JP-5 Tweaks and Tips?

[DPA]

I’d like to hear if anyone has tweaked the JP5 yet. I.E. springs, locking pieces and triggers. 126 pf versus 136? Or if this info is located somewhere else in the forums can you point me in that direction. Thanks. 

 

Edited November 30, 2022 by DPA
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[Darqusoull13]

1 hour ago, DPA said:

I’d like to hear if anyone has tweaked the JP5 yet. I.E. springs, locking pieces and triggers. 126 pf versus 136? Or if this info is located somewhere else in the forums can you point me in that direction. Thanks. 

 

See this thread: https://forums.brianenos.com/topic/296875-jp-5-reviewsinput/

 

[DPA]

Thank you sir. 

[Ac02117]

I shot the stock JP5 until the lock pieces became avaliable. I have a 70, 80 and 90 lock piece. I have shot subminor loads around 115PF for Steel Challenge and 131PF for USPSA with all 3 locking pieces and they ran reliably. The 70 lock piece felt the best in all cases. The way I've understood it best is that the lower the number the longer the "delay". If your ammo was lower PF you might need a higher number lock piece to run reliably. If you were running +P ammo you would want a lower number piece so the gun doesn't beat itself to death. 

[DPA]

On 12/7/2022 at 5:18 PM, Ac02117 said:

I shot the stock JP5 until the lock pieces became avaliable. I have a 70, 80 and 90 lock piece. I have shot subminor loads around 115PF for Steel Challenge and 131PF for USPSA with all 3 locking pieces and they ran reliably. The 70 lock piece felt the best in all cases. The way I've understood it best is that the lower the number the longer the "delay". If your ammo was lower PF you might need a higher number lock piece to run reliably. If you were running +P ammo you would want a lower number piece so the gun doesn't beat itself to death. 

Have you’ve tried out a 60?

Thanks

[Sparryttaren]

6 hours ago, DPA said:

Have you’ve tried out a 60?

Thanks

I shoot S&B 115gr and I use Lock piece 60˚. This works even better than 70˚ but there is still room for improvement.

[mrvip27]

19 hours ago, Sparryttaren said:

I shoot S&B 115gr and I use Lock piece 60˚. This works even better than 70˚ but there is still room for improvement.

 

S&B (i have used 124gr) is toasty out of my 10.5 barrel. I gain over 70 fps on my regular blowblack gun lol. So it is understandable a 60* locking piece works best.

 

Not sure how it runs out of a JP-5 though

Edited December 15, 2022 by mrvip27

[Fasthenk65]

20 hours ago, Sparryttaren said:

I shoot S&B 115gr and I use Lock piece 60˚. This works even better than 70˚ but there is still room for improvement.

They are very hot / hard... like 150PF up, did you try softer factory ammo like Geco 124 or Geco DTX 115???

 

[Sparryttaren]

47 minutes ago, Fasthenk65 said:

They are very hot / hard... like 150PF up, did you try softer factory ammo like Geco 124 or Geco DTX 115???

 

Yes, I have. Even S&B and Geco124gr. 115gr is little more snappier but those feels absolutely best. Next I will try an other SCS-spring.

Edited December 15, 2022 by Sparryttaren

[Stefan77]

I found that a lot of 115grn stuff works with the 60*.  I had posted this in the other JP5 thread.

 

 

Here is some of what I have tried so far.  I still have a bunch more testing to do and this is all subjective with what feels best.  

 

60*:

115grn Blazer Brass cycled and bolt would hold open (I had a couple of times that it didn't hold the bolt open).

130grn Syntech, bolt cycled but would not hold open.

150grn syntech, bolt would not cycle

 

70*:

130grn Syntech I noticed a little more recoil, bolt cycled and held open

150grn Syntech, bolt cycled and it held open but I can't remember if it was consistent.

 

As far as what felt good to me?

 The 115grn BB felt really nice.  Cycled fast and felt light (what I mean by light is that it wasn't a heavy'sh push)

The 130grn Syntech was pretty good, it shot well.  I was happy with it but I don't like the bolt not holding open.

