I have recently built a 3 barrel set for a Browning Lever Rifle. It started life as a stainless 300 win mag takedown. I purchased two additional 7mm Rem Mag barrels, and both headspaced as received. All three barrels would close on a go and a no-go, but none would close on a field. Headspace was checked with the extractor and ejector in the bolt head, I did not want to mess too much with a BLR. I intentionally made the barrels look very different from one another.
Jess at 35caliber.com rebored the 7mm’s, one to a 338 win mag and the second to a 375-338 win mag, aka 375 Taylor, aka 375 Chatfield Taylor. The 338 got a normal chamber, the 375 I had him cut a little longer, so that the cartridge overall length fills the magazine with just a little room to spare. All three cartridges feed and function fine. The factory 300 win mag feeds and ejects fine with 150 and 180 Nosler Partitions, over max loads of A3100. The 338 with 225 NP, max A3100, and 160 TTSX over very reduced H4895, also works fine. Currently working up the 375 with 300 triple shocks, 1.3 grains below what I consider max of RL-17, based on a Quick Load simulation. I need to part with the cash and buy a chronograph. My goal is 2500 fps with the Barnes 300 grain triple shocks. I will then work up a solid load.
The dies for the 375 are from CH4D, and size the cases to a good fit for my chamber. I start with new Winchester 338 brass, then trim to 2.490. I open up the 338 brass in two steps in a decapping die. First to 35 caliber, then to 375, I just use RCBS case lube. The cases shortened as I expand the necks. I have trouble chambering a case that is right as max of 2.5, so I will trim to 2.475 initially to get several reloads without trimming. The 2.475 length will allow crimping in the middle of a groove if needed. I then just lightly wash the brass, and bevel inside and out. Finally resize in the 375 Taylor die.
I really what to thank those that have given me advice and help.
For the future I have some properly headstamped brass on order, 3 to 6 weeks out. I might consider rechambering to 375 Ruger.

Link to photo:

BLR 3 barrel set

No photo visible; I recommend getting an Imgur account. It's free.

Taking a whack from Imgur:

Nice setup.

arneit,

Nice picture. May want to try 'postimage' for pix. So clean, easy to get started and no BS hoops to jump through. No need to sign in if you are at the computer you used to join/start your images. Beats Photobucket by a mile, better than imgur.

Just out of curiosity what made you choose the 375 Taylor over the 416 Taylor?

I stopped at a 375 for several reasons. First, the magnum contour barrels are really skinny, the muzzle at 0.607 or so, at 22 inches 0.623 and so on not a lot of meat for the 416. Second the ejection port is narrow at the front, and I had a concern with ejecting complete rounds. Third the BLR is light, and I didn't want too much of a beating. Last, I own a stainless 458 Lott in a Montana 1999 that I really like, even though it does beat me up some.