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Which Recoil System? JP SCS Gen 2 vs MBX PCC Buffer System


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39 minutes ago, tyler2you said:

For those of you looking for more space to stuff in Smalley Springs, Quarters, cut down buffers, etc., Primary Arms has the Vltor A5 Receiver Extensions on sale for a good price:

 

http://www.primaryarms.com/vltor-re-a5-a5-receiver-extension-re-a5

 

 

Hello: That is a good price for Vltor stuff. Top shelf products for sure. Thanks, Eric

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On 9/15/2017 at 6:49 PM, Aircooled6racer said:

Hello: You can try the shorter stroke but also try the longer stroke to see what is faster for you. Setup three targets and use a timer to see what gives you better hits and faster times. The short stroke feels different and may not be the best way to go. Thanks, Eric

 

Caution, if you are going to extend the stroke, be aware that the length of stroke that you can have is limited by the upper receiver and the "gas port" in the BCG.  If you use a standard carbine buffer in a longer buffer tube, you could have the BCG come through the back of the charging handle and hit the buffer tube.  You need to add spacers to limit the compressed travel to less than what is available by the upper.  

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  • 3 weeks later...

Tossing my set up out there in hopes that it helps somebody else who may be struggling with all the options out there. 


Parts list:
NFA upper/lower.
JP 9mm Tactical Compensator

JP 9mm Barrel 14.5"
JP 9mm Bolt
Blitzkrieg hydraulic 9mm buffer with JP rifle spring
Vltor A5 Tube
Hiperfire 24c trigger
Strikefire lower parts kit with some of their upgrades.
Several Glock branded 31 round mags.  Taccom splice is on the way.


Keeping track of my trigger reset, I worked the charging handle several times and marked where the trigger reset each time.

Started plugging up the long A5 tube based on the measurements I collected about the trigger reset.  I wanted the bolt to come back just far enough to reset the trigger 100% of the time.

This is what worked for my rifle with ALL credit going to Max and his excellent recommendations. 

Stuffed 3 quarters at the rear of the A5 tube.  Wave spring next.   (I ordered the 5 pack from Amazon and have extras if anybody wants to pay for shipping)
Plugged a KAK buffer nipple in.
Then came the JP rifle spring and hydraulic 9mm buffer

Went to the range with 60 rounds (limited sample size.)
 and several different magazines.   No failures.  Action was fast enough and flat enough for me.  Far faster than I can shoot it.  I'm not a good shooter by any means.

Was using 124gr Berry's round nose in the video with some CFE pistol.  They were loaded to 1.13"   I didn't experience any issues.    These passed the plunk and spin test in the JP barrel easily.  I suspect I can load significantly longer than most folks in this thread.

last round bolt hold open does not work, but that was completely expected with how far I plugged up the buffer tube.

 

 

img0774.jpg

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I'd like to try to blitzkrieg setup but ehh, I'm having trouble sorting out the other parts I need.

 

The smalley wave spring,

 

and then the blue piece that has a metal collar on the other end?  I dunoo what this is and haven't seen it mentioned.

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7 hours ago, jtrump said:

I'd like to try to blitzkrieg setup but ehh, I'm having trouble sorting out the other parts I need.

 

The smalley wave spring,

 

and then the blue piece that has a metal collar on the other end?  I dunoo what this is and haven't seen it mentioned.

I assume you're talking about this piece:

 

http://i.imgur.com/teGKplN.jpg

 

Max explained earlier in the thread that it's just a regular buffer that's been cut down with the bumper re-pinned.  You can also use a Delrin buffer spacer like the one NFA sells.  The wave spring addition isn't really necessary to get the benefits of the Blitzkrieg buffer.  Some folks like the wave set-up and others don't.

Edited by tyler2you
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Hello: I would pass on the Smalley spring. It gives a funny recoil impulse to me and some others that have tried it with the Blitzkrieg buffer. Just use the Blitzkrieg buffer and JP 308 spring and you will have a good setup. I am still using the JP buffer setup with the weight and spring mods. Thanks, Eric

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IMO, the Smalley spring's purpose is to replicate the function of what the Blitzkrieg buffer already does.   

I also think that the buffer is "softer" and does the job better.

 

If you are using an SCS, with the hard bumper (travel limiter) you might benefit from replacing that with a larger and softer rubber bumper to simulate the Smalley.  Just make sure that the travel is limited on full compression to keep the bolt from over-traveling. 

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1 hour ago, Aircooled6racer said:

Hello: I would pass on the Smalley spring. It gives a funny recoil impulse to me and some others that have tried it with the Blitzkrieg buffer. Just use the Blitzkrieg buffer and JP 308 spring and you will have a good setup. I am still using the JP buffer setup with the weight and spring mods. Thanks, Eric

Hello Eric,  thanks for the replies everyone.  So pretty much is I want to try the blitzkrieg just buy the one with the JP polished 308 spring.  And then I can play with my JP buffer system weights and springs to see what suits me best.

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Eric, Here’s a thought. When using the scs/smalley setup, what about not using the JP bumper at all, but instead using a simple spacer like one of the ones I have from you? I think part of that weird impulse we feel might be from the bolt hitting the bumper which then flexes a little just as it squeezes the smalley.  With just a spacer it would let the bolt travel a little further and hit something solid that will immediately transfer energy to the smalley.

Thoughts?

 

Im going to try it today and see if there’s any noticeable difference.

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10 minutes ago, nickbfishn said:

Eric, Here’s a thought. When using the scs/smalley setup, what about not using the JP bumper at all, but instead using a simple spacer like one of the ones I have from you? I think part of that weird impulse we feel might be from the bolt hitting the bumper which then flexes a little just as it squeezes the smalley.  With just a spacer it would let the bolt travel a little further and hit something solid that will immediately transfer energy to the smalley.

