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JP Rifle build questions

DuneShoot

Canned SemiAuto
Full Member
Minuteman
Apr 24, 2014
404
146
AZ
I am looking into a new JP Rifle in 5.56 which will be used 100% suppressed.
I have 3 suppressors I could use, each with varying amounts of back pressure.
I’d like one with an 18” barrel and I have a few questions.

I see a few JP-15 rifles in stock at Arnzen arms. They have the low mass BCG and adjustable gas block. I also see a couple of the SCI rifles with the same BCG and gas block.

1. On the JP-15’s- if I used the low mass BCG but added the H2 SCS spring, a suppressor, and tuned the gas block: would I still experience the super soft recoil impulse similar to using the standard SCS and low mass BCG while firing unsuppressed? Or would it be a waste of time to combine a H2 SCS to a low mass BCG?

2. Would it be better to use the H2 SCS and their heavier BCG’s shooting suppressed? This adds considerable extra cost.

3. On the SCI (side charger) rifles, I would think there would be quite a bit less gas to the face while shooting suppressed. How much better is it over the JP-15 receiver sets as far as being sealed where the charging handle usually is?

I've run a fair amount of suppressed rifles and they always need tuning depending on the amount of back pressure the suppressor ads. Had a JP-15 a few years back. Ran great. Then I added a suppressor and tuning the gas block it wasn't the same.
Trying to figure out of the extras from JP liek the H2 buffer and or a heavier BCG would be worth it.

Any experience with any of the above?
 
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Once you step outside of that JP-pioneered formula of large muzzle brake, adjustable gas tuned down, and balanced reciprocating mass relative to the specific load you’re shooting, especially by adding an accumulator to the muzzle, I haven’t seen one that remained as smooth.

As you know, a tuned JP .223 AR just lets the reticle stay right on-target when you break the shot.

With cans, I have noticed more push-type recoil.

Your best bet will be a flow-through can I think, but it still won’t have that ability to bite into the air like a muzzle brake does. That brake really does most of the work in keeping the rifle perfectly tame, and the back-end is all about disrupting the sight picture the least amount as possible during the return stroke into battery.

I’ve seen some cans with a brake integrated onto the front of them like SiCo Harvester, but I haven’t shot one on a JP that I can recall.
 
Once you step outside of that JP-pioneered formula of large muzzle brake, adjustable gas tuned down, and balanced reciprocating mass relative to the specific load you’re shooting, especially by adding an accumulator to the muzzle, I haven’t seen one that remained as smooth.

As you know, a tuned JP .223 AR just lets the reticle stay right on-target when you break the shot.

With cans, I have noticed more push-type recoil.

Your best bet will be a flow-through can I think, but it still won’t have that ability to bite into the air like a muzzle brake does. That brake really does most of the work in keeping the rifle perfectly tame, and the back-end is all about disrupting the sight picture the least amount as possible during the return stroke into battery.

I’ve seen some cans with a brake integrated onto the front of them like SiCo Harvester, but I haven’t shot one on a JP that I can recall.
You have cost me many dollars in the grendel relm, love that round!

I know it will not be the same as unsuppressed. Trying to figure out what I need to make it as close as possible. H2 SCS or run the standard SCS and tune the gas block. Or H2 and heavier BCG.

And is the side charging receiver set worth the upgrade.
 
Between answers from JP and Arnzen Arms I ordered a JP SCI-20 with 18" barrel from Arnzen today.
 
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LMOS was all that was available. Added 2 tungsten weights to add to the SCS. Should run good suppressed. Muzzle is their 3 port brake which will be removed anyway.
 
LMOS was all that was available. Added 2 tungsten weights to add to the SCS. Should run good suppressed. Muzzle is their 3 port brake which will be removed anyway.
Gotcha. I’m waiting for a call back from Matt at Arnzens about possibly doing a CTR02 but set up with FMOS and H2 SCS. I might have to just stop in there when I’m in EP this week.
 
Matt helped me out too. Tried to remove the LMOS from mine but it didn’t look new enough for him to sell as new.
 
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It runs excellent with the heavier SCS weights suppressed.
Was able to get consistent hits at 800 yards with 77gr reloads. Even a few hits at 1K.
 
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Forgot I had made a video of the bullet traces with this rifle at different distances.

 
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Awesome video! I’m excited fo mine, should be here in the next 6 weeks or so. I completely switched my CTR build. Ended up getting curios about a rifle length gas system so went with a 18” vs 16” and from FMOS/H2 SCS to the LMOS and standard weight SCS system.

All black with orange fade thermal dissipator and 3 port JP comp.
 
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What’s the consensus on the bolt carrier and buffer combo on an SCI-20 for 100% suppressed shooting? I’d be hunting, no competition.

The options are a bit dizzying… Bolt carriers: Variable weight, full weight, lightweight? And then there’s the tungsten SCS and other versions of the SCS, including the foldable one.

Jeez, lots of options.
 
Yes 2 extra weights with the LMOS. Was all that was available at the time I wanted one.
I forget the gas setting.
Been tossing around the idea of freeing up funds and letting my JP go.