I recently took delivery of my new custom Swift. It has a Shilen bbl., Bell & Carlson stock, Timney trigger, bedded and floated. The bbl. floating is suspicious. The floating job is the tightest I've had. You can pull a dollar bill almost to the lugs but it is a tight pull in certain places. It's tight but it always goes by.

My problem is that my groups are moving. If I shoot 5 shots, 3 are in a good group near the bull and 2 are in a good group inches away from the first 3 bullet holes.

It seems like the problem could be bbl. contact.... even though the dollar bill still passes when the bbl. is hot (a little tighter when hot).

My question is.. Can hot (expanded) barrel whip jump the narrow floating area and contact the stock, causing the group to move to a higher spot?

Maybe I should just sand the bbl. channel down some more and see if that fixes it. Any ideas?

I would sand it out a little. it may be contacting the stock. also check the scope and mounts. make sure the recoil lug is in tight.
the stock screws should be good and snug. i torque mine to about 50 inch pounds some a a little tighter.
is it on pillers? what action ?
If its a savage make sure the rear tang doess not touch the stock. If its a winchester the middle screw should just be tight enough so it does not fall out. if its a wimpy barrel 3 shot groups will be about as good as you can get before you cool it down.
Dave

sounds to me like an action bedding problem

If you could tell me which shots went together and which two went out of the group I can probably tell you exactly where the problem is.

in other words number each shot from 1 to 5 and let me know where they hit the target.

What I suspect may be the prolem is the the action is shifting and that can be caused by the front screw being loose or tightened fully but is too long to pull the recoil lug into position.

hivelosity wrote:-------------
I would sand it out a little. It may be contacting the stock. Also check the scope and mounts. Make sure the recoil lug is in tight.
The stock screws should be good and snug. I torque mine to about 50 inch pounds some a little tighter. Is is it on pillars? What
action?
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The action is a Ruger 77 w/ tang safety. I've torqued everything that moves. The barrel is a #3 contour Shilen SS with a 4x12 Leupold on top.

Atkinson wrote:---------------
If you could tell me which shots went together and which two went out of the group I can probably tell you exactly where the problem is.
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This has happened several times. I put the first three shots into a 1/2" group and start thinking I have a load. Then shots 4 and 5 are about 2" high (but in a good group as well).
I've tried letting the barrel cool several minutes after the first couple of shots but it doesn't seem to help.

Since the dollar bill always passes down the barrel (even when hot) I wonder if I am getting some whip that touches the stock and changes the harmonics. Possible?

Thanks for the ideas and experience. Maybe I just need to get out the sandpaper and make the air space even bigger.

quote:

Originally posted by Atkinson:
If you could tell me which shots went together and which two went out of the group I can probably tell you exactly where the problem is.

in other words number each shot from 1 to 5 and let me know where they hit the target.

What I suspect may be the prolem is the the action is shifting and that can be caused by the front screw being loose or tightened fully but is too long to pull the recoil lug into position.

atkinson, what happens if it doesnt it at random?

quote:

.... even though the dollar bill still passes when the bbl. is hot (a little tighter when hot).

Whatever your "problem" is from, that's NOT enough barrel clearance to be floated.

The oft suggested "dollar bill" test is foolish, it only means there is .003" of clearance. Maybe .002" where it gets tight.

Any stock forearm will bend that much depending on where/how you hold or support it and that will cause inconsistant contact that destroys accuracy.

Thanks for the reply Jim C. I've always wondered how much space constitutes "floating". I have a tight grouping 25-06 that has so much space (about 1/16th") around the bbl that it looks funky. I hoped the Swift could be grouped and still look like it is properly fitted.

The Bell and Carlson stock (my first non-wood)is rubbery in the forend. I can pull it away from the bbl. I have been shooting off the bench with the front support close to the bbl lug to try to stay away from the forend. How much do I need to float it to eliminate contact problems?

Mr.Atkinson - Thanks for your idea. You were right. The screw was bottomed out. I shortened it and shot several groups. I still get the first two shots in a half inch and then the next shots an inch or so to the NorthEast.
I am using 55 V Max's, 53 TSX's, and 60 Hornady SHP's and all group well with the first 2 shots.

Just my 2 cents but I had the same problem w/ a remington 700 pss. I was about to throw it in a river but then realized that my $1100 brand new scope was trash. Changed scope equalled instant tack driver. If you havent changed scopes you might just want to try it.