Thoughts?

 

Im going to try it today and see if there’s any noticeable difference.

Nick: I tried it. That is why I sent you the spare plastic spacers for you to try them. I don't like the double recoil impulse with the Smalley spring. If you shoot higher power factor loads it may not be as much of an issue. I am running 131-138PF loads with 147's mostly. Using 115's at 150PF it maybe a different story. With the velocity of the bolt coming back with the higher power factor loads it may not be as noticeable. A couple of us here have tried the Smalley springs and none of us liked it with the Blitzkrieg and the JP setups. We are using lower power factor loads and 124, 147 bullets. As a side note I don't like the recoil master or the Glock gen 4 recoil systems. For me playing with setups is part of the fun also. Thanks, Eric

Edited by Aircooled6racer
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The way I see most people install the Smalley, they are pre-loading the Smalley with the recoil Spring.  The  rate of the smalley has to be high enough so that the weight of the compressed recoil spring does not compress them very much, and then they feelstoo stiff, giving you the 2-stage feeling that Eric describes.  

 

My idea was to allow the existing recoil spring to run within the Smalley (full length) and then use a lighter rate Smalley.  That way, once the buffer nears the end of it's travel, the Smalley is not pre-loaded and the rate of the Smalley increases slowly, bringing the buffer to a stop. 

 

Think about it this way, the Blitzkrieg and Taccom buffers both use an extra spring  (and oil, in the case of the Blitz) that softly engages at the end of the travel without being pre-loaded.  That small amount of increased rate slows the buffer to a stop.

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  • 10 months later...
On 7/14/2017 at 2:52 AM, Maxamundo said:

teGKplN.jpg

 

Interally my buffer system looks almost identical to this, except I use an inverted delrin .223 buffer instead of this custom cut milspec one with bumper.
 

 

I installed this setup in a rifle length tube with the delrin spacer that comes with the JP SCS. This makes it a carbine length tube.

 

The bolt travel is not enough to load a round,  it seems to bottom out before that.

I checked: Delrin spacer, M10 wave spring, cut buffer, carbine spring, Blitzkrieg buffer. 

Without the Delrin spacer all feels very soft.

 

What am I missing?

 

Edited by GhostDog
spelling
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On 10/26/2017 at 11:12 AM, Aircooled6racer said:

Nick: I tried it. That is why I sent you the spare plastic spacers for you to try them. I don't like the double recoil impulse with the Smalley spring. If you shoot higher power factor loads it may not be as much of an issue. I am running 131-138PF loads with 147's mostly. Using 115's at 150PF it maybe a different story. With the velocity of the bolt coming back with the higher power factor loads it may not be as noticeable. A couple of us here have tried the Smalley springs and none of us liked it with the Blitzkrieg and the JP setups. We are using lower power factor loads and 124, 147 bullets. As a side note I don't like the recoil master or the Glock gen 4 recoil systems. For me playing with setups is part of the fun also. Thanks, Eric

Eric,

I have a Blitzkrieg carbine buffer on the way. I run a rifle length stock.

Do I have to use a spacer in the tube for the system to work?

I tried a MBX spring buffer. It came with a 2-3/4 spacer. With the spacer in, the gun

doubled and tripled. Gold 308 trigger. No problem before the buffer.

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Hello: Yes you will have to run a spacer with the carbine buffer in a rifle length buffer tube. I have run a Blitzkrieg 9mm buffer, JP 308 rifle spring and it works great in a carbine buffer. You have to limit the amount the bolt comes back. A 1/4" past the bolt release is a good place to start. After that you can play with short stroking if you want. Go to a Hardware store and get some white plastic spacers and stack them to see what amount of spacer you will need. This is all done by just dry testing no live shooting until you get the distance close. Sounds like your MBX setup was right on the edge of short stroking so it was not always fully resetting the trigger. Possibly bump firing also? Check the bolt travel to see if it has the 1/4" past the bolt release. Thanks, Eric

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3 hours ago, Aircooled6racer said:

Hello: Yes you will have to run a spacer with the carbine buffer in a rifle length buffer tube. I have run a Blitzkrieg 9mm buffer, JP 308 rifle spring and it works great in a carbine buffer. You have to limit the amount the bolt comes back. A 1/4" past the bolt release is a good place to start. After that you can play with short stroking if you want. Go to a Hardware store and get some white plastic spacers and stack them to see what amount of spacer you will need. This is all done by just dry testing no live shooting until you get the distance close. Sounds like your MBX setup was right on the edge of short stroking so it was not always fully resetting the trigger. Possibly bump firing also? Check the bolt travel to see if it has the 1/4" past the bolt release. Thanks, Eric

Thanks,

Will do.

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On 9/26/2018 at 6:24 AM, dmshozer1 said:

Eric,

I have a Blitzkrieg carbine buffer on the way. I run a rifle length stock.

Do I have to use a spacer in the tube for the system to work?

I tried a MBX spring buffer. It came with a 2-3/4 spacer. With the spacer in, the gun

doubled and tripled. Gold 308 trigger. No problem before the buffer.

When I tried the MBX buffer I was getting some doubles and triples as well, had mine in a carbine tube set up with a hyperfire 24c trigger. Had the issue in 2 different pcc’s set up the same. I ended up settling on the JPSCS buffer, having it tuned to my load and pcc has made it great. I really wanted to like the MBX system, it was the only system that ever doubled or tripled on me and I have tried several different systems.

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