Heavy 357 mag loads

[crabo]

What powders are you finding that work best for heavy loads for 357 rifle? I am using a 180 grain gc.

13.5 of 296 is working pretty good, but I don't have a clue what it's velocity is. I don't have a chrongraph. Anyone have a guess?

Anyone have a guess what 7 grains of Unique behind the 180 gc would do also?

Thanks,

[felix]

Measure the cases just above the rim. Compare the two loads for expansion. That would give you a positive clue on what load you should choose for those velocities, whatever they are. You can decipher that by time of impact over a 100 yards. If you cannot tell with the naked eye, there won't be enough difference between them, so choose the lesser pressure load to preserve your cases. I suspect your Unique load is too much for case longevity. ... felix

[Jon K]

crabo,

What gun? Groove diameter?
I have been looking for the chrono data, but haven't found it yet. Results will vary a lot depending on your chamber, bore groove diameter.
7 gr Unique will not work if the groove diameter is tight, I seperated NEW Starline brass first firing. Same gun 6.7 gr will work with Win or Federal brass, but life is not long. Uberti 73 .356 groove diameter, RCBS 180 Sil, or Saeco #399, or Saeco #354.

Your 296 load, again depending on gun & specs will vary in speed. That is a good load though.

4227 works good too.

Best I can remember speeds for your 2 loads ranges from 1250-1370 fps. I will look around more for the data.
I did get more speed from Browniing 92, without over working the brass.

Jon

[imashooter2]

The RCBS Cast Bullet Manual lists 14.0 of 296 under their 180 grain silhouette boolit as 1,398 fps average from an 18.5 inch rifle.

I've been getting highest speeds with Lil' Gun and best accuracy with 2400 using the Lee C360-180-RF group buy boolit or the SAECO #353 plain base in my 1894C.

A couple data points:
Lee group buy, 14.9 grains of Lil' Gun, 1,703 fps average.
Lee group buy, 12.0 grains of 2400, 1,489 fps average. This is my accuracy load with the gas check boolit.
#353, 10.5 grains of 2400, 1,349 fps average. This is my accuracy load with the plain base boolit.

[crabo]

I was worried about the 7 grains of Unique being too hot, but man does it shoot. I have my gun set up with a 4.5x14 Luepold with a lace on cheekpiece for testing. I have been shooting at an indoor 50 yard range. It is an ideal situation for working up loads.

My groove diameter was measured at .3565, but these are sized at .359. I am using speed green lube, and I coat them with LLA after I install the gc, lube and size. I have found that the extra LLA step eliminates the leading while I am still slicking up my barrels. I didn't remember to check my brass after shooting the Unique load. I was too excited to think about it. I had been pretty happy with the 6.5 of Unique and HS6 until I tried 7 of Unique.

I want to try these at 100 yards, but haven't had the chance yet. This is a 180 grain Mountain Mold that I had made. It has a 73% meplat, secant, with a .325 nose. I had to modify the carrier to get it to feed the boolit. I lube the gc and the lube groove.

Imashooter2, I did not know that RCBS had that book out and looked it up on line. Is it worth the money? I have 6 books, but lack good cast data.

[Bass Ackward]

Quickload says:

7 gr of Unique is 36,000 for 1400 fps.

13.5 of 296 is 25,000 for 1500 fps.

This was for a 20" barrel and my 180 grainer. Muzzle pressures at bullet launch were about 2000 psi for the Unique, @ 4,000 for the 296 with this length barrel. Without more information and matching, this should be ball park.

[felix]

Knowing that, John, it seems the now defunct WW630 would be the best compromise. Alas, there remains that burn speed hole between BD and 2400. It should produce the same velocity, if not more, than 2400, and hopefully with the same exit pressure. I still have about 3 pounds of it for just this kind of experiment, but still no equipment and prolly never will be acquired. Just not cost effective for me these days. ... felix

[crabo]

Bass, what happens to pressures when you drop down to 6.5 of Unique and HS6?

I checked on Quickload, but for $150, I need to get a chronograph first.

Thanks,

[Bass Ackward]

I am down to about 2# of it. I find that 630 burns very close to Quickloads AA#9 data up to about 25/6,000 and then above that it gravitates to BD data using cast. Magnum primers help.

With the extra resistance of jacketed, I can use BD figures and get within 50 fps of predicted velocity. So I see why they shut it down. Much like H110-296 in burn characteristics which were poor by today's standards.

