Throating a Marlin 336 in .35 Rem

[MtGun44]

After not being able to chamber the RD 190, which I believe was specifically
intended for the Marlin, due to too short/tight a throat, I tried some Remington
factory ammo. Even this will barely close, marks the 1/16th" of bullet just
ahead of the brass all the way around, almost can't close. I had a bit of
problem with Lyman 358315, too. So far, this gun won't digest ANYTHING
without a really hard push on the lever at the end. The factory ammo is
the final straw for me.

So - I am contemplating renting a throating reamer from ReamerRentals. The
cost is only $15. Any advice from those that have done this job.??

I haven't tried this before, not sure what the driver is like, not clear in the photo.
I assume hand driven, but what does it need to apply fwd pressure and
turn it? What lube is recommended - I'm thinking a tapping lube.
I just want to cut enough to chamber the factory ammo and probably the
RD design, if that doesn't involve cutting too much metal.

Any advice will be greatly appreciated.

Bill

[Mk42gunner]

Bill,

I have never used a throating reamer, but have hand chambered four or five rifles from short chambered barrels. The cutting oil I used at the time was Brownell's Do-Drill, which I am reasonably certain is just repackaged high sulfur content cutting oil.

I used a tap handle to drive the reamer, but I also did it with the barrel off the action. The chambering reamers that I used had a 3/8" square that fit easily into the tap handle, ask what type of extension you will need when you order the reamer.

As short as your throat is, are you sure the headspace is correct on your rifle? I know I have read many many times about the short throat on Marlins in .35 Remington; but it wouldn't hurt to check with a headspace gauge, or at least make sure the rifle will digest an empty case.

Chamber reamers, at least the new ones I used, will practically pull themselves into the barrel. You probably won't need to apply pressure to get it to cut. I would recommend checking progress every few turns (like one or two turns) of the reamer with dummy rounds. It is easy to ream more, but pretty hard to put rifling back if you go too far.

If you have more questions, feel free to ask.

Robert

[Piedmont]

You might consider fire lapping this one with cast bullets rolled in lapping compound. It can't hurt. It will likely help the rest of the barrel and it certainly can wear the throat a bit.

[MtGun44]

I don't trust fire lapping to do what I want and where I want, too random for me.

Bill

[Piedmont]

I don't trust fire lapping to do what I want and where I want, too random for me.

Bill

I wish I could show you the throat in my .45-70 Marlin after I fire lapped it. I think you might change your mind. It always cuts most aggressively in the beginning, then at any tight spots further down, like bands, hangars, and sight attachments. I speak only of cast firelappers rolled between plates, not the jacketed kits.

Something else you could do is get a Lee factory crimp die and just seat the bullets a bit deeper and crimp wherever you need to to allow easy chambering. If you shoot the rifle a lot the throat will eventually wear anyway and allow you to seat out further but with mild loads that could be a long time.

[MtGun44]

IMO not being able to freely chamber factory ammo is a problem that
needs actual gunsmithing. I have no problem with firelapping to polish and
smooth a bore, but I need to remove some metal in the area about 0.10 in
front of the chamber and nowhere else.

Bill

[largom]

I have throated several rifles using PTG reamers which can be adjusted, with a stop, for the amount of throat needed. I do not know if they rent reamers. They also sell a long "T" handle for use with the reamer. Very little "Finger" pressure is needed for the reamer to cut. Don't know if PTG rents reamers always bought the ones I needed. Do not have one for 35 cal.

Larry

[DeanWinchester]

***watchin this one***

Keep us updated. This one is close to home for me. I'd like to hear your results.

[JMtoolman]

Bill, when I ream the throat of a barrel, I take a fired case and cut off the front half of the case. Then chuck the rear in a lathe and bore a hole to match the diameter of the reamer shank. Carefully turn the reamer by hand, using the cut off case to support the reamer as a guide. Make a mark on the shank of the reamer about an eight of an inch from your starting point. Have an unloaded case with a bullet seated where you want it to be and check the cut with it. It really doesn't take as much to get it where you want as you might think. Good luck, the toolman.

[MtGun44]

JM -
Thanks for the tip. I already expect that this is like shaving - taking off just a hair and
making sure you don't cut too deep.

Bill

[roysha]

I had to do this in my 358 NM so I could chamber the 358009 bullet. I purchased a .355 chucking reamer from MSC and used a drilled out case with the neck and shoulder cut off as a guide. Hand turned using a tap wrench and lots of cutting oil.

Unfortunately, with any other bullet I have a LOT of freebore but since I don't plan on using any other bullet I really don't care.

[MtGun44]

I'd like to be able to use RD 190 and factory Rem, at least. I have a 358315 mold and would
like to use that one, too, but I will see how the process goes.

Bill

[uscra112]

I'm curious to know if yours is a Ballard-rifled barrel. I have my old dad's 336, which is an early Microgroove .35 Rem., and have never had any such trouble.