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indyhunter

modifying JP Enterprises Silent Captured Spring buffer for DPMS Gen 2 Hunter

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Hello everyone

I recently bought a Gen 2 Hunter and really like the gun. Not that I have a lot to compare to, but its accurate and lite, so will suit my needs for deer hunting.  But the buffer spring is loud. Really loud. I would like to be able to ease a round into the chamber quietly.  I had an AR with the JP SCS and it was really nice and would like to use one on this rifle but have been told it will not fit.  They would not say why exactly but I have to believe that it would be possible to modify the SCS to work? Any ideas or does anyone know an AR gunsmith who would do this type of work? 

 

And on a side note...Why on earth did they use such a big firing pin hole in the bolt face?  Everything i shoot in it craters, but they told me don’t worry about it that it was safe...

 

Thanks

Edited by indyhunter

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sounds like it can be used in either or. As long as the correct tube is used

 

from JP's website

 

Compatibility

The JPSCS-AR10 is designed to work in standard 7-inch M16/M4-length buffer extension tubes on .308 AR-type rifles like the DPMS LR-308. Armalite .308 rifles, likewise, use these standard M16 extension tubes with rifle-length stocks, so the JPSCS-AR10 will function normally when installed with the supplied spacer. However, Armalite’s .308 carbines use a slightly longer, nonstandard carbine extension tube. The JPSCS-AR10 can still be used with these extension tubes by installing the spacer, which must be modified to fit. Alternately, the system will function readily if the longer Armalite carbine tube is replaced with a standard 7-inch .223 carbine extension tube.

The JPSCS-AR10 is not compatible with the Rock River Arms LAR-8 because of its longer bolt stroke and subsequently longer extension tube.

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The G2 uses the same buffer system as the LR308 G1, so from a buffer system point of view it should work.

My guess is that opening in the back of the G2 carrier is too small to allow the rod of the SCS to pass through. My PWS MK2's carrier is like that.

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Yeah at first glance it looked like it would work but calls to DPMS resulted in an “I don’t know, Buddy” and Jp Enterprises just said no but couldn’t explain why.  I don’t know enough about them to even put forward a reason but will keep digging.  

@ BigP- I usually don’t like climbing into the stand with a round chambered and so ease a round in once I’m on stand, but the gun is just too loud.  I have to rack it pretty hard for a round to chamber properly and its noisy.  Just looking for a way to quiet it down.

Anyone have any ideas about the JP buffer spring could be modified?

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Just FYI for anyone interested. JP Enterprises tech said they may offer a “work around solution” for those wanting to use the captured buffer springs in G2 and other non-compatible rifles.  It sounds like it could involve using a spacer at the front or the buffer rather than at the rear like when using the captured buffer spring in longer rifle length buffer tubes.  This will give adequate clearance for the G2 bolt carrier.  Sounds like that might work, right?

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Just FYI for anyone interested. JP Enterprises tech said they may offer a “work around solution” for those wanting to use the captured buffer springs in G2 and other non-compatible rifles.  It sounds like it could involve using a spacer at the front or the buffer rather than at the rear like when using the captured buffer spring in longer rifle length buffer tubes.  This will give adequate clearance for the G2 bolt carrier.  Sounds like that might work, right?

So does that mean the issue is with the spring guide not fitting into the rear opening of the carrier? I can see how a spacer up from that has an opening large enough for the spring guide would work if that is the issue. The only difference is that they're changing the reciprocating mass, but that might not be a bad thing since the G2 could use a heavier buffer anyways.

Edited by FaRKle!

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I think the guide rod would fit the opening but perhaps the carrier group does not have adequate depth or length. The carrier travels too far and would "bottom out" on the rod, unless the spacer was used.

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I just bought a JP SCS for my G2 Bull. The spacer was a bit too long, the bolt catch wasn't keeping the bolt locked back. I took off enough material to lock it back. Now there is a gap between the bolt and buffer when the bolt is closed and there isn't enough pressure to close the bolt. I need to call about this theoretical work around. It is probably because the G2 is bigger than an AR-15 and smaller than an AR-10. These G2s are cool but not compatible with everything. 

 

Story behind my purchase... Recently bought a lot of PMC. I didn't have my Allen keys for the adjustable gas block I installed and these round were hot. The guys I shoot with reload and we dumped out a cartridge. There was a whole lot more than 40 grains of powder. I mean I had two failures to feed. The rounds jammed in diagonally and we had to pull the charging handle hard to get these out. I mean the cases were bent. It was either a bolt bounce or the rounds were knocked out of the mag (as opposed to being 'stripped off' and loaded) and wasn't able to seat correctly. My solutions, aside from remembering to reset the gas block for each new load, was to find a buffer system that wouldn't ram the rounds so hard they bend if they get caught wrong. The JP SCS is smooth and does not have a lot of tension. I imagine it works awesome.

 

I will update this post after I talk to JP and/or DPMS.

