I just purchased a very nice Marlin 375 Winchester from a good friend who had two of them. I assume all the 375's had microgroove rifling. Do these rifles handle cast bullets well? I've been shooting Sierra and Hornady JFP's, but really like using cast bullets in my lever guns. Any help appreciated.

longhunter,

Yes I believe all of the Marlin 375's came with Microgroove rifling. They do handle hardcast well but need to pay some special attention...see the posting below about cast bullets in microgroove.

I had a heck of a time with my 375 until I finally got all of the copper fouling out. Thanksgiving weekend 3 years ago I spent most of the weekend cleaning mine and it still wasn't clean. Finally resorted to a method I read about online somewhere involving vinegar and peroxide. After 3 treatments of this concoction I realized what a clean microgroove barrel really was! Didn't even know that copper fouling was the problem until I saw the color of the solution that came out of the barrel. (Be sure to pay close attention if you ever try this cleaning method as it can damage the barrel if you get distracted. PM me if you are interested). I notice that mine picks up some lead but it comes out easily. Firelapping can improve things too. I picked up 60 fps with my loading for the 250gr BTB after that procedure. Every cast bullet I've tried has worked well.

Nice rifles...wish I had 2...more...

I had an email last week from someone who wanted to hear about the vinegar and peroxide cleaning procedure but I got too quick on the delete key and lost the message, so will describe it here. Be aware that this procedure could cause harm to your favorite shooting iron if you don't slow down and take your time. Don't blame me if this happens...I'm not even suggesting that you try it, but only that it worked for me with no apparent harm. The guy that described this to me told me that he left it too long at first and had some very light rust to deal with. I was desparate and took the chance. You're on your own.

Put a rubber or cork stopper in the chamber end of the barrel. Make sure it fits good and tight...don't want any of the solution getting back into the action or you'll be learning how to disassemble your rifle real quickly! A Marlin is probably a lot easier to work with and I would suggest removing the bolt, lever and ejector spring. This solution is pretty corrosive. The person I got this from warned that leaving the solution in the barrel longer than 15 minutes or so will result in a light coating of rust over the entire bore. I elected to be on the conservative side and limit my soak times to 5 minutes. You'll need something that you can use to "hose" the bore down after you're done. I bought a water bottle that's intended for watering flowers that are hung up high. It has a hooked spout that just happens to be about 375 caliber...works great. Mix a 50/50 solution of vinegar and peroxide. Use a beaker or small measuring cup to carefully pour it down the barrel. A small funnel would be an added safety feature. If any of this stuff gets on the bluing you'd better be getting it off cause it works fast. Within a few minutes after pouring it in you should see some bubbles, although not really active. Dump the barrel out after about 5 minutes and flush with water. Then swab the barrel out good. Repeat as necessary...the color of the solution should tell you something about how it's working. I got gray stuff out the first time, then bright green, and finally lightly tinted green on the 3rd time. One more time might have been ok but I was wanting to start cleaning/oiling ASAP by that point.

I'm not a chemist so I don't really know how this works. Maybe someone else here can explain how a solution of acetic acid and hydrogen peroxide reacts with lead or copper...or steel.

This solution is an excellent penetrant and will settle into screw and barrel threads quickly. Rust to the point of thread failure is possible. This solution is talked up in muzzleloader cleaning and breech plugs have failed from repeated uses.
Work fast and neutralize that concoction and you should be all right.

Not to take the thread off too far on a tangent, but I noticed an ad in the last issue of Handloader for some stuff called CopperMelt. It's talked up at www.coppermelt.com. Has anyone tried it? The risk of the vinegar/peroxide mix might make $30/bottle a worthwhile investment if it works.