good a job as the standard configuration's moving solid weights, their purpose is to prevent BCG bounce.