different bullets - groups in different locations?

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different bullets - groups in different locations?

Post by Chris_D on 1/15/2012, 7:10 pm

I have loaded up some ammo as such:

200 SWC with 3.9 grains of bullseye

185 HPSWC with 3.9 grains of bullseye --> CORRECTION 3.9 gains of bullseye

I have shot about 400 rounds of each of this and an settled in but there is something very strange. With the 200 grain bullets, my group is 1/2" left of center and with the 185 grain bullets, by center is 1/2" right of center. I have tried a bunch of different tests and checks to make sure it wasn't something I was doing to cause this and today's efforts confirmed it. When I say 1/2" it could actually be 3/4" and this is at 25 yards.

The only thing I can think of that would cause a left-right shift of groups would be how my wrist breaks during the shot. I will admit that since up-ing the load from 3.4 grains to 3.9 grains, my wrist has been hurting a LOT more. While I do believe the recoil is a bit less with the 185 grain bullets, I really didn't think it was that much different.

Now I could see a change in the group locations vertically, but other than wrist-break, I can't think of anything else that would cause the shift in groups.

Anyone else had a similar condition at some point?

Chris D


Last edited by Chris_D on 1/16/2012, 4:48 am; edited 1 time in total

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Re: different bullets - groups in different locations?

Post by Rob Kovach on 1/15/2012, 7:49 pm

Maybe the Less mass in the 185gr bullets makes it show more spin-drift?
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Re: different bullets - groups in different locations?

Post by Founder on 1/15/2012, 9:32 pm

Chris you are shooting dissimilar bullets and expecting similar results? And are the 185gr at 3.0 or 4.0 of Bullseye? What distance are you shooting these at?

I can tell you that the 185 SWCHP will give you less felt recoil when loaded with the same charge as a 200. I have noticed this myself and like the 185's for 50' and 25 yards for quicker recovery to target.

The bullet is long gone from the barrel before your wrist breaks, many people have argued this but from what I have seen in photos and video that bullet is gone. I speak of this only with the 45 ACP as that is the only evidence I have seen.
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Re: different bullets - groups in different locations?

Post by Chris_D on 1/16/2012, 4:53 am

Correction was made to the O.P., it is 3.9 grains of B.E. for both bullets.

The shooting is all done at 25 yards, on the same day, with the same gun. I would certainly expect the same left-right, zero point between the loads.



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Re: different bullets - groups in different locations?

Post by DavidR on 1/16/2012, 9:55 am

Its never the same with different bullets, want even more of a difference, load a 185 fmj-hp like a nosler compared with lead. The guys shooting top scores shoot all the same bullet at 50 and 25. Some reduce the powder slightly for 25 some dont.
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Re: different bullets - groups in different locations?

Post by Jack H on 1/16/2012, 1:05 pm

Heck, I can move the sand bagged group just by regripping my hand. Same everything else.

Yes changing any one thing in your load can move the group. Or not.

At least you are recognizing groups.


Last edited by Jack H on 1/16/2012, 1:45 pm; edited 3 times in total
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Re: different bullets - groups in different locations?

Post by clark2245 on 1/18/2012, 3:25 pm

I had the same sort of thing happen with some bullets I tried a couple
of years ago with a distinct move of the group to the left. It took
4-5 clicks to the right to center the group at 25 yards, and then the
same number back to the left when I switched back to my regular load.
Couldn't get them to group anyway so I gave some to a friend to try and
he reported exactly the same thing in his gun. Never could figure out
what might cause a horizontal change in the group with a change in
bullet design.

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Re: different bullets - groups in different locations?

Post by Larry Lang on 1/18/2012, 10:55 pm

Chris_D wrote:Correction was made to the O.P., it is 3.9 grains of B.E. for both bullets.

The shooting is all done at 25 yards, on the same day, with the same gun. I would certainly expect the same left-right, zero point between the loads.

Chris

I suggest you try 4.1g BE it works well for me, but you may have to make a + sight adjustment for the SHORT-LINE
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