357 Lead accuracy at low velocity.

[sgabel1]

I shoot a 4" S&W 586. I get good accuracy at high velocity with Lyman 358477 sized 358 with carnuba red lube. I have checked the throats of the cylinders and they are all ~ .3575. When I try to slow things down for target work in either 38 or 357 cases group sizes seem to open up. I have also tried Lyman 358091 sized 358 with the same effect. I have used, Red Dot. Bullseye, Solo 1250, Unique powders. The one exception is with some old National Bullet SWC 141 gr bullet that were real consistent and accurate at the lower FPS. These bullets measured 357 diameter. (Does anyone know what mold was used to make these bullets?).

I have tried the old standard of 2.8-3.0 grs Bullseye in 38 Spc. case but there always seems to be some flyers, most of my shooting is done free hand at 30'. My wife recently got her conceal carry enjoys the revolver but not the recoil of the 357 load. Is it possible that sizing to 358 is causing the issue at low speed. There was little leading in the barrel at 357 or 358 sizing. The most accurate load I had found was the 141 gr National bullet with 4.6 gr Solo 1250 which is near equivalent to Unique. ~ 1000 rounds through the gun...Looking for feedback.

[Larry Gibson]

You would be surprised at how erratic even target level .38 SPL WCs burn. While the ES is usually good as is accuracy the time/pressure curves are very erratic and any one who panics at "pressure spikes" looking at time/pressure traces would surely panic looking at those. With regular 150-158 gr 38 SPL loads the time/pressure traces begin to smooth out but still have a lot of "spikes. Attached is an Oehler M43 PBL data print out of standard Winchester 158 gr RN 38 SPL ammunition. The SD and ES are excellent but from the time/pressure trace we see the powder still burned erraticly. Note the accuracy isn't all that bad but not great either. Remington equivelnt factory ammo had similar traces but much worse accuracy. Speer 150 SWC factory also had similar traces with similar accuracy.

Your loads of 2.8 -3 gr Bullseye are good with WCs seated flush with the case mouth because the bullet takes up a lot of the case capacity and thus loading density is good. With the 358477 a lot more of the bullet is out front and the loading density is poor. Thus at such lower levels accuracy usually isn't all that great. Many consider it sufficient though. You'll need to use 3.8 - 4 gr of Bullseye to equal the Winchester load with the 358477 and the time/pressure curve will look close to the same. With 4 gr of Bullseye under my 358477s (sized .357 - 360>doesn't matter which) in 38 SPL cases I've also found accuracy in my M15, M19 and Security Six to be about the same; 2 - 3" at 25 yards off sandbags with groups of twice around the cylinder. However, when I was a LEO firearms instructor the practice SWC ammo we used was loaded with 3.5 gr Bullseye and it performed well in all our M15s and M19s out to 25 yards on the TRC (Tactical Revolver Course) used for qualification.

If you want better and more consistent accuracy with lighter loads then switch to a WC and reduce the case capacity to increase the loading density. Otherwise with 358477 then try 3.5 - 4 gr Bullseye.

Larry Gibson

[subsonic]

Have you played with "fluffier" powders like Trailboss and SR4759?

Or flake powders like 700-X, Larry?

I've been playing with crimping over the front driving band to reduce case capacity on .44spls when using 44-250-K and 7gr of Rex III (flake). Powder doesn't rattle when I shake these. Seems to shoot pretty well, but have not done anything scientific yet with it.

[bobthenailer]

Try 4.0 gr of Bullseye in a 357 mag case & fed spp @780 fps with just about any bullet from 148 to 180 gr
at least 7 different bullets designes that ive used and in at least 10 different 357 mag handguns has shot excellent in every one .
however i did run into one 158 gr swc bullet designe that would not group well until i was over 1,200 fps
good luck bob

[PacMan]

5.1 grains of 700X under a 160gr FN does real well in my 5"GP100.

[subsonic]

I hope 357shooter doesn't mind me linking him:
http://357shooter.blogspot.com/2011/09/favorite-357-magnum-bullet-moulds-and.html

He has found some interesting loads that are listed there that are quite accurate in his guns.

[200swc]

This is a nice "powder Puff" load. (.38 special case, wsp - length [i'll get back to you])

105 gr. (MBC) lswc over 4.0gr bullseye (Wife likes this out of a Ruger Police Six - great round to teach women.)

[NSB]

358156 bullet with 4.1g of 231. Scoped off bags shoots one ragged hole at 25 yds. with my customized (extensivily customized) Ruger Security Six.

[Char-Gar]

In some sixguns using the shorter Special case in the longer Magnum charge hole will cause groups to be larger.

Other than that I think Larry is dead on.

[2shot]

I may be way off the mark here but here it goes.

There was a reason why Bullseye shooters would take a S&W gun (1-18" twist) and put a Cold Python barrel on it (1-14 twist). The accuracy nuts (like me) found out the the slow twist in the S&W just wasn't as predictable accuracy wise with walking speed wad cutters out of a 38 Special. Much more predictable with the faster twist Colt barrels. These Smolts as we called them were much better in the hands on Master and High Master shooters than th stock S&W's. At the slow fire range of 50 yards the faster twist stabalized the WC better and got no tipping common to the slower twist barrels and because of this less tipping was less effected by the wind also.

That being said, I'm sure that your not looking for sub 2" groups at 50 yards but more of a decent group at self defense ranges. I think the 141 grain SWC'ers are grouping better because they have a shorter overall lenght and are better suited to the slow twist/low velocity although I have shot the 173 grain Lyman 358429's with as little as 2.5 of Bullseye powder and got fair accuracy out of my 2 S&W 28's.

Try using a lighter bullet in th 105-140 grain range or upping the powder charge slightly and see what happens. I doubt that the 357 diameter is causing the problem. Sounds like more of an understabalized or a to heavy for the twist and velocity problem to me.

2shot

[Larry Gibson]

2shot

We used to call those "Smython's". I looked hard back then (early - mid '70s) for a Python barrel and couldn't find on short of buying a Python (should have done that too!). Had Power put a 16" twist barrel on my PPC/TRC M15:D. Got into IPSC heavily and sold the PPC/TRC revolver......shouldn't have done that.......:(

Larry Gibson

[2shot]

Ditto on the should have bought a Python back in the early 70's when I could have afforded one. Stuck with my S&W 14's, 15's and 28's and they have served me well but they're not a Python.

2shot

[David LaPell]

I used to load #358429's in trimmed brass with a lighter lod of Unique and I would get oneragged hole at 25 yards with my 5-inch Model 27.