Marlin 30-30 mold

[texasboar]

Was wanting to know which mold would be best for accuracy since the Marlins have oversized bores for the 30-30
This is a new gun with the micro groove barrel.

Thanks
TexasBoar

[WHITETAIL]

Texesbore, Welcome to the forum!:drinks:

[WHITETAIL]

I have had good luck with the Lyman 311041.

[runfiverun]

me too...... welcome.

[DLCTEX]

I'm casting Lee's 311-170 fp and using it with good results in my Marlin. It engraves the bore riding portion and sometimes requires a firm squeeze on the lever to close the action on a round. WDWW, I size them .311, gas check, and load them ahead of Reloader 7. I crimp with a Lee FCD to prevent pulling the boolit due to engraving.

[grumpy one]

I think the main implication of the oversized bore is that you will probably have to lap a mould to get decent accuracy.

My journey, which featured a Marlin 336 with an extremely oversized and very rough bore (even though it was new at the start of the journey - the barrel was made rough at the factory, and should have been thrown in the scrap skip) began by slugging the barrel to find the required size of both bore and groove. I tried a few bullet moulds, both round and flat-nosed - 311291, 311255, Lee C309-170F, RCBS 150 FP - and quickly found that the Lee was the only one that seemed to have promise. It is a bore-rider, so I lapped the nose portion to be slightly larger than the bore, as well as lapping the drive bands to be slightly larger than the groove diameter. The mould started, and finished, somewhat oval; this seems to be common with Lees.

When you slug the barrel, check for variations in diameter. Mine tightens very slightly in two places: where Marlin have rolled the barrel to embed the whole owner's manual on the right side just in front of the breech; and where they did something regrettable whilst attaching the front sight, thus squashing the barrel vertically a bit.

You may or may not find that the Lee gives the best results in your Marlin. Based on my results it seems worth trying; I've had quite a few 55-yard groups of around 0.6 inches from it, while I've never done better than 1.3 inches with anything else. The bullet design seemed to make even more difference than how well it fitted the barrel.

[Maven]

TXB, I don't know whether the Marlin #336 .30-30Win. Microgroove bores are oversized or not, but I got outstanding accuracy from two CB's, not usually associated with the .30-30: Ideal/Lyman #311466 and Saeco #315. Both were sized to .310" and were plenty accurate. You can try .311", but I got better accuracy with the smaller diameter. Btw, I use these CB's in my .30-06, but size them to .311", which leads me to believe the Marlin bbl. isn't oversized at all.*


*I also have a #336 Marlin Microgroove in .45-70 and size to .459" .458" is accurate, but .459" is better. Does this seem oversized to you?

[texasboar]

Thank You for all the replys I am new to this game so I am sure I will have a bunch if questions.

Cant seem to find the Lee's 311-170 fp mold on there site just a 309-170


Thank You
TexasBoar

[mroliver77]

My Marlin MG likes boolits sized at .310. With the MG the nose riding section on the nose riding boolit must be bigger to make up for the rifling being shallow, I have a Lee group buy 311440 that came with a .302 nose. My Marlin loves this boolit! It really shines with non bore riders if one can be found that is set up properly. I have an LBT 150gr that does well in this gun also. My Marlin does not have a conventional throat but what could be describes as a "funnel" The starts at the neck size of the loaded round and tapers to the "bore" size very abruptly. It will shoot though when the right combination is found.
Jay