Cast boolits in 9mm and 1:10 twist

[wv109323]

I am trying to load a round for USPSA minor power factor.This is bullet weight times velocity/1000. So a 125 g. Boolit must be 1000 fps to meet the required powder factor of 125.
I am loading in a CZ 75B with a 1:10twist.
My problem when I approach the velocity required for power factor, accuracy falls off. Loads around 800 fps are acceptable.
I have tried 120 g.powder coated, 135 coated ,147 coated. The 135 and 147 are commercially coated by two different manufacturers. The 120g. boolits are my cast and coated. Powders have been Bullseye, WW231,Unique,CFE, Blue Dot, WST and AA No.7. Still accuracy is Ransom Rested and probably averages 4" at 20 YARDS.
Groups range from 3" to whatever. Bore is slugged at .3562 and my boolits are sized at .3572. Commercial coated are .355 and .356". I have sized my boolits to .3583, with no better success.
Jacketed Hornady 124 g. Bullets are acceptable. At 1 1/2 to 1 3/4".
All bullets were crimped at .378. Same headstamp brass was used and compared to misc. Brass. Same headstamp seems to help and the powder that shows the better results is Blue aDot.
What would you do to improve accuracy with a power factor of 125?
I have also tried my cast 125 RNFP with lube at .3582 with no sucess.

[rintinglen]

I would try water dropping and tumble lubing my cast boolits. My surmise is that your commercial boolits are too small and your cast boolits are too soft for best results. Powder coating prevents leading but the heating robs the boolit of some of its strength. That 1-10 twist is better for heavy boolits, IMO. A 147 at 900 should easily make your PF.

[nhyrum]

I second water dropping, and quenching again after PCing. I would recommend trying vv 3n38, if you have it already. Otherwise it's probably impossible to get

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[nicovanj]

Have you tried a 124gr bullet with CFE pistol? Which case mouth expander die are you using?

I use the Lee TL356-124-2R with 4.8 grs of CFE Pistol coated with Hi-Tek. It makes factor and is accurate. I found expanding with the Lyman "M" die the bullet is centered in the case when bullet seating.

[Old Caster]

I would pull some of the loaded bullets with an inertia puller and measure what size they got swaged by the case. I bet they are then much smaller specifically if it is lead softer than around 15 BHN.

[nhyrum]

I would pull some of the loaded bullets with an inertia puller and measure what size they got swaged by the case. I bet they are then much smaller specifically if it is lead softer than around 15 BHN.That's a good point. The Lee fcd is known to do that even to jacketed bullets

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[wv109323]

I load on a Dillon 550 which has an aftermarket powder funnel that expands the neck to where there is no sizing of the bullet when seating. I have pulled boolits and there is only .0002" difference between sized and pulled seated boolits. Dies are dillon and taper crimp in a separate die.
I have tried some hard commercial cast 147g. and they were not impressive with the loads I used. They were .356.

[wv109323]

I will try some 125 RFN sized at .3582 with 4.8 CFE.

[Meatpuppet]

I shoot a lot of commercially cast and coated 9mm in a CZ SP-01 Shadow. It likes 357 & .358 dia bullets.

I prefer 125gr with iron sights. They seem to settle quicker back on target, using 4.0gr of VV N320, sized .358 and a 1.10 OAL, I get 1028fps / 127 Power Factor.

For Carry Optics I like 147gr or 165gr. The dot rarely leaves the optic with the heavier bullets.

[dverna]

A hard alloy at .358 should help (92-6-2). I knew a guy who used linotype alloy with a 1/10 twist and it worked for him at .357.

If you are getting good accuracy with jacketed that it the direction I would go.

[1006]

I have a Sig226 with a 1/10 twist. I have had the same problem with lighter cast or swaged bullets. Lead seems to shoot best from a 1/16 twist.

I found some success with a 135 grain bullet from Bayou Bullets. It is cast hard and coated.

3.5 Red Dot with a 135 coated Bayou Bullet gives me 957fps in the 226 for a 129 power factor. The SD=8fps. 1.13 COAL

I think you could use 3.5 to 4.0 Bulls Eye.

[wv109323]

1006 I have some 135 Bayou. What powder and load are you using? Oal also?

[1006]

Edited post above for data

[45DUDE]

If the Hornady 124 jacketed does 1 1/2 I would think the gun is border and it should do better from a rest at 20y. Xtreme has a good buy on 124g plated at this time. I use these in a stock 1911 with N340 and N350 powder. Different powder and speed can make a difference. Some times you have to try 1 thing at a time. I ended up seating my 124's shorter than book which would raise pressure but not a max load. N340 has about the same powder weight as Unique but is cleaner. A little more powder could tighten the group.<just something to think about>I would like to know the results.