Why is my accuracy suffering

[Babaganoosh]

I was shooting a 40 major load that comprised of a Berrys 180 grain flat point, mixed brass, federal primer seated to 1.125. Shot like a laser.

I have a steel match tomo. Got my hands on some Montana Golds. I used a 180 grain flat point, mixed brass, federal primer. Seated to the same 1.125.

Did some quick testing and they are not shooting accurately, They aren't off the paper but they are nowhere near as accurate. I didnt have time to try them off bags but there is a difference. My dad fired a few and noticed it as well. This is not going to make for a fun match tomo.

Shot out of a M&P pro .40.

The berrys major chronoed to 175 power factor. Little high I know but was gonna bump the powder down .2 grains. I didn't get to chrono the MG minor rounds yet though.

Any ideas?

[Hi-Power Jack]

I was shooting Berrys 180 grain flat point seated to 1.125. Shot like a laser.

MG 180 grain flat point, Seated to the same 1.125.

Did some quick testing and they are not shooting accurately,

Baba, you might need to seat the MG's to a different OAL - depends

on the shape of the bullets. That's the easiest to check.

Or your gun might shoot Berrys more accurately??

Jack

[yoshidaex]

Powder?

[PKT1106]

You can't just change components without testing and expect the same accuracy or power. You have to test with the new components to get the load right for your gun.

[jmbaccolyte]

I agree with yosidaex. It would help to know the powder you're using and amounts involved. If you're using the same powder and you dropped from 175pf to 135pf, that may have more of an effect on accuracy than the change in distance to the rifling due to the change in bullet ogive, from going from one flatpoint to another.

Personally, I use Win WST for major and Clays for minor.

[Babaganoosh]

Sorry, titegroup for both. 4.7 for major, 3.6 for minor.

[jmbaccolyte]

Hodgdon's website lists 4.2 grains as their lowest charge for that weight bullet, maybe it's not burning properly. You could change powders to something like Clays or play with the O.A.L. like Hi-Power Jack suggested or change various things and test each change like PKT1106 suggested. Maybe someone who uses TG will have better advice. Sorry, I couldn't help.

[sdrr72]

I've shot TG as low as 2.9g with 180g Bayou Bullets, and accuracy for me was fine (G35, stock and KKM barrel). It was actually better for me than 2.8g Clays in the same gun. Not sure what to tell you, except maybe your powder measure is having trouble with consistency with the very light charge? Just a wild guess. I use a Dillon, and I cannot go much below 2.9g TG before I run out of adjustment with the measure.

[Babaganoosh]

I've shot TG as low as 2.9g with 180g Bayou Bullets, and accuracy for me was fine (G35, stock and KKM barrel). It was actually better for me than 2.8g Clays in the same gun. Not sure what to tell you, except maybe your powder measure is having trouble with consistency with the very light charge? Just a wild guess. I use a Dillon, and I cannot go much below 2.9g TG before I run out of adjustment with the measure.

The hornady powder measure is scary consistent. With the pistol rotor it's dead on.

[MarkCO]

In .40, I have found the 180 (CMJ) MGs to be very accurate at minor PF, not as good at Major. Berry's better at major, and not as good at minor.

[Sarge]

You can't just change components without testing and expect the same accuracy or power. You have to test with the new components to get the load right for your gun.

+1

Changes of this magnitude are actually like starting over again with load development. This is why I generally put a target downrange when working with the chrono. I have loaded rounds that were 134 pf that would shoot 10" groups, made a few small changes and was same pf and shot 4" groups. Amazing how things can change by adjusting oal, powder drop, bullet weight, etc.

[Babaganoosh]

You can't just change components without testing and expect the same accuracy or power. You have to test with the new components to get the load right for your gun.

+1

Changes of this magnitude are actually like starting over again with load development. This is why I generally put a target downrange when working with the chrono. I have loaded rounds that were 134 pf that would shoot 10" groups, made a few small changes and was same pf and shot 4" groups. Amazing how things can change by adjusting oal, powder drop, bullet weight, etc.

Unfortunately that's what I thought but was hoping it would work out better.

[PKT1106]

No shortcuts to greatness. I know it can be a lengthy process, but once you dial it in, it's good to go.

[Babaganoosh]

The Berry's bullet is also slightly bigger in diameter then the MG. Perhaps it's grabbing the rifling better?

[Yagi]

Have you tried right around 135-145pf... At times when shooters are accustomed to major then switches to minor their accuracy suffers... Have you tried a lighter bullet wt? Try155gr.

[RH45]

My IDPA load is 3.7 grains of Titegroup, behind a Zero 180 jhp at 1.2" OAL. I'm close to 140pf, but, would rather be too high, than too low. I've loaded as low as 3 grains of Titegroup, loaded short, for Glock mags, but, was a little under 125pf.

In every pistol I own, when I've tried MG fmjs, or cmjs, accuracy has been what I consider horrible. For instance, during the component shortage, when I couldn't get Zeros for my 9mms, I picked up some CMJs, and tried them in one of my open guns. I was shooting 3/4" groups at 25 yards with Zeros, but, the cmjs opened up to 3-4"