Problem with CP heavies keyholing at 50

Problem with CP heavies keyholing at 50

Joined: April 23rd, 2010, 8:52 pm

October 28th, 2010, 1:04 pm #1

I'm shooting the cp 10.5 out of a LW barrel. They are pretty accurate but I find a lot of hits on paper at fifty yards where the pellet struck sideways. What I would like to do is find a barrel with a faster twist rate. Does anyone have any ideas?
Thanks,
Dan

see pics below
Last edited by Obturate on October 29th, 2010, 1:46 am, edited 1 time in total.
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Joined: February 15th, 2010, 10:01 pm

October 28th, 2010, 5:07 pm #2

my Daystate MK4. Each had minor differences but I NEVER had key holing. Your a sharp guy so I'm not going to bother with the suggestions of clipping, odd tears of paper, etc...

(+) Paul (+)
USFT #230
Daystate MK 4 iS MCT
FX Whisper .22
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Joined: April 12th, 2006, 7:56 am

October 28th, 2010, 8:55 pm #3

I'm shooting the cp 10.5 out of a LW barrel. They are pretty accurate but I find a lot of hits on paper at fifty yards where the pellet struck sideways. What I would like to do is find a barrel with a faster twist rate. Does anyone have any ideas?
Thanks,
Dan

see pics below
Grouping, vertical stringing or patterning? If they're grouping sub 1" @ 50, use those pellets for practicing. Never heard of CPH's keyholing from any 12FPE+ airgun even well past 55 yards.
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lhd
Joined: January 9th, 2002, 2:30 am

October 28th, 2010, 11:09 pm #4

I'm shooting the cp 10.5 out of a LW barrel. They are pretty accurate but I find a lot of hits on paper at fifty yards where the pellet struck sideways. What I would like to do is find a barrel with a faster twist rate. Does anyone have any ideas?
Thanks,
Dan

see pics below
Also. Sometimes it was the breech had a little problem, sometimes the muzzle, once I went thru em and made em right, I got nice round holes. Mostly, I look to some sort of gizmo the owner has decided to hang on the barrel cause it looks cool.

I have shot LW and HW barrels at 10yds and fifty yds, and its not common to see keyholing.

I have written this before, and want to repeat it: if even ONE barrel with a given twist rate can shoot those pellets without keyholing, then I say look for another reason for the keyholing.

I know its pretty popular for folks that have read a bit about firearms barrels and the Greenhill "formula" to want to talk about rifling twist quite bit. I figger they mostly do this because its one of the FEW things the average Joe is capable of measuring with any degree of accuracy. But just because its so easy to measure doesn't make it all that important.
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Joined: April 19th, 2004, 7:02 pm

October 29th, 2010, 12:01 am #5

1)the breech was choked in addition to the muzzle ?


"Thumper2"
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lhd
Joined: January 9th, 2002, 2:30 am

October 29th, 2010, 12:16 am #6

That's a very common condition in many, many break-barreled springers, and usually, there is NO outward symptom so long as the choke at the breech is at least the size of the one at the leade.
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Joined: April 19th, 2004, 7:02 pm

October 29th, 2010, 12:18 am #7

nt

"Thumper2"
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Joined: April 23rd, 2010, 8:52 pm

October 29th, 2010, 12:52 am #8

I'm shooting the cp 10.5 out of a LW barrel. They are pretty accurate but I find a lot of hits on paper at fifty yards where the pellet struck sideways. What I would like to do is find a barrel with a faster twist rate. Does anyone have any ideas?
Thanks,
Dan

see pics below
Perhaps keyholing is too strong a term, how about yawing.


I'm not so arrogant as to propose that my barrel prep skills are perfect, it is possibly the cause. I have seen it in other peoples .177 targets at 50 yards and they weren't aware that it was happening.
If you look at the first photo that is 5 shots inside of .15" at 50 yards with a sixth shot outside the group with definite imperfect angle of entry.
The second target has four shots inside of .185" and one outside. I would think that if the gun can make groups like this that the barrel prep is probably not the cause.
Dan
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Joined: April 23rd, 2010, 8:52 pm

October 29th, 2010, 1:15 am #9

I should add, I don't see the keyholing with pellets less than ten grains or when shot at 25 yards.
Dan
Last edited by Obturate on October 29th, 2010, 1:18 am, edited 1 time in total.
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Joined: April 12th, 2006, 7:56 am

October 29th, 2010, 2:36 am #10

Perhaps keyholing is too strong a term, how about yawing.


I'm not so arrogant as to propose that my barrel prep skills are perfect, it is possibly the cause. I have seen it in other peoples .177 targets at 50 yards and they weren't aware that it was happening.
If you look at the first photo that is 5 shots inside of .15" at 50 yards with a sixth shot outside the group with definite imperfect angle of entry.
The second target has four shots inside of .185" and one outside. I would think that if the gun can make groups like this that the barrel prep is probably not the cause.
Dan
With a flyer 1/5 times. I'd say you've got a tiny burr somewhere that builds up lead and the fifth shot knocks it off. As far as entering with some yaw, most of my roundnosed pellets don't cut paper that cleanly even at 10 yards. If you're a 10m shooter whose always shot wadcutters, round nosed holes can be disconcerting at first glance
but the accuracy is there.
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