Marlin 336 358 Win and the 270 Bullshop Stomper

Awhile back I picked up a Marlin 336 that had been rechambered to 358 Winchester. At the time, we had just moved west, closer to the Bullshop home base, and I did not have any reloading equipment set up, so did not get to play with the rifle a whole lot. Today I was finally able to set back up my bench, and get some ammo produced and do some load testing. I swapped the 3x9 bushnell for a Lyman receiver sight and a Williams fire sight on the front. After digging through the piles of bullets laying around at the bullshop head quarters, the only ones I could find that were sized and lubed were a box of the 270 Bullshop design smashers cast out of water quenched wheel weights. I did try a couple of other bullets today, and shot about 200 rounds total, but had the best success with this 270 grain so that is what this post is about.


I tried 2 powders, but had better luck with older IMR4895 surplus powder. I started at 35 grains and worked my way up in .5 gran increments, stopping at 40 because I believed that any more then that would be pushing the physical limits of the rifle. With the Winchester primers, with both powders that I tried, and any charge I was having problems with double grouping and groups spreading out more then I was happy with. Switching to a CCI primer solved this. Surprisingly the Winchester primer gave a lower extreme spread then the CCI primer with the final charge of 40 grains. The Winchester primer gave a extreme spread of 6 with 3 shots, where the CCI primer gave 18 with three shots. The best group that I shot with the Winchester primers was right at about 2 inches at 100 yards with the peep sights shooting off of a bench and sandbags, and the worst at about 3.5". The CCI just kept shooting better and better the more powder I added, with my best group of 3 being .9 inches. I was able to shoot several groups in the 1 MOA range with this rifle and load using the CCI primers.


After getting the load worked up, I lined up six milk jugs full of water and shot them, and the bullet passed through all 6 and still had enough energy to embed itself into a cottonwood tree just over a inch. Shooting into dry red fir, I was able to get 18" of penetration with 193 grains retained weight. The one shot into the water jugs retained 238 grains.

One other issue I had, was because of how long the nose on this bullet is, I had to seat it a good ways inside of the case, and trying to crimp with a 358 crimp die, I couldn't get enough crimp on it to keep the bullets from setting back in the case during recoil while in the magazine. This was solved by using a Lee collet crimp die for 35 Remington which put a crimp ring about 3/16" of a inch down the neck of the case and firmly held the bullet in place.

Hopefully I will get to try this load on a bear or a deer this hunting season. On a side note the Lee reloading manual shows a load for the 358 Winchester with a 275 grain jacketed shooting at 2150, so I am not too far off of that mark.

A few photos of the load and some targets. All groups shot at 100 yards

5 rounds and the bullet recovered from the cotton wood tree after going through six gallons of water.



Best 5 round group with the Winchester primers.


Three unmarked holes in the center touching were with the CCI primer. Best group shot.


2 five shot groups. Ones marked were with Winchester primers, unmarked with CCI primers.