tried out my 40 s&w reloads. . random spark show

[z7]

everything went well, shooting 160g ranier, which didn't group well over 6.8 grains of autocomp

then went to 155 xtps, grouped well over 7.0 grains of autocomp with decent recoil in my glock 23

i had one shot where i got a shower of sparks out the barrel. normal sound, normal recoil and function. just to check i dropped the mag, ejected the chambered round and dissassembled the gun right there. everything looked good, barrel was clear, i was able to find that particular piece of brass, everything looked good. i don't know what happened, but it only happened once.

anyone know what the cause is? i suspect I might need to up my crimp, i barely crimp as is, being new to reloading i tend to try to do things with moderation.

thanks for any help you all lend

 

[rcmodel]

Probably a light load didn't light off right.
Autocomp needs full pressure to burn well.

7.0 is the Starting load for a 155 XTP.
7.8 is Max.

Increasing Taper-Crimp in an auto pistol will do nothing good.

Any more then straightening out the case mouth bell is detrimental to case neck tension.

The .40 S&W taper-crimp should measure .421" at the case mouth.
No more, no less!

rc

 

[Laphroaig]

Is it possible that you had some leftover tumbling media in the case? Like tumbled after sizing but before priming? Just a WAG.

Laphroaig

 

[z7]

Thanks for the replies,
I will say it is a remote chance, I am far from perfect and may have missed a few particles of media.

Also, beyond a more efficient and cleaner burn, accuracy and velocity what is the benefit of working up the charge? I like the way 7.0 feels, I tried 7.4 and it was a little on the sharp side for my plinking loads. Is there any danger to staying low?

 

[Havok7416]

Several of my reloads do this as well as factory 9x18mm steel case. I wouldn't worry about it.

For what it's worth, I use some very light loads, and after I've now shot several thousand in a variety of calibers, I can tell you that you will be ok. If your rounds are generally intended for target use, then whatever charge you feel comfortable with is fine (up to published max).

 

[LiveLife]

Also, beyond a more efficient and cleaner burn, accuracy and velocity what is the benefit of working up the charge?

Satisfaction of knowing you have done a full powder work up. For many, if the powder charge reliably cycles the slide and produce acceptable level of accuracy, that's good enough. For me that's not good enough as the objectives of handloading/reloading/full powder work up are:

- To produce more accurate than factory full-power loads
- To meet power factor specified for match shooting (USPSA, IDPA, GSSF, etc.)
- To produce the most accurate target load with reduced felt recoil/less wear and tear on firearms
- If applicable, to identify accurate loads slightly below published load data

For me, how clean/dirty a particular load burns is secondary to accuracy as I consider accuracy the overall result of more consistent powder burn/chamber pressure build up and peak averages/muzzle velocities that produce lower SD numbers and smallest shot groups.

Without powder work up, you won't know this.

For pistol powders, I separate W231/HP-38 and faster burn rate from Unique/Universal and slower burn rate powders. Auto Comp is a "relative" slower burn rate pistol powder and slower than Unique/Universal powders tend to produce optimal accuracy at high-to-near max load data while faster than W231/HP-38 powders can produce very good accuracy even at mid range load data. It is for these reasons why many match shooters, especially bullseye match shooters who must have the most accurate loads tend to use faster than W231/HP-38 powders.

 

[Matt Dillon]

Another factor to consider, especially if you are using lead projectiles, is that you want to push the projectile fast enough to obdurate the barrel well, if you don't want lead built up in the barrel. I usually have a goal if finding the correct powder charge somewhere in tge middle if tge range between mud and max loads.

 

[Wreck-n-Crew]

I have seen it before too and with other powders. But Autocomp is really awesome in 40caliber and my new go to powder for 40's. I worked up a nice accurate and clean burning load using Autocomp with 5.9gr behind a 180gr Berry's FP. Really love it. (My new crack)

 

[z7]

I know it meters really well

 

[gamestalker]

Bds, that's an excellent description and analogy of why we need to do a "work up". You conveyed an important aspect of the powder work up that is essential to, if not critical in understanding and interpreting load characteristics, both internal, and external ballistics.

I originally became fascinated with reloading before I ever pulled the handle on a press. What fascinated me the most, and still does, is the ability to build the most proficient load. Just having the ability to control the consistency of a load, and at it's full and typical potential, well, it kind of makes me feel privileged some how. I never really thought of reloading as a way to save money, I simply wanted to gain more consistent accuracy and velocity, nothing more.

Thanks again Bds!

GS