Need advice about Rimrock .38/.357 SWCHP bullet

[rhodesengr]

Hi all. In a previous thread here, it was suggested I try this bullet for 38spl and/or 357mag defensive loads. I have an S&W 686 Competitor to run either case size. So I bought some.
g/ch .38/.357 158 gr. SWC-HP per 100/ in a plastic ammo box

I can not find any actual load data for it that bullet. I also have some plain lead 158gr SWC bullets for comparison.
.38/.357 SWC 158 gr. per 800

My plan is to pick one powder charge for both. Check the speeds and then mostly shoot the plain SWCs. The idea being the they should both feel and shoot about the same but the plain SWCs would be much less expensive for practice.

I am interested in a load ending up around 1000fps. Maybe 1100. I am working mostly with AA#5. I made up some rounds with each type bullet last night using 8.6gr of AA#5 which is about in the middle of the AA#5 load data for 158gr LSWC bullet in 357magnum cases. Here is my concern. The HP bullet is a bit longer from the crimp canellure to the base than the LSWC bullet or any other bullet I have where there is actual load data. The volume in the loaded case will be less. Do I have to worry about overpressure? I have a chrono so I can measure actual speed but no way to measure pressure.

It would be nice to find some actual load data with the LSWCHP bullet.

 

[Goldstar225]

I use Power Pistol. 6.0 grains under a 158 LSWC cast from an RCBS 150 SWC mold is giving me 1050 FPS from a 4" model 15. This is a max PP load direct from Alliants site.

 

[rhodesengr]

The closest actual load I have is from Western Powder v8. It calls out a Laser Cast (LC) 158 SWC with 8 to 9 grains of AA#5. I don't know that the bullet from LC has the same dimension as the one from Rimrock but the hollow point version with gas check is definitely longer and will definitely leave less volume than the plain SWC.

 

[kleeber]

I've shot the 158 Laser Cast in the past. I don't have one in front of me to measure but the Rimrock SWC you linked to sure looks like the same, classic design. Of course, there could be other differences such as bullet hardness or diameter. So if I were you I'd start at 8gr and work up toward 9gr, hopefully getting to your velocity target without getting sticky ejection. I would think you could then work up to that same velocity with the HP bullet (maybe with a lighter charge) without pressure problems.

 

[ArchAngelCD]

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.

 

[rhodesengr]

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.

Can you say more about that. I've been wondering what speed a bullet can take. I though the idea of the gas check was so they could go faster. What happens if a bullet goes too fast? Lead in the barrel? I am just learning about this stuff.

 

[Scharfschuetzer]

Can you say more about that. I've been wondering what speed a bullet can take. I though the idea of the gas check was so they could go faster. What happens if a bullet goes too fast? Lead in the barrel? I am just learning about this stuff.

Yes, a soft (BH 5) bullet will start to lead at much over 800 fps. Harder alloy bullets (BH 12 or so) are very usably at 1,000 fps without any leading. A good alloy of about 96% lead, 2% Tin, and 2% Antimony will handle just about all of your cast bullet shooting needs.

You will also want to shoot a bullet of .358" or slightly over your bore diameter in order for the bullet to obturate in the barrel and prevent gas blow by which can happen with hard bullets sized to bore diameter. A good bullet lubricant will also help to prevent leading. The hard wax lube on most commercially cast bullets is just sufficient and not really the best. I still use the old NRA Alox lube (Lyman and RCBS brands) for most of my cast bullets.

Gas checks really are not necessary for target loads in the 38 and the 357 magnum cartridges unless you are really pushing the envelope in the magnum with soft bullets. I use them exclusively with my cast rifle bullets, but they are generally shot at around 1,800 fps and not the slower speeds of revolvers.

Good luck with your project. Cast bullets allow you to shoot a lot more for less than when using jacketed bullets. Paper, cans, dirt clods, etc., can't tell the difference. Well cast bullets will shoot just as accurately as the best jacketed bullets so you'll take no back seat in that area either.

 

[rhodesengr]

I think the idea of the g/c bullet as a hollow point is to be soft so it flattens out. The gas check allows higher speed than you could normally use for that hardness. But Rimrock doesn't quote a speed rating.

My understanding is that Buffalo bore uses this bullet in some of their ammo. here are some actual speeds they claim they get with that same bullet
source
Heavy .38 Special +P Pistol and Handgun Ammo
➤ 1,040 fps (379 ft. lbs.) -- S&W mod. 60, 2-inch
➤ 1,059 fps (393 ft. lbs.) -- S&W mod. 66, 2.5-inch
➤ 1,143 fps (458 ft. lbs.) -- Ruger SP101, 3-inch
➤ 1,162 fps (474 ft. lbs.) -- S&W Mt. Gun, 4-inch

so they are up to 1162 in 38spl

I don't want to go faster but I want to use my 357 brass. I know... uses more powder. That's OK. Plus this is mostly a learning experience.

The Western Powder data for AA#5 in 357 shows the LC 158gr SWC (BHN 12) tested up to 1200FPS. I am loading in the middle of the range so nominally maybe 1150. But based on some loads I did last weekend, I was tending to get actuals around 100fps less than suggested by the powder data. So I think I am OK at 1100fps with either bullet and I am trying for an actual speed between 1000 and 1100. But this gets back to original question... the effect of the g/c bullet taking up more volume leaving less in the powder area.