I am guessing that because it was slow enough for the typical cartridges that you would use this in, that they accepted the risk that people would push 296 and make do with a warning NOT to reduce the charges.

The 630 was not a top velocity production powder, so the risk there was that it would / could be reduced as we are always taught to start low and come up. Especially since it was in the burn class as BD which was a flake.

Wonder if this is why the hole remains unfilled today?

[Old Ironsights]

The RCBS Cast Bullet Manual lists 14.0 of 296 under their 180 grain silhouette boolit as 1,398 fps average from an 18.5 inch rifle.

I've been getting highest speeds with Lil' Gun and best accuracy with 2400 using the Lee C360-180-RF group buy boolit or the SAECO #353 plain base in my 1894C.

A couple data points:
Lee group buy, 14.9 grains of Lil' Gun, 1,703 fps average.
Lee group buy, 12.0 grains of 2400, 1,489 fps average. This is my accuracy load with the gas check boolit.
#353, 10.5 grains of 2400, 1,349 fps average. This is my accuracy load with the plain base boolit.

I'm with imashooter here... though I push the LilGun load to 16gr in my gun for about 1800-1850fps (doesn't shoot too bad out of the SP101 either... but it does bite).

I'm going to do a bunch of 2400 loads later - probably as my go-to load since I don't need Whompumstompum most of the time. [smilie=1:

[crabo]

Here's what a couple of my 2400 groups looked like. I'm pretty happy with this boolit so far, but who knows what will happen at 100?

I was not happy with the way the Saeco 323 shot in my gun. The front drive band measured 3 or so thousands smaller than the other bands. My gun did not shoot it well.

[Bass Ackward]

Bass, what happens to pressures when you drop down to 6.5 of Unique and HS6?

I checked on Quickload, but for $150, I need to get a chronograph first.

Thanks,

Oh Common Craig. Next thing you will be giving me a bad back excuse or something. :grin:

6.5 Unique is 31,000 psi for 1338 fps
6.5 HS-6 is 19,000 for 1200 fps.

Remember, Quickload gives to 100% seal velocity. So 99% of the time, you are going to be below that. How far you are below that will tell you how much pressure you lost before seal.

8.5 grains of HS-6 is max using my design. 7.5 is about 26,000 for 1350 (wink, wink).

[Blammer]

I like Lilgun in my 357 mag rifle with the 180gr GC lead bullet.

I think I'm up around 17gr but I'd start a work up at 15 gr.

[JesterGrin_1]

For such loads I tend to like W-296 and H-110. When you get out to 100 yards try the 13.5 gr of W-296 and maybe step it down to 13.OGr to see if the groups tighten up some. And please do stick with a Mag Primer as I did try the standard primer as I do with W-296 for my .44 Mag loads for my Marlin but it did not shoot well.

Even though these two groups are with a 180Gr Hornady XTP/HP it shot pretty good with 13.OGr of W-296. Top two then bottom three after sight correction but I pulled one into the bull lol. But I am happy with this load at 100 yards. And yes gang I am going to go to a lead slug when RD has some molds to try out. :)
http://img.photobucket.com/albums/v453/SHAKERATTLEROLL/Marlin357.jpg

With fast powders such as Unique and TightGroup keep in mind that these powders are for mid loads. When you do step these up do so slow and watch for pressure sighns as the pressure can build up real fast. Even before the max load in the books.

As for speed also think you are throwing a 180Gr hunk of lead down there which should do fine up to Deer size critters out to 100 yards or so. So to be honest I do not think to gain only 100 or 200 FPS would not be worth pushing the pressure up and to loose case life.

But that is just my view. :)

[imashooter2]

I like Lilgun in my 357 mag rifle with the 180gr GC lead bullet.

I think I'm up around 17gr but I'd start a work up at 15 gr.

Hodgdon lists 15 grains as max with a 180 grain XTP. I don't doubt that 17 is safe in your gun, but I'd start lower than 15 and work up.

Anyone remember that load Clark was using? He was compressing the stuff like diamond with custom dies... It was a scary overload, but safe in his guns.

[imashooter2]

Imashooter2, I did not know that RCBS had that book out and looked it up on line. Is it worth the money? I have 6 books, but lack good cast data.

The powder selection in the load data is limited and a little dated. When I got mine there was a guy on eBay with 5 or 6 auctions running at a time. I just low balled a series of them until one came home. At less than $6 delivered, I like it. I wouldn't pay retail for it though.

[felix]

Very well could be, John. ... felix