Need accurate load for 357 GP100

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Hylander

Single-Sixer
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May 1, 2008
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343
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So far the handloads I have loaded have not been that great.
It si not the nut behind the wheel, I can shoot the 44 mag into 1" @ 25yds.
and my 1858 .45 colt into 2" easily @ 25yd.
Best factory load of .38 has been about 5"
3" is about the best at 25yds. with handloads.
Before I send it back to Ruger, what are you guys getting for accuracy and what is your pet loads.
Not full house, but mild to mid-range
 

Jimbo357mag

Hawkeye
Joined
Feb 22, 2007
Messages
10,201
Location
So. Florida
Sounds like there might be a problem with your gun. Can you check the throats, the cylinder/barrel alignment, barrel constriction and the crown?

My standard for accuracy testing is Federal 'Classic' 158gr soft or hollow points. Some of my best .357 handloads use 158gr XTP's with moderate loads of Blue Dot or Accurate #9. For 38 Specials I use 158gr XTP's with a Max or +P load of Universal or HP-38/W231, which is actually put in 357 mag brass.
 
Joined
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Woodbury, Tn
158 gr lead SWC over 13.5 grs 2400. Start around 12.5 and work up til you get the accuracy you desire. You might also need to size the bullet to your gun to get good accuracy. Good luck.
gramps
 

sliclee

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Sep 22, 2011
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Miami Beach Florida
what is the diameter of the bullet, the barrel may be different, if a deep crimp groove, YUK.
I stopped using crimp grooves they have different depths, some makers cheat a bit.
I crimp only on a parralel flat surface in front of crimp groove.
When I order my cast bullets no crimp grooves. Removes that problem of crunching the edge of the case, which in turn can and does
decrease internal pressure in case.
 

Biggfoot44

Blackhawk
Joined
Sep 6, 2009
Messages
821
If you can shoot DA revolvers with similar precision as reported with SA revolvers, you have a problem with your GP100 .

Back in the day, Federal 158jsp.357 mag would give sub 1inch groups in guns capable of that.

For handloads a 158 gr cast ( suitable hardness and sizing, etc) with 3.2gr WW231 had very consistant vels, and could do sub 1in in guns capable of that.

In .357 cases, 158gr cast ( same disclaimers) 13.5gr 2400, std primer . Can't guarantee 1.0in in all guns, but should be half or less what you're reporting.

A little more thought required,158gr cast again . 4227, 90% load density with that specific bullet. Every combination I tried with normalish to slightly heavier for cal cast bullets, gave 1.25in or smaller .
 

gwpercle

Bearcat
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Aug 7, 2012
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26
Location
Baton Rouge , Louisiana
If 3 grains of Bullseye under any properly sized cast lead bullet from 140 to 160 grains doesn't group well, something's wrong. I get 1 1/2 inch 10 shot groups at 25 yards with this ....and I'm half blind .
Bullet diameter, throat diameter and barrel groove diameter have to be compatible.
Undersized or oversized throats will play havoc with accuracy.
Gary
 

Hylander

Single-Sixer
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May 1, 2008
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343
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California
Well I tried more load combo's., accuracy is still no better than 3.5" @ 25yds. with no consistency.
Looking at the muzzle, the lands and grooves on the right are crisp and defined, on the left
they are hard to discern.
Gun goes back to Ruger today.
 

LAH

Buckeye
Joined
Jun 6, 2002
Messages
1,432
Location
WV
Hylander said:
Looking at the muzzle, the lands and grooves on the right are crisp and defined, on the left they are hard to discern. Gun goes back to Ruger today.

Yes send her back.
 

Hylander

Single-Sixer
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May 1, 2008
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Received my GP 100 back today.
They installed a new barrel and pawl.
Sent back with test target at 15yds., All shots touching.
Won't get to shoot it until next week
 

Jimbo357mag

Hawkeye
Joined
Feb 22, 2007
Messages
10,201
Location
So. Florida
Hylander said:
Received my GP 100 back today.
They installed a new barrel and pawl.
Sent back with test target at 15yds., All shots touching.
Won't get to shoot it until next week
That is good news. It is hard to shoot good groups with a bad barrel. :lol:
 

Hylander

Single-Sixer
Joined
May 1, 2008
Messages
343
Location
California
Shot it today, shoots good.
1.25" group at 10yds. offhand with one flyer an inch out using Aguila 158gr. JSP.
This ammo is fairly stout, I was surprised.
Now to work on hand loads again.
 

Prescut

Single-Sixer
Joined
Sep 2, 2015
Messages
255
How's it going? Have you found the group you want yet?

On expectations:
Under an inch at 25 yards is the criteria for most of us who handload 357 mag. I've gotten that thru many 357 mag guns and with all kinds of powder and bullet combos. I develop 5 different loads for any one combo. I add .5 grain more powder for each load in the 5.

My goal is for group size to get smaller and then get larger.
I love it when I get 5 groups measuring 2", 1.25", .75", 1.25", and 2". I know my starting load and ending load were not the best. Too little powder and too much powder. I know my middle load was clearly the best. This is the way your data should look after the range trip.

The above should be your target.
Your data seems to indicate a hardware issue. I am really curious if Ruger got it right or just got it returned?
When I read the 1.25" at 10 yards with Aguila, I knew you were close.
Keep those range reports coming on your handloads. Under an inch?
I was surprised that your 38 specials were worst than the 357 mag.
 

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