Need some help on starting load

[vaalpens]

165 GR. BERB FP
Winchester AutoComp .400" 1.125" 6.3 1,051 25,900 PSI 7.0 1,171 33,300 PSI

165 GR. SIE JHP
Winchester AutoComp .400" 1.125" 6.5 1,037 25,600 PSI 7.1 1,124 31,500 PSI

180 GR. BERB FP
Winchester AutoComp .400" 1.125" 5.7 971 26,700 PSI 6.2 1,060 33,000 PSI

Above are the Hodgdon load data that I have used when loading Xtreme 165gr CP RNFP.

The Xtreme 165gr CP RNFP projectiles were loaded with 6.3gr AutoComp, with a COL of 1.142". I am happy with this load an is doing some more testing to see if I need to make any minor adjustments.

I have not loaded Xtreme 180gr CP RNFP projectiles yet, but if I did, then I would probably start with 5.7gr listed above without any issues.

So I decided to try my hand at loading the Xtreme 165gr CP HP projectiles since I have heard good things about them, and I also wanted to try something else. The issue I have is to decide on a starting load based on the data above.

The average projectile lengths are the following:
X-Treme 40 S&W 165 CP RNFP 0.5348
X-Treme 40 S&W 165 CP HP 0.5730
X-Treme 40 S&W 180 CP RNFP 0.5798

As you can see, the 165 HP is much closer in length to to 180 RNFP, than the 165 RNFP. This means to me that if I want to keep the 1.142" COL, then there is now way I can start at 6.3gr like the 165gr RNFP, but I should be closer to the 180 FP data. The max load for the 180 FP is lower than the starting load for the 165 FP, so it seems I need to be careful here.

My choises are one of the following:
-Increase the COL assuming it will cycle without any issues to 1.142"+(0.573"-0.5348")=1.18" and also start with 6.3gr. The 1.18" is to high, with the maximun COL I can go is 1.158". My working COL has been 1.142", so this is probably not the time to change my working COL.
-Keep the 1.142" COL, but adjust the starting load to 10% below the above 165 GR. SIE JHP data, and start with 5.8gr
-Keep the 1.142" COL, but adjust the starting load to 5.7gr + 15.1% which is the percentage of the difference of projectile lengths, and start with 5.8gr

I would appreciate it if you can comment on the direction I am taking. I want to be safe, and need to start with a load that is not to low or to high.

 

[blue32]

You didn't say but I'm guessing this is for .40S&W? Even so, Id much rather adjust COAL on the HP than fool with charge weights. The HP COAL might have to be slightly less than the RNFP and you can tune that easier for function than guessing pressure curves with load data designed for 180gr. bullets.

 

[rcmodel]

Load it at the starting load for BERB 165 plated bullets, and ignore the published OAL.

You need to use a Seated OAL to the length that 'plunk Tests' in your guns chamber.

That is what starting loads are for.
They are safe, no matter much what else you do.

Rc

 

[vaalpens]

Load it at the starting load for BERB 165 plated bullets, and ignore the published OAL.

You need to use a Seated OAL to the length that 'plunk Tests' in your guns chamber.

That is what starting loads are for.
They are safe, no matter much what else you do.

Rc

rcmodel, thanks for the feedback. I will use your advice and go with the starting load and with the 1.158" COL. This COL passes the plunk test and cycles through the gun without any setback.

 

[vaalpens]

You didn't say but I'm guessing this is for .40S&W? Even so, Id much rather adjust COAL on the HP than fool with charge weights. The HP COAL might have to be slightly less than the RNFP and you can tune that easier for function than guessing pressure curves with load data designed for 180gr. bullets.

blue32, thanks for your comments. Yes it is for a 40S&W. The only reason why I posted this question was that the ranges for the 165gr and 180gr did not overlap, so I was a bit concerned that I could load to high or to low depending on the direction I am taking.