Adjustible gas blocks with Full weight BCGs & LW buffer

[ChaseMarshall]

I am going to purchase a Syrac Gen II adjustible gas block for my 18" midlength AR. It is a bit over gassed right now and I would like to tone it down.

I have some questions regarding Light weight bolt carrier groups and Buffer weight combos.

I currently have a full auto style Rainer NiBo BCG and I have put in a Spikes ST-2 (4.3oz) heavy buffer (from another rifle) in attempt to counteract the over-gassing. I have no intentions of buying a LW BCG at this time but I am wondering if I can get away with a super light buffer to decrease the recipricating mass and have similar results.

The way I think about it it seems like the BCG and Buffer move together. Would having a Full mass BCG and a light buffer play well together? Do I need to change buffer spring weight?

I was thinking about taking all the weights out of a standard carbine buffer (3oz) and running it empty (giving me a .5oz buffer?) or trying the Taccom UL buffer (don't know weight)

From Taccom website : "Designed for the AR15 Rifle or Carbine Buffer tubes, our UL Recoil System works with standard weight or Light Weight STEEL* carriers and adjustable gas blocks**.)

What are your thoughts.

Thanks,

Chase

[ChaseMarshall]

I didn't even realize this was my first post, I've been lurking for a long time.

[Therealkoop]

The buffer acts as a "deadblow" hammer to prevent the carrier from bouncing. It might work, but on -MY- rifle I was getting carrier bounce when I tried to run a weightless buffer. I know a lot of people dont have issues, but I didnt want to risk getting malfunctions after I experienced a couple.

One thing I DO know for sure is that the Syrac gas block sucks ass. Ive recently picked up an SLR rifleworks unit and its much better designed. Ive only got maybe 1k rounds through it so far, but so far its still working like new.

My syrac siezed pretty quick, and you cant disassemble it.

[ChaseMarshall]

Thanks for the info on thre Syrac, I had read alot of good reviews on it and the reason I was going to go with it vs some of the other is the fact that it has a detent to hold your settings.

All the others are pretty much the same, I could easily drill and tap a hole in the side of my current low profile gas block for a set screw.

What do you mean "it siezed"? It has a small roll pin on the side that holds the dentent spring and ball. Seems like you could drive that out and access everything.

Did you have the Gen 1? The first one with the little plunger you had to press to adjust looked like a poor design.

Just trying to make an educated purchase, $109 is high for a gas block so if it is no good, I'll go another route.

Thanks,

Chase

[Therealkoop]

Yeah mine has the plunger/button you press on the front to allow it to move. If you search for Syrac on the forums you will see a decent number of people have sized them. If I press the button on mine the allen screw absolutely will not move. Someone else will have to chime in on the quality of the Gen 2 version.

The slr also has detents, and theres no button. The design allows you to fully disassemble it from the side if you want, and you can get replacement parts for it. So far its much better than my syrac (gen 1) in both design and operation. The allen still spins as freely as a new unit.

[B45C22]

The roll pin holds the gas tube. The plunger is on the new ones as well and is very well designed. They will all seize up at a point. Very high pressure carbon is being forced into every nook and cranny. The threads just fill up.

Stay away from the clamp style syrac. Go with the set screws. The set screws actually hold the gas block tight against the barrel where the port is. The clamp style holds tight against the SIDES of the barrel, not the top. Mine never sealed up well enough to run the gun reliably.

I swapped to the carbon arms non adjustable gas block and followed mark's advise and went with a Jp low mass BCG and lightened the total reciprocating mass (BCG and buffer) to 10.5oz. It feels very soft and is ultimately very reliable.

[Jaxshooter]

I am not a fan of Syrac gas blocks either. I am using adjustable JP low profile gas blocks on my rifles. Easy to get to adjustment under hand guard also.

[ChaseMarshall]

B45C22, there is a second roll pin that runs parallel to the barrel on the Syrac gen II that retains the dentent spring and ball. I will definitely be going with a set screw type gas block over the clamp on for the ressons you mentioned. I'm certainly not set on the syrac.

I like to SLR DA7 gas block as well. I will look into that.

I have a JP adjustable on my LRP-07 and it is cool but it can be hard to adjust under the handguard and I want the click adjustments that the detents offer.

I appreciate the feedback on the gas blocks but I was really looking for some feedback on the buffer weight options. Does anyone have experience with light weight buffers and full mass BCGs? Will I need to change spring rates? Can I offset a full mass BCG with an extra light buffer?

Thanks,

Chase

[ChaseMarshall]

The SLR Sentry 7 set screw gas block looks badass. No little balls or tiny coil springs.

Thanks Therealkoop.

[B45C22]

B45C22, there is a second roll pin that runs parallel to the barrel on the Syrac gen II that retains the dentent spring and ball. I will definitely be going with a set screw type gas block over the clamp on for the ressons you mentioned. I'm certainly not set on the syrac.

Well slap me and call me Shirley - i checked their website and you are exactly right. They changed it up quite a bit.

