? On loading 357 mag,360 DW

Hunterreed

Ten Pointer
I got some 360 dw brass to load for my 357 mag handi rifle being it's one that has the extra chamber space for it. My main goal is to have the longer case length and getting bullets closer to the rifling as I am dealing with the long forcing cone issue and have not reamed it out. I have magnum powders for the hot loads that are listed for 360 dw but I have been all over the internet especially graybeards looking for lower velocity loads for cast bullets. I have a good bit of green dot,herco and small rifle primers and have always loaded 357 mag cases but would like to see if these lower pressure loads will become more accurate getting them closer to the rifling. Any reason I can't use 357 mag charges of herco,green dot in the 360 dw case to get cast bullet velocities?
 

45/70 hunter

Old Mossy Horns
Contributor
I'll try to remember to check my reloading books tonight. I believe there are some 360 DW loads in there. The H&R factory 357 Maxi I had shot 357 Mag ammo very well despite the long jump. This is a 50 yard group.
 

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Hunterreed

Ten Pointer
Hopefully an actual 360DW user will chime in, but I found some cast load data here:


You may check out the cast boolits forum for help as well.
Thanks I definitely bookmarked that page. Shooting through an 18 inch barrel I have to calculate the extra velocity with handgun data so I don't start leading the barrel but even that gets complex with different hardness bullets. I got several hundred acme cast bullets that I believe are in the 16 hardness range that may withstand up to 1400 fps. I know a lot of straight wall rifle cartridges are very forgiving with fast burning powders when working with subsonic loads plus I'm only working with an additional .2 inches of case capacity. That seems marginal considering the seating depth difference between 125 and 180 or heavier bullets used in the 357 mag. I know a member on here has posted about owning a few handi rifles even 357 maximum before and was wondering if anyone else has tried these faster burn powders.
 

Hunterreed

Ten Pointer
I'll try to remember to check my reloading books tonight. I believe there are some 360 DW loads in there. The H&R factory 357 Maxi I had shot 357 Mag ammo very well despite the long jump. This is a 50 yard group.
From what I have learned the problem with the 357 mag models is the forcing cone is so long that before the bullet gets to the rifling it gets yawed around slamming against the cone and deforms before the rifling straightens it out. The real fix is reaming to max length to eliminate the long cone but I am going to try the dw first. The 357 max models may have eliminated that issue because all my research online they give the best accuracy with all the shorter cases. This gun is the older 058 topper model I bought new in the 80s that I have had to tinker with the forearm and polish the locking plate in the reciever but just can't give up on it. I think I seen some of your rifles in post on here,some really fine looking pieces
 

45/70 hunter

Old Mossy Horns
Contributor
From what I have learned the problem with the 357 mag models is the forcing cone is so long that before the bullet gets to the rifling it gets yawed around slamming against the cone and deforms before the rifling straightens it out. The real fix is reaming to max length to eliminate the long cone but I am going to try the dw first. The 357 max models may have eliminated that issue because all my research online they give the best accuracy with all the shorter cases. This gun is the older 058 topper model I bought new in the 80s that I have had to tinker with the forearm and polish the locking plate in the reciever but just can't give up on it. I think I seen some of your rifles in post on here,some really fine looking pieces
Pics man pics!!
 

Hunterreed

Ten Pointer
Definitely a work in progress, I used to have a red dot on it so I haven't camouflaged the scope yet that I pulled off an old 30-30. Twenty gauge barrel came with it. I like hunting with it because it's short and has a good balance. I have shot some deer with various loads from hot 357 soft points to low velocity wad cutters it just hasn't reached it's full potential as a accurate 100 yard plus firearm yet. I'm starting to think that other than someone like me that's trying to solve accuracy problems with the 360 dw that no one has a need for less than full power loads in 360dw or even 357 max. Most firearms that shoot 357 mag accurately just use it for lower velocity loads instead of loading down the 360dw because I haven't found any published load data other than the slower burning magnum powders 20220922_164442.jpg20220922_164642.jpg
 

Hunterreed

Ten Pointer
Notice the gap between the black plastic piece on the forearm and receiver. That piece was tight before I cut relief into it. Every time the rifle was breached and closed it would bind and had a big impact on accuracy. Just about drove me mad until I started reading about issues on greybeards and started shooting without the forearm. Now I have an o ring between the forearm and barrel also and I get groups at least. Just got to tighten them up a little to be confident past 75 yards
 

45/70 hunter

Old Mossy Horns
Contributor
Just looked, the only cast data I have for green dot is 357 mag. Never seen a spacer with a gap like that. When I have one that is tight I wrap sandpaper in a deep socket and sand it some.
 
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