Trimming .357 max. to .360 DW?

[GrizzLeeBear]

I got a NEF Handi rifle in .357 mag. (the newer one on the SB1 frame) and it shoots well with the RCBS 35-200-FN and 15 gr. of Lil Gun in .357 mag. brass. I have read that these will chamber .360 Dan Wesson so I would like to try some in it to get a little more velocity. I don't want to ream it out to a .357 max. since it is on the shotgun frame. Problem is, .360 DW brass in not available. Has anyone made .360 DW by trimming .357 max. brass?

[2ndAmendmentNut]

I have never done it, but I have heard that you can make 360DW brass from trimmed 357max. Are you sure it is safe to shoot 360 DW in a gun chambered for 357mag? Just because it will fit does not mean it will be safe.

[GrizzLeeBear]

2ANut, I have seen lots of posts over at the Graybeard site (and elsewhere) by guys shooting 360's in the .357 mag. handi. From what I understand, the .360 runs at the same pressure as the mag, just has a bigger boiler room to get more power. Some have even rechambered SB1 mags to maxi, but I don't want to mess with the gun and the maxi runs at higher pressure.
I still have to do some measureing to see if 360 brass will chamber and I do plan to start at mag loads and work my way up though.

[leftiye]

Ream it out to .357 Max. The shotgun frame will handle 12 gauge? That's got more thrust on the breech than a belted magnum does (yup, do the math). Plus the .357 headsize is much smaller than the 30-30 headsize that also came on those SB1s. The Max. only runs at 52,000 psi. if you load it that way.

[357maximum]

Andy

Have you tried a piece of brass in her yet? I have seen 1 handi 357mag that was longer than 357max already...as issued.

If you need a few pieces of brass in order to know what you have ...just holler eh...I think I know a fella that might have a few pieces of rem stamped 357maximum brass kicking around.[smilie=s: :shock:

I personally wish 357UBER-maximum brass at about 1.9in was available...then I could do what I do in mine with a slower powder and at lower pressures than I currently run.:violin: I use N-120 as it is the only way I have been able to balance the speed I want with the accuracy I want....a little more room would change that.

and I REALLY REALLY wish starline made 357max brass....I have pleaded my case on deaf ears on that one. Remington brass in the max can be iffy on the quality end. I have 299 pcs of nickel fed brass...I guard that with my life and only use it for hunting loads.

Your nef sb1 frame will take whatever you can dish out...I would not concern myself with that at all. They run 280rems in that thing and as long as you did not get a soft pivot block (it happens) there is no issues.

[Blammer]

Trimming Max brass to DW is a lotta trimming.

I think the DW brass is a seasonal run thing. I picked some up when midway was sellingout of DW brass at $21 per 100. :) ok sorry for the gloating.

[rhead]

Use a tubing cutter to cut it to about a tenth long and then use your trimmer to true everything up. You will like the neck tension. Make sure that your chamber is one of the longer ones. I have heard that both sizes were released. I have never owned one that was not chambered for 360 DW. Measure your own chamber and do not trust to luck.

[GrizzLeeBear]

Hey, Mike! Nice meeting you and Matt this weekend. Thanks for the help.

Well I figured out a way to measure the chamber depth without any 357 max. brass. I have a bunch of .223 in the scrap bucket, so I cut a .223 off at the neck/shoulder junction. Ran it into a 30-06 die, then a .35 Rem. die (took several passes, lubing in between with each die) to open it up to .35 cal. Then trimmed it to 1.5" and chamfered and deburred. Then ran it into a Lee powder thru expander die to flare the mouth a little and finished it by running a short ways into the factory crimp die. This made a bit of an hourglass shaped case, but is the same dimension as a .357 case at the mouth.
As expected the 1.5" case was a little too long to chamber. Cut it back to 1.43" (was trying for 1.45 but trimmed it just a little too much) and tried again. Would almost go in, but wouldn't quite close on it. Cut it back to 1.41" and it went right in. So looks like the 360 would fit just about perfect.

After seeing you guys' comments, maybe I will ream it out to the max. If I have to buy max brass, why not use it, eh? I'll just try to keep it at .357 mag. pressures and take advantage of the bigger boiler room. Anyone have a reamer I could borrow?

[357maximum]

Hey, Mike! Nice meeting you and Matt this weekend. Thanks for the help.

Yes that was nice....you just never know when you are gonna run into a cast booliteer.

Well I figured out a way to measure the chamber depth without any 357 max. brass. I have a bunch of .223 in the scrap bucket, so I cut a .223 off at the neck/shoulder junction. Ran it into a 30-06 die, then a .35 Rem. die (took several passes, lubing in between with each die) to open it up to .35 cal. Then trimmed it to 1.5" and chamfered and deburred. Then ran it into a Lee powder thru expander die to flare the mouth a little and finished it by running a short ways into the factory crimp die. This made a bit of an hourglass shaped case, but is the same dimension as a .357 case at the mouth.
As expected the 1.5" case was a little too long to chamber. Cut it back to 1.43" (was trying for 1.45 but trimmed it just a little too much) and tried again. Would almost go in, but wouldn't quite close on it. Cut it back to 1.41" and it went right in. So looks like the 360 would fit just about perfect.

After seeing you guys' comments, maybe I will ream it out to the max. If I have to buy max brass, why not use it, eh? I'll just try to keep it at .357 mag. pressures and take advantage of the bigger boiler room. Anyone have a reamer I could borrow?

I would go with the max and never look back....the extra boiler room could make for some uber gentle launches at 357mag velocities with a slower than normal powder...

You should be able to rent one from reamerentals.com or something like that. Or you could buy a reamer ....I could borrow it in a year or so that way.:p

The offer stands if you end up needing some brass. if you have some excess 308 commercial or 7X57 brass kicking around.....might be able to do a swap for brand new or 1X max brass....I do have some in excess of my immediate needs[smilie=1

I even have almost 3 full boxes of original remington 357max j-word rounds....I will never fire them very likely: