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Having some wierd .30-06 issues ?? |
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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Posted: January/23/2013 at 10:00 |
Maybe you guys can help me. I am having some wierd stuff going on with my Cooper Excalibur .30-06. I had a Sako 75 .30-06 previously. I have shot 168 Winchester Ballistic tips out of both.
I put my Bushnell 6500 on the Cooper about a month ago. I sighted it in about 2.5 weeks ago and shot about a 1/4" 3 shot group at 100 yrds. I had it sighted in 2" high at 100 and at 300 yrds it was basically dead on. I know this should not be the case . I ended up setting it dead on at 100yrds and it was 9" low at 300 yrds......which basically were I had my .270 wsm Tikka T3 set. I shot a doe last weekend at 235yrds with the gun set at 100yrds and held dead on and nailed her with no noticable drop. I know the gun should not shoot that flat. The Sako sighted in 2.5" high at 100 yrds with the same bullets, same range, same targets, shot 8" low at 300 yrds. I think the barrel was about 2" shorter than the Cooper but that shouldn't make that big of a difference I don't think.
Well another thing popped up too. I have shot probably 30 of the 168 Win. BT through it with with no issues. But last weekend I was loading a bullet that was hard to bolt and it stuck in the chamber. I pulled really hard and it came out with marks on the bullet from the lands. So I sarted going through 3 boxes of shells and every other shell (or even 2 out of 3) is hitting the lands.One box is a year old and I bought 2 this weekend that I had not opened until I decided to check them against the old box.
Is that really wierd ? I don't see how my first couple of boxes would have worked. They are noticably longer OAL than 165 grain Fed. Sierra Gamekings or 165 Core loks. Just seems like overnight it just started.
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3_tens
Optics Jedi Master Joined: January/08/2007 Location: Oklahoma Status: Offline Points: 7853 |
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Are you shooting hand loads or variants of factory loads. There is often a sizable difference between factory specs. Even between the same version of ammunition by the same manufacture but with a different batch number. This is the primary reason to reload your own shells. So you can limit the variations. Carefully measure the shells that work vs the shell that are binding. If you have access to a chronograph, check the velocity if each batch of ammunition vs the others. Between these measurements you will see where your problem starts.
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Folks ain't got a sense of humor no more. They don't laugh they just get sore.
Need to follow the rules. Just hard to determine which set of rules to follow Now the rules have changed again. |
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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These are all factory loads. I don't have a chronograph but I have some digital calipers at work. |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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If your bullets are being pressed into the lands in your Cooper your driving up pressures which will account for an increase in velocity and a flatter trajectory. How much over your T3 is hard to say not knowing where the lands are in respect to the bullet in it.
Are you noticing any hard case extractions,more than usual recoil,or louder report from the Cooper? I'd compare the looks of the fired casings from each rifle. See how the primers compare. Are there any bulges? Is this coming from the Winchester ammo only not that it should make a difference?
I ran a few figures through a ballistics calculator and if the trajectories you posted are at least close to being accurate pressures are over the top. Edited by 300S&W - January/23/2013 at 12:48 |
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"I ain't got time to bleed!"
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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It has been kicking like a SOB the last couple times I shot the .30-06. I thought it was because I shot my 6.5x55 all season and wasn't used to it. And my scope mount screws loosened, I know they were tight. My scope slid back about a 1/4" before I noticed it. I didn't keep any of the casings last time I shot. This gun has always had trouble ejecting shells, Cooper replaced the extractor but it still will not eject a case without shells in the magazine. I feel like the spent case has to be supported before it will eject it and sometimes it still doesn't eject them. They are coming out of the barrel fine but don't want to "fly" out of the reciever, they just drop back on top of the magazine.
I know a guy that reloads, I will let him look at my cases and see what he thinks. Edited by cbm - January/23/2013 at 13:19 |
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RifleDude
MODERATOR EVIL OPPRESSOR Joined: October/13/2006 Location: Texas Status: Offline Points: 16337 |
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Are you certain you fired enough groups from both rifles to conclusively determine that your observations are from good, representative samples of true point of impact? Or, how do you know your scope on one of your rifles isn't shifting POI? If you're relying on only a group or two to draw your conclusions from, you can't be certain your results aren't due to normal shot dispersion from mechanical issues with your rifle/scope/mounts/ammo system affecting your achievable precision.
