Chamber casting Marlin 336

[archeryrob]

I am having a lot of issues trying to find out how is the best way to cast the chamber for these lever actions. Bolt I just break it down and can cast the barrel. Can even pound cast it in a filled case and then sloowly tap open the bolt and tap it all loose and out. Cerrosafe is simple in these too.

I am not sure I can pound cast lever action. Can I just lightly open the lever while tapping the top of the cast when finished? I don't want to stick it or break the extractor. I am really not looking forward to pouring Cerrosafe through a tube into the chamber as it looks like a lot can get messed up, or just spill in places you don;t want it to be.

I have everything to cast and reload 30-30 except my chamber dimensions. How is the best way to get them in a lever action?

[Mk42gunner]

As long as you pre-warmed the tube from the funnel, and watch what you are doing; I don't think it would be too hard to do a chamber cast on a Marlin.

With that said, I took the easy route with my .30-30 Marlin. I just started with boolits sized to .311". They worked fine for me and my carbine, I never looked any further.

Robert

[jim147]

Can I ask why?

[Tom Myers]

Maybe this will help

Cast Bullet Design Help files:

View the complete on-line Help File for the Cast Bullet Design ~ Ultimate software

Then go to this page in the help files:

Chamber impact Impression

Hope this helps.

[archeryrob]

Can I ask why?

Sure, because I was told to match my bullets to my bore. Also was told trying to seat bullets closer to lands gave better consistency shooting.

Thanks Tom, I think I will follow that and its the first reference I seen of anyone using it in a lever.

HK42, I planned to PC my bullets and resize back to 309. I'd have to size back to 311 anyways, but if the bore is 308 doesn't the extra two thousands have negative effects?

[popper]

I just started with boolits sized to .311" Same here, cast, GC or not & PC, then size. Works fine. Most marlin 336 bore are tight under the roll stamp and front sight. Most chambers are on the large size. Expand the neck ~ 2 thous. flare mouth slightly and load some cast for a dummy (no powder/primer) till you find the seating depth that feeds and chambers best. Face it, your sizing die is NOT the same as your chamber. You can send some fired full load factory cases and a bunch of $$ to get a custom die made - for a 336? Not worth it.

[jim147]

Ok i was wondering if you wanted you chamber for brass sizing or bore for boolits.

Pound some soft lead down the bore. And as for .309 or .311 you just need to try it and see what works best.

[Mk42gunner]

The nominal groove diameter for commercial .30 caliber rifles in the U.S. is .308", however Marlin's microgroove rifling tends to run a bit large. I don't remember now, but I probably slugged the bore and decided to go with the on hand .311" rather than spend money on a new sizer. Money was a bit tight then.

Plus I was already using .311" for my military barrels in 7.62 NATO (read that as .308 Winchester) and also for my H&R Model 158 in .30-30. I tried it in the Marlin and it worked.

My go to size for most .30 cals is .311". Only if that doesn't work do I try anything else.

Still haven't got around to getting a .309 or .310 sizing die. Maybe one day.

Robert

[RickinTN]

I wouldn't fool with a chamber cast. A pound cast of the throat could be beneficial as far as bullet shape and diameters at different spots.
I've worked with several Marlin 30-30's from the middle 40's through the early 80's versions and the one thing they have in common is that they will all shoot a .310" bullet fairly well. I have found the design of the bullet to be more important than the size.
Good Luck,
Rick

[MostlyLeverGuns]

You can do a lot of fussing with pound casts and cerrosafe, but for most .30 cals I start with a .310 as long as chambering is not an issue, seldom is. With lever guns that are fired from the magazine, overall length is restricted by the what the action will handle, probably 2.55" in a Marlin 30-30. Most molds designed for the .30-30 work quite well this way. With the Marlins, .310 or .311 should work well. The are many theories on how to find an accurate load, but shooting is the ultimate test. Once you are grouping under 2" at 100 yards, tweaking the rifle, learning bench technique that works for you and the rifle, then, maybe, a fatter nose on your bullet or other experiments can make groups smaller. Even single loaded, unfired cartridges need to extracted/ejected sometimes so Cartridge Overall Length (COL) is still limited by the rifle. In the Marlin 30-30, the Lee 150 and 170 flatnoses, the RCBS 180 flatnose or the NOE clone and the 31141 style from NOE, Accurate, Arsenal all work well.

[popper]

Marlin doesn't have much if any throat. You want to match the chamber, not the bore. You have to watch the seating depth so you don't have to jam the bullet into the bore - very hard on the lever locking lugs.

[uscra112]

Hopefully Outpost75 will see this thread. He published a couple of articles in the Rifleman 30 or 40 years ago about Microgroove barrels and the .30-30. I still have them somewhere. Bottom lines are yes the Microgroove barrels like bullets that run .310 or even .312, they don't like bullets with a long bore-diameter nose (311299 for example), and yes, the leade specified for the standard .30-30 reamer is too steep - they benefit from re-throating.