Reaming Marlin 336 35 Rem. throat?

[GrizzLeeBear]

Been shooting the RCBS 35-200-FN bullets in my 336 and it has the usual short throat so I have to seat the bullet to crimp on the top of the 1st driving band. Has anyone reamed the throat on one of these deeper so you could seat it to crimp in the crimp groove? This would put the base of the bullet about right at the base of the neck too, so you wouldn't have to push the bullet down into the powder space like I do now.
I am a new caster too and am learning as I go with this rifle. One other thing I found out is I have to pay more attention to making sure I have the mold closed tightly when casting. I had 2 or 3 round that I had to put a little pressure on the lever to get it closed. I also had 1 that I could not close the gun on. When I pulled the round out I could see the obvious land marks on the sides of the nose. Upon closer inspection the bullet had very prominent seam lines and the land marks were on the sides 90 degrees to the mold seams. I haven't measured it, but I'm sure I will find that the bullet is fat in that direction.
I also shot some Lyman 358156 with the same powder charge in it as well. These shoot great in it as well.

[felix]

GLB, the more you shoot the gun, the more the throat will wear in. Therefore, if you plan on shooting this gun often, like 1K or more per year, then don't alter the throat. Instead, find a size die that you can use to squish the nose by sizing nose first, and do so just enough to seat the boolit correctly. Take your time. ... felix

[uscra112]

If that's a Microgroove Marlin, don't reduce the nose too much. The Microgroove needs at least 65% (mo is betta) of the length at full grove diameter. There's not much land for a bore-rider nose to ride on, and the boolit will leave the muzzle cockeyed. I agree, however, with felix - don't go reaming that thing out. It's real hard to put that metal back if you decide it wasn't the right thing to do after all.

The .30-30 Marlin does benefit (so I've read) from making the leed taper shallower. I haven't seen the same suggestion for the .35 Rem however.

Slug that barrel, so you KNOW what the groove diameter is. You may be trying to fit a boolit into that throat that's larger than it needs to be.

[Boomer Mikey]

I shoot lots of RCBS 35-200FN's, It's a great bullet in many applications.

It's easy to overlook a small speck of lead on the surface of the mold blocks holding them open slightly or attached to a burr on a cavity edge. I use leadaway cloth material and wipe the mating surfaces of the mold to minimize specks sticking to the surface and clean any spots from the mold with a small piece of that material clamped in a pair of hemostats while the mold is hot. Avoid getting the chemicals inside the cavities. This works well on the sprue plate and mold top too to prevent lead smearing on those surfaces. Many use an artist's graphite lead too.

felix knows what he's talking about, I wouldn't consider throating it either.

Another easy method to try... spray the nose of the cavities with some moly mold prep - lightly - cast a few and measure the difference in the nose diameter of a cooled bullet. Add more spray to the nose area to reduce the diameter until you get what you want, wipe the mold surfaces clean, you only want the mold prep in the nose of the cavities . A little orderless mineral spirits on a Q-tip will remove the moly when it is no longer needed or desired.

Boomer :Fire:

[GrizzLeeBear]

Thanks for the replies guys! I think I'm going to leave the gun alone. Its shoots good the way it is with both the 35-200 seated deep and the 358156 (if it ain't broke, don't fix it!). Just wanted to see if anyone has had any good/bad results with lengthening the throat. I may try to get one of the Ranch Dogs 180 gr. GB molds in the future.
Uscra, I have slugged the bore (at both ends) and size the bullets to .358. I get NO leading. Like I said, most of the loads cycle through it just fine. Only a few "fat" ones where I didn't get the mold closed all the way give me trouble. No problem, I will just sort the bullets out and use the fat ones in my .357 Herret Contender barrel. It has a real long throat. I use the 200 grainer for IHMSA ram killers.

[Marlin Junky]

If it's a new RCBS 35-200FN, the alignment pins may be out excessively thus preventing the mold from closing all the way in the nose area.

MJ

[uscra112]

Gee, that doesn't say much good about RCBS molds! Getting the pin alignment right is child's play with modern CNC machine tools. Have you actually seen this?

GLB: If an oversize boolit won't go in properly, but a correct one does, you've got a pretty decent fit. Life is good.

[Marlin Junky]

Gee, that doesn't say much good about RCBS molds! Getting the pin alignment right is child's play with modern CNC machine tools. Have you actually seen this?

If I haven't seen it for myself I wouldn't say it. It's no big deal to tap the pins in a little to suit one's individual needs. When I called RCBS a couple years ago about this "feature" on a 35-200FN they said the pins are out a tiny bit to allow for alignment hole wear.

MJ

[GrizzLeeBear]

Guys, I'm sure its not a mold pin problem. I finally got around to measuring a bunch of the bullets and the offending one. I sifted through the container of a little over 100 of these that I cast so far and pulled out any that had easy to see mold lines. The majority of the bullets have little or no seam lines and measure .348 - .349 (90 degrees to the seam) just ahead of the driving band. Ones with a well defined but very thin seam line measured .349 - .350 (there were only a few of these). I could not find any that were fatter than these.
The one that would not chamber in the gun measured a whopping .356! No wonder it wouldn't go in! You can easily see the vent holes on this bullet, they appear as dots along the seam line. On the fattest of the bullets that are .350 across the nose, these dots are just barely visible or not at all along the seam. Now that I know what to look for, this will be easy to spot when I am culling the bullets after casting or when sizing.

Uscra, I think you are right. I think this bullet is about a perfect fit in the nose for this gun. I just need to pay more attention to getting the blocks closed tight every time and make sure the surfaces are clean. I'm still a nubie at this casting stuff, but it sure is fun!