9mm + cast bullet = poor accuracy

rp85

hello;

using cast bullets in my 9's. having accuracy issues only with the s&w 5906 and 5903.

bullets sized are from the lee 358-125rf and 356-1242r. sized bullets to
.356, .357, and .358".

accuracy still poor, 4-6+" at 12 yards. accuracy is good with my rugers, browings, sigs. @2" groups. lube is 45/45/10 recluse.

using 3.3 grains of hp38 because accuracy goes out the window with all pistols with an increase of powder. never had a failure to feed, fire, or eject in any of my 9mm pistols with this load.

o.a.l for 358-125 is 1.030" and o.a.l for the 356-124 is 1.135"

any suggestions thanks for any input.

rp

jonk

Lots of possible things here.

First, 9mm is a fairly high intensity cartridge for a handgun, developing a fair amount of pressure. As such it can be tricky to get it to shoot well with cast lead. Some tips:

1. You did try different sizing sizes, which is good. However, did you slug your bore? What if you have a .360" bore? Or a .354"? You never know until you do, and that can make all the difference.
2. Have you pulled down a loaded round to see if the brass is sizing the bullet down upon seating? It's a fairly common problem, one which often requires a custom expander or sizer, or some opening up to an existing one.
3. What alloy are you using?
4. Recluse lube is good stuff; have you tried others though?
5. I'd try a different powder. Don't get me wrong, HP 38 is fine, but I personally run clays or bullseye or red dot in my 9mms, and the difference between them is quite notable (I prefer bullseye personally). What works in one gun might not in another.
6. All that said... it mgiht be that they just don't like that bullet weight. Try a heavier or lighter bullet, maybe 115 or 147 gr. It's really strange, but I have one 9mm that really likes a 158 gr semi wadcutter over 2.5 gr of bullseye. Not your normal out of the box solution, but again, works for me.

txfeller

It appears that you are just using the wrong bullet. The bullet you are using was designed for a 38 special. That being the case, there is no info I can offer, as there is nothing I can compare to a 9mm bullet. A quick guess would be that the shoulder length is much longer than the 9mm. That would be indicated by the browning with a fast twist liking it and the smith with a very slow twist hating it.

I really think you would be better served all the way around if you change to a bullet that is designed for a 9mm.

noylj

I find that ANY other style of bullet is more accurate than a RN. Even my pre-WWII P-08s and WWII P-38s feed L-SWCs without problem and are reasonably accurate.
I approve of your choice of a .38 cast bullet in 9x19. They are my choice, too. 0.356" bullets just haven't performed well, even in barrels with a groove diameter of 0.355". Even 0.357" jacketed bullets are almost always more accurate than 0.355".
If the bullet is accurate enough in your other 9x19s, it may just be the gun. Have you inspected the barrel for any damage? It doesn't take much damage to ruin cast bullet accuracy, compared to jacketed bullets.
There are 115gn and 124gn L-SWCs that are accurate. SAECO makes an excellent 115gn L-SWC as I remember.
3.3gn is generally a sub-minor load (PF~113). 4.2gn of 231/HP38 has generally been very accurate for me with all my 9x19 pistols and 121-125gn lead bullets
I have a S&W 5906 and it is almost the least accurate pistol I have--of any caliber. My first BHP with a groove diameter of 0.3588" is the worst. The 5906 has a 0.3555" groove, but it still likes to throw bullets all over the place. I would love to try a S&W 952, though.
I found decades ago that sizing cast bullets always hurts accuracy, at least in all the guns I experimented with.
TXFELLER made very good points. Follow those and let us know what happens.
Your COL is very short for the L-RN. Is this because anything longer won't chamber? Most RN bullets perform better at 1.160-1.130". My BHP is the only 9x19 I have that NEEDS a short COL, but even it doesn't need them that short.
Finally, I have never found the 9x19 to be very accurate. There is no good reason for this as far as the cartridge is concerned, but I wonder if any real attempts at optimal twist-rate or other work were ever conducted.

rp85

hello;

thanks for replys.

speed is not important to me, accuracy is. the 9mm pistols all like 3.3gr of hp38 and the slides work.

3.3gr. hp38 and the lee 356-125rn, sized to .357", give good accuracy. o.a.l. is 1.135. accuracy is o.k.

the lee 358-125rnfp, sized to .357" is accurate in all my 9mm pistols. o.a.l. must set at 1.035" to feed in the smiths. this bullet is a real gem in 9mm and 38spl pistols. 4.0 gr of hp38 in the 38spl and a o.a.l. of 1.445" works great. again 38spl speed is not great but accuracy is great.

think the 9mm accuracy improved when i started using larger expanding die. may have been resizing the bullets to something less than .357" when i put a taper crimp on the cases.

thx again for input.

rp

noylj

I've said it before: Try NOT sizing the bullets and shoot as-cast with a tumble lube of LLA. Cheap and easy to try.

Nordicwargod

It may be the gun or the barrel as some have suggested to me when I had accuracy problems with 9mm lead. NOYLJ and I both agree that 231/hp38 is a great powder for 9mm lead bullets. I also use 4.2gr of 231. Try this load as I think 3.3 is not hot enough. I have tried loads as low as 3.6 and they did not work at all and did not cycle the slide on my glock. If this load still does not work buy some 125gr truncated bullets from Missouri bullets and give them a try with this load, its a tack driver for me. If they work, measure both bullets with a caliper and see how close in diameter they are. Others here know much more about casting than I. Bullseye and Reddot work fine for me with 40 and 45 lead bullets but give me fits with 9. Good luck