Zebulon said
Before I forget to ask, what is the height of the replacement front sight you installed?
I've put a receiver sight on a new 86 45-90 but haven't sighted it in yet. I know it's going to require a higher front sight.  The barrel is 2" longer than yours and is an octagonal of larger diameter at the muzzle, so the same would probably be a little off.  However, it would be a place to start..
  

.41

I've put a receiver sight on a new 86 45-90 but haven't sighted it in yet. I know it's going to require a higher front sight.  The barrel is 2" longer than yours and is an octagonal of larger diameter at the muzzle, so the same would probably be a little off.  However, it would be a place to start..

This is more of a proof of concept than anything, have $100 in it all together.  

BTW, I'm late to this conversation, so wanted to get in my 2 cents about slugging barrels.  I believe it was in Wal-Mart I picked up some pure lead "bullet weights" that are, in fact fishing weights shaped like a truncated cone with a hole down the center that you can push monofilament through if you're using it for fishing weights, but obviously not useful for our application.  They come in small plastic bags hanging with the other fishing weights, so you can get whatever diameter you need to push through the barrel of your rifle.  I used them for slugging the barrel of a bolt-action benchrest rifle I was building, and they worked quite well.  That was .30 caliber, and I don't recall if they had large enough sizes to slug a .45, but they probably do.    

Dave M. said
Bert,
I pulled one of the Remington bullets, and it's 200 grain. It looks just like a 35 Rem core-lokt bullet.
So I'm assuming it's a Rem. 200 grain core-lokt bullet they loaded for the 348 Win.
  

Not a surprise... based on what I have observed, the factory 200-grain load was the most popular with the people who shot & hunted with a Model 71.  The 250-grain loads were a bit on the stout side, and only popular with the fellows who routinely hunted in the northern regions of Canada and Alaska.

Bert

Dave M. said
What bullet did remington load for the 348 winchester, back in the day?
The LGS gave me a half box of Win. 348, 200 grain Silver tips. But there's also 10 factory Rem 348 shells in the box.
I'm going to pull a bullet to see what weight it is. And it looks like a core-lokt bullet.
  

With the wide spread of possibilities you should be able to weigh the cartridge and determine the bullet weight. OTOH if there's any doubt about them being factory loads pulling at least one is a good idea. If you are looking for factory rounds I believe Winchester made a run recently and they will likely be scarce again before long.

Mike

I pulled one of the Remington bullets, and it's 200 grain. It looks just like a 35 Rem core-lokt bullet.

So I'm assuming it's a Rem. 200 grain core-lokt bullet they loaded for the 348 Win.