150grn Syntech felt a little sluggish when shooting it.

 

These are just my "feels" so not a really objective thing.  

Edited December 20, 2022 by Stefan77

[DPA]

On 12/20/2022 at 12:13 PM, Stefan77 said:

I found that a lot of 115grn stuff works with the 60*.  I had posted this in the other JP5 thread.

 

 

Here is some of what I have tried so far.  I still have a bunch more testing to do and this is all subjective with what feels best.  

 

60*:

115grn Blazer Brass cycled and bolt would hold open (I had a couple of times that it didn't hold the bolt open).

130grn Syntech, bolt cycled but would not hold open.

150grn syntech, bolt would not cycle

 

70*:

130grn Syntech I noticed a little more recoil, bolt cycled and held open

150grn Syntech, bolt cycled and it held open but I can't remember if it was consistent.

 

As far as what felt good to me?

 The 115grn BB felt really nice.  Cycled fast and felt light (what I mean by light is that it wasn't a heavy'sh push)

The 130grn Syntech was pretty good, it shot well.  I was happy with it but I don't like the bolt not holding open.

150grn Syntech felt a little sluggish when shooting it.

 

These are just my "feels" so not a really objective thing.  

Are you using the stock SCS? 

[Sparryttaren]

On 12/15/2022 at 8:11 PM, Fasthenk65 said:

They are very hot / hard... like 150PF up, did you try softer factory ammo like Geco 124 or Geco DTX 115???

 

Yes, they are. Yesterday I tested the strongest AR-10 SCS and 60˚ and it worked together. I still do prefer S&B 115gr.

[Stefan77]

On 12/28/2022 at 7:35 AM, DPA said:

Are you using the stock SCS? 

Yes.

 

I haven't played with the springs yet.

 

I did find that with the 115grn ELLEY that when I cant the PCC around a barricade (ejection port up) I had a failure of the round to fully eject.  I'll probably try to recreate the incident and start playing with spring weights.

Edited January 18, 2023 by Stefan77

[telligentgunner]

On 12/14/2022 at 2:59 PM, Sparryttaren said:

I shoot S&B 115gr and I use Lock piece 60˚. This works even better than 70˚ but there is still room for improvement.

 

I also shoot 115gr S&B with the 60˚ lock piece, but only in IDPA due to the higher required power factor.  Through my testing and tweaking the SCS, the bolt only locked back with the 2 steel weights and the lightest AR 15-80 spring installed.  I tried 2 tungsten weights, it cycled, and it was a bit softer, but the bolt didn't lock back on the last round.

 

If anyone needs parts or intends to purchase the JP-5, use code "miles" for 10% off parts and 5% off firearms.

 

 

Edited July 5, 2023 by telligentgunner

[seako_916]

Any trigger mods besides running the yellow springs? 

[GregJ]

In my somewhat limited testing so far, to me, tuning the JP-5 is very similar to tuning an AR with an adj gas block.  Proper brass ejection is critical to optimum performance. You might be able to get it to shoot really soft, but will it be at the cost of optimum reliability?   JP has recommended in their vids that brass should land about 3 yds away for optimal performance.  For my loads that are running 135-140PF (mostly 147 Blue Bullets), the stock 80* works best.  I have tried the 70*, but brass would dribble out and land about 1-2 ft away, and an occasional FTEject.  With lower PF loads (120-125PF 115 for SC), the 80* would work, but had an occasional FTEject.  Softer loads seemed to eject brass better with the 90*.

 

Recoil will never be as soft as my MPX, but that is ok, the JP-5 excels in so many other areas.  It is not that much more to be so noticeable anyway.

 

As an FYI, JP also recommended adjusting first with different Timing Pieces, then weights (swapping steel for tungsten on the SCS).  They suggested not changing the spring, as their testing has proven the stock black spring has performed the best.  I know others have done a lot of testing/changing with springs. To me it made little difference in how soft it shoots, but big difference in brass ejection and reliability.  YMMV

[philmadxx]

On 7/13/2023 at 8:59 AM, GregJ said:

Recoil will never be as soft as my MPX, but that is ok, the JP-5 excels in so many other areas.  It is not that much more to be so noticeable anyway.

