3 in loads or 2 1/2 in loads at 1300 fps.
Congrats on your new weapon. Let us know how it shoots.

 

3 in loads or 2 1/2 in loads at 1300 fps.
Congrats on your new weapon. Let us know how it shoots.

Thanks,

I'm aware such things can well be finicky. So stay at 1/2 oz of shot? Or should it be more?

 

I would not consider a 2.5" .410 shell a magnum. I always considered the 3" .410 a magnum. I have seen Tristar shotguns that would shoot light loads right out of the box. You can shoot a box of 3" shells thru it, or try lighter shells. If the lighter loads don't cycle, shoot a heavier load. Trying a lighter load first is not going to hurt anything.

 

The first loads out my new Tri star 410 Viper were my 2 1/2" reloads. 16.5 gr H110 witH 1/2 shot. Never missed a beat. Any of the 1300 fps loads or 3" loads should work. Clean and oil/ de grease everything before forging the first time also helps. I personally like CLP on the mag tube under the gas piston. The only time mine hangs up is with the 3" Fiocchi hulls I have reloaded with HW 15 using Lilgun. Does not built enough pressure to cycle the bolt back that last 1/16" to clear that long hull out of the chamber at times. Everything else rejects and cycles perfect. Have fun, they are so nice to shoot and carry. Chuckars,quail,and ducks with mine.

 

The first loads out my new Tri star 410 Viper were my 2 1/2" reloads. 16.5 gr H110 witH 1/2 shot. Never missed a beat. Any of the 1300 fps loads of 3" loads should work. Clean and oil/ decrease everything before forging the first time also helps. I personally like CLP on the mag tube under the gas piston. The only time mine hangs up is with the 3" Fiocchi hulls I have reloaded with HW 15 using Lilgun. Does not built enough pressure to cycle the bolt back that last 1/16" to clear that long hull out of the chamber at times. Everything else rejects and cycles perfect. Have fun, they are so nice to shoot and carry. Chuckars,quail,and ducks with mine.

OK, I think I'll follow your lead. I wasn't going to remove the factory grease but I will now. It does seem to be overly gooey.
I've never been a fan of Fiocchi ammunition of any kind, pistol or rifle. I do think I'll go with 2-1/2" loads with your recipe. I have the ability to reload shotshells. Although I'm new at shotgun loads, I'm very experienced with rifles and pistols.

 

I had an old box of 3" hunting ammo that, IIRC, were 11/16 oz. of #6. After a box of those, my Viper shot Winchester AA skeet loads reliably.

 

I have a mossberg SA 410ga TSS turkey gun. I used reloads 3 inch 6 shot. Shot 6 of them to get my red dot on paper. Then i shot 2 2.5 loads. I shot 3 TSS turkey loads. My mossberg cycled everyone of them. Tristar and mossberg are twins.

 

Magnum .410 - 3" with 11/16 or 3/4 ounce shot. 2.5" are not magnum in my opinion.

 

Magnum .410 - 3" with 11/16 or 3/4 ounce shot. 2.5" are not magnum in my opinion.

This +1

 

So I've obtained a Tristar Viper G2 semiautomatic 410. Taped on the inside of the box lid is a sticker that reads:

" Notice, Your shotgun may require a break-in period. Please shoot magnum loads for the first 20 rounds. Thereafter light load shells will work with greater ease."

The sticker is not bore-specific. Magnum load has no definition: it is hard to find a 3 inch or 3-1/2 inch 12 gauge "non-magnum" load. It just means heavy, non-target loads for break in.