Buffer weights for Huldra and BCM?

[Tronster]

I'm shooting a pair of 16" middy AR's, a piston Huldra and a direct gas BCM, and I'm trying to slow down their bolt carriers to reduce wear and recoil impulse. I only run hotter 5.56 (M193, LC and PMC green tip, Q3131) and none of the Russian steel cased stuff (I know ammo pressures play a big part in this).

Both have run 100% using a standard carbine buffer, and also limited testing with an H buffer. How would you go about matching the buffer to the different operating systems? Increase the buffer weight til it starts short stroking or ejecting poorly and back it off one weight? If you have the same setup, what weight do you run?

[UnaStamus]

If you are running a BCM barrel, they are specifically designed to shoot M193 and M855 5.56mm pressure ammunition. The low pressure stuff is actually where you can get issues with the BCMs. Most problems that occur in BCMs happen because of low pressure ammunition and people over-buffering their rifles. For the most part, run a BCM with a standard carbine weight buffer for midlength 14.5" or 16", and H buffer for carbine gas length non-NFA systems. For NFA systems it's H or H2 depending on barrel length. If you feel the need to put in an H buffer, that's fine. Just make sure to have a standard buffer handy if you want to run low powered stuff.

For the Huldra, you're dealing with a piston system so it doesn't work by the same dynamics as a DI system. Dave@huldraarms is the best resource on this one and can give you the best response here.
Here's what the Huldra website says:

6. What is the recommended buffer for the Huldra Mark IV Complete Uppers?

We use and recommend standard weight carbine buffers and standard weight recoil/buffer springs. Our uppers have gas ports and pressures designed to be used with appropriate ammunition to the caliber and for optimal performance with the mentioned buffer and spring set up. The use of heavy buffers is not necessary, however you may try different buffer as you wish. Keep in mind that running too heavy of a buffer may cause function issues with some ammunition. For our 5.45 upper, we have tested most every 5.45 round available commercially, including surplus, and found this buffer/spring set up to work the best. The use of rifle stocks with rifle buffer and spring is not optimal for our uppers.

Huldra rifles work exceptionally well out of the box, and I wouldn't monkey with them. They are tuned for 5.56 military grade ammunition, so going to a heavier buffer may increase chances of cycling issues if you were to opt to shoot the lower quality/lower pressure ammunition. If the rifle works well with 5.56 using a carbine buffer, I would recommend against changing out that buffer.

Overall, don't get too wrapped-up in the whole buffer issue. The debate has erupted dramatically due to a lot of people buying lower quality or mid-grade rifles like DPMS, Bushmaster, Olympic, etc. All of those rifles are intentionally over-gassed by the manufacturer so that they will run a wide variety of ammunition. Over-gassing does often require buffer to balance out the timing of the BCG. Higher quality rifles are more stringently tuned to function on a narrower band of ammunition, so monkeying with buffers with those is much less of an issue. Often times the buffer debate is just people looking for real solutions to imaginary problems.

[Hmac]

It's easy to change a buffer and they aren't that expensive, so no harm in experimenting. Personally, I always have 3-4 buffers of different weights in my range bag and in this day of using whatever ammo I can get, I just use the heaviest one I can that will reliably cycle the ammo I am shooting. As a rule, I favor reliable performance over mitigating theoretical excess wear. It would be rare that any of us would even come close to shooting enough rounds through a rifle for excess receiver or BCG/bolt wear to manifest itself on a quality rifle like a BCM or Huldra.

[Back In Black]

Huldra rifles work exceptionally well out of the box, and I wouldn't monkey with them. They are tuned for 5.56 military grade ammunition, so going to a heavier buffer may increase chances of cycling issues if you were to opt to shoot the lower quality/lower pressure ammunition. If the rifle works well with 5.56 using a carbine buffer, I would recommend against changing out that buffer.

I found this to be spot on. I tried PMC Bronze and Federal American Eagle .223 in my Huldra middy and Korstog (DI) middy. Both had issues cycling. No issues at all with every brand of 5.56 I've fed them though.

[10-32 Solutions]

I've found in my BCM Midlength that it has run everything so far with a H buffer. However, my LMT Mk18 is more sensitive where H buffers work best with the full pressure loads, but a Standard buffer is fine with lower pressured loads like PMC and steel case. Mine stopped shortstroking with lowered those lower pressure loads with the standard. I have not had the need to use H2 or H3 buffers.

I use FA carriers though too for more mass than semi auto. Why do you feel you need to slow yours down? What are you seeing for wear?

Either way, like Hmac said, buffers are so easy to switch. I have a spare Standard for that reason.

As for the Huldra, will all the shooting I did with one for that SWAT article, it functioned fine with .223 pressure ammunition setup as it was, but I concur that Dave would be the guy to ask if messing with it would even give you what you're looking for.

[Tronster]

Thanks for the responses guys...I don't think I am seeing any excessive wear yet. Both rifles use FA carriers and standard carbine springs.

So it was such a nice evening, I thought I would go out to SMSC range and do a little ammo/buffer test on both rifles.

