JP-5 reviews/input

[brian45acp]

The trunion is on the other side inside where the bullets feed. This part doesn’t affect the barrel but side.

[brian45acp]

1 minute ago, cferree said:

The handguard process in the same.

I have no plans to mess with the barrel in any way.

If I have an issue, the upper/whole gun is going back to JP.

Sounds like I should leave it alone lol. 
 

I am going to try the SD3G trigger because most guys here and Max say it’s awesome. But the other parts I am too worried to mess with.

Some local guys did the handguard swap but I also know they don’t care about things like loctite or torque specs lol.

 

[cferree]

I also run the SD3G.  I just came in from a practice session, and I finally got into the 0.12-0.13 splits (0.14-0.15 were the norm).  The GMR had an Eclipse, and I could run it faster.  I'll get used to the SD3G in time.

 

My GMR-15 had the shrouded barrel.  I wasn't use to the added weight of the 14 1/2" pinned and welded comp barrel.  The Smoke took almost 8 oz. off the the front of the gun.

 

 

[brian45acp]

1 hour ago, cferree said:

I also run the SD3G.  I just came in from a practice session, and I finally got into the 0.12-0.13 splits (0.14-0.15 were the norm).  The GMR had an Eclipse, and I could run it faster.  I'll get used to the SD3G in time.

 

My GMR-15 had the shrouded barrel.  I wasn't use to the added weight of the 14 1/2" pinned and welded comp barrel.  The Smoke took almost 8 oz. off the the front of the gun.

 

 

This is why I would love to go with smoke parts. 
I’ve built my last gmr13 upper and it wasn’t hard. Is swapping the jp5 handguard easy? I’m nervous because the barrel is different and I don’t know what to expect. Another guy here posted pics of his barrel and it looks different.

 

[Bdh821]

23 hours ago, brian45acp said:

This is why I would love to go with smoke parts. 
I’ve built my last gmr13 upper and it wasn’t hard. Is swapping the jp5 handguard easy? I’m nervous because the barrel is different and I don’t know what to expect. Another guy here posted pics of his barrel and it looks different.

 

It’s the same as swapping any handguard on an AR platform. It was super easy.

[brian45acp]

21 hours ago, Bdh821 said:

It’s the same as swapping any handguard on an AR platform. It was super easy.

Awesome thanks. I’ll go order it all. 

[K1L0]

Is anyone else seeing some wear at the rear of the ejection port? It looks like casings have been hitting there, and there are also two marks at the top of the ejection port.

[Part_time_redneck]

12 hours ago, K1L0 said:

Is anyone else seeing some wear at the rear of the ejection port? It looks like casings have been hitting there, and there are also two marks at the top of the ejection port.

Well, you made me look.  
 

My newer gun only has about 1500 through it and port still look’s factory. My older one has about 8500 on it and shows the same wear you described. Rear of port has a line about 1/4” long and upper part of port has a slightly smaller area. Still runs amazing so a drop of oil is my fix. 

[brian45acp]

You guys talking about brass marks or the alloy upper is damaged? 
 

Jp is really good about taking care of their products so I wouldn’t worry about it. 

[K1L0]

On 8/10/2023 at 11:41 AM, Part_time_redneck said:

Well, you made me look.  
 

My newer gun only has about 1500 through it and port still look’s factory. My older one has about 8500 on it and shows the same wear you described. Rear of port has a line about 1/4” long and upper part of port has a slightly smaller area. Still runs amazing so a drop of oil is my fix. 

 

That's interesting, thanks for checking!

 

I think it might be a BCG and rail tolerance thing, the marks at the back of the ejection port at least on my gun seem to be from the edge of the BCG striking the opening. The marks are on the edge closest to the BCG and it doesn't seem like brass could strike there since the bolt head is in the way when the BCG is pulled all the way back. I'll take a picture.

 

Regarding JP standing behind products... My upper and lower receivers rattled against each other out of the box and JP has been ignoring my emails. I called and they said they would ship an oversized takedown pin but that was almost a month ago and I haven't received anything yet. In the meantime, I've just been using layers of built up super glue to take out the slop haha...