I'm not at all implying you don't know what you're doing; just going down the checklist of potential causes. |
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Ted
Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle. |
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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I don't own the 270WSM or Sako 30-06 anymore but I remember how they shot/were set up. I shot both of those guns probably 20-25 groups at this range, at the 300 yrd target. The Cooper I have shot less there but I shot at least 7 groups the other day between the Winchesters and I shot some 168 Federal Match Kings too. They were hitting in the same general area. The scope had gotten loose and shifted backward. The gun was shooting a little left compared to when I shot it two weeks ago but the elevation had not changed. I experienced no bullets hitting the lands I knew of two weeks ago. That started on this trip using the same box of ammo. But I do think I combined two boxes a while back into this particular box. But like I said, the new one's I bought on the way down are doing it too. Just seems wierd to me !
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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The thing that concerns me more than the trajectory info is the bullets into the lands (hard you say) with factory ammo. Also I can't think of any way the bbl could have gotten set back by itself. Without you having equipment to measure headspace or to measure the distance from the bolt face to lands my suggestion would be to locate someone who can. I take it this ammo fits into the magazine and feeds ok?
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"I ain't got time to bleed!"
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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Yes, it feeds fine and loads into the magazine fine. It did not do this a couple of years ago when I bought it/sighted it in originally. I have swapped scopes 3 times and resighted everytime with this ammo over the past couple of years. I doubt I have shot more than 100 rounds through it and have never noticed anything unusual until last weekend. I got some mud on the action and thought that was why the first one seized up the bolt. I did look in there and find a tiny piece if mud where the case rim seats into the barrel and removed it. But then the next few shells all seized up and when I yanked them out I could see the marks on the bullets. I think I shot it a couple of times with that piece of dirt down in there, it was about the size of a pin head but was hard to get out.It kept wanting to slide all the way around the rim instead of popping right out.
But all that was after I was shooting at the range and has nothing to do with the trajectory issues. |
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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Sounds like that debris was keeping the rounds fro hitting the lands. I'd have the Cooper gauged to find out how much throat she has. I'm guessing practically none! Also try a lighter bullet that should be a little shorter AOL wise....see if she goes smoothly into battery and doesn't kick much if she does...
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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tejas
Optics Journeyman Joined: March/08/2010 Location: Lone Star State Status: Offline Points: 575 |
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The overall length of one cartridge compared to another doesn't necessarily equate to one bullet touching the lands while another doesn't. It's more about ogive than length-the pointier sharper bullet can be longer and NOT touch the lands, than one thats blunt, like a 30/30 bullet.
Also, 30/06 head spaces from the shoulder-not the rim. Not sure where you removed the dirt from exactly, I doubt if that's your problem. When you measure the ammo, it should be 3.320 according to my Nosler reloading book. If it's an E-tip, 3.300. Ask your friend that reloads to help you. He probably will know how to check and compare different bullets in your chamber to see if it's out of spec. Good Luck. |
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8shots
Optics Jedi Knight Lord Of The Flies Joined: March/14/2007 Location: South Africa Status: Offline Points: 6253 |
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Another issue to check is the size of the chamber. A friend and I both shoot 308 Win. Same loads same specs, yet he had a flatter trajectory. What was apparent was the fact that if we only did neck resize (not full resize) my rounds would not fit in his rifle. You could not close the bolt on the round. His rounds would however fit easily in my rifle.
So maybe your rifle has a very tight cut chamber??
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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Thats what I was eluding too Wouter. tejas was correct ion siting the Olgive as being important as AOL, I just took a short-cut and said lighter round since Olgive is a function of bullet length but weight is moreso.
I'm betting the Cooper has a close tolerance chamber with a very short throat to boot... I seem to remember that Coopers have match grade chambering... (tight)
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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He's saying that with factory ammo the bullets are being pressed into the rifling. That wouldn't be caused by a tight chamber. To short or no leade maybe but he would have had the problem from the start. He's saying this just started. And yes the ogive varies on different bullets but we're talking factory ammo here. Hard to know what's wrong without having the rifle to see. Hopefully he'll get it to someone that can check it and the ammo out.
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"I ain't got time to bleed!"
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budperm
Optics Retard show me your sheep!! Joined: January/01/2009 Location: Pennsylvania Status: Offline Points: 31710 |
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Yep, he did remove debris that was keeping the casing from fully seating and making the bolt a hard throw. A tight chamber wouldn't cause issue (or shouldn't) with factory loads, once fireds possibly. he did say once fireds from his buddy's gun wouldn't chamber in his but once fireds from his aways fit this buddies gun fine. That tells me his chamber is tighter than his buddy's. When I say 'throat' I mean the amount of space between a chambered bullet and the beginning of the rifling.
