162 gr. cast .38 SW problem

[machinegun]

My S&W K38 Target Masterpiece will normally group 1" at 25 yds with factory match 148 gr. WC, or my loads with 158 gr. factory SW over 3.2 gr of Bullseye.
I cast 1,500 162 gr SW, loaded a couple hundred over 3.2 gr of Bullseye and expected the same results. Wrong.
I was lucky to get a 3" group at 25 yds. The bullets are plenty hard and look great. I use a Star Lubersizer and a Star loader.
Everything I have cast previously have given excellent results, why would this load be so different?

[Dale53]

I would suspect an alloy problem with the bullet ending up undersize. Have you checked the size with a micrometer?

Dale53

[Johnch]

It could be to hard of a bullet , it dosn't expand to fill the bore

It coulld be the bullet is just to small

Have you checked what bore dia you have ?
What size are you sizing to , what are the factory sized to ( not what they list )

I like to run as big of a bullet as soft as I can
Normaly I get the best results that way

It could be your gun just dosn't like that load
You are using the same charge with 2 different bullet weights
The 4 gr of listed bullet weight ( might be a lot more if you weighted them ) dosn't sound like much
But it could make a world of differance , might have to tweek the load a little up or down

John

[longshotbml]

I think the guys are on to something about bullet diameter. 148's are usually hollow base and soft, ment to be driven at low velociy. That hollow base allows the bullet to expand and obturate the bore.

Good Luck

[kjg]

are those 162 grain semi wad cutters? from rcbs if so they also have a shank designed for, gaschecks and as others have suggested bullet sized a little on the small size, if you havent as of yet slug your barrel and find out what you have, then of cource your revolver just might not like the load, your variables could change using different load. kjg

[Scrounger]

I have been known to make a mistake but I'd swear that I have seen some of those molds designed for gas check bullets and some without. I never researched but I just assumed RCBS changed the mold design at some point. A collector would know.

[Bret4207]

See the posts above. Anytime I see the word "hard" connected to an accuracy problem with cast alloy boolits I see an issue right off. The shooting press and commercial casters have done us a great disservice by some how selling the idea a cast boolit must be HARD to work well. Quite the opposite is usually true. Medium soft to soft alloys often work much better than the expensive "hard" alloys. The hard alloys are best reserved for specialized applications in hunting and high velocity experiments. If the boolit fits you gun, that is if it is of throat diameter or nearly so and the throats are at least the same size as your barrel, a softer alloy should meet your needs. Straight WW works well for example.

My guess would be either your mould casts undersize in your alloy or your need to go to a larger diameter sizer die. Try shooting a few as cast, that is without sizing, and see if the groups tighten up.

[machinegun]

I have "miked" quite a few of the sized bullets. They run a pretty uniform .3575. My Star sizer is supposed to be .358 and is just two yrs old. I will mike some as cast and see if they too are .3575 or larger.
In the last 400 or so 1 lb ingots I have moulded I included a number of pieces friends have given me. These have been airplane tiedowns anchored in the concrete at airports (about 4" in dia with a cable hole) 15 to 20 lbs. and some lead bearings. These were very hard and may have included babbitt.
What I don't understand, however is I have been using the same ingots to cast .45 bullets with great success. I will shoot them at Camp Perry next month.

[machinegun]

I have now miked several of these bullets as cast. They remain .3575 for the most part. If I happen to measure where the two halves of the mould come together it increased to .3580-.3590, the sizer apparently brings them to a more or less uniform .3575 all around.

[454PB]

Now you need to measure the revolver cylinder throats and barrel. .3575 boolits may be undersized for you gun. Most all of my .38 caliber guns (I have six of them) like .358" boolits, but you can't assume anything.

[Bret4207]

.3575 is on the small side for an S+W. The Smith traditionally like a full .358 or better. Colts barrels tended to run a bit tighter. An overly hard boolit that's slightly undersize rarely gives the best accuracy. You need to know your throat size and size to that diameter or maybe a bit more if the sizer die is a little small. If the throats are smaller than the barrel you have a problem that hard boolits will only aggravate.

[357tex]

I am with johnch.I like big soft boolits.Even ww is some times to hard.

[STP22]

machinegun,

Your 162gr boolit is a bit long for the K38`s rate of twist (1:18.75 inch)

The 158`s are probably right on edge of stability. Do you see any evidence of oblong holes on your targets? If so, that would be the evidence.