I had a 6mm Remington 700 that shot like that about 40 years ago. We tried everything. It would shoot two shots in .350 or less then the group would move southwest about 3/4 or 1". Always to the same spot. This was a sporter bbl. The trouble wound up being a bbl. that had been straightened, which almost all sporters have been, but when it got hot it would return to it's original shape. As long as i didn't shoot more than two shots every thirty minutes it would shoot under 1/2". If it did get hot i knew where it was going and could compensate. As this was a walk around groundhog rifle and my buddy and i took turns shooting, i shot the bbl. out of it the way it was. Took a ton of groundhogs with that rifle. Anyway just food for thought, something to check out. Maybe go out some day when you have good conditions and try waiting 30 minutes between 3 shot groups.

Go fast,
From your description I think the problem is in the tang of your rifle being bedded too low. That causes one or two shots to go high from the group..

Paul in NZ,
If its random and has no pattern then it can be shooter era, bad barrel, bad crown and several others problems and you have to go with a process of elemination I suppose..

I will only tolerate these problems so long then off comes the barrel and on goes a new one. some barrels are finicky and they will never be a good barrel IMO...Use'em for tent stakes!

I vote with Jim C. The first thing I would do with that rifle is make sure it had at least 1/16"th clearance its whole length in the barrel channel. Or at least I would if it was not a "plastic" stock. With the composite ones such as yours, I am not sure if the stock walls are thick enough to let you do that without ruining the stock.

You mention that the last 2 shots of a 5-shot group are generally the bad ones. Here's a sheaf of things to think on. No. 1, barrels don't get stiffer as they warm up. A barrel with a little warming may be just a tiny tad more flexible, just enough to twang against that stock as a bullet moves through it

2nd. barrels do expand and contract as the bullet moves through them. You can actually feel a bullet move through a barrel, if you have your fingers around the barrel when it is fired (assuming a small enough charge of powder to not make the recoil hide that feeling). Try it with a light barreled .22 LR; you'll be surprised how clearly you can feel the bullet pass between your fingers.

3rd. - The barrel at rest is an entirely different shape than a barrel during firing. During firing, the barrel is shaped more like a moving snake, a series of waves rather than a perfectly straight line. So, during the movement it may be hitting the stock.

No. 4, barrels lengthen as they warm. If they are tapered, that moves them forward, closer to the stock's tapered bore channel.

So, combining all those things, even though none of them by itself may do the dirty deed, working together they may be creating contact when you want it least, as the barrel warms even slightly.

Whether or not anything else is wrong (and it may well be), I'd open the barrel channel substantially.

Now, about looks....if you leave the very top of the stock's barrel channel almost where it is at now, and relieve the channel by undercutting that top edge and opening the bottom half of the channel, you can get lots of clearance almost without having any of it show at a casual glance. It takes a lot more time and care to open it that way, but it is done regularly by some professionals.

Good luck.

Several things as mentioned but I doubt the barrel floating has any thing to do with it. If the dollar bill slips by even by a little then 3 shots isn't going to heat it enough to cause a 2" POI shift. I'd say the bedding is suspect as mentioned. When the fron action screw is tightened macke sure the tang does not rise up out of the stock. Then as the tang screw is tightened make sure the tang does not move down into the staock. If either occurs the action is binding and not bedded correctly. Then I'd look at the scope mounts to make sure they are tight. If so I would then suspect the scope, also as mentioned, and put a scope of known performance on the rifle and test it.

Larry Gibson

quote:

Originally posted by Larry Gibson:
Several things as mentioned but I doubt the barrel floating has any thing to do with it. If the dollar bill slips by even by a little then 3 shots isn't going to heat it enough to cause a 2" POI shift. I'd say the bedding is suspect as mentioned. When the fron action screw is tightened macke sure the tang does not rise up out of the stock. Then as the tang screw is tightened make sure the tang does not move down into the staock. If either occurs the action is binding and not bedded correctly. Then I'd look at the scope mounts to make sure they are tight. If so I would then suspect the scope, also as mentioned, and put a scope of known performance on the rifle and test it.

Larry Gibson

Begging your pardon Larry, but it is not the "heating" per se which might cause the POI change for the last two shots in groups. It could be caused IF there was a change from no contact to any contact at all, though. That could well do it.

Since none of us know what is happening, as none of us can see the rifle or test it, we have to list the things which COULD be causing or contributing to problems. Eliminating any possibility of barrel contact with the stock would eliminate that potential source.

It could well be something else altogether but none of us here actually KNOW that to be a fact.

So we had to start somewhere in eliminating possible contributors to the problem. I just listed what I would start with. It was not suggested as a probable cure-all.

As to the bedding, that could also be a problem, but why do you think the bedding regularly does NOT allow such a move for the first three shots, then all of a sudden allows it for the last two? (And then apparently re-sets itself for the next group...)

That appears to be the pattern of the problem he has reported and is seeking help for.

