Need advice about Rimrock .38/.357 SWCHP bullet

[SuperMan]

Discontinued IMR SR4756 really used to shine in these type loads

...sad day when that powder was discontinued...it made "Specials" really SPECIAL...

 

[sniper]

I would not try to push a soft bullet like the Rimrock bullets to 1100 fps. They are only rated @5 BHN. You usually want at least a 12 BHN or better for that kind of pressure and they need to fit the barrel well too.

I load that bullet with either W231 or better yet HS-6 but Power Pistol should do fine.

The bullet has a gas check, which minimizes leading.

 

[1sailor]

I was just at the Rim Rock site looking at those bullets. They sure are spendy for a cast bullet. A lot more than I've ever paid for JHP's or JSP's. Gas checks aren't that expensive.

 

[John Patrick]

great posts guys. Thanks.
having basically settled on the load, I am now looking at the different dies. I made my first batch with the Hornady dies. It was a few weeks back but I don't recall having any problems other than needing more expansion for the g/c bullet. Sunday, I made another batch using my RCBS dies. I got through the run but I think there was an issue with the RCBS expander.

The g/c OD is .360. I had to go pretty deep with the expander to get the bullet in. I had used those dies before with Hornady XTP bullets that have a nice smooth jacket with .357OD. The RCBS expander worked well on those.

With enough flair to get the g/c into the case, the case mouth was hitting the mouth of the seat/crimp die. They went in with a little force but I saw some brass shavings collecting around the case holder.

I am going to try my Hornady dies again and I also now have Lee dies to try but seems like that .360OD on the g/c is a bit of a problem.

Any tips about this issue with the g/c and the expander die?

I loaded some with Lee dies just a bit of flare from the expander.

The flair was minimally set for a Bear Creek 158gr Hi Tec coated SWC.

That setting worked with the Rim Rocks but took a bit of attention to set the bullet reasonably straight before seating the bullet.

The crimp was a heavy crimp which looked like the Buffalo Bore crimp I was trying to imitate. Crimp with the Lee FCD.

When I pulled the Rim Rock the gas check stayed in the case. It looked flat as far as I could tell.

I didn’t measure the Rim Rock but I measured a couple of pulled Bear Creek SWCs done with the same die settings and there was no difference in diameter between pulled bullets and out of the box bullets.

No damage to the Hi Tec coating either.

I loaded six live rounds of each and my first impression was the Bear Creeks shot very accurately while the Rim Rocks did not. I’m going to change powders and work up a 2400 load.

When I go into “production” I’ll load Bear Creeks then add a bit more flair and load the Rim Rocks.

FWIW, I don’t think the Reading Profile Crimp Die I use for my wadcutter load would be a great choice for the Rim Rock gas checked bullets.

Photo of my 357 dummies with a Buffalo Bore 38spl +P SWCHP-GC below.

 

[BillBro]

Ramshot TrueBlue may be a powder choice you should consider here. Im launching 158gr SWCHP's from Matts bullets, 20:1, no gc at 1220fps with 8.5gr of TrueBlue with ZERO leading from a 5"627. ES=24 and SD=8. This is in 357 not 38 though. I had to load that load a secind time to confirm the stats and got almost identical specs.
Im really glad that TrueBlue is showing such promise, in several calibers I load, since I bought 10lbs of it.
The Western manual shows 1176fps at 8.8gr with a LC SWC, which are harder than the 20:1 Matt casts all of his hollowpoints with which is why I dipped down a little below Westerns recommended start charge.

Maybe TB would be a powder you could give a try. It always seems to be available too. I think Hodgdon has it, Midsouth has it, Natchez has it......
It always gives very low numbers, except velocity, often down in the low single digits. Itd amazing in my 44mags and Specials.

Just a thought.

 

[John Patrick]

Ramshot TrueBlue may be a powder choice you should consider here. Im launching 158gr SWCHP's from Matts bullets, 20:1, no gc at 1220fps with 8.5gr of TrueBlue with ZERO leading from a 5"627. ES=24 and SD=8. This is in 357 not 38 though. I had to load that load a secind time to confirm the stats and got almost identical specs.
Im really glad that TrueBlue is showing such promise, in several calibers I load, since I bought 10lbs of it.
The Western manual shows 1176fps at 8.8gr with a LC SWC, which are harder than the 20:1 Matt casts all of his hollowpoints with which is why I dipped down a little below Westerns recommended start charge.

Maybe TB would be a powder you could give a try. It always seems to be available too. I think Hodgdon has it, Midsouth has it, Natchez has it......
It always gives very low numbers, except velocity, often down in the low single digits. Itd amazing in my 44mags and Specials.

Just a thought.

I have some True Blue and was thinking about trying it to duplicate Buffalo Bore’s performance in 357 cases.

The Western starting load is right about the velocity range I’m looking for.

Was the TB clean burning?

 

[38SPL HV]

I’ve had success using N340 with 150 - 170 gr cast in 357 Magnum. Tighter ESs and lower SDs compared to AA5 and True Blue and very good accuracy in my hands and very clean burning.