My curiosity always seems to get the best of me and I couldn't wait to get the new Marlin 336 Cowboy Conversion out to the range. Every cast 30 caliber bullet I could find in my reloading supplies was loaded and taken to the range. Here are the results (DOUBLE CHECK ALL DATA! USE AT YOUR OWN RISK!)
The first bullets down the barrel were the Oregon Trail 170 grain laser cast .310" RNFP bullet. A load that has proven accurate in all (five) of my 336's is 5 grains of Red Dot powder did in fact prove be accurate in the 336 Cowboy Conversion too. Averaging 1047 fps it produced the best group of the day. This was also the only bullet in this session that was NOT gas checked.
The next load tested was the Lee C309-113F ("Soup Can") over 10.5 grains of IMR SR 4756. I use this charge in my 45 Colts (Ruger and Marlin) and has a dedicated powder measure with that charge. 30-30 data shows I'm well under max pressure and used it as a starting point. The load averaged 1652 fps and also hinted at promising accuracy.
The "Soup Can" bullet was also tested with 3.3 grains (.5cc Lee powder scoop) of Red Dot Powder. At 30 yards the accuracy showed promise measuring .740" under less than ideal conditions, sitting position, poor light, wind and rain. The velocity averaged 856 fps.
My expectation for the Ranch Dog TLC311-165RF was high. It too has proven to be an accurate bullet in my Marlins and it proved to be so again. The weather limited the range I could shoot but I suspect this will be the bullet of choice for Hunting and Silhouette.
My 30-30 silhouette load for my other Marlin 336 Cowboy is the 10.5 grain charge of SR 4756. The new Cowboy conversion averaged about 50 fps slower than my original Cowboy but looks like it will be equally as accurate - perhaps more so, I'll have to tell you when I go 10 for 10 on the 200 meter rams The average velocity was 1402 fps. For those who buy into formulas, using the Veral Smith wound channel estimate for this load gets almost .80" - not bad for a soft shooting load. Shot selection would be critical for adequate penetration - probably stick to archery angles. Ideal would be 1" up to 1.25" wound channel for fast anchoring of delicious deer sized wild critters.
I also use the Ranch Dog bullet over 5 grains of Red Dot for Grouse loads as it typically shoots very close to full powder Jacketed bullet hunting loads out to 50 yards or so. In this rifle it averaged 944 fps which makes for a nice soft recoiling and quiet subsonic load. At 30 yards the group, including the flier was a little over 1/2". Throwing out the flier the group printed into one enlarged hole. It should make easy work for Grouse - still have till the end of the year to try it... - and it is a fun inexpensive plinking load - the gas check and the primer account for most of the cost but I still end up in under ten cents per round, or $2 a box.
-My eyes appreciate that extra 4" distance on the front sight.
-That 4" is noticeable maneuvering around the house, meaning less than ideal for HD. We'll see how that translates in the field later this month.
-It does feel heavier than my 20" 336's. Nice for target shooting, might not be so welcome after walking around with it for a few hours.
-No leading was detected while cleaning the rifle afterward.
-The throat is a bit tighter than my other Marlins - except for the SDT (now owned by Pine Cone). The driving band on the Soup Can bullet does engrave on the rifling.
-Octagon barrels look cool.
-I expect this rifle will do well at long range. There is plenty of sight ramp left to reach out to 300 yards and maybe beyond. Balistic calcs indicate I should be able to hold right on out to nearly 400 yards with the top notch setting using the "soup can" load. That doesn't mean it will but generally they aren't far off.
-To get the estimated wound channel I want for deer hunting using the Ranch Dog bullet I need to find a load that will get me over 1800 fps. That will be the focus of my loading the next batch of RD bullets.
-So far I am very pleased. Marlin returned a rifle that is beautiful and more importantly accurate.