358 Win. heavy loads - 235/250 grain.

[OFFSHORE]

I recently have built a 358 Winchester rifle on the T/C Encore platform and it is solely going to be a cast boolit shooter. The mold I have chosen for this rifle is from Tom at Accurate Molds. . .the 36-240K. This is a gas checked boolit and my beginning alloy is 30:1 COWW/Pewter coming in at 235.8 grains. I am looking for an accurate yet speedy load for this bullet. Powders I have for this case (I shoot A LOT of .308 Win) is IMR4064, Varget, RL15 and then I have some faster powders I use for my "hand cannons" which is AA1680, RL7 and VV N120. These are just powders I have on hand that "may" work in the 358Win case, I am open to any other suggested powders for this weight class bullet. If you have any load data you wish to share please do, and I look forward to looking it over. Thank you.

PLEASE - lets stick to the targeted bullet weight in question. I have read an awful lot of load data for the 200 and 225 grain bullets. . .I would just like to focus on 235 gr. to 250 gr. bullets and their performance and load data. Please and thank you.

[Beerd]

I shoot that bullet in a .356 Win.
With my alloy it weighs 245 grains, checked & lubed.
Best results so far in my rebored Marlin have been with IMR4064 with BL-C2 & Varget tied for second.
..

[oso]

How long is your barrel? What do you consider speedy? My format is an Argentine Mauser re-barreled at 17.75". I reviewed my notes with 2 of the powders you mentioned.
RL15: Using a Hoch GC nose pour 233 gr seated to the lands my best accuracy 10 shots off sand bags 1.5 - 2 MOA @ 200 yds, worst was 3 MOA, using 39 - 40 gr RL15 max I tested. This was done quite a while ago by a much younger me.
Using same loading with a Saeco 242 gr GC did not group as well as the Hoch.
RL7: Less extensive notes with RL7 at 31 - 32 grains max tested showed the Saeco 242 gr grouping better at 2.5 MOA than the Hoch 233 gr grouping 3.5 - 4 MOA at 200 yds.
I did not generate enough data with RL7 to draw any conclusions but velocities with both propellants seemed comparable. Too many other powder choices (wish I had more 3031 and 322) - not enough time. No short cuts - work up your own loads carefully!

[OFFSHORE]

Thanks for the reply guys! This started out as an MGM 26" SS 338 Federal barrel. It has been sent off to JES for a 358 WIN rebore 1:14 twist, barrel cut/re-crowned to 23" (couldn't decide between 22" or 24", so I settled). I'm a woods/swamp hunter, mostly in a tree saddle or some sort of elevated stand, but some areas I hunt I can pull off a 200/250 yard shot. By "speedy", I would like to achieve 2250+ FPS in a accurate load. I have access to MANY types of powders, I would just like to get a good reference point for this bullet weight to start at in a cast bullet with this velocity target. I have a friend out west who mostly shoots a 35 Whelen (I know, totally different animal) who feels the earth sun and moon revolve around VV N135 as a "The" powder in these two 35's. I'm open for anything to start out with.

Beerd - I would be interested in your load data and velocities with IMR4064 in your .356 Winny. PM me if you would prefer. Thank you.

[farmbif]

both 4895 and accurate 2520 might be a couple candidates get you where you want to be

[brasshog]

I'm following this thread. I am waiting on my 358 re-barreling to be completed so I don't have any loads worked up at the moment but I am gathering data. Once I can break away from work I'll lookin the shop at the three lyman manuals that recently came in and see if there is anything there for you.

[OFFSHORE]

I'm following this thread. I am waiting on my 358 re-barreling to be completed so I don't have any loads worked up at the moment but I am gathering data. Once I can break away from work I'll lookin the shop at the three lyman manuals that recently came in and see if there is anything there for you.

Sounds good, Brasshog. Panhandle caster. . .I love the area from Chipley on up through into Alabama. PLEASE - keep me posted on your findings on this boolit and I'll do the same once I get crank'n.

[NyFirefighter357]

[Beerd]

re: .356 Win & IMR 4064

loads were developed from published Hodgdon .358 Win data with 250 grain bullets.
maximum listed load (44.0gr) reduced 10% or 39.5gr for starters.
I found 41.5gr to be most accurate. never went over 42.0 in my levergun.

chrono numbers will be coming later this spring.
..