TC Seneca Project

[Idaholewis]

Got another Project cooking up As some of you know I have owned 2 Thompson Center Seneca’s in .36 Cal for quite sometime now, Unfortunately both bores were Rough when i got them. Both rifles shot ok, but as anyone familiar with Blackpowder Rifles know, it is TOUGH to maintain a Rough pitted bore from getting worse over time. Both of my Seneca’s have the Rare to find Seneca/Cherokee Tang mounted peeps, And Both rifles are in excellent condition exterior wise.
Skip ahead a bit, i ended up trading 1 of these Seneca’s to Forum member willfish4fud, I fully explained to him the Bore condition, and what my future plans were, He and i have become good friends through here, He is a Darn Good guy, But a BAD INFLUENCE!!
My idea with 1 of these little Seneca’s has always been to strip the Barrel down and send it to Bob Hoyt for a Re Bore to .40 Cal and Twist it to shoot .40 Cal Pistol Bullets, But i have stalled on doing it (To Many Irons in the Fire!) Both Little Seneca’s have just Sat around in Idle, After Explaining my idea to Forum member willfish4fud he and I decided to get the project underway! I played around with Rifle Twist figures and Bullet weights, 1:36-1:38 Twist Looked really good for the Pistol Bullets, And Velocities we plan to shoot, so we went 1:37 Twist . I spoke with Hoyt, We both shipped our Barrels Off to him. Hoyt told me the Bore Diameters will end up at .400, and no larger than .402, He will Bore and Rifle our Barrels at the same time (1 after the other)
This will be the First bullet we work with, this one should end up around 180 Grains with my 1-40 Alloy, for safety I am having the Mold Cut to .403 using Tom’s Positive tolerance (+.002/-.000) Which means the diameter will be AT LEAST .403, and with Tom’s Tolerance window of .002 it could end up .405, We also ordered a Lee .401 Push through Bullet Sizer so I can Customize bullet fit to our Bores. I am Looking forward to both of us getting our Barrels back and “Wringing them out” i will post updates as things progress along

 

[Harleysboss]

The first step to recovery is admitting you have a problem. That's a cool project and will be a fun little popper!

 

[Saxtonyoung]

Lewis,

What kind of velocities are you looking for and what is your intentions for this gun ? Targets ? Game hunting ?

 

[Idaholewis]

Lewis,

What kind of velocities are you looking for and what is your intentions for this gun ? Targets ? Game hunting ?

Velocity wise i plan to stay in the 1300-1400 FPS Range, 50-60 Grains of Swiss 2F should get me right in there. I really put Thought in to the Seneca Rifle itself in this Build, As you know the Seneca’s are a Slim/Trim Little Rifle and not meant to Push Hard, i went off of TC’s Load data for the 45 Seneca and Maxi Ball/Maxi Hunter, Those 2 bullets are in the 240-250 Grain Range, TC lists the Hottest end at 80 Grains of 2F with a Velocity of 1,541, I have never been a Fan of the .45 in the Seneca due to the Slim/Trim design of the Seneca, i know a few guy’s that have cracked their Stocks when pushing the 45 Maxi Ball/Maxi Hunter with upper end Hot loads. So by going with a .40 Cal Bullet under 200 Grains, and Staying in the 1300-1400 FPS Range i will be well under their .45 load Data for the Seneca. These little Rifles will be able to digest this Day in, and Day out
I used JBM’s Stability Calculator, A number of 1.5 is the military Standard for Stability, As you can see by the Bullet length, Weight, Twist Rate, and Velocity i chose in this build, it puts me right in there

 

[Idaholewis]

Lewis,

What kind of velocities are you looking for and what is your intentions for this gun ? Targets ? Game hunting ?

As for intentions of use? I will speak on my behalf here. Just another fun gun to Shoot I have always loved the Feel of the little Seneca’s, They are such a nimble, nice handling little rifle, who wouldn’t like one?

 

[Saxtonyoung]

Just for fun I ran your bullet at 1300 fps on another ballistic calculator and seen it was going to work just fine with the twist you picked out. Sure sounds like a fun project, I like how the Seneca and Cherokee rifles handle and would much prefer a slip fit bullet rather than patch and ball. In my neck of the woods any caliber muzzleloader can be used for deer hunting but I would probably go with a wider metplat and keep ranges reasonable if that's what I decided to use it for. Looking forward to your upcoming range report.

 

[Willfish4fud]

I intend to chase whitetail in MS with mine. Going to be a pleasure to carry vs a .50 renegade that I toted this year

 

[Idaholewis]

I just got my .36 Seneca Re bore to .40 Barrel back from Mr. Hoyt, That was Fast! And it looks AWESOME!! I just did a Quick bore polish, Cleaned it thoroughly, and oiled it up. Waiting on the Accurate Mold, and .401 Sizer, Willfish4fud and i are Close to Making Smoke with these!

 

[Idaholewis]

Put back together and ready for it’s Maiden Voyage This one has the Seneca Tang Peep, and of course i added a Lyman 17 Globe so i can use my Shaver’s BPCR inserts. I bet there aren’t many 1:37 Twist .40 Cal TC Seneca’s around? I only know of 1 other, But he hasn’t gotten his yet

 

[Willfish4fud]

Put back together and ready for it’s Maiden Voyage This one has the Seneca Tang Peep, and of course i added a Lyman 17 Globe so i can use my Shaver’s BPCR inserts. I bet there aren’t many 1:37 Twist .40 Cal TC Seneca’s around? I only know of 1 other, But he hasn’t gotten his yet

Still hating.....

 

[Harleysboss]

Sweet little pea shooter you have there. Willfish, was Mr Hoyt able to mill the bend out of your barrel? Probably not. Why dont you contact him and just have it delivered to my house. Those are going to be fun!

 

[Willfish4fud]

Sweet little pea shooter you have there. Willfish, was Mr Hoyt able to mill the bend out of your barrel? Probably not. Why dont you contact him and just have it delivered to my house. Those are going to be fun!

Not you too Harley!
Y’all are killin me. And Lewis’ is bored off center I’m pretty sure

 

[Harleysboss]

I'm sure of it

 

[WVAED]

I love this project. I have a Seneca in 36. My bore is excellent, so I won't be getting it rebored, but I will keep my eyes open. Neat project.

 

[Ninering62]

Still hating.....

TE="Idaholewis, post: 272609, member: 20775"]
Put back together and ready for it’s Maiden Voyage This one has the Seneca Tang Peep, and of course i added a Lyman 17 Globe so i can use my Shaver’s BPCR inserts. I bet there aren’t many 1:37 Twist .40 Cal TC Seneca’s around? I only know of 1 other, But he hasn’t gotten his yet

[/QUOTE]
I just completely inadvertently ran across this thread this morn. Really cool to see & read your & Lewis' posts about the Seneca's. I was a fan & follower of IdahoLewis on Youtube way before I ever found MML. But I didn't put it together until I watched his YT vid on his fast twist .36 & its issues. It was super cool for me when I finally made the connection. I had to hit Lewis up & tell him & introduce myself. Awesome dude. So, I'm guessin this is " my new baby "? Well I'm happier than Liberace' with a whole piano pull of peckers. This is an amazing adventure unfolding for me. Much appreciated. Kind regards