RCBS 38-150 bullet mold ??

[gray wolf]

Quick question,
I had a chance to look at some bullets from an RCBS 38-150 SWC bullet mold and the bullet looked a little odd. The rear driving band, the base band, seemed to be unusually wide, like well over .100 and the front band seem narrow. Is there a reason for this geometry ? as apposed to say the Lyman 477 150 grain.Does this bullet shoot well with the extra thick rear band ?


Sam

[Scharfschuetze]

I've use the RCBS 150 grain SWC mould (38-150-SWC) for almost 40 years and it is probably my favorite 38 and 357 magnum boolit for general shooting, vermin hunting and plinking. As it was my first SWC mould, it seems very normal to me and I never gave the thick driving band any thought. My mould has always produced excellent boolits with excellent results down range with groups the equal of any other cast boolit in several S&Ws.

Depending on the alloy used, it's a great projectile at 700 fps all the way up to 1300 fps. While it may carry a little too much lube for light 38 loads, it seems about right for magnum level loads.

[.22-10-45]

It doesn't appear any wider than the Lyman 358249 Keith..and that has a long succesful history.

[bhn22]

Ideally, the bands would be the same, the front band needs reinforcement too. Keith specified three driving bands, all equal in size in every way, at least for his designs. Lyman rarely ever produced a bullet that was close. Narrow base bands don't work out well as far as preventing flame cutting. I once sold a 44 mold unused because I felt the base band was too narrow. On the design you're looking at, the goal appears to be for a semi-wadcutter design of a particular weight, the base band has a minimum spec, and the grease groove has a minimum spec, and the rest of the bullet weight is divided proportionally between the remaining physical features. I've heard that this bullet shoots pretty well, but I never bought one because I always felt that it could use another 10-12 grains of weight up front. Just a personal opinion of course.

[gray wolf]

The base band seems to be about .150 wide, that is a tad wide compared to other bullets. Yes the front band is a little narrow, but so is it on the Lyman #477 I have a 44 mag 421429 with a narrow front band that shoots exceptionally well and it also has a narrow front band and it's a little undersized to boot.
The grease groove is a little wide on the Lyman #477 and on the RCBS 38-150, but I don't see that as problem.
When looking at the RCBS bullet the first thing that caught my eye was the thick rear band, that made me want to ask why. Yes both bullets have been know to shoot very well and people that use the Lyman or the rcbs seem to be pleased with both of them. The RCBS seems to have less of a taper on the crimp groove also.
Funny but when RCBS was questioned on this they said they left the longer taper on the GC version but changed it on the 38-150 as to not copy the Kieth bullet ?? go figure. Anyway the thicker rear band should make a better gas seal, and from other reports it does not seem to effect the function and accuracy of the bullet.
I don't question the higher speed with the correct lube and alloy. A little wider front band would be nice, but that may or may not create a cambering problem with some pistol chambers and slightly oversize bullets.


It doesn't appear any wider than the Lyman 358249 Keith..and that has a long successful history.
It's much wider.
I was not knocking the RCBS bullet so there is no need to defend any aspect of it. I simple questioned the thought behind the wide rear band.

Thank yo for all your comments and explanations.

[detox]

You have the modern designed version. This bullet shoots pretty good in my 686....not the best, but good. I got best groups by seating bullet longer in cylinder throats. I crimped bullet behind crimp groove on drive band.

[Hardcast416taylor]

This was and still is a favorite mold of mine to shoot in my .38`s. Problem is I couldn`t seem to make them fast enough with just a 2 holer mold. I finally got a 6 holer from NOE and now I can keep up with myself.Robert

[gray wolf]

You have the modern designed version. This bullet shoots pretty good in my 686....not the best, but good. I got best groups by seating bullet longer in cylinder throats. I crimped bullet behind crimp groove on drive band.
Did you have any problem with the bullet jumping the crimp by using the drive band ? or were the loads all light loads ? I ask cause I have a different bullet that may need crimping ON THE FRONT drive band
( front band is to long and it hits the chamber throat. I don't want to size it smaller.

[cbrick]

Perhaps a check of other RCBS molds would show one much the same except gas checked. I have a mold that I had the bevel base removed and it left the base band just like the RCBS boolit your asking about. On another RCBS mold I had the gas check removed and again a rather wide base band but it shoots great. SAECO numbers 396 and 399 are identical boolits except 396 is PB and 399 is gas check, the checked boolit has a normal width base band and the plain base has a much wider base band.