I have a Weatherby Ultralight in 3006 that would walk after 2 to 3 shots depending on how long I would wait between shots. I removed the barreled action and discovered that the 2 little pressure bumps at the end of the synthetic stock were mashed, malformed. This was the first time I had removed the barreled action from the stock. I decided to free float the barrel. Instead of removing material from the stock, I raised and shimmed the forward recoil lug about 1/16â€. This free floated the barrel back to the receiver. I was pleasantly surprised with the groups I got at the Range, 3 & 4 shot groups a little over 1†with both 180gr. & 165 gr. Sierra heads. This was accomplished without waiting long periods of time between shots. Due to the slim barrel it has left a larger than normal space between the barrel & stock, a dollar bill starts to get tight 1 1/2†before the receiver. As long as I am getting this kind of groups I am not going to be too concerned about how this looks.

Gofast,
If you can send me the pictues of the groups and number the shots in order that they were fired, then I can better tell you where the problems lie..

quote:

My question is.. Can hot (expanded) barrel whip jump the narrow floating area and contact the stock, causing the group to move to a higher spot?

Yes, it could. But believe me, NOT all barrels shoot their best when free-floated! Some require stock contact, usually but not always consisting of 10-20 pounds of upward pressure in the forend, to shoot well. I have even had a couple that shot best when FULLY glass-bedded the entire lenght of the channel from the rear of the receiver ring to the muzzle!

Alberta Canuck

"As to the bedding, that could also be a problem, but why do you think the bedding regularly does NOT allow such a move for the first three shots, then all of a sudden allows it for the last two? (And then apparently re-sets itself for the next group...)"

Because I've seen this exact problem too many times over the years to not suspect the bedding or loose scope mounts first. It very well could be that the bedding is allowing the action to shift and the barrel to touch the stock. If so it is still a bedding problem (especialy if the action is bending when the action screws are tightened) and not a barrel floating problem. Sorry but I don't see that we're in disagreement here.

Larry Gibson

quote:

Originally posted by Larry Gibson:
Alberta Canuck

"As to the bedding, that could also be a problem, but why do you think the bedding regularly does NOT allow such a move for the first three shots, then all of a sudden allows it for the last two? (And then apparently re-sets itself for the next group...)"

Because I've seen this exact problem too many times over the years to not suspect the bedding or loose scope mounts first. It very well could be that the bedding is allowing the action to shift and the barrel to touch the stock. If so it is still a bedding problem (especialy if the action is bending when the action screws are tightened) and not a barrel floating problem. Sorry but I don't see that we're in disagreement here.

Larry Gibson

And it COULD be that with even a tiny bit of heating and all three of the changes such heating can cause, it COULD cause the barrel to begin touching the stock during firing, as the clearance is almost non-existant to begin with.

I certainly agree it could be bedding, but it is easy to eliminate the potential clearance/touching problem, while it is more difficult to re-do the bedding (especially for those not practiced at it). So, I was simply suggesting starting with the easiest one to eliminate as a problem.

As to the bedding holding firm for three shots, then moving for two, then moving back on its own, I wasn't suggesting it didn't do that. I was asking what particular bedding problem you thought might cause that pattern of POI behavior, at least partially so he might have a clue what to look for there.

Bell & Carlson stocks are easily sanded. Should be a quick check to take a little more out of the barrel channel.

I REALLY appreciate the technical support you guys provide. I am going to work the bbl channel tomorrow and shoot some groups. I have taken about 1/64 to 1/32 or so out of the channel and will try to double that. The forend seems kind of "flexy" now and that will probably worsen.

One thing I was messing up on was screw tightening. I recently found out about the center screw (being tightened less). I had it real tight. Hope I didn't bend anything.

Also, I'm going to look closely at the tang to see if it rocks when I tighten the recoil lug. I'll post progress.... and thanks again for the knowledge.

Well, I completed the changes outlined in the above post. It is getting worse. I took the Swift to the deer lease loaded with 53 gr TSX's that shot a 1" group last week hoping to thin the hogs some. I transported it in a hard case. First shots were missing POA by 6". I made the changes above and was rewarded with a 4" group. Things must change.

Tomorrow it is going back to the custom gunsmith. I'll demand a new bedding job. I can see faults in the bedding and have identified others as a result of helpful posts. 250 rounds and no consistant improvement is too much work for nothing. Thanks for the help to date.....arrrrgggh! More later.

Sorry to hear it wasn't easily solved. At least you now know for a fact it is not something you can fix in a hurry yourself.

I don't remember, but did you say you checked your barrrel crown? That probably is not the problem, as it hasn't changed yet the groups have worsened. Still, you might want to check it with a magnifying glass before going to the 'smith. If it has any nicks or mars, you can have him quickly repair that too, while it is there.

