Need advice reloading .40 S&W

[griffgil1]

Details first:
1) Reloading 40 for USPSA, shot from Glock 35.
2) Been reloading for years, so not new to it.....but AM NEW to working with a chrony....and this is where I'm having problems.
3) Attempted load: Starline brass, Fed small match primers, Hornady 180 gr. FMJ pills, and either N330 or Tightgroup powders.

OK, since I'm trying to load to a power factor of 170, I'm wanting to keep my vel right around 945. Worked up some loads with both above mentioned powders, but there are two problems 1) every .1 grain change of powder moves the velocity exponentially away from my target, so I can't seem to even come close...either way too high or too low, 2) the ES and SD are HUGE on all the loadings....like ES in the 30's to 50's and SD way over 15. Tried changing seating depth, but that didn't help.

So, my question is: how important is ES/SD for my purposes? I'm new to using a chrony and am just going by what I've been told and have read, about keeping these two numbers low. I know that if the ES is too big, I run a risk of not making pf at a match, unless I up the fps to the point where the loads are WAY over pf and not comfortable to shoot. Another question is regarding fine tuning this load....it seems I am not able to because the change in fps per .1 grain of powder is pretty dramatic.

Anyway, I'm thinking, maybe I should NOT obsess about ES/SD, and being within "X" fps of 945 fps, and just work up a comfortable load that is reliable. I'd appreciate some input from other competition reloaders with more experience than me. Thanks in advance.

 

[nksmfamjp]

I would focus on power factor and groups.

 

[ppaul]

To gain some control over your velocity I would try some slower powders. The fast numbers like tightgroup are nice from an economic point of view, but you lose some of the control of your velocity number. If these were different times I'd just say run out and get some brand x, and try it. Those days are gone for the foreseeable future. Look for a powder in the Accurate #7 burn rate. This should also help getting control over your ES and SD. As with any of this let the target be the final arbiter.

Good luck, Paul

 

[joshb]

When I load for pistol with powders like Unique, Titegroup and Power Pistol, I go to my book and find the middle of the suggested charge weights. I ‘ll load some test loads a little below and a little above. Then I hit the range and test them in my gun for accuracy and function. I pick the best load and make 500-1000 of that combo. That’s it.
I pick the middle of the loads so I have a safety cushion, to protect me and my gun. I save my fussy loading time for my rifles.

 

[EOD Rob]

When I load for pistol with powders like Unique, Titegroup and Power Pistol, I go to my book and find the middle of the suggested charge weights. I ‘ll load some test loads a little below and a little above. Then I hit the range and test them in my gun for accuracy and function. I pick the best load and make 500-1000 of that combo. That’s it.
I pick the middle of the loads so I have a safety cushion, to protect me and my gun. I save my fussy loading time for my rifles.

Second that!

 

[Forum Boss]

It will be hard to really ascertain the accuracy shooting a Glock 35. Yes you can rest it, but it may perform a little differently when hand held. As others have suggested, don't worry about ES/SD, as I doubt you will be shooting farther than 25 yards in 95% of your USPSA stages.

Your instincts to shoot the lowest velocity load that makes power factor are logical.

 

[kneedtospeed]

I understand what you're trying to accomplish.
Good match loads, making Major, will take some Experimenting. Shooting heavy bullets with fast powder reduces felt recoil (without a comp), but also flirts with overpressures.
Polygonal barrels are not recommend shooting lead, but many do it Carefully, and you can reach higher velocities at lower pressures, to reach PF.
Don't let lead build. That's a whole 'nother subject.
Slower powders reach PF safer, and with more stable numbers, but we always push that fine line in competition.
I've had good luck with 180 Lead and WST, although it is reverse temp sensitive.
There are Too many variables involved, to just quote a load.
Work slow and safe.

 

[griffgil1]

Thanks for the input all. The more reading/research I do, I am figuring out that getting hung up on detailed chrony stats is really pointless with pistol loads.....I really just need to make sure the average velocity makes PF, and that the ES is not over about 40, and that I shoot a large string (20 rds +) to validate that. The best chrony stats in the world mean nothing if my groups are all over the target and I can't score well. Boy it is fun playing with the Labradar though! Pretty nifty piece of equipment.