Need advice about Rimrock .38/.357 SWCHP bullet

[STORMINORMAN]

Just buy some Buffalo Bore, Cor Bon, Underwood, etc., 357 Magnum ammo and fire a few cylinders. It won't take you long to "experience" full bore loads & figure it out... Then you can load 'em up to your heart's content. If you so choose?

Before you hurt yourself!

Cheers!

 

[rhodesengr]

Before you hurt yourself!

Cheers!

Have more faith
I work with high-voltage and lasers all day in a lab where we test explosives. Actually true.

The fact is buying ammo where I live is very difficult. I'd have to find an online shop that even has your suggestions AND will ship to my FFL. I have bought ammo online. Places like Buds and Natchez will ship to FFL. Midway will not; only guns.

At this point it much easier to just make what I want. If the loads published are correct, then I am good.

 

[rhodesengr]

Well as I suspected I didn't blow myself or my gun up
Had more fun with the chrono today. Still working on my 158gr FBI type load but in 357 brass. I think I am done. I dropped down to 8.0grains of AA#5 and the average was 1056fps. So I think that is about where I want to be and coincidentally, it is low end of the load range as listed in Wester Powder V8 for that bullet and powder in 357mag. It wasn't with the actual hollow point g/c bullet but the less expensive LSWCs which I use as a stand-in for the hollow points. Here is the chrono summary

Even more fun was testing some rounds using Enforcer with the 125gr XTP bullet. The range is 16gr to 18 gr. I started near 16gr and measured an average of 1340fps. I actually had 12 shots but some of them were crazy high like 9000fps. That must be some glitch with the chrono which I have not see before. Maybe I was too close. Anyway, that bullet is rated up to 1500fps so I am going to bump up to 17gr and probably call it good. Got to say I really like the sound these rounds make. Definitely more of boom than a crack and shot with my 686 Comp, the recoil was no big deal
Chrono data with the weird super high ones deleted.

 

[Nevada Ed]

Just buy some Buffalo Bore, Cor Bon, Underwood, etc., 357 Magnum ammo and fire a few cylinders. It won't take you long to "experience" full bore loads & figure it out... Then you can load 'em up to your heart's content. If you so choose?

Before you hurt yourself!

Cheers!

The problem with this idea is that..............
they use special "Blends" of powders to adjust their fps in making ammo
with test done every so often to keep their ammo safe.

Even with shotgun ammo, Remington pressure and fps test are done during a run,
to make sure the ammo is within spec;s.

We don't get to "Mix powders" to get perfect pressures and fps....
or at least we have been told, not to !!

With just one type of powder, all we can do is get close to their data, be it fps or their pressures..........
I don't think that getting both of these with the powders sold to us
will achieve both psi & fps, unless very lucky.

 

[jem102]

The problem with this idea is that..............
they use special "Blends" of powders to adjust their fps in making ammo
with test done every so often to keep their ammo safe.

Even with shotgun ammo, Remington pressure and fps test are done during a run,
to make sure the ammo is within spec;s.

We don't get to "Mix powders" to get perfect pressures and fps....
or at least we have been told, not to !!

With just one type of powder, all we can do is get close to their data, be it fps or their pressures..........
I don't think that getting both of these with the powders sold to us
will achieve both psi & fps, unless very lucky.

This has always been my understanding on "factory" ammo and as you have stated is controlled during the production run/lot. Somewhere along the line (I have been handloading for 60 years now) I came across information that the method for developing these blends is accomplished by means of a "closed bomb" test. I believe it was in some documentation from a Dr. Leonard Brownell. I will see if I can find it again.

 

[rhodesengr]

I don't know about you guys but I have no plans to mix powders and I don't see the need. I am finding the speeds I want based on published loads and little testing with my actual 686.

 

[jem102]

I don't know about you guys but I have no plans to mix powders and I don't see the need. I am finding the speeds I want based on published loads and little testing with my actual 686.

Understood, and what we are presenting is reasoning why you should not mix powders, and that being, the vast majority, if not all, handloaders, do not have access to "closed bomb" testing methods... Just saying...

 

[alwslate]

I don’t think anybody is advocating mixing powders...ever. Seems some misunderstanding here. The reality is, I think, that factories may mix different lots of powders to get the ballistics they want and create canister lots of powders that are not available to handloaders.

 

[Biggfoot44]

Did I blink when " mixing powders " came into the discussion ?

Yes OEM ammo mfgs have various options not available with consumer grade Cannister Powders . But in the OP's thread here so far , and contemplated further exploits , his Canister Powders will meet his goals easily with no issues .

Is that a typo , or did you switch bullets ? The thread started out with SWC and SWC/ HP- GC , but latest spreadsheet is showing LFP ?

