Let's talk .358 molds

[wv109323]

I would guess over time the .38 Spec. and .45 ACP bullets are the most common cast boolits.
I am interested in the potentially most accurate bullet for a .38 Spec. target load of around 700-800 FPS. I want at least a four cavity mold. Firearm is a S&W Model 14 with a 6" barrel. I shoot NRA Distinguished Revolver so I need 50 yard accuracy. The bullets is required to be 158 gn. SWC or RN.
I bought a custom 158-SWC. The mold has one grease groove and two crimping grooves. The mold casts a beautiful bullet but it is not accurate. My thoughts are the bullet is nose heavy. The old Keith bullet(no.51) was one grease groove and one crimp groove.
There are some designs with two grease grooves and one crimping groove.
What are your thoughts on the optimum bullet profile for the .38 Spec?
I can get the RCBS 158RN to shoot. That bullet has one grease groove and one crimping groove. My guess is the CG is toward the rear of the bullet. Do you think a heavy base bullet is more accurate?

[reddog81]

The only RN 38 mold I own is a Lyman 358311 and it is very accurate. My most accurate SWC is actually the LEE 140 in 6 cavity but it sounds like you need something heavier than that.

[gunarea]

WV109323
Shoot the slug that the game was designed around. I'll go out into my cave today and see if I can find the 358421 mould for you. Mine is a double cavity but is an original. Trick I found that worked for me was to seat the top driving band flush with top of the brass. The other thing which must be accounted for is the low velocity pressure that necessitates a soft alloy for proper obturation. Powder selection becomes critical at very low levels with initial pressure spike needed. Small charges become location sensitive and can be easily checked with chrono work. Your observation on heavy base effectiveness is lost on full wadcutters which testing has shown to work in either direction. The 158 swc is a legendary projectile capable of great accuracy but needs a special diet. Cast your slug from a very soft alloy and use 3.2 gr of Red dot to yield a velocity around 750fps. Note here, powder forward and powder back have a velocity difference of around 35fps. You may find the mould in hand will tighten the group significantly with these subtle changes. Let us know how you make out.
Roy

[Artful]

I second that the 358311 158 grn RN is one of the most accurate at 50 yards that I shoot.

[fecmech]

I have shot the H&G #39 RN for many years. I believe it is very similar to Lyman 358311 and it is my 100 yd ram load for Hunters pistol silhouette in my Model 14 S&W. Here are 3 groups I shot off the bench@100yds a few years back. Avg for 3, 6 shot groups was 3".

[rintinglen]

358-342 160 grain boolit. Very accurate,

[gwpercle]

After much testing, my best results have come from the Lyman #358432 160 grain boolit.
This design has been discontinued by Lyman but is available from NOE in their 360-160-WC recreation. This boolit , sized .358 loaded over 2.8 grains of Bullseye is the accuracy winner in my guns.
Fired from a model 64 with a red dot sight at 25 yards I shot a group of 15 shots that was 1 inch wide and 1 1/2 inches tall . If I hold steady it will shoot groups like this regularly, no other boolit or powder combination will better this load at 25 yards .
Gary

[paul h]

Why can't the bullet be an ogival wadcutter? I'd say the Mihec 359640 or similar designs would likely be the most accurate.

SWC's can be very accurate if everything is properly aligned between the cylinder and forcing cone, but that square transition if the shoulder can through off accuracy if everything isn't aligned.

If I were going to design a custom mold for target work at 700-800 fps I'd take a full wadcutter body to take up as much of the case capacity as possible and hence aid in the powder burning for the lower velocity loads, and then add a short (~.25" long) round nose section to help align the bullet with the forcing cone as it enters the forcing cone. I'd also go with two smaller lube grooves than one large one. I think the smaller grooves help fillout of the mold and the designs seem to be a bit more accurate.

[wv109323]

fecmech,
would you care to give the loads you shot those groups with. I can't make them out from the pic.
I settled on 3.5 g. of WST or 3.3g of BE.

[fecmech]

would you care to give the loads you shot those groups with.

The load shot there is 4.2/Bullseye which is listed as a max std pressure load in the 3rd Lyman Cast Bullet handbook. It clocks right at 900 fps out of my 6" gun. I have fired well north of 10K of these through this gun with no ill effects but it may have more recoil than you care for in your application.

[dubber123]

358311 if it must be a RN or SWC. It was one of the most accurate for me at 50 yards from my 6" M14. It easily beat any wadcutter at 50 yards, and I tried a bunch. Distance is not a friend to wadcutters.

[GWM]

I too second the Ideal/Lyman 358311. It has always been the most accurate for me.

[wv109323]

Fecmech,
I found accuracy with an NEI mold 158 SWC with 4.6 gn. of WW231. It had quite a bit of recoil but it shot 11 rounds into a 1 5/8" group at 50 yards. Of course that is out of a Ransom Rest.The trouble was I ran out of WW231. The mold is a 2 cavity with very short handles, and your hands get hot from the pot. I think you are on to something with the higher velocity or as someone else mentioned a softer alloy for obturation. I may end up with a 50 yard load and a lighter 25 yard load for timed and rapid fire. I don't want to do that, I was trying to get one load and crank them out on my Star loader. I was trying to find a mold with more cavities to decrease casting time.
For others the bullet is mandated by the rules to be a 158 gn. SWC or RN, no WC or TC.

[wv109323]

I forgot to add to the last post a thank you for all responses.

[Rattlesnake Charlie]

I forgot to add to the last post a thank you for all responses.

I made no response to the OP, but i appreciate your acknowledgement of those who did. I must also add that this thread did not stray far from the OP, which I appreciate.

[warf73]

Have you thought about the TL358-158-2R, does come in a 6 cavity mold you could buy the 2 cavity to try out. I use the 358-150-1R and is very accurate in my S&W but to light for what your doing.

[tazman]

I have used the TL358-158-2R in my revolvers with outstanding results. It rivals the 358311 in performance. With the mold I have, I don't need to size them since it drops right at the diameter I need.
I wasn't expecting that since the TL bullets fail in my 9mm. I guess it must be the pressure difference. I haven't tried this boolit in 357 mag so cannot comment on it's use there.

[wv109323]

I agree the RN is a good design. I have the RCBS mold but it is a 2 cavity. I ordered a NOE 158 SWC mold that has two small lube grooves and one crimp groove. We will see if it works out. IIRC NOE does not have a 158 RN mold.

[dubber123]

I agree the RN is a good design. I have the RCBS mold but it is a 2 cavity. I ordered a NOE 158 SWC mold that has two small lube grooves and one crimp groove. We will see if it works out. IIRC NOE does not have a 158 RN mold.

The Lyman 358311 is nearly as common as dirt in a 4 cavity configuration.

[wv109323]

Not as common and available as you think.
RCBS - only a two cavity
Lyman -Yes but who wants to depend on Lyman quality right now. Also I have no Lyman molds so that would necessitate buying handles also.
Saeco- Yes A four cavity mold is $179-$199. The NOE was $85.00 delivered
Accurate Molds- Yes $150
H&G- Yes but Good Luck finding one that was not drug through a war.
Lee- I cant remember if they have a 358-158 RNwith a flat base in a six cavity or not. I know they make the RN in a TL.