 

Video of the rattle:

 

https://youtu.be/rYovytIPOiQ

[brian45acp]

That’s not good. I would talk to Ben. Out of all the people who have answered he’s been the best and knows everything. I also emailed them about my trigger and didn’t get a reply until I emailed a second time. I was offered another trigger but it never came so I called and left a message with the guy who was taking care it.

 

They are a solid company but probably busy so follow up on it. 
 

I spent so much money on this thing I hope not to have issues. My gmr13 has been strong for 70k+ rounds.

Edited August 12, 2023 by brian45acp

[mmchambers06]

On 8/10/2023 at 1:02 AM, K1L0 said:

Is anyone else seeing some wear at the rear of the ejection port? It looks like casings have been hitting there, and there are also two marks at the top of the ejection port.

Mine has some digs at the top of the ejection port.  I haven't worried about it.  Gun runs and runs...

[mmchambers06]

On 8/7/2023 at 2:24 PM, Bdh821 said:

It’s the same as swapping any handguard on an AR platform. It was super easy.

Pretty much. I was expecting my barrel nut to be very hard to get off and it wasn't, with the right tools.

 

I almost went carbon fiber, but went with a Centurion because I like them, and I semi-frequently run a flashlight. Kind of different...A lot of the handguards that have the indexing tabs won't fit against the JP-5 upper, though. Just something to keep in mind. 

 

[brian45acp]

Just tried this out and it worked amazing.

 

https://www.mcmaster.com/product/1561T625

 

Placed behind the plastic bumper on the SCS. I’m running 70 lock piece and stock SCS with 124gr 133-135pf jhp.

 

Even less dot movement. Going to run it next week in the match but during practice I get lock back and no malfunctions.

Ran the SD3G trigger and it’s nice but I don’t think magical vs a prepped and adjusted jp component trigger. I’m on the fence about this one.

Edited August 13, 2023 by brian45acp

[brian45acp]

with this I don’t need tungsten or heavy springs which just slam the bolt forward and move the dot more. It seems to cushion the end travel of the buffer very well.

I can’t think of anything “wrong” with this idea but chime in with thoughts please.

 

Edited August 13, 2023 by brian45acp

[Bdh821]

I managed to 100% classifier 22-04 yesterday with my factory internals JP5 (except for SD3G trigger).  I did a 12.0253HF 6.32sec 14A 2C. The recorded HFF is 10.6399 according to the USPSA app.   I have minimal dot bounce but I try not to focus on those things.  I use the same recipe of ammo I did in my MPX.  4.5gr Sport Pistol under a 115 Everglades V2 plated projo with fiocchi SPP @ 1.120" 

 

 

[Boomstick303]

1 hour ago, Bdh821 said:

I use the same recipe of ammo I did in my MPX.  4.5gr Sport Pistol under a 115 Everglades V2 plated projo with fiocchi SPP @ 1.120" 

 

NICE!!  What is the PF of that ammo?

[Bdh821]

14 hours ago, Boomstick303 said:

 

NICE!!  What is the PF of that ammo?

It’s 140pf 

[brian45acp]

I’m curious as to the thought on the spring Max is using. He’s using the heaviest AR10 spring but I don’t know the difference of jp springs AR15 vs AR10 to understand why he chose that.

 

The spring mod I tried worked great but I’m scared to tinker and change things from how the rifle is supposed to run. I may try 1 tungsten weight on the stock SCS and see how that goes but it’s increasing reciprocating mass.

[Darqusoull13]

1 hour ago, brian45acp said:

I’m curious as to the thought on the spring Max is using. He’s using the heaviest AR10 spring but I don’t know the difference of jp springs AR15 vs AR10 to understand why he chose that.

 

The spring mod I tried worked great but I’m scared to tinker and change things from how the rifle is supposed to run. I may try 1 tungsten weight on the stock SCS and see how that goes but it’s increasing reciprocating mass.

There's so little difference in changing springs that, for me, it wasn't even worth the time to take the SCS apart. 

Increasing SCS mass with tungsten is only going to increase dot bounce. 