Many PPC and Bullseye shooters often re-barrled to 1-14 twist rate and then were able to use the longer boolits with success. (I never did)

HTH

[9.3X62AL]

My S&Ws get .359" boolits, the Colts get .358".

[fecmech]

After reading this thread my question is what is so sacred about 3.2 of Bullseye? Just because his 158 shoots with 3.2 BE does not mean that the 162 should. Yes it probably should but there are no guarantees that I'm aware of. I'd be trying some other powders or bumping up the BE a bit.

[Bret4207]

Bullseye loads between 2.5 and 4.0 grains have been recommended at times for the 150'ish gr boolits in the 38 Special. There's quite a bit of room to experiment there and if you add in seating depth it gets even more complex. 2.7 gr is the "standard" 38 target load.

[Machinegunson]

Machine gun it sounds like you may have a defective pistol. How about you give it to me and start from scratch? But seriously, my .32 is very particular and the long line proves it. With the wrong ammo (Fiocchi) some shots make an H pattern on the paper because the bullet is tumbling badly and went through sideways. I imagine your bullet isn't stabilized. Can't wait to shoot with you again.

[Cherokee]

Machinegun & son - welcome to the forum !! I use ww for most everything in revolvers, mild to high, but not wild.

[Bass Ackward]

Everything I have cast previously have given excellent results, why would this load be so different?

Can be many reasons.

Lube and hardness interact. You can be too hard / soft or too slippery / not slippery enough.

You can't just go by bullet weight or style and say close is good enough. Might work that way once in awhile, but often times it won't. Some guys run through bullet mold after another until conditions match up for what they want to do and then they credit or blame bullet design. Design is affected by hardness and lube.

And then antimony in bullets will throw them outta balance causing the need for higher RPMs to stabilize if you are shooting low velocity like that. Which is why guys liked the tin / lead mixes for low velocity work, not just hardness, but balance. Using antimony without tin are we?

As little a .1 or .2 either way could peak out performance with that powder. Then you need to play with lube. And then seating depth. And then back to powder. And then lube again. And did I mention primer? Opps, start all over. :grin:

This process continues until you give up whether that be because you are satisfied or just give up. Which begs the question, is it better to be lucky or good? I prefer lucky every time. :grin:

[HeavyMetal]

I'm going to suggest two things:

Double check the chamber throats, a .357 boolit and a throat of .359 aren't going to get you anything.

Weigh your boolits, all of them, I suspect you'll find a weight difference of more than several grains across the "lot" you cast. Sort them into groups of weight with only a .5 grain spread load and shoot from one specific group at a time.

Keep in mind that factory lead boolits are swaged not cast. Swaging will compress the lead and will produce a much more consistant boolit weight.

If you want to compete with match ammo accuracy you'll have to do match ammo work to get what you want. Trty weighing boolits and see if that helps.

[crowbeaner]

I'm willing to bet that the load you are using is just too light for the SHAPE of the bullet. I'd try some loads with 5.0 of Unique or SR4756 and see if the Smith tightens up. I've shot uncounted thousands of 162 to 170 grain bullets in the two dozen or so Smiths I've owned. I size my bullets to .358 for them and .356 or .357 for the half dozen Colts I've had.

[sniper]

My Lee sizer, marked .358, in reality, sizes .3575, which is fairly close to my cylinder mouth diameter of ~.3582 Is that enough difference to worry about?

I talked with a Lee tech, and he was not very encouraging about sending it back to be opened up.

I am going to shoot some of my wheel weight 162gr. GC boolits,(RCBS mould) and see how they do. Hopefullly, they will be O.K., or maybe I can carefully open ithe sizer up myself.

I figure to start with 220 grit and finish with 400. What do you think?

[DLCTEX]

Start with the 400 unless you can get 600. Go slow and check often, It's not hard to remove a thou. from a Lee sizer IMHO. DALE

[Wayne Smith]

You can get 600 to 2000 at almost any auto store. Its used to smooth the finish when you paint your auto.

[w30wcf]

And then antimony in bullets will throw them outta balance causing the need for higher RPMs to stabilize if you are shooting low velocity like that.

Hmmmm. I've shot some very good groups with no leading from several different revolvers using w.w. + 2% tin alloy at speeds less than 900 f.p.s. Antimony is dispersed evenly throughout a bullet containing it, but if a bullet was out of balance for any reason, accuracy would get worse as the velocity increases.

w30wcf