As I understand it (please correct me if wrong) Since a 30-06 is a lipped casing it is the lip that is the contact point in the chamber and not the shoulder of the casing as is a lipless one. If debris was preventing the casing from fully seating then that would take a longer AOL to touch the lands.
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"Peace is that brief glorious moment in history when everybody stands around reloading".
--Thomas Jefferson |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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I'm guessing when you say lip your meaning neck? The 06 is a bottle neck case and headspaces on the shoulder(belted cases on the belt unless you resize them right). Optimumly lightly touching the shoulder area of the chamber. If it's too much away from it you'll get case separations from stretching. Shoulder too far forward or debris in that area and it won't chamber.
In the neck area you have to allow for expansion so they can't be cut overly tight. You have to keep the necks trimmed so they don't hit the front of the chamber thereby cutting into the bullet causing high pressures with loads that normally wouldn't when the cases are kept to that rifles oal spec. In front of the neck you have the leade,throat,freebore. All the same.
Without having his rifle it's just a guess as to what the problem is. From what he's describing the rifling got too close to the bullet or the bullet got too close to the rifling.
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"I ain't got time to bleed!"
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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I may have missed something or siad something wrong. I haven't shot any with anyone else's gun, no once fired in mine or vise versa. This is all with factory Winchester 168 grain Ballistic Silvertips straight off the shelf. But I have shot them in two different rifles of mine(SAKO 75 and this Cooper)
The Sako definately did not have this issue.
The casings were tight with the debris and without the debris(probably more with the debris but could have been those particular cartridges used I guess, they are the worst two I have tried so far). I thought it was the debris causing the bolt to be hard to close but it had no affect on closing the bolt once it was removed. Or I guess there was no change.
Like I say, I sighted the gun in mainly with this ammo. I can't remember exactly how many rounds I have shot but I shot at least a box . Then partial of two boxes. I never had a problem. I combined those two boxes and haven't shot it in a year. I shot a few Core lok 165's to get it roughly on after swapping scopes and then shot the combined box of Winchesters (that I used before)to dial it in(probably12 shells shooting from 100 and 300). I shot some matchking 168's too. I went down to hunt this time and shot 3 or 4 times at the range without a problem......then one cartridge was a little hard to bolt. Went hunting later and the next cartridge got stuck in the chamber and then all this started. Now every other one basically I have tried is somewhat hard to close the bolt. But the two particular ones have deep grooves in the bullet, a few have faint grooves, a bunch are a tad hard to get in but show no obvious grooves.
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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I hadn't got the impression from anything you said that you had used reloads or used the ammo in someone else's rifle. I'd also say the debris isn't or wasn't the problem. Going by what you've posted the bullet has gotten closer to the rifling(slipped forward in the case) or the rifling has gotten closer to the bullet(bbl moved back). If it we're mine I'd be getting a measurement from face of the bolt(closed unfired on safe) to the rifling. And compare that measurement to a measurement of one of those Winchester cartridges. Anyone into advanced handloading should be able to do it. One other possibility,and stranger things have happened,would be if some of that ammo had been loaded with the next size up in bullet diameter (8mm/.323)by mistake.
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"I ain't got time to bleed!"
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cbm
Optics Journeyman Joined: January/11/2008 Location: SC Status: Offline Points: 580 |
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I thought Bud had got the impression I was using other loads and guns, sorry. I talked to my buddy that reloads and he said he would take a look at it. Might have to take it to the gun smith too. But the ammo was purchased a couple years apart. Some I bought just last weekend and the box I started off using last weekend is a year or two old. All boxes have some hitting, some not. |
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300S&W
Optics God Joined: January/27/2008 Location: Burlington,WV Status: Offline Points: 10592 |
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It's probably best not to be firing it until it's found to be within spec. TOO NICE of a rifle to damage. Not to mention your extremeties too.
As far as some of the ammo having the wrong size bullet goes,the summer before last I came across a box of new factory .270 ammo where(per a letter from the manufacturer)a worn out sizer had set the shoulder too far back to where the ammo wouldn't fire. Things happen.
HOPE you get her straightened out.
Oh,and be sure to let us know the findings if you would.
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"I ain't got time to bleed!"
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