I had to take two weights out of my buffer. I replaced the weights with a piece of rubber hose as a space filler. A total for the reciprocating mass on mine is 10.5 oz, but that is with a non adjustable gb. YMMV

[BitchinCamaro]

What are you trying to accomplish with the buffer weight again (you may have stated it, but I got lost in the syrac chatter)?

If it's overgassed as is, then that's a problem that needs to be addressed independently of the buffer weight or spring rate. Tune it down with the gas block.

If you then change buffers for the sake of lowering reciprocating mass, you'll likely be overgassed again with a light buffer, so tune appropriately. If there are cycling issues,then consider spring rates.

[BitchinCamaro]

FWIW, my syrac gen 1 clamp on works fine. I suppose there is a little gas "bleed" around the top as evidenced by some carbon, but not any more than most detent styles. I shoot it suppressed and it gets crudded up pretty good, but nothing a little penetrating oil doesn't break up. My adjustment screw is anti-seized.

[ChaseMarshall]

BitchinCamaro-"What are you trying to accomplish"

This is always a good thing to keep in mind. The original intent of the adjustable gas block was to address the over gassing. When this is addressed I can put the ST-2 buffer back in the rifle it came from. Now I have the option to reduce the reciprocating mass with a LW buffer.

Is the combined weight of the buffer & BCG all that matters? Do they need to be reduced in tandem? What weight is a good place to be?

I started throwing stuff on the scale :

Rainer arms match grade Nickel Boron BCG = 11.7 oz

Spikes ST-2 buffer = 4.1 oz

Current total mass = 15.8 oz

Carbine buffer = 3 oz

I opened up a standard carbine buffer and got:

Empty buffer = 1oz

Each weight = ~.6 oz

Plus some little rubber disks.

So I can run my current BCG with an empty buffer and be at 12.7 oz but I might have some carrier bounce like Therealkoop experienced.

If I ran one weight (with a spacer made of hose) I would be at 13.3 oz.

Or I could run 3/4-1oz of #8 lead shot in the buffer for a dead blow effect.

Any thoughts?

[iswope]

I'm currently running a Taccom ultra low recoil buffer system with a standard mil-spec bcg and a Syrac gas block with no problems at all. Shoots incredibly smooth and flat.

Sent from my HTC One using Tapatalk

[BitchinCamaro]

Soooooo, I just wrote 5 paragraphs here trying to explain the physics of my explanation and realized that I wasn't even a 1/4 of the way through. I'll save that for another thread I suppose!

In short, for me, priority for controlling your cycle is gas block > reciprocating weight > spring rate.

A bone stock gun with a fancy gas block is going to reap the benefits of it's parts way before a rifle with a stock gas block and lightweight bits on the inside.

That's just an opinion based on math and confirmed with experience.

This is what I posted on another thread:

After a long talk with JP and dusting off my old Physics textbooks, I (and JP) decided to run a heavier than stock spring rate with lightened reciprocating guts.

A heavier spring rate gives the bcg enough force to get back into battery while keeping the reciprocating length and momentum to a minimum during both strokes of it's cycle.
It's true that for a given displacement a stronger spring will give a mass more velocity (and thus, momentum) relative to a lighter rate pushing the same mass. But if you limit the backwards stroke initially with a heavier spring rate (for a given gas volume), then there is an overall reduction in displacement and limit to the velocity on the bcg's return to battery- a convenient and directly proportional limitation to momentum.

That's my approach at least. Mechanical recoil is reciprocating inertia. Reduce the inertia first, then limit the maxima of momentum for given masses by limiting input forces into the system (gas volume and pressure), and spring displacement.

Light buffer springs might cycle fine, but the math isn't optimal for rabbit farts.

[BitchinCamaro]

As far as carrier bounce goes, it's going to be a balance of mass and spring rate, which mathematically is balancing carrier momentum with the kinetic energy imparted to the system on the forward stroke, respectively.

For a given input (gas setting), a reduction in mass is a directly proportional change in momentum, but the change in kinetic energy is not;

-assuming the same buffer spring rate, the entire system moves back further with less mass, thus storing more potential energy in the longer stroke

-the longer stroke imparts more speed to the mass on the forward stroke, which increases KE by the square of it's value.

So, a light mass with a light spring may bounce because the proportion of it's momentum and KE are less than optimal.

Again, this is an opinion. I'm wrong all the time.

Edited April 17, 2014 by BitchinCamaro

[67 LS1 Camaro]

Thanks for the vid. I knew Camaro owners was smart.

[TRUBL]

Nice postings!!!

I do believe that you need to adjust your gas to refine the system.....I would not go to a lighter spring, either keep the mil spec or go a little heavier. Lightening up the BCG/Buffer system....allows for more range on the gas adjustment. With standard set ups.....the difference between function and non function has typically been a quarter turn or less.

you do want to keep bolt bounce to a minimum....however.....it's not as much of a problem with semi auto as it is with a full auto 'closed bolt' machine gun where timing is everything. The main thing is that after the bounce.....you want the bolt to actually go back into battery and not hang up. This is where a little bit stronger spring or a little bit more preload on the current spring can help a lot.