 

While I haven't completed testing with different loads, have not found this to be true, the JP5 seems significantly softer to me than the MPX - at least on hotter handloads and some random factory loads.  I am testing with 60, 70, 80 and 100 degree lock pieces.  Testing is at an early stage as I blew out my knee and haven't shot in several weeks.  Hopefully next month.  

[PaleoMan]

I just got my JP-5 (Steel Challenge version, with an 80 degree lock piece) and purchased 124 gr Syntech ammo to use to break it in.

 

With a chrono, checking groups of 10 rounds, I saw a PF of 151 and 149 on two runs. It is ejecting 2-3 yards.

 

I also tried my reloads (Precision Bullets 125 gr, round nose, coated, with CFE pistol powder and Fiocchi/Wolf primers). I did a quick chrono and two runs showed about 130 PF. Unfortunately I was near the right end of the range, so I couldn't check the distance it was ejecting rounds (wall there). I don't think it was as far, but I need to test in an open bay, where I can check better.

 

The good thing was that (with a small sample of 20 rounds, and another 20 I shot when zeroing the optic), the reloads I made fed fine. One thing that surprised me (only because this is my first PCC, so I have no experience) was that the PF I see with the reloads in the JP-5 is the same as what I see with my 5" Walther Q5 SF. I guess I was expecting it to be different.

 

One thing I don't fully understand, is that my reloads have a much larger spread and standard deviation, than the Syntech rounds. I'm wondering if that is due to some variation in OAL when I press them, a variation in powder drop, or something else?

 

I was also a little surprised that the PF was considerably higher (about 200 fps more) with the Syntech ammo. I know there's powder and primer differences, and a different bullet shape, but it "seems" quite a bit higher. I haven't really compared other brands, but maybe it's normal to see such a difference.

 

The reloads, obviously, with the lower PF, felt softer than the Syntech ammo.

 

I did buy a 70 degree lock piece, but didn't get to try it much at all.

 

I've got some more testing to do on the next trip to the range...

• Check the ejection distance of the reloads.
• Run more reloads through to make sure there are no issues to FTF, FTE, etc.
• Give a try with the 70 degree lock piece to see what kind of ejection distance I get and how the recoil feels.
• Try the Syntech ammo in my Walther Q5 SF and check the PF.
• Check the OAL of the Syntech and my reloads to see what the variation is, round to round, and just for some comparison overall.

 

Any other suggestions folks have?

 

 

 

[aldukz]

Has anyone tried the 90 and 100 lock piece on the shorter barrel JP5?

[Blackstone45]

3 hours ago, aldukz said:

Has anyone tried the 90 and 100 lock piece on the shorter barrel JP5?

I have an 8" barrel and run the 70 on it. I know that a short barrel length should mean less pressure (and therefore a higher lock piece needed) but certainly not to the extent that you need to go to a 90 or 100. Why do you want to run such high lock pieces?

[philmadxx]

On 2/5/2024 at 4:28 AM, aldukz said:

Has anyone tried the 90 and 100 lock piece on the shorter barrel JP5?

 

I just ordered an Ultralight upper (5.5" barrel) for my JP5, no delivery date yet.  I'll let you know when I get it.  I am getting a 90 with it and already have a 100.  

[JM_]

On 2/5/2024 at 3:28 AM, aldukz said:

Has anyone tried the 90 and 100 lock piece on the shorter barrel JP5?

Not many people have their hands on a ultralight Jp5 yet. I’m getting mine in a week or so and will be able to test a multitude of locking pieces with factory ammo so I will get back with the info if I remember.

[kwrdkc]

How did you order the new barrel? It’s not even listed on the website yet. Only the GMR-15 ultralight barrel is listed. 

[Jasonub]

On 1/28/2024 at 11:15 AM, PaleoMan said:

I just got my JP-5 (Steel Challenge version, with an 80 degree lock piece) and purchased 124 gr Syntech ammo to use to break it in.

