Incomplete combustion in .45 reloads?

Curious any input on incomplete or delayed powder burn with reloads?   After doing some recent reloading of .45 using 3.6 grains Clays powder, large Winchester primers and 185 gr Zero SWCHP bullets I've noticed there are some (not a lot) of "fireworks" shooting out the barrel after the bullet and, in some cases, enough still-burning powder fragments to notice a few on my face during case ejection.  Is this a symptom of any obvious mistake I might be making during reloading?  Old powder? Wrong primer?  Any advice appreciated.  The loads seem to group fine, so the performance is good but the sparklers aren't desirable. Thanks!

Never heard of 1.6 from clays. Sounds way under for that weight bullet. Isn’t standard around 3.4??? Probably not building enough pressure for complete combustion. What distance is it accurate at?

Thanks Jim!  Correction!  3.6 grains Clays.  Brain must also be sparking this morning.

What is your crimp set at?

You might bump it up.  The starting load on the IMR reloading website is 4.5 grains of Clays for that bullet.  I know we try to soft-ball loads, but that seems a wide margin.
http://www.hodgdonreloading.com/data/pistol

3.6 should work fine. As stated, tightening your crimp might help.

I use powfer puff loads with BE powder. My arm is covered with flakes of powder after shooting. It really doesn't matter. I'm concerned about performance not the powder flakes. If your getting good results then I say charge on! 
Jon

3.8 gr. Clays seems to be a sweet spot for 185 & 200 gr. lead bullets.  As said here previously, you should probably try a tighter crimp, say .464 - .468".  Clays is good stuff, but I've had better luck with WST and Titegroup.  Sometimes you'll get flakes on your arm, but like Jon said as long as the load performs well and accurately, who cares?

Many years ago, I attended handgun training classes that were held indoors with a smooth linoleum surface.  After our class I was surprised to find piles of unburnt powder on the ground when we pushed a dry mop around to gather the empty casing.  It's a very common thing...  Most of those were of course factory ammo...

Sparkles come from the glass added to the priming compound....l have some sk magazine 22 with lots of them. Says you're looking in the right spot, not at the target.

Thanks everyone for the good advice so far.  Following Zane's advice I measured 10 loads from the same batch of reloads.  The crimp is .468-.469 very consistently.  Does anyone think I should move the crimp in to .464-.465?  If I can even dial-in that small of a change.  Or just leave things alone?  Also, based on the comments above, and agreeing lighter loading is better so long as the bullet flies straight, how many grains of powder would be considered "powder puff" load using: (a) BE, (b) WST or (c) Tightgroup?

I would change the crimp to the advised range. 3.4 BE and 3.4 WST have worked fine in my pistols for the short line in warmer weather.
Jon

I'm at 3.7 gr titegroup with a 170 gr bullet. Frame mount with a 12 lb recoil spring. It's pretty "puffy" to me, significantly lighter than 3.3gr of ba 10 with same bullet.

If they fly straight and group tight, leave it alone. Don’t fix what’s not broken. Cliff, “powder puff” is directly relative to how “manly” you are.....

Higher pressure burns powder better.  Delaying bullet movement can increase pressure.  
Neck tension-  measure  case OD at  neck, before and after seating a bullet. After seating, the  OD needs to expand by about  .002"   or more. But it should not size a lead bullet smaller  in diameter.

To much taper crimp may also size the bullet smaller.

Delay the opening of the action?

 Heavier recoil spring?

EGW firing pin stop. I know litte on this subject.  https://forum.m1911.org/showthread.php?13060-Amazing-reduction-in-perceived-recoil-with-a-simple-part-change-EGW-firing-pin-stop

The idea is to delay opening of the action. If this is possible??

Or load a 200 gr lswc that has more bullet shank in the case, less air space.

This provides more neck tension , bullet bearing surface in contact with case.

Cleaner burn provided by more pressure.