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I called JP this morning. There is no work around. The JP SCS will not fit the Gen 2 series. The piston, and therefore the stroke length is too short. Oh well. They are cool enough to send me a replacement spacer (and a retention screw for their adjustable gas block) so I can send this back to Brownell. 

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Foreground: I've shot about 5K rounds through my DPMS Gen2 Recon since I purchased it early in 2013.  

 

Do not mess with the DPMS Gen2 buffer system - it is indeed proprietary and tuned for the weight of that particular Gen2 BCG.  .308 AR BCG's are not at all standardized like the AR15.  In fact, the DPMS Gen2 Bolt Carrier is a proprietary monolithic billet design.  

 

I would argue that the DPMS Gen 2 has more parts interchangeability with the AR 15 than any other .308 AR design I know of.  I use a Geisselle AR15 trigger and a Nordic Components AR15 free float front rail, and some BCM AR15 furniture.

 

Action (buffer) spring "twang" is common in all AR's.  Simply remove the buffer spring and buffer by depressing the detent, and coat the spring with wheel bearing grease.  It's a common trick that's been done for years.

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I have a Palmetto State Armory 6.5 Creedmoor Gen 2 upper with a PSA Gen 2 lower and rifle length gas tube a2 and purchased the JP SCS with spacer installed and have been playing with 2-3 tungsten weights and different spring kit springs to try to get it to function properly it does not seem to have enough Force to push the bolt forward completely when you just lightly pull the charging handle and release it does not fully enter the barrel extension and lock (although the rifle length buffer and spring works fine). Every 5 to 10 rounds I get case that does not eject and causes a double feed (one empty one fresh). Other than that the gun fires there is no gap between the SCS and BCG. I am awaiting the third tungsten weight I'm going to make it an h3 and see if that helps but any recommendations I would really appreciate that as I am running out of ideas!

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42 minutes ago, 6.5 Creed love said:

I have a Palmetto State Armory 6.5 Creedmoor Gen 2 upper with a PSA Gen 2 lower and rifle length gas tube a2 and purchased the JP SCS with spacer installed and have been playing with 2-3 tungsten weights and different spring kit springs to try to get it to function properly it does not seem to have enough Force to push the bolt forward completely when you just lightly pull the charging handle and release it does not fully enter the barrel extension and lock (although the rifle length buffer and spring works fine). Every 5 to 10 rounds I get case that does not eject and causes a double feed (one empty one fresh). Other than that the gun fires there is no gap between the SCS and BCG. I am awaiting the third tungsten weight I'm going to make it an h3 and see if that helps but any recommendations I would really appreciate that as I am running out of ideas!

PA-10 problems.... it’ll cost you $0.75 to fix it. 

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34 minutes ago, Robocop1051 said:

PA-10 problems.... it’ll cost you $0.75 to fix it. 

Are you saying put 3 quarters behind spacer? I tried one, but if you had any experience with three and it worked I'll give it a shot.

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3 hours ago, 6.5 Creed love said:

 Every 5 to 10 rounds I get case that does not eject and causes a double feed (one empty one fresh).

That is not a "Double Feed."  A true Double Feed is only a magazine problem, forever and a day, Amen.  A true Double Feed is two live rounds trying to enter the chamber at the same time - and that's the magazine's fault (either feed lips or spring pressure).  Nothing else on this planet can cause a true Double Feed.  Think about the name - you're double-feeding, two live rounds.

The problem you have is a Failure to Eject.

Edited by 98Z5V

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4 hours ago, 6.5 Creed love said:

I have a Palmetto State Armory 6.5 Creedmoor Gen 2 upper with a PSA Gen 2 lower and rifle length gas tube a2 and purchased the JP SCS with spacer installed and have been playing with 2-3 tungsten weights and different spring kit springs to try to get it to function properly it does not seem to have enough Force to push the bolt forward completely when you just lightly pull the charging handle and release it does not fully enter the barrel extension and lock (although the rifle length buffer and spring works fine).

I stopped after your first sentence.  ^^^   That thing above is literally, your first sentence...   First, don't complicate shiit with complicated shiit.  You did.  The easiest wayto figure this all out is to buy a cheap Armalite AR-10 Rifle Receiver Extension kit, install it, and see if your gun functions.  You've gone way overboard with this JP SCS and a spacer to make it fit, playing with weights, all that.  Start from the basics and get a running gun, first.  Once you have a running gun, go wild, and add as much complicated shiit as you want - one complicated part at a time, so you know what fails and doesn't work.

Edited by 98Z5V

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PS. The PSA PA-10 Gen2 is NOT a DPMS GenII. This thread was started (4 years ago!) about the DPMS GenII which is a completely different format 308AR. There are very few compatible parts that will interchange from the GenII into any other format 308AR.

Your PA-10 is a DPMS LR308 compatible build, and should have an Aramalite AR-10 length receiver extension (buffer tube). Your SCC is not pushing hard enough on the rear of the carrier when it is closed. Just shrink up that space.

