.40 Accuracy Problem

[BadShot]

Hey Everyone,

I've got a .40 Kimber single stack that I am trying work up loads for. If I shoot factory Winchester target loads (180 gr) thru it I get 1.5 to 2.5 inch groups at 25 yards. When I load 180 gr. Winchester FP over 4.6 grains of TiteGroup at 1.114 AOL I get 4-6inch groups. The crimp is at .416. Using Berry's 180 gr plated bullets gives slightly larger groups. Any thoughts??

Thanks,

Skip

[Crusher]

The crimp is at .416. Using Berry's 180 gr plated bullets

You have "crimped" through the plating, back it off to .420 or even .421 and the group size should shrink.

My rule of thumb is casewall thickness x2 + .001" and stop there and repeat this mantra for auto loader rounds:

"CRIMP DOES NOT HOLD A BULLET IN THE CASE, WALL TENSION DOES."

[Putty]

Some people have acc. probs with plated bullets. Jacketed if the above crimp does not fix.

[BadShot]

That make sense for the Berry's plated bullets. Would this have the same effect on the Winchester FPm which are jacketed?

Skip

[HSMITH]

Yes, you are mangling the hell out of the bullet with a .416" crimp, you are also increasing the chance of a bullet setting back in the case and resulting overpressure situations/

Pull one of the Winchester bullets and look at it, it will be pretty obvious.

Set crimp to .420" at the TIGHTEST. Try again and see what happens.

[benny hill]

Also load longer for better accuracy.

[Mick]

I've never had Berry's plated bullets shoot well in any of my guns.

I had some CCI plated bullets that were pretty good until the rifling

got old and the keyholing started.

Try some brass alloy bullets like Montana Gold or Armscor

and see if they shoot better.

[BadShot]

Okay,

I took some of the Winchester 180gr FP and loaded them to 1.18 with 4.6gr of Titegroup. The crimp was 1/8 of a turn past the point where the die just touched the brass. It just leaves a slight ring on the round if I pull them apart. The groups got smaller, 3-4 inches at 25 yards. Better, but still not as good as the factory rounds. The factory rounds are 1.115 in length. I can't tell what powder they use, but it weighs 5.5 gr. I'd shoot 5 of factory and 5 of reloads and the factory was more accurate each time.

I weighed and measure each bullet as I built them.

Any thoughts?

Skip

[DougCarden]

SKip, try loading to 1.200. I would also try some Universal Clays and W231 for powder. My load with 165fmj/jhp 5.7 VV320 1.200 touches at 25yds as well.

Good luck,

DougC

[HSMITH]

Skip, back the crimp off. Sounds like you are using a factory crimp die and trying to follow the directions. If that is the case DON'T. Set your crimp with calipers and disregard the instructions. The instructions for that die have you overcrimping.

Set your crimp at a MINIMUM of .420". .422" would be great. OAL is quite unimportant.

[billdncn]

Okay,

I took some of the Winchester 180gr FP and loaded them to 1.18 with 4.6gr of Titegroup. The crimp was 1/8 of a turn past the point where the die just touched the brass. It just leaves a slight ring on the round if I pull them apart. The groups got smaller, 3-4 inches at 25 yards. Better, but still not as good as the factory rounds. The factory rounds are 1.115 in length. I can't tell what powder they use, but it weighs 5.5 gr. I'd shoot 5 of factory and 5 of reloads and the factory was more accurate each time.

I weighed and measure each bullet as I built them.

Any thoughts?

Skip

+1 on what everyone has said about your crimp. Should be anywhere from .420"/.422".

How did you know to load to 1.180"?

Have you checked your chamber for max. oal for this bullet?

I take a fire case. Slightly flare the mouth. Insert a bullet, and use it to find the maximum oal. of the chamber. Then I back off .010/.015", and start from there.

I don't think this works with Glocks though because of feeding issues due to the magazine dimensions.

Others may do this differently, and chime in with there suggestions.

BTW, I would note bother weighing each round.

Good luck

[revchuck]

Skip - A quick-and-dirty way to match the crimp on the factory ammo is to back off your crimp die, run a factory round all the way to the top of the ram's travel, then screw the crimp die down until it contacts the round. Lower the ram and screw the crimp die in another eighth turn, and you should be right there.

The crimp die doesn't contribute to holding the bullet in an autoloader, it just removes the belling.

[Mick]

I've got a bunch of UMC factory ammo that has no crimp...it's glued in with a tar like sealer.

I just crimp .003"

[BadShot]

First of all, thanks for all of your help. Good advice all over the place. I loaded the FMJ Wincester 180gr out to 1.200 and used a very light crimp. I matched it to the factory crimp. I used several powders - 231, TiteGroup, and some International Clays (spooky stuff, but very soft). All of them shot about 2-3 inch groups!!!!!

Again thanks for all of your help, I learned a bunch....

Skip