410 pattern variations?

[Ridge Rooster]

Just curious if yall 410 hand loaders are seeing variations like we are in our handloads? Using 300MP powder we are seeing shot counts in the 40 that vary seemingly from the weather. I understand that we are dealing with a low amount of pellets in the 410 than any other gauge but we have seen as high as 225 down to 125 using the same load. These are counts in the 10" at 40 and only thing that has changed is the temperature. The 225 being a 70 degree day and the 125 being a 45 degree day. We have repeated the same results several different shooting sessions so it seems normal for us just curious if others are seeing the same?

Another question is that we are using 383gr of shot and have kinda been stuck on that amount. Just curious if anyone else has better consistency with a lighter charge?

Above issue with consistency has been noticed in at least 4 different 410's with various chokes etc.

Ridge Rooster

[huntinsomd]

I've been out of the .410 game this past year, but I ordered a Stevens 301 to try out in the next week or so. I have reloaded about 50 shells probably with the same formula that you are referring to. I'll let you know what kind of results I get.

[WV Ridge Reaper]

Are you using anything such as a OSC or Nitro card under your wad ?

Further more how often are you cleaning the barrel ?

[Ridge Rooster]

Yes on the OSC under wad and yes on cleaning often along with using bore snake between shells. We have tried it in various bore conditions.

Ridge Rooster

[Hayudog]

My recipe using the same 383gr of shot and TPS wad did not call for a card or anything under the wad. I found I had a powder migration issue with Cheddite hulls. The TPS wad is concave under by design, and gas seal doesn't make good contact with the hull wall in the shell. I've heard of two methods to help with the seal.  One I've tried.
I've taken a piece of tyvek ( usps mailer ) cut it and then started the wad into the hull. Just enough to crease the tyvek. Remove it, and trim so that I have maybe an 1/8" cup. I use this under the wad. It conforms to the concave of the bottom of the wad when you apply your wad pressure, and seals the powder so migration isn't an issue. 

Question might be pressure variations using an over shot card, or spacer.  Just thinking out loud.

Second method I heard about is using a steel ball to make the gas seal on the bottom of the wad a little more pronounced. This would keep it so it matches my recipe exactly, no tyvek.