My ultimate goal is to have about the same speed for both bullets. Test the HP ones so I know the load is correct and then keep them around for the situation that will probably never happen. In the meantime, I can practice with the plain SWC ones for less cost. Those g/c bullets are like 37cents each.

 

[BLUEDOT37]

Rim Rock 158gr L-SWC-HP-GC

I think the idea of the g/c bullet as a hollow point is to be soft so it flattens out. The gas check allows higher speed than you could normally use for that hardness.
But Rimrock doesn't quote a speed rating.

When I was considering those bullets I emailed Rim Rock & they told me they suggest not going over 1150fps.

You are correct that the gas check allows a higher velocity to be used, than normal, with the softer lead bullets that give better expansion at the (relatively) lower speeds than full magnums.

.

This bullet had a seating depth for me that was .377" of it's .701" BOAL.

Many common 158gr JHP bullets seat ~.345" but some, like Nosler & Hornady, seat .366" & .370" deep.

Since your loads won't be full tilt, because of their speed restriction, I don't see a need to get concerned about it's difference.

Gas checked bullets act more like jacketed bullets than an all lead bullet does pressure-wise.

.



.

 

[alwslate]

In Handloader magazine #304 Brian Pearce reached 1014 FPS with your bullet in a 6” K38 with a +P .38 spl load of 6.8 grs of AA5.

 

[STORMINORMAN]

According to Hodgdons the 8.6gr of #5 in 357 Magnum should be in the ballpark for 1100 fps with a 158gr LSWC: they show a MAX of 9gr.

Your results may vary...

Cheers!

 

[gwpercle]

The difference in volume is very small ... Too small to be concerned about with your middle of the road load of 8.6 grs AA#5 ... it will be just fine with both bullets . Load both and give them a test .
Don't let the "it must be hard" bunch deter you from testing .
Improved lubricants , coatings and gas checks all fight leading and here is a "truth" ... bullet size is more important than bullet hardness (bhn)
People way overate hardness .
Take those bullets , 8.6 grs AA#5 , load them up and then as we say in Louisiana ...
... CHOOT EM' !
Gary

 

[boatbum101]

As gwpercle stated you'll be fine . Gascheck & a good quality lube are important , but fit is king with cast bullets . As longer as you stay @ 1150 or below that bullet won't overexpand . Cast hollowpoints take a bit of work as alloy needs to match impact velocity plus be ductile enough that it doesn't come apart . For those interested read Fryxell's articles on the Los Angles Silhouette Club page .
FWIW I've pushed the Rimrock copy of Keith's 170gr LY 358429 BHN 12 to 1400 fps in 357 mag & 1200 in 38/44 loads . It is a plain based design , has a good lube & fits my guns .

 

[mikerjf]

I think you said you have a chrono? I would just start light and find that 1040fps that Buffalo Bore does, no need to go faster than that with this bullet. It’s unlikely the different bullet lengths will cause a pressure issue at this level.

When I get the elusive “round tuit”, I’m going to try this... probably something like ~6g Unique (357 case).

 

[rhodesengr]

tell me more about lube please

Thanks, the last few posts are really great.
I have 12 each of both SWC and SWCHP all loaded up and will be testing tomorrow. 8.62grains AA#5

A couple of you mentioned lube. I have not read up on that yet. Sorry if its a newb question but where does the lube go? I see most of my bullet types have a ring of "wax" just below the crimp groove. I assume that is to help seal the bullet in the case? Should I be putting more lube on the base of the bullet before pressing in?

Edit: I watched some bullet lube videos on Youtube. Seems my commercial bullets are already lubed (that colored ring of wax). Do I need to add more lube that what they come with?

 

[Nevada Ed]

In my 686, 6", I have loaded a lead 158 gr. swc & Lhp , with good results.

38 special case......... 750 to 1024fps.

.357 case................. 788 to 1320fps.

With a "Soft Bullet" barrel cleaning is much quicker if the fps is at 980 or lower.

I have never used a GC with any of my lead bullets.

 

[ironhead7544]

It is going to depend on your barrel, but the soft gas checked bullet should work OK for at least 12 shots at 1100 fps. Leading can easily be removed. Wrap some material from a Chore Boy all copper scouring pad around a brass bore brush for a tight fit in the barrel.

The powder used can make a difference in leading. I find that IMR4227 gives less leading with some revolvers.

I think that 158 gr HPGC at 1100 fps would be a good serious social purpose loading. I would use the 357 Magnum cases for this loading.

 

[martyd]

I shoot a lot of Rim Rock bullets in 9mm - 357 - 41mag - 45 acp.

The BHN varies greatly depending on the bullet style and caliber.

All the calibers and bullet style/weight are 15 BHN.

They have a .357 wadcutter in 15 BHN which shoots great.

I know they have 5 - 12 - 15 - 22 BHN lead available.

They also offer 22 BHN.

I believe they will still cast in 22 BHN if you want a particular caliber / style / weight.

Send them an email and ask, they respond quickly to emails.
The owner Frank is a great person to do business with.

 

[martyd]

Rim Rock Bullets

Oops,

Forgot to mention Frank will size to different sizes (diameters), just ask him he will occomadate the best he can.

 

[boatbum101]

Red wax ring is the lube , no additional needed . If i have bullets that are missing some lube I either remelt / recast them or tumble lube with White Label 45-45-10 & use them in lighter ( 800 fps or less ) loads .