Good luck with the re-bed.

AC

As a stock maker, I abhor big gaps on each side of the barrel and it really accomplishes nothing but a place to hide bugs, dirt, grass burrs, snow, rain, beer caps, horseshoe nails, and all manor of trash type "thangs"

One can "inlet" a barrel channel leaving a knife edge of wood without disturbing barrel sonics. If that wood moves left or right with in big gap inletted stock, it may not make contact with the forend because of the gappadoses you created, but it WILL bind at the tang and that will deplete accuracy..

Makes a good case for stable wood or composite stocks, I prefer stable wood, and yes such wood does exist and is on many of my old rifles.

How many old pre 64 model 70s have we seen with gaposis on each side of the barrel channel and ruined the value of the gun..Many many is my count and ugly ugly is my opine.

Yeh, Ray, when you're talking well done stocking, with good stable wood, I'd agree with you wholeheartedly.

Unfortunately in these days lots of stocking (and lots of gunsmithing) is not particularly well done, and much of the wood of today we would have used to light the kitchen stove some years ago. At least it would then have served a useful purpose... making fresh bread.

But in this instance we were talking something a bit different as to gun components, and those "easy" fixes which MIGHT have alleviated the problem at least temporarily. Turns out floating didn't do the trick,but then we don't know yet if re-bedding will either. We don't know lots of the niceties of the gun's construction, its assembly concentricity, actual barrel quality, soundness of the telescope sight, and a zillion other things.

So, we were applying the SWAG principle....which is about all one can expect from on-line diagnosis & prescription. Some times it works, some times the patient dies.

These moving groups - I have spent a week on a roll forming machine that keeps changing the products shape! It seems that some irregularities (unrelieved stress, misalignment etc) will cause extreme sensitivity to small changes in temperature. Maybe in a gun, the same can happen with small changes in hand hold too? My beloved 22lr (Remington 512 Sportmaster) shot fine untill I put a 'silencer' on it with slightly out of line baffles. That's how I found out the muzzle was worn open like a funnel! (I have since cut back the barrel, re-crowned it and fitted a straight silencer of my own design, and it now shoots scary accurate! - Even when I shoot it. - shortest and quietest 22lr silencer I have ever seen/not-heard! - even without my boasting! ) Before that, I tried bedding it, fitting a second mounting screw, all the ammo brands under the New Zealand sun - (or is that rain?) Hey, great place this! I happen to love the rain! (And the mud!)

Alberta Canuck, I always enjoy reading your posts - you are a very wise man! I have learned a lot from you. Thanks!

Ray, I would like to ask whether there would be any merit in filling a 'substantial' gap between barrel and channel (assuming a stable and heavy fore-end) with a rubbery type compound such as polyurethane rubber, without pre-tension but 'bonded' to both channel and barrel? This would at least keep 'stuff' out. This leads to a secon question on bedding, I have always used a 'flexible' compound for my bedding jobs and have always seemed to have success (I make it sound like I have done many - no, just a few, way to few to draw any conclusions). Would a flexible (even more than mine) compound be of any benefit? and if used in the full fore-end? (As opposed to a flexible damping fill)? (Remembering that I do not posses your stock making skills). Thanks in advance.

gofast, thanks for 'letting' me 'borrow' your thread! I hope my questions are relevent to you too!

Gentlemen, I appreciate your help on my 220 Swift "moving groups" problem and I figure I owe you a final accounting.

The problem was "fixable" poor workmanship and a deceptive gunsmith. I ordered a 1:12 twist barrel because I wanted to shoot longer bullets....specifically the 53gr TSX. I shot boxes of the things trying to get a group. You guys helped me clean up the workmanship issues.

Turns out that the problem all along was that the gunsmith sold me a Shilen he had on hand that was a 1:14 twist. I checked it as I was cleaning the barrel and was shocked. I wondered why he was so adamant that I use 52 gr. Shilen bullets. We argued many times over the 52's because I told him I didn't want to use a paper punching bullet on coyotes, hogs, and such.

Long 53 gr. TSX's won't stabilize in the 1:14 barrel...hence the flyers. That was it all the time. Damn him. It cost me a lot of money and frustration. No offer from him to make it right. Thanks again for the help.

quote:

As a stock maker, I abhor big gaps on each side of the barrel

Ray, I fully concur, in concept. But, springy tupperware stocks, of any brand, ain't much for classic good loods anyway.

A stock gap that is large enough so it can't be warped by changing hand pressure to contact the barrel in erratic ways "looks" better than a tighter fit that fouls accuracy!