Help me figure out the cause of my squib

[springer99]

Originally Posted by Radny97

Lyman 49th says max for a 160 gn cast is 4.9. +p is 5.2. I’m certain I’m okay on the load.
Question is what caused the squib.
I’m increasingly certain that it was caused by an insufficient drop of powder, probably because i let the powder get too low in the hopper. I am pretty particular about not short stroking it, but i have to acknowledge that as a potential possibility as well.


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Yes, I use 4.9gr of HP38/W231 all the time with HiTech coated, cast 158gr. SWC in my 642. A bit snappy but not near max. according to Lyman.

Suggestion.... don't let the powder level drop much below half full. There's no baffle in the Lee Pro measure to compensate for powder weight. Also, make sure the powder measure isn't spinning loose on the drop tube. This can effect whether or not you're getting a full extension into the drop tube.

[Radny97]

Good suggestion springer99. That will be my practice going forward.


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[Radny97]

Well I went to the range today and shot the rest of the batch. No issues. Everything shot smoothly and accurately. No underpowered loads no overpowered loads. Not really sure what that means other than I’m guessing I just didn’t have enough powder in the hopper and one of the powder drops bridged and did not drop a full load in one round.


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[jmorris]

No/low powder charge is the #1 cause. Why I like powder checks along with eyeing every case, when I can. A good powder check can detect differences too small for the eye to see as well.

https://www.youtube.com/watch?v=6EU9deSKm48&t=2s

[ms6852]

Originally Posted by Mississippi

I'll give my insights, though there are folks on here with more experience.

Primers: bad primers do not really cause squibs. Incorrect primer selection can cause ignition problems like using a standard primer with a large volume of ball powder....i.e 58 gr of H335 called for a magnum primer to ignite it reliably. But it won't squib, just won't be consistent. I had a bad lot of CCI-250's and they just failed to ignite. Which is what happens with bad primers.


Extra case lube could cause a squib. I had some factory ammo with oil in the case that caused squibs. I found out by pulling then apart and sent that ammo back promptly.

Too little powder can obviously cause a squib as powders generally need to hit a certain pressure to burn cleanly and thoroughly .

Finally, a plugged primer pocket could cause a squib too. If you tumble in certain media like Walnut shells...I have seen pieces lodged in the flash hole.

The primer comment was more of a reply to light strikes as mentioned by OP.