 

[rhodesengr]

Is that a typo , or did you switch bullets ? The thread started out with SWC and SWC/ HP- GC , but latest spreadsheet is showing LFP ?

It wasn't a typo. It was just me zoning on the correct name for the bullet. The plain lead ones are SWC. But SWC and LFP are pretty close to the same thing, yes? The important thing is to have a 158grain, less expensive bullet that I can load the same as the more expensive SWC/ HP- GC.

 

[ArchAngelCD]

Understood, and what we are presenting is reasoning why you should not mix powders, and that being, the vast majority, if not all, handloaders, do not have access to "closed bomb" testing methods... Just saying...

The reason why reloaded should never mix powders is pressure and pressure spikes. We have no way of knowing what pressures are being generated by mixing different powders. (not powder lots)

Canister powders we can buy are designed to be stable in the pressures they generate with a fixed charge weight in a chosen cartridge and bullet combination. Non-canister powders are not stable lot to lot but can be pressure tested by the bullet manufacturer. They do mix lots to achieve the pressures vs velocities they require to match their factory ammo specs. I'm not a chemist or ballistic engineer but I do a lot of reading and that's my understanding of what goes on. Of course I can be wrong but I am fairly sure I got this one right.

 

[Paul in Nevada]

Bottom line... Assuming you had a good fit for cylinder and barrel, what should be the FPS ceiling for a bullet like this? I have been contemplating a few loads for LSWCHP's but I have been looking at bullets with way higher BNH and no GC.

 

[rhodesengr]

what should be the FPS ceiling for a bullet like this?

If you figure it out, please let me know. But here is what I have found. If you look at the commercial Buffalo Bore 38spl that uses the LSWHP g/c they spec that product at 1000fps but they show data from certain revolvers as high as 1160fps from a 4" revolver. Below that, they show external ballistics for speeds as high as 1500fps. I can't tell if that is actual data or a computer calculation. They do not say how they achieved 1500FPS. That seems crazy high for 158gr even with 357mag. I have not seen commercial 357 ammo with 158gr bullets much higher than 1300fps.

I got on to that bullet from this thread as it was suggested as an available bullet to build "The FBI load" which is technically 38special.

I don't have the means to look at terminal ballistics but seems like 900 to 1100fps will do the job with this bullet. Based on the rated speed and speeds shown for the commercial version, 1000fps seemed like a good design point. That is high-end for 38spl and low end for 357mag. I had fun doing the tests and I learned a lot. My production run is 8gr of AA#5 in357mag which gives just over 1000fps in my 6" 686 Comp.

Commercial version
Heavy .38 Special +P Pistol and Handgun Ammo

 

[John Patrick]

If you figure it out, please let me know. But here is what I have found. If you look at the commercial Buffalo Bore 38spl that uses the LSWHP g/c they spec that product at 1000fps but they show data from certain revolvers as high as 1160fps from a 4" revolver. Below that, they show external ballistics for speeds as high as 1500fps. I can't tell if that is actual data or a computer calculation. They do not say how they achieved 1500FPS. That seems crazy high for 158gr even with 357mag. I have not seen commercial 357 ammo with 158gr bullets much higher than 1300fps.

I got on to that bullet from this thread as it was suggested as an available bullet to build "The FBI load" which is technically 38special.

I don't have the means to look at terminal ballistics but seems like 900 to 1100fps will do the job with this bullet. Based on the rated speed and speeds shown for the commercial version, 1000fps seemed like a good design point. That is high-end for 38spl and low end for 357mag. I had fun doing the tests and I learned a lot. My production run is 8gr of AA#5 in357mag which gives just over 1000fps in my 6" 686 Comp.

Commercial version
Heavy .38 Special +P Pistol and Handgun Ammo

I’m pretty sure the velocity/trajectory tables on BB’s site are computer generated. On the other hand, the actual velocities shown for different revolvers with different barrel lengths are real world, and close to what you can expect from similar revolvers.

I suspect the velocity limit of the 158gr SWCHP GC is near the 1,162fps real world velocity from the 4” revolver since BB doesn’t load that bullet in 357 magnum.

I want to duplicate your results with the Rimrock bullet and 357 cases, but can’t find your powder. I did find ~1,100fps (max) 357 loads with Hogdon HP-38 and TiteGroup with 158gr LSWCs via Hogdon’s Reloading Data Center. And I have those powders.

 

[Forrest r]

You really need to break down the anatomy of the different bullets at this point to get an idea of what does or doesn't work. Along with at what point things will start to go south.

A good way to test those rim rock bullets is to take 12" of newspaper and tape it into a bundle. Put the bundle in a cooler and fill the cooler with water and let the bundle sit overnight. Drain the water the next day and take the cooler to the range and staple a target to the newly made wetpack bundle and test away.

This will give you a good idea of the strength of the design of the bullet. Same cast bullet with different hp pins.