There is a LOT of information here about us unfucking the PSA PA-10. Search through and you'll see a wealth of information. It all comes down to the buffer assembly not being appropriate for the rest of the rifle.

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18 minutes ago, Robocop1051 said:

Your PA-10 is a DPMS LR308 compatible build,

In a very, very minimal way...  by the way...   :thumbup:

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4 hours ago, 98Z5V said:

I stopped after your first sentence.  ^^^   That thing above is literally, your first sentence...   First, don't complicate shiit with complicated shiit.  You did.  The easiest wayto figure this all out is to buy a cheap Armalite AR-10 Rifle Receiver Extension kit, install it, and see if your gun functions.  You've gone way overboard with this JP SCS and a spacer to make it fit, playing with weights, all that.  Start from the basics and get a running gun, first.  Once you have a running gun, go wild, and add as much complicated shiit as you want - one complicated part at a time, so you know what fails and doesn't work.

Well I've used the standard rifle length buffer and spring with no issue, then bought the SCS which comes with the fifle length spacer. I was going by what JP customer service recommended which was an (H2 setup). For the $$ I want to make it work. This didn't completely work either. The gun runs better than with the steel weights it comes with, just not 100%. Sorry if it seemed"complicated", I was trying to provide all the info of the build. It did function better with the 2 tungsten weights on the SCS. Again, any useful information would be appreciated. Questions? Ask. Thanks.

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4 hours ago, Robocop1051 said:

PS. The PSA PA-10 Gen2 is NOT a DPMS GenII. This thread was started (4 years ago!) about the DPMS GenII which is a completely different format 308AR. There are very few compatible parts that will interchange from the GenII into any other format 308AR.

Your PA-10 is a DPMS LR308 compatible build, and should have an Aramalite AR-10 length receiver extension (buffer tube). Your SCC is not pushing hard enough on the rear of the carrier when it is closed. Just shrink up that space.

There is a LOT of information here about us unfucking the PSA PA-10. Search through and you'll see a wealth of information. It all comes down to the buffer assembly not being appropriate for the rest of the rifle.

Thanks, I'll search through.

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11 minutes ago, 6.5 Creed love said:

Well I've used the standard rifle length buffer and spring with no issue, then bought the SCS which comes with the fifle length spacer. I was going by what JP customer service recommended which was an (H2 setup). For the $$ I want to make it work. This didn't completely work either. The gun runs better than with the steel weights it comes with, just not 100%. Sorry if it seemed"complicated", I was trying to provide all the info of the build. It did function better with the 2 tungsten weights on the SCS. Again, any useful information would be appreciated. Questions? Ask. Thanks.

Your gun ran fine with a rifle-length buffer and spring, before, and the issues have cropped up now? 

Start with a buffer weight of 5.4oz, and see where you go from there.  H2 weight is 4.6oz.  JP Rifles are awesome at race-gun shiit.  Are you trying to build a competitive race-gun - or an operational gun?...  Start with an operational gun, then do what you want, piece by piece. 

I'm here to help you, not battle you.  Your gun doesn't work right now.  I'm trying to get your gun to work, then you can experiment.  Comprende?...  :thumbup:

Edited by 98Z5V

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27 minutes ago, 6.5 Creed love said:

. Sorry if it seemed"complicated",

It's not at all "complicated" to me, in the least. I understand all of it, completely.   I just build these things based on what I know, and have learned, then run the gun.  I don't have functional issues with my builds. I use my own combination of recoil system parts, I check the gas tube length, and I measure the gas port diameter.  If anything is off with the gas tube length, I fix that. If anything is off with the gas port diameter in the barrel - I drill it.  My recoil system never fails me (now), not once, ever (after I learned why the first one was completely FUBAR'd and jacked-the-fuk-up - FROM a reputable manufacturer).  I build functional guns, and they run, right out of the gate, everytime. 

That's only based on learning that there are manufacturers out there that don't know what it takes to make a "functional gun."  My first rodeo with a carbine recoil system was my last - I dove head-deep into learning WHY it fucked up, and got hip-deep into recoil systems.  At that point, I had my own answers, and never looked back.

You stated yourself that it ran before.  You need to look at what you changed, to make it into a non-functional rifle...

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27 minutes ago, 98Z5V said:

Your gun ran fine with a rifle-length buffer and spring, before, and the issues have cropped up now? 

Start with a buffer weight of 5.4oz, and see where you go from there.  H2 weight is 4.6oz.  JP Rifles are awesome at race-gun shiit.  Are you trying to build a competitive race-gun - or an operational gun?...  Start with an operational gun, then do what you want, piece by piece. 

I'm here to help you, not battle you.  Your gun doesn't work right now.  I'm trying to get your gun to work, then you can experiment.  Comprende?...  :thumbup:

Right, and I appreciate your help. The rifle worked with the stock rifle length buffer 5oz and spring, although looking for ideas on how to make the silent capture spring work with it. The SCS is just a +$200 paperweight at this point. Reason I entered this post was for all the talk about the silent captured spring and if I could find any ideas based off of someone else's problem.

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