Next step: OAL or Powder?

[scgun]

Hello everyone,

 

current situation:

145gr copper plated bullets; 3,6gr lovex s 015 powder 

OAL 1.145" (plunk test barrel chamber OAL = 1.16" in my CZ s2)

chrono results: 880-920fps (900avg)

 

my goal is to have PF 135

should I shorten the OAL or increase powder charge for better results?

 

 

Edited November 19, 2020 by scgun

[4n2t0]

More powder...maybe!? You didn't tell us what powder so we don't know if 3.6gr is a min/mid/max charge. It's hard to help without that information but generally you should only need to adjust OAL to help solve functional problems.

[zzt]

If you are not at max published load, add more powder.  That will also help with your SD.

[scgun]

2 hours ago, 4n2t0 said:

More powder...maybe!? You didn't tell us what powder so we don't know if 3.6gr is a min/mid/max charge. It's hard to help without that information but generally you should only need to adjust OAL to help solve functional problems.

mea culpa...

 

info added

[CZ85Combat]

Your at the upper end of OAL, try 1.140"

[mrd]

18 hours ago, CZ85Combat said:

Your at the upper end of OAL, try 1.140"

 

What makes you say this? His rounds passes his plunk test and he's using 145 grain bullets that are generally quite long, so plenty of bullet in the case. 

[Jim Watson]

Agree, if not at the maximum, increase the load.

But why?  you are at f 127 on the low side, f 133 on the high side, f 130 average.  Which is right where I want to be.

[zzt]

5 minutes ago, Jim Watson said:

Agree, if not at the maximum, increase the load.

But why?  you are at f 127 on the low side, f 133 on the high side, f 130 average.  Which is right where I want to be.

 

Because the quality of the chrono readings you get at a match are dependent on the skill or the RO doing the shooting.  Any bullet path that deviates from along the long axis of the chrono and parallel to the sensor windows decreases velocity read.  Since the bullet takes a longer path (more time to cross the sensors), the reading is lower.  This is especially true with Open guns with high, frame mounted dots.  That's one of the reasons you see so many Open shooters going with 172 PF or higher.  Even iron sighted pistol can be at risk.  One Limited shooter at my club ran 167 PF loads.  Most of the time he skated by, sometimes on the second try.  At one major he chrono'd 164 both tries and got dropped to minor.  He was pissed.

 

Another reason is the OP's SD is not so hot.  He doesn't say what it was, but a 40 fps ES suggests it is higher than desirable.  Increasing the powder charge should help with that.

 

As an example, when I was working up potential 9mm major loads with a 124 gr JHP I found the following (all with 10 shot chrono strings).  9.1 gr of a powder gave an ES of 44 fps.  9.3 dropped that to 32, and 9.4 dropped it to 27.  At that point I was at 175 PF with an SD of 9.44  I didn't use that load for a variety of reasons.

[Butterpuc]

I performed a load development experiment many years ago.  Varying OAL and powder charges over many ranges, creating my own bell curves.  The powder of choice for me, which created the most accurate, regarding measured variables and accuracy was VV N320.  Ultimately, for my gun (G34), 3.15gr of VV N320 with 147gr coated bullets loaded to 1.135" OAL was the best I could get regarding accuracy and consistency of PF.  It was very consistent between 127-129PF with a SD 2 fps.  It did take quite a bit of effort to do this, and most people don't care that their loads are that accurate, but I was pleased with it.

[zzt]

1 hour ago, Butterpuc said:

Ultimately, for my gun (G34), 3.15gr of VV N320 with 147gr coated bullets loaded to 1.135" OAL was the best I could get regarding accuracy and consistency of PF.  It was very consistent between 127-129PF with a SD 2 fps. 

 

Interesting.  While developing my preferred minor loads (I need four different ones) I experimented with different powders and OALs for 1.090" to 1.55".  I too found that 1.135" was the sweet spot. My PCC load of 3.2gr Alliant Sport Pistol (an N320 clone) with a 147 gives me a sloid 130 PF load out of a 5" barrel.  I also discovered that using the same load with 124 and 115 bullets gave lower PFs as expected, but they all shot to the same POI.  So I can use the lighter bullets for steel challenge and the 147s for when I need to make PF, all without ever changing zero.

[CZ85Combat]

8 hours ago, mrd said:

 

What makes you say this? His rounds passes his plunk test and he's using 145 grain bullets that are generally quite long, so plenty of bullet in the case. 

OP is @ 1.160" SAAMI max is 1.169".  Op is looking for more velocity out of this round, experimenting with shorter loads may give him the results he looking for without adding powder, and with the price & availability of reloading components every little bit counts.

[4n2t0]

24 minutes ago, CZ85Combat said:

OP is @ 1.160" SAAMI max is 1.169".  Op is looking for more velocity out of this round, experimenting with shorter loads may give him the results he looking for without adding powder, and with the price & availability of reloading components every little bit counts.

 

The OP's at 1.145.

[CZ85Combat]

1 minute ago, 4n2t0 said:

 

The OP's at 1.145.

I think it was edited.

[scgun]

7 hours ago, CZ85Combat said:

I think it was edited.

Just added powder type.

 

thx everyone. Your inputs have helped me.