The penta point hp's will open at lower velocities then the small round hp.

I did a lot of testing with the lyman 358156 bullet which is similar in design to that rimrock bullet. I had 2 different molds and 3 different hp pins. Typical lyman hp pins are .125" in diameter for the 9mm/38spl/357 molds. You used to be able to special order the larger .140" 41/44/45 pin or the .156" 44/45 pin.

I had molds with the .125" pins (short/long depth) and a .156" pinned mold. Not my picture but this is what I used.

This link gives a little insight into how the different alloys perform.
10 to 1 12bhn
20 to 1 10bhn
40 to 1 8bhn
pure lead 5bhn

Keep in mind that a lead/tin alloy acts completely different then an alloy with antimony in it.
http://www.goodrichfamilyassoc.org/44_Special_Articles/44 spl - may 1953 american rifleman.pdf

The 1500fps bb used for the ballistic chart was computer generated. I can get close (1480'sfps) with my 6" comp 686 (same revolver that the op has) with a couple of different cast 158/160gr bullets using h110 or mp-300.

BB used a powder in the aa7/power pistol range for that 38spl p+ load.

I actually think the op's velocities are on the low side. Sort of makes me wonder what reloading dies and more specifically what expander die he's using?

 

[IAM Rand]

After seeing this post I decided to go out and get some of these bullets and reload them. Can't wait to see what I get. I will be doing both 38 and 357. From what I saw on the BB website, you need to have at least 800fps for a good expansion. Not sure I am out to go crazy and try for 1300fps+. 1000-1100 is good enough for me.

I have already gone down the Keith rabbit hole with his 170 SWC loading it hot.

 

[rhodesengr]

I actually think the op's velocities are on the low side. Sort of makes me wonder what reloading dies and more specifically what expander die he's using?

Low for the bullet to "perform" or low performance from my gun?
I used Hornady Nitride die set. #546527. How to set the dies is a good point. In general, I don't have any way to accurately set the crimp. I have not seen anything written about it yet and it seems like it is a more or less by feel type thing. I run my finger down the case and feel for the edge. I crimp enough so that I can't feel the edge. I suppose I could do several batches with different amounts of crimp and see if it makes a velocity difference. I probably won't though

About the expander, I noticed something. Since I was working with the plain SWC and the HP g/c bullets around the same time, I noticed that the g/c is bigger OD than the plan SWC bullet so I needed more expansion to get the g/c bullet into the case. I expanded cases for both bullets at the same setting so the SWC bullet was looser. I didn't see much speed difference so doesn't seem like the amount of expansion changed much.

 

[rhodesengr]

I want to duplicate your results with the Rimrock bullet and 357 cases, but can’t find your powder. I did find ~1,100fps (max) 357 loads with Hogdon HP-38 and TiteGroup with 158gr LSWCs via Hogdon’s Reloading Data Center. And I have those powders.

Can't find the powder to buy or the load data?

AA#5 is available right now on hodgdon.com
Accurate No. 5(R) | Hodgdon
and Powder Valley
Accurate #5 Propellant - Powder Valley

Probably other placers too.

Data is in Western Power V8. I think I already posted a link for that but here it is again
https://ramshot.com/wp-content/uploads/2020/08/WesternPowdersHandloadingGuide8.0_WEB.pdf

I don't think there is anything magic about AA#5 though. It does seem to be a decent general purpose powder. But no doubt you can use any powder with a listed load for 158gr SWC in 357mag or 38spl that is a bit higher than you actually want to end up with. HS6 seems popular and that is in stock right now at Hodgdon also

 

[Paul in Nevada]

I don't have any way to accurately set the crimp. I have not seen anything written about it yet and it seems like it is a more or less by feel type thing. I run my finger down the case and feel for the edge. I crimp enough so that I can't feel the edge.

This is something I have always wondered about as well. You can try to copy what crimps look like in pictures but otherwise it's arbitrary. We measure several things exactly: case length, bullet weight, charge weight, OAL, etc. You wish the load recipes would also say "set your die for a #3 crimp" and there word be these nice graduations inscribed on the die or something.

One thing that has helped me is to use loaded cartridge gauges to get me in the ballpark with my crimps. When you are crimping exactly enough for the cartridge to drop freely in and out of the gauge you have successfully removed the flare. This is all the crimp you need for auto pistols. With revolvers, especially heavy bullets and warm loads, you will need to go deeper. So 9nce you establish a base line with the guage, put a sharpie mark on the die or crimp stem. Increase the crimp by turning the die/stem in 1/8 to 1/4 at a time. Now you can write this number down in your load data and have a repeatable way to crimp cases.

 

[John Patrick]

“Can’t find…” meant in my LGSs, if they’d have had a pound, I’d have bought it. But a little searching for loads for powders I have produced.