The biggest bang for your buck, and the one that takes the least time to test, is the lock pieces. Lock pieces will drastically change the perceived recoil, but be aware there are limits on power required for 60, 70 and to a lesser extent 80 degree lock pieces. 

[Bdh821]

I guess I forgot I also changed the SCS spring. I originally tried Max’s setup but found that the 70 locker with JP scs AR15 green spring to be “best” for my preference with my load data posted above 

[brian45acp]

Well my wave spring seems to feel amazing. I’ll have to do some matches with it before knowing it’s reliable. So far just ripping off rounds in practice it felt really good.

 

I agree tungsten is just going to disrupt the dot more but I always trip out about doing mods. I guess if it works then send it. Stronger spring would also disrupt the dot I imagine.

 

I am running the 70 lock and am interested in the 60. I talked with JP and their guy is running the 60 but with 115gr and 148pf. I am at 124gr 130-135pf so I think the 60 would not run.

 

So many combos it makes your head hurt. I’ll likely do what  I did with my gmr13 and just shoot the gun after sticking with something simple. 

[Heniv77]

On 8/15/2023 at 9:10 PM, brian45acp said:

Well my wave spring seems to feel amazing. I’ll have to do some matches with it before knowing it’s reliable. So far just ripping off rounds in practice it felt really good.

 

I agree tungsten is just going to disrupt the dot more but I always trip out about doing mods. I guess if it works then send it. Stronger spring would also disrupt the dot I imagine.

 

I am running the 70 lock and am interested in the 60. I talked with JP and their guy is running the 60 but with 115gr and 148pf. I am at 124gr 130-135pf so I think the 60 would not run.

 

So many combos it makes your head hurt. I’ll likely do what  I did with my gmr13 and just shoot the gun after sticking with something simple. 

I am currently testing a 133-139 pf load (125gr HAP) with my 60 lock.  Tried about 250 rounds so far with around 2 meters of brass throw distance and lock back on empty mag every time (10 plus times). Intentionally did not clean the rifle before these tests so around a 1000 rounds since last cleaning before testing. 

 

I have shot about 10k rounds with the 60 lock at 144-149 pf 123gr previously and the difference with the new load is mind blowing. I understand where the .22 analogies is coming from and it now feels similar to how I remember my unreliable but super soft MPX. Time will tell if this is reliable every time, but brass throw seems comforting. Will test with 70 lock also.

[DwightSchrute]

4 hours ago, Heniv77 said:

I am currently testing a 133-139 pf load (125gr HAP) with my 60 lock.  Tried about 250 rounds so far with around 2 meters of brass throw distance and lock back on empty mag every time (10 plus times). Intentionally did not clean the rifle before these tests so around a 1000 rounds since last cleaning before testing. 

I had a match-killing failure to eject using 130 PF rounds with a 70-degree lock piece.  I went back to the 80-degree lock piece and haven’t had any problems.  You might be tempting fate with 60-degree lock piece for PFs in the 130s.

 

What OAL are you loading the HAPs to?  Several years ago, I called Hornady and they said to use XTP data for the HAPs.  They recommended 1.060” for the XTPs, which seemed rather short to me.  It’s the only reason I shied away from the HAPs at the time.  A couple of months ago, I found some of of the unloaded HAPs in my workshop, so I loaded a few without changing my 1.120” FMJ seating die, and they came out to 1.085”.  I worked up a ladder with N340 from 4.0 to 4.6, and to make a long story short, 125 grain HAPs with 4.3 grains of N340 at 1.085” averaged 132.5 PF in my JP-5, and they felt great with the 80-degree lock piece.  Quiet power with smile-inducing accuracy is the best way to describe it.  I might get some 124 grain “competition style” bullets from Everglades (which look like a HAP copy, but are .355” and 124 grains instead of the HAP’s .356” and 125 grains) and make them my new match ammo.

Edited August 17, 2023 by DwightSchrute

[Boomstick303]

I have not been able to get the JP5 to run reliably with the 70 degree lock piece with any ammo having a PF of 140 and less.  This is with the stock SCS Spring.  I run the 80 degree lock piece and have had zero failures.  I cannot see the need for the 60 degree lock piece unless you were shooting some seriously hot 9 mm ammo.