Sucess...finally!

[pdawg_shooter]

I traded for a Marlin 336 in 30-30 awhile back and have been looking for a light bullet load for critters around the house. Haven’t had much luck with my favorite 311466, grouping around 2 ¾ to three inches. Then I remembered one other micro-groove barrel from years ago. So I flat pointed about 30, sized them down to .302 and patched them up like usual…except I used 20# paper instead of 16#. Let dry, lubed and run them through a .311 die and loaded them over 33 gr. AA2520. Success! Groups dropped to around 1 ½” Guess a fellow just has to keep trying.

[edwin41]

wow , thats a great improvement !
you got this by just changing the paper , have i read this correctly?

i didn t realise that a little different paper made such a difference !

[pdawg_shooter]

Yep, If I remember correctly, Those 12 lands and grooves took a thicker paper and a tight fit to get it to shoot well. BTW, the lube was straight JPW and the final size was .312.

[Nobade]

Interesting that it worked so well. Usually the bore on a microgroove 30 cal. is about .303" That thick paper must keep everything going straight.

I have been shooting the RCBS 150gr. cowboy boolit, sized to .303" and patched to .310" in my 336 with very good results. 30.0gr. IMR 3031 plus enough filler to make a lightly compressed load.

The nose on that boolit is .300" and it rattles down the barrel unless patched. Shoots terrible naked in microgroove barrels. Works great in normal 30 cal. though.

[pdawg_shooter]

The bore on mine is .3015, so I size .302. I think that micro groove barrels are harder on the paper. The thicker paper holds up better.

[Haggway]

I will be writing this tip down. I plan on doing the same for my 308 marlin.

[geargnasher]

Pdawg, my 336 is also a 12-groove but has a .303" bore similar to Nobade's. It also has a .309" groove and shoots well with .304" boolits patched to .312" and run thorough a .311" sizer. Wet Meade sketch paper does the trick with that one.

Edwin, it's all about getting the right balance between core size, patch thickness, and loaded case neck diameter and the gun's dimensions.

Gear

[edwin41]

well gear,
i think i have the core diameter and neck diameter variable , so the testing can begin