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#1 RobertR

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Posted 14 March 2009 - 05:18 PM

I have had good luck with the 36 grain varmint grenades but the 50 grain grenades will not stabilize out of my gun. I have a 22-250, 700 BDL 1 in 14 twist barrel which Barnes recommends a 1 in 10 or greater twist for these leads. I have tried different powders and from the minimum to maximum loads to seating the lead from just off the lands to the SAMMI standard with no good results. These leads do nothing but key hole through the target even at 25 yards. I Have sent Barnes an email but no response yet. I have tole a friend who has a slower twist in his gun I would give him the leads if they would shoot out of his gun accuratly. If not Barnes is getting them back.

Here is why I am disgusted.
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#2 Spirithawk

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Posted 14 March 2009 - 05:33 PM

Wish I had an answer for you bud. Thats some serious tumbling! I don't blame you for being upset.

#3 Jeremiah

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Posted 14 March 2009 - 05:54 PM

:eek:

I've never seen anything that repeatedly bad before.

I'll be interested to hear what Barnes has to say.

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#4 PA RIDGE RUNNER

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Posted 14 March 2009 - 08:00 PM

If I recall correctly, Barnes bullets are all copper bullets so to get the weight they are much longer than a lead core bullet. That may be the cause.
It looks like your 1 in 14 twist is just too slow to stabilize that weight and length of bullet. My neighbor has a 22-250 that was a 1 in 12 twist. It shot bullets up to 55 grains very well but he wanted to shoot the 69 grain bullets. He sent it off and had it rebarreled for 22-250 Ackley Improved (AI) and a 1 in 9 twist. Now he shoots the 69 grain bullets extremely well but cannot shoot the lighter ones worth a hoot. I tried to tell him that would happen but he disagreed.
RR you may try the lead core 50 grain offerings and see if they will stabilize. I shoot a 222 rem with I believe a 1 in 12 twist and it does very well up to 55 grains. I had a guy give me some full metal jacket 50 grain bullets and I could not even hit the paper at 100 yds with several different powder charges. It shot so bad that I went and got my normal bullets and shot and got my usual 3/4 inch group so it was the bullet not the rifle. I would be very interested in what Barnes says, keep us posted.
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#5 RobertR

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Posted 15 March 2009 - 08:12 AM

PA you are right about the copper in more ways than one because not only does it have a copper jacket but the inside is compressed copper pellets so the impact is designed to be highly explosive. The 50 grain Barnes Grenade is a full 1/16th of an inch longer than the 55 grain Ballistic Tip Nosler's. I think your right about the length to weight ratio in this case. How ever this gun shoots 55 grain Nosler Ballistic Tips very accurate and I have had the same accuracy with the 60 grain Solid Base Noslers.
So I think it comes down to the rate of twist and faster is what these leads are designed for but we will see what reply from Barnes will be and I think they will say either barrel twist or use a different powder I'm guessing.
I think I'll stay with Nosler Ballistic Tips or Hornaday for varmint leads.
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#6 Leo

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Posted 16 March 2009 - 10:19 AM

I think what you are seeing there isn't technically "tumbling". When bullets have a tendency to tumble it's really pretty rare for them to all hit perfectly on the side of the bullet and cut out a neat silhouette of it's shape. There's usually more randomness to the shape cut out and they will point in a more consistent direction. Yours are clocking around.

Undoubtedly that's short axis rotation you are seeing but it looks like short axis rotation on the short axis which is parallel to the direction of travel. Tumbling happens when the bullet rotates around the short axis perpendicular to the axis of travel.

The reason that distinction is important is that sometimes short axis rotation around the parallel travel short axis doesn't effect accuracy! Interestingly, sometimes this effect sometimes actually improves long range accuracy. What happens is as the rotation slows down the bullets actually drop back into rotating around the long axis like they should. Kind of like those tops some of us got when we were kids. You spin them laying down and when they slow to the right rotation speed they "magically" stand up. I think it was Shilen barrels that figured this out but I don't think I can find the article now.

My point is close range keyholes aren't always what folks think they are.

Have you tried the same load at 100yards? I won't guarantee it's accurate but based on what I see on this one target it might be just fine.
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#7 PA RIDGE RUNNER

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Posted 16 March 2009 - 11:39 AM

Yea what Leo said ( I think). Just kidding Leo. Something is causing those bullets to yaw so badly that they are flying sideways and spinning as you say on the short axis. My One Hornady reloading manual gives an explanation of a bullet weighted to one side. In the barrel the bullet spins around the center of form but once it exits the barrel it rotates around the center of mass. There could be an off center weight problem since the cavity is filled with those pellets and there is bound to be voids between the pellets. At the rpms a bullet is rotating during flight it does not take much to throw them off. I am much interested in Barnes (a respected bullet manufacturer) explanation of what can be the cause.
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#8 Leo

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Posted 17 March 2009 - 11:00 AM

I suspect I didn't explain myself very well. It's really kinda tough to describe with words.

If a bullet is tumbling. It is rotating around the short axis perpendicular to its direction of travel. This is similar to the action of an axe being thrown at a target flipping end over end. On bullets this typically happens when the bullet is not spinning quickly enough around its long axis. Eventually all bullets do this as they run out of spin energy at long range.

As PA pointed out perhaps there is an imbalance where the geometric center does not coincide with the mass center. The imbalance problem can cause close range keyholes. But this really isn't tumbling. This is more like an airplane propeller spinning as normal travelling towards the target. This can cause the consistent printing of the side view of the bullet you are seeing. And because it's due to an error or inconsistentcy in bullet manufacture your accuracy will suffer. Based on the construction of the bullet you described this is a likely scenario.

You can also have a situation where the bullet is over twisted and goes into the same propeller type mode. If the bullet is balanced around its short axis. It actually can come out of this mode as it looses spin and start spinning around the long axis until it runs out of spin energy. This really weird behavior doesn't necessarily destroy accuracy. In some cases it's actually an advantage to do this because the bullet will have more spin energy to stabilize it further down range. I need to try and find that article I referred to earlier.
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#9 PA RIDGE RUNNER

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Posted 17 March 2009 - 08:21 PM

Here are the clues I saw to suggest an off center imbalance. He has shot from min to max powder charge with the same result. A 22-250 is a very fast rifle. A 1/12 or 1/14 is very common rate of twist. This rate of twist will normally readily handle from 40 to 55 or 60 gr bullets with great accuracy and speeds from 3200 to nearly 4000 fps. Since he can shoot standard bullets ok then the only variable in the equation is the different style of bullet.
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#10 Leo

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Posted 17 March 2009 - 08:42 PM

Well there is one more explanation that just occurred to me. Try micing these bullets to determine if they are undersized. It's possible they are 20cal and not 22cal.
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