 

With a chrono, checking groups of 10 rounds, I saw a PF of 151 and 149 on two runs. It is ejecting 2-3 yards.

 

I also tried my reloads (Precision Bullets 125 gr, round nose, coated, with CFE pistol powder and Fiocchi/Wolf primers). I did a quick chrono and two runs showed about 130 PF. Unfortunately I was near the right end of the range, so I couldn't check the distance it was ejecting rounds (wall there). I don't think it was as far, but I need to test in an open bay, where I can check better.

 

The good thing was that (with a small sample of 20 rounds, and another 20 I shot when zeroing the optic), the reloads I made fed fine. One thing that surprised me (only because this is my first PCC, so I have no experience) was that the PF I see with the reloads in the JP-5 is the same as what I see with my 5" Walther Q5 SF. I guess I was expecting it to be different.

 

One thing I don't fully understand, is that my reloads have a much larger spread and standard deviation, than the Syntech rounds. I'm wondering if that is due to some variation in OAL when I press them, a variation in powder drop, or something else?

 

I was also a little surprised that the PF was considerably higher (about 200 fps more) with the Syntech ammo. I know there's powder and primer differences, and a different bullet shape, but it "seems" quite a bit higher. I haven't really compared other brands, but maybe it's normal to see such a difference.

 

The reloads, obviously, with the lower PF, felt softer than the Syntech ammo.

 

I did buy a 70 degree lock piece, but didn't get to try it much at all.

 

I've got some more testing to do on the next trip to the range...

• Check the ejection distance of the reloads.
• Run more reloads through to make sure there are no issues to FTF, FTE, etc.
• Give a try with the 70 degree lock piece to see what kind of ejection distance I get and how the recoil feels.
• Try the Syntech ammo in my Walther Q5 SF and check the PF.
• Check the OAL of the Syntech and my reloads to see what the variation is, round to round, and just for some comparison overall.

 

Any other suggestions folks have?

 

 

 

Any news on your experiment yet?

 

[PaleoMan]

23 hours ago, Jasonub said:

Any news on your experiment yet?

 

Yeah, I reported in a different thread on reloading...

 

I think one issue I had was that the OAL was quite short (1.157" IIRC), and folks were thinking that the bullet was jumping to the lands and being inconsistent. I did drop checks on the JP-5 and realized that the OAL could be up to ~1.132", so I made some rounds at that OAL. The std deviation was MUCH better.  Of course, I then realized the comment someone had made about the TF mag extensions won't work well with OAL > 1.125", so I changed the OAL again.

 

I also found some HP-38 powder (just a pound), in addition to the ton of CFE Pistol Powder I have. With my 125gr coated bullets, I found these results...

 

With CFE Pistol Powder, I got the best std. dev. and spread  with 4.8gr of powder. Getting about 143 PF. Seemed to work well with 70 degree lock and recoil seems OK (better than if I use Syntech 124 gr cartridges).

 

I got reasonable stats for a 4.0gr load (119 PF) and it shot very soft (4.2gr worked well too), using a 80 degree lock.

 

With HP-38, 4.4gr @ 152 PF worked well, and a 3.6gr load shot very soft (127 PF). In general, I seemed to get better numbers with the HP-38 (a faster powder).

 

In all cases, using 70 degree locks for the higher PF and 80 degree lock with lower PF, there never were any issues with feeding/ejecting of rounds. Ran flawless with easily 1000 rounds of testing and I even tried it at a Steel Challenge match.

 

On my Walther Q5, which also worked well with these rounds, I found that the stats were better with a hotter load, but manageable. I'll likely use the loads best for JP-5, as they were pretty good on the Q5 too. I don't want to build multiple loads, for each gun, if I can help it.

 

I'll likely settle on the 4.8gr CFE pistol powder. I do want to find some faster powders to try (Tightgroup, AA2,...) just to see how things work out, as a future powder to try. I also may try the low PF in a match to see how it works out.

 

In the future, I may want to try different bullet weights, but I've got quite a few of the 125gr Precision Bullets left.

 

It's been fun playing.