LEE 358-158-SWC-TL Seating Depth?

[jdgabbard]

Where do you guys like to seat your 158 SWC-TL boolits to? I am used to using boolits with a clear crimping groove. However, the Lees don't have one. Should I crimp into the first grease groove, or crimp over the front driving band?

[Junior1942]

I crimp it in the 1st grease groove for my Rossi 92 rifle..

[Treeman]

I leave one band outside the case. In theory that will center the bullet in the chamber better. In practice that makes the powder encroachment equal most other popular .38 special 158-160 grain bullets.

[shooting on a shoestring]

I've seated it in the first micro groove and also in front of the first driving band. I haven't seen any measureable difference in velocity or any performance factor. Therefore I don't think it matters. Choose what looks best to you. They'll shoot fine.

[jdgabbard]

In the first groove wins.

[timkelley]

1st groove.:smile:

[missionary5155]

Good morning Those grease grooves are defacto crimp grooves. Experiment.. you may discover your S&W likes the boolit seated out to the 2nd groove or more. My Dan Wesson 357 mag has long cylinders and boolits seated out to the extreme shoot far better than short overall length. My Colt Police Possitive 38 special and my S&W model 10 are different inseating length for best accuracy.

[jdgabbard]

In order to not start another thread I have a question on load data for this boolit. I am casting straight WW, and the weights are coming out to 163 +/- 1 gn. Is loading these for a 158gn SWC going to have that much of a difference? I do have data for a 160gn LRN. Using Lyman 3rd Edition Revolver and Pistol Handbook.

[Dale53]

You should not have a problem. It is always advisable to start a bit low and "work up".

Dale53

[Treeman]

Minor weight differences can usually be ignored. Weight is PART of thge whole equation but seating depth and bearing surface are the big factors in pressure development. The Keith designed 358429 weighs 173 grains (+ or-) but much of the weight is in the nose. Powder encroachment and bearing surface are comparable to many 158 grain bullets and a lot of guys interchange the bullets. If you check data from Lyman you'll find different charge weights for that bullet and various 158-162 grain bullets...but not much different -you aren't likely to get into dangerous territory with such a swap. FWIW I consider the data for Lyman's 357446 as the most accurate for the Lee TL SWC.