JP-5 Build advice sought...

[PaleoMan]

I asked about the TTI pads in a PM to Darqusoull13. The TTI base pads have a button so that they can be quickly removed for cleaning, in case you get sand/dirt in the mag during a match.

 

 

[Darqusoull13]

5 hours ago, Blackstone45 said:

Any particular reason you mentioned the TTI base pads for reload mags, in addition to the TF pads?

Taran Tactical toolless base pads for easy removal and cleaning. When you reload the mag that falls in the sand gets cleaned before it gets used again. TF's require a tool, TTI's just have a pin which can be pressed to remove the basepad for easy cleaning. 

[PaleoMan]

Now that I have the JP-5 and have been playing with it using Syntech 124gr and my reloads, I have a few questions...

 

With my reloads I have Precision Bullets coated round nose 125 gr bullets, CFE pistol powder, Wolf primers. Initially, I had a 1.115" OAL I had a Hellcat where it was not chambering with a longer OAL, so I lowered it. However, with this OAL, I was seeing a high spread and std dev on both the JP-5 and my Walther Q5 match SF. Here is tests, comparing with Syntech 124gr rounds.

 

JP-5

PB 125gr 4.6 gr CFE   Syntech 124gr
Ave Vel.       931         1034
Max Vel.       949         1044
Min Vel.       870         1022
Spread.      78.75        24.54
Std Dev.     23.45         7.96
PF.            116          128

Walther Q5

PB 125gr 4.6gr CFE     Syntech 124gr
Ave Vel.      1012         1111
Max Vel.      1057         1139
Min Vel.       943         1089
Spread.     114.18        40.66
Std Dev.     34.71        12.39
PF.            126          138

 

As you can seem, much higher variance with the reloads (granted, different bullet shaped, primer, powder...). The accuracy was not as well as I expected. I posted in the reloading section, and there were two suggestions, one that the CFE pistol powder was a slower burning powder, and the other that the bullet may be jumping to the land and causing the deviation.

 

I did some plunk tests and checking and realized that both the Q5 and JP-5 would accept up to about 1.132-1.133" before touching the lands. I created a ladder of loads with this OAL and got better results:

 

JP-5    4.6gr    4.8gr   5.0gr
Ave V0   1045     1107    1167
Max V0   1087     1128    1212
Min V0   1005     1078    1116
Spread  81.72    49.47   96.31
Std Dev 27.96    17.58   30.07
PF        130      138     145

 

I made more cartridges with the 4.8gr, as it had the better std dev. for the JP-5.

 

Q5      4.6gr    4.8gr   5.0gr
Ave V0   1007    1054     1098
Max V0   1051    1089     1118
Min V0    955    1028     1080
Spread  95.47   60.55    37.74
Std Dev 27.19   18.84    13.91
PF        126     131      137

 

I also had some HP-38 powder and did a ladder with that, giving these  (even better) results:

 

JP-5

JP-5    4.0gr   4.2gr   4.4gr
Ave V0   1103    1154    1198
Max V0   1114    1180    1240
Min V0   1087    1124    1182
Spread  26.87   56.10   57.63
Std Dev  9.81   18.73   17.63
PF        137     144     149

Walther Q5

 

Re-reading this thread, I noticed the comment about the Goliath mags (I have two, but haven't used them yet) and using 1.125" OAL.

 

Q1: Anyone have suggestions about how I balance, what seems to be better performance with the longer OAL and the need to lower the OAL for the mags?  Granted, I didn't try higher loads, when I did the shorter 1.115" OAL, as I was looking for about 130 PF.

 

Q2: With the Syntech (giving about 150 PF) and the CFE loads with 4.8gr and ~1.132" OAL, I see the cases going 8-10' with the 80 degree lock, and about 6-8' with the 70 degree lock. I recall hearing about the desire for 2-3 yards for case ejection. Should I explore a 60 degree lock? At what point should I be concerned about for ejection? 3 ' or less?

 

So far, everything has been reliable, both reloads and Syntechs. I have about 400 rounds through the JP-5 (I finally cleaned it). I've been using several mags, only filled with 10-20 rounds though.

 

I guess I need to try filling mags and seeing how things go.

 

I need to shoot more with the different lock pieces to get a feel for the recoil. It's my first PCC, so I have no reference yet.

 

I also haven't put any though yet into trying bunny fart loads for Steel Challenge use (something I've never done before- I usually keep it around 130 PF, as I was using the Walther Q5 for IDPA/USPSA).

 

Any other suggestions by folks?

 

[Darqusoull13]

On 2/11/2024 at 2:40 PM, PaleoMan said:

 

Any other suggestions by folks?

 

Spend a ton of time shooting it and less time tinkering. 

Q1: Function > All with mags. Load to manufacturer recommendation. 
Q2: Syntech -> 80 degree lock. 124/5 gr Reloads -> 70 degree lock. 

Run your accurate reloads or factory and practice, practice, practice. 

[PaleoMan]

@Darqusoull13 Thanks. I did spend several hours last Saturday, shooting a Steel Challenge Pendulum setup with friends. It was lots of fun (and great to meet up with folks I hadn't seen for a while and play with everyone's toys). I'm really enjoying the JP-5.

 

When I first started, the loads that I had, were showing a large std dev on both Q5 and JP-5, and that is when I decided to tinker, lengthening the OAL and getting better std dev (and accuracy).

 

I had revisited several threads in the forum about JP-5, and realized I didn't think about checking the mags, and about the mention of a shorter OAL. So, today, I just adjusted my OAL so that it is 1.125-1.127, and created a new ladder with powder to see how the std. dev and PF look with the new length.

 

Goal Friday (weather permitting), is to see if the 1.125 and/or 1.133 rounds feed reliably from FULL mags with TF extension, which I have not checked. In addition, I'll check the PF and std dev of the 1.125 rounds, using the ladder I created to see what works best. With that ironed out, I want to then focus on how the recoil is with both reloads and Syntech.

 

I had a mistake on the chrono data for the Syntech ammo above (it was for the Q5). For the JP-5 with Syntech, I get:

 

Average v0 fps   1217     1202
High fps         1242     1231
Low fps          1196     1168
Spread fps      46.03    63.45
Std dev         14.92    26.37
PF                151      149

 

So reloads have been 130-145 with one powder, and 137-149 with another, and about 150 for Syntech.