Henry .38-55 Side Loading Gate Rifle - Groove Diameter

[Prairie Cowboy]

I am strongly considering the purchase of one of these rifles.

Before buying, I want to round up what I need to produce ammo. I have located Redding Dies, Starline brass, and the Lee mold, but I need to know what the groove diameter runs in these rifles to choose a Lee bullet sizing kit. While these are custom I know a supplier that has these in .377",.378", and .379". Since the Lee mold is a .379", it will probably drop boolits around .380", based on past Lee mold experience.

I would appreciate hearing from anyone who has slugged a Henry .38-55 bore, what they measured, and what they sized to.

[The_Eccentric]

I you don't get an answer here, try contacting HRA. Years ago I had a question about the barrels on their .44mag Golden Boy. They got back to me with an answer the same day.

[RickinTN]

The only advice I would have is to reconsider the Redding die set. I love the Redding dies, and think they are about the best you can buy. I have several sets. I have had a couple of sets which I could not use with cast as they will not seat a bullet larger than standard jacketed for the cartridge. I believe you would be restricted to a .375" bullet. Redding used to offer a service where they would open up their dies in the event they were too tight. I called and was told they discontinued this service several years ago.
Good Luck,
Rick

[Prairie Cowboy]

Thanks for the replies guys.
It's what I need to know before taking the plunge.

I did indeed contact HRA as well, and they did get back to me this morning with this:

"Our .38-55 barrels have a .366" bore diameter and a .377" groove diameter."

So, assuming that individual specimens may run .376"-.378" groove diameter, I am guessing that I need cast bullets of at least .378"-.379" depending on how the bore actually slugs out.
If Redding is sizing it's dies on the small size that is a problem.