I think that even Jerry claims to only be able to do about 450 rounds/minute with the AR....as opposed to 900 -1200 RPM for an M16

Even the above ave 3gunner Joe will not pull the trigger on the actual bounce.......but he may be pulling the trigger on a hang up

Just emptying out the buffer with a LM BCG might work....but it might not....you may need to go a little heavier on the spring.

Adding preload like we do with our LW recoil system is one way of going too.

Tim

[ChaseMarshall]

Thanks for all the input guys.

I'm going to get the adjustible gas bolck and tune it for the standard (3 oz) buffer and then I might look at the Taccom LW buffer later. Does the Taccon LW buffer system come with the Spring and a Nylon (?) spacer? Thats what it looks like from the initial product anouncment thread here on the forum. Iif I'm correct the spacer is for Rifle length buffer systems?

Thanks,

Chase

[TRUBL]

Thanks for all the input guys.

I'm going to get the adjustible gas bolck and tune it for the standard (3 oz) buffer and then I might look at the Taccom LW buffer later. Does the Taccon LW buffer system come with the Spring and a Nylon (?) spacer? Thats what it looks like from the initial product anouncment thread here on the forum. Iif I'm correct the spacer is for Rifle length buffer systems?

Thanks,

Chase

WE just changed the configurations......there is a carbine model and a rifle model. Went away with the springs as, well, everyone has the springs anyways (for the most part).....this way it can be all around more affordable than it already was.

[ChaseMarshall]

TRUBL, your responsiveness on the forum is awesome and the reason I order your products!

Do you recomned the JP tuned buffer Spring? It's advertised as 7% stronger than it's milspec counterpart.

Thanks,

Chase

[BitchinCamaro]

Consider running what you have now and get all your reciprocating weight reduction done later in one stupid, horribly expensive purchase and be done with it.

Not to say that there is anything wrong with the taccom products (I have load 2s and they're great- my shotgun times suck slightly less now!). It's just that if you're going low mass for recoil benefits, then you're going to realize that lighter is better (to a practical limit).

For instance, check out the buffer bounce video above. Watch a segment where the BC bounces- then compare some part of the rifle (like the edge of the eotech) to the background trees. Notice the overall recoil of the gun. Now go to the segment with no bolt bounce and compare the same point.

Or just experiment with mid-weigh stuff now and get a baseline before you drink the kool-aid and go with a JP Lmos and SCS.

Love mine!

[Mark Gale]

The set screws actually hold the gas block tight against the barrel where the port is. The clamp style holds tight against the SIDES of the barrel, not the top. Mine never sealed up well enough to run the gun reliably.

Given a properly manufactured barrel and gas block, I have to disagree with this statement. A clamp style will provide a better seal than a set screw. I'd argue that your experience was a result of a barrel or gas block that was out of spec or tolerance stacking between them.

[TRUBL]

TRUBL, your responsiveness on the forum is awesome and the reason I order your products!

Do you recomned the JP tuned buffer Spring? It's advertised as 7% stronger than it's milspec counterpart.

Thanks,

Chase

It would not be a bad idea.....not required......but not a bad idea.

[TRUBL]

Consider running what you have now and get all your reciprocating weight reduction done later in one stupid, horribly expensive purchase and be done with it.

Not to say that there is anything wrong with the taccom products (I have load 2s and they're great- my shotgun times suck slightly less now!). It's just that if you're going low mass for recoil benefits, then you're going to realize that lighter is better (to a practical limit).

For instance, check out the buffer bounce video above. Watch a segment where the BC bounces- then compare some part of the rifle (like the edge of the eotech) to the background trees. Notice the overall recoil of the gun. Now go to the segment with no bolt bounce and compare the same point.

Or just experiment with mid-weigh stuff now and get a baseline before you drink the kool-aid and go with a JP Lmos and SCS.

Love mine!

Oh....drink the cool aid.

It's actually, not a bad idea to have that base line......I was just talking abotu that with someone this morning. He run's a JP rifle, but with a Rolling Thunder Comp. He switched out to the TACCOM LW recoil system and loves it......I showed him the LWC comp today and gave him a weight comparision to Bennie's comp (FYI.....I presently use the Bennie Rolling Thunder Comp as well)......and there was a 5 ounce difference in the comps.

Will the LWC comp be as effective? debatable and been talked about for years (the great comp debate).....anyways......I told him that if 6 months ago, we swapped out BOTH the comp and the recoil system......his rifle probably would have felt the same....BUT.....with over a 1/4 pound removed from the very front end of his rifle.

Something to think about eh???

Tim

PS.....with less recipricating mass as the roughly the same speed, and being able to actually have an adjustable gas range....the comp will no longer be the major component that tunes your recoil.