The weakest stuff I have is PMC bronze .223 (which is actually decent plinking ammo). So I shot 40 rounds of bronze through each rifle with an H1 buffer (yea I know that's not alot of rounds) and no issues at all, and all ejected about 10 feet at 4o'clock. Shooting some Lake City it was noticably more kick, so I think it's safe to say an H1 would be a good all around buffer for hot 5.56 and weaker .223 (I'll keep a carbine buffer in the range bag just in case).



With the guns setup nearly identical I do notice the Huldra kicks a little more than the BCM, but since those are apple to orange op-systems it's probably the nature of the beast.

The only malfunction I could induce was Lake City ammo with a carbine buffer in the Huldra set on Suppressor. Short stroked every time and barely ejected the brass, but that's no surprise given the reduced gas setting. Maybe someday they will do away with the suppressor ban in this state!

[Back In Black]

So it was such a nice evening, I thought I would go out to SMSC range and do a little ammo/buffer test on both rifles.

I was out there today too. Probably just missed you.

[Tronster]

I was at the 100/200 lane from about 6:30 to 7:30. There was someone at the plates and another at the far pistol lanes, and as I was leaving a couple people shooting rifle at the 50. As nice as it's been outside I'm surprised how empty the range has been lately. Even on the weekends.

[Hmac]

I built a couple of 11.5 SBR's using BCM barrels. I emailed Paul Buffoni about buffers and he recommended that H buffer would work with virtually all ammo. I found that for most of my shooting, an H2 buffer worked fine - no cycling issues - but at a rifle course last year I found myself trying to shoot a partcular batch of PMC Bronze .223 that just wouldn't cycle. I actually had to drop back to a carbine buffer to fix that issue with that particular lot. As it turned out, I had a gas tube problem but it demonstrated for me carrying extra buffers to the range was a useful thing.

[Tronster]

Did a little reading about the various 5.56/.223 ammo that I typically use, and holy cow that PMC bronze is way downloaded, like a good 400 fps slower than M193. I guess I'll relegate my 1500 rounds of it to the Mini 14 since that gun is so overgassed, or just swap a light buffer in the AR's when I shoot bronze.

[Dave Timm]

Howdy Everyone,

For our Hudlras we recommend using the standard carbine weight buffer as that will run generally anything decent. If you are running import ammo or really lower power stuff you may have to use a reduced power spring. We purposely don't over gas our guns like other companies do as this causes a lot of issues and wear. In my 16 mid Huldras I run generally an H buffer or carbine buffer. I really only shoot Federal 556 or similar as it is still about the cheapest in bulk. I also am still playing with the JP silent spring system in a couple rifles too for something different and to stay current on what's out there.

The suppressor setting does significantly reduce the gas so without a can on you can expect short stroking.

Back In Black, both your guns should run Amer Eagle just fine, we shoot a ton of that too. PMC is overall a little weaker but still the 223 should work just fine. If your guns aren't cycling either well feel free to drop me a line and I'd be happy to help out, inspect them etc. Also, I'm sure you already did this, but if they are new clean off all of the packing oil. That stuff is just there for shipping and gets kind of sticky when it gets hot. Once clean, apply a generous healthy amount of a good lube, like Slip2000. Again I am here to help if you need anything.

Thanks
Dave

[Tronster]

Thanks for the feedback Dave.

For the record my Huldra midlength upper/lower has run 100% with 800 rounds of 5.56 using the carbine buffer. But if you've had good luck running an H1 buffer I think that's what I'll run in mine. The Huldra LE lower's trigger will be getting swapped out for an ALG ACT trigger, I've been spoiled with the one I installed in my other rifle.

I had never tried the suppressor setting but the results were exactly what I suspected without a can on.

Overall both the Huldra and the BCM/Mega are running great.
+1 on the slip 2000.

[Holland&Holland]

I built a couple of 11.5 SBR's using BCM barrels. I emailed Paul Buffoni about buffers and he recommended that H buffer would work with virtually all ammo. I found that for most of my shooting, an H2 buffer worked fine - no cycling issues - but at a rifle course last year I found myself trying to shoot a partcular batch of PMC Bronze .223 that just wouldn't cycle. I actually had to drop back to a carbine buffer to fix that issue with that particular lot. As it turned out, I had a gas tube problem but it demonstrated for me carrying extra buffers to the range was a useful thing.

So what is the benefit of changing to an H buffer from the standard carbine buffer in a SBR? Easier on the gun?

[Hmac]

So what is the benefit of changing to an H buffer from the standard carbine buffer in a SBR? Easier on the gun?

Yes, I think so, and the heavier cycling mass will spread the recoil impulse over a longer period of time, lessening the perceived recoil. Not by much by itself, but maybe noticeable in conjunction with a rifle with a good quality buffer spring, full-auto carrier, and BattleComp. Not that .223 or even 5.56 is a brutal round, but I believe I can get the rifle back on target maybe a little quicker using that stuff.

[Uffdaphil]

A while back I emailed BCM about buffer for 14.5" middy using only mil spec ammo. They recommend H. So I would expect that would be considered a +1 for a 16". With no spec for middy gas ports size, i'm sure what works best will vary even among the best manufacturers. I have up to H3 in my range bag to see what cycles best in my Centurion 10.5". The Vltor A5 rifle length system I'm trying for S&W 5.45 16" is one I have know idea which weight will be optimal. Hopefully one of the two on hand. Theirs are a bit expensive.