97957

Rick

[detox]

Did you have any problem with the bullet jumping the crimp by using the drive band ? or were the loads all light loads ? I ask cause I have a different bullet that may need crimping ON THE FRONT drive band
( front band is to long and it hits the chamber throat. I don't want to size it smaller.

NO movement. I loaded these to 1050fps using new Starline bass and Linotype or Lyman "2 alloy. The stiff Starline brass has plenty of neck tension. Softer Remington brass may not.

[gray wolf]

O movement. I loaded these to 1050fps using new Starline bass and Linotype or Lyman "2 alloy.
Thank you for the answer.

Rick that is exactly what I am talking about,
different bullet but it does indeed show the wide rear band. You have to admit it is a tad wide, I have no doubt it shoots well.
Thanks

[MtGun44]

Something odd here. I have a 38-150 K, which I believe was renamed 38-150 SWC and it
is identical to my 358477 except for the lube groove is round on the 477 and square on the
RCBS. Sounds like either a different mold entirely or things have changed a lot with
that RCBS mold.

Bill

[cbrick]

Bill, I don't have that particular RCBS mold so I looked it up at Midway and the base band is exactly like the SAECO I pictured in post #9. What it really looks like to me is that at some point in the past it was a gas check boolit that was changed to a plain base. Anyway, I have molds like that and it doesn't seem to hurt a thing.

Rick

[MtGun44]

Weird to me.

Here is the pic on RCBS's site, a drawing, not a photo.
http://castboolits.gunloads.com/attachment.php?attachmentid=97973&d=1393460689

Here is one of my 358477 molds.

http://castboolits.gunloads.com/attachment.php?attachmentid=52350&d=1304396899

My 38-150-K will almost drop into this mold.

Bill

[cbrick]

RCBS 2-Cavity Bullet Mold 38-150-SWC 38 Caliber (358 Diameter) 150 Grain Semi-Wadcutter

97975

This is on the Midway site and for $75.99.

The drawing of the boolit doesn't look so much like that but look at the base band in the mold.

Rick

[Leadmelter]

I cut my casting chops on that mold back in the 80's. With a nice charge of WW231, I could shoot double action out of S&W Model 28 and later 586 all day and totally cut out the bullseye. Still have it and keep a batch on hand.
Leadmelter
MI

[PWS]

....Does this bullet shoot well with the extra thick rear band ?


Sam

I too, have gotten so accustomed to the aesthetics of bands of equal length than anything else looks strange. But, the consensus is that a thicker base band generally works just fine?

[Hardcast416taylor]

I wonder if it would be appropriate to mention the price I paid for the RCBS mold and attached handles at a flea market? The table renter had a shocking price on the combo because the sprue plate had several rust spots on it. The ASKING price was $20! I didn`t even argue with him.Robert

[MtGun44]

Tear your pocket getting your wallet out? :bigsmyl2:

Clearly the 38 150 SWC is NOT the same as the old 38 150 K, I will keep that
in mind in the future.

Bill

[220swiftfn]

Something odd here. I have a 38-150 K, which I believe was renamed 38-150 SWC and it
is identical to my 358477 except for the lube groove is round on the 477 and square on the
RCBS. Sounds like either a different mold entirely or things have changed a lot with
that RCBS mold.

Bill

I don't know when it changed, but there are two different designs for the 38-150-SWC (K). There's a site that has CAD (ish) drawings of both of them, and one of them has a tighter radius on the nose, leading to a cylindrical section before the front driving band. The other has a longer radius to the driving band.... (I think RCBS thought that Lyman shouldn't have ALL the fun messing with casters....)


Dan

[cbrick]

The RCBS 35 cal 150 is not the only RCBS boolit to change over the years. Both of these RCBS molds are marked 22 55 gr. FNGC. The one on the left is the new version.

Rick

98024 98025

[MtGun44]

Quite a redesign on that .22 boolit, pretty amazing that they didn't bother to rename
it when they made massive design changes.

Bill

[randy_68]

I have the RCBS 38-150swc 2 hole mold with the square lube groove. I also thought that it carries too much lube for the .38 but it shoots good in my 686 in .357 mag and .38 cases. I just loaded some .357 mags up with imr4227 to try out but haven't shot them yet. Can't remember the powder I used in the .38's right now, they were accurate but smoked alot.