I have loaded Lapua brass (06) for my 280AI, with redding neck bushing dies, sizing down .003", and seated with a redding also. My runout on fouler's is only .002" at the most. All bullets used for groups are .001" or less. All cases are trimmed to match, gold medal primers, either RL22 or 7828 is the powder. My rounds are very concentric, but I am still getting a few FLYERS The first few will go hole-in-hole, and all of a sudden one will shoot off a 1/2" I have decided to try my RCBS casemaster guage to measure case thickness inside, at the case head/web area. The directions state that as you drag the case under the ball of the guage, and with the pointed rod inisde, if the guage reversed it's direction as you are removing the case, that means there is a thickness issue. Does this play a role in flyers??? or is this not related at all.

I am embarrassed to admit that I havn't tracked all the cases and their number of firings. Some have this reverse showing on the guage, and some don't. Could the ones with the reverse be my flyers?

Thanks

JustC--

I once formed 308-inch and a halfs from straight cases that I'd plunge milled to all the same shape and size. It' was a .300 rifle either way. I couldn't tell the difference.

If the bolt face is not square and is shot again out of phase it can cause a flyer, but out of square bolt faces can always throw flyers.

Inconsistent primer seating depth can also cause flyers.

I think what you are measuring is incipient case separation usually caused from too much headspace.

[ 04-07-2003, 07:28: Message edited by: onefunzr2 ]

My action is trued, lugs lapped etc. I wouldn't think that was it, but I can have the smith check it all.

Also, my cases are such, that when I close the bolt, the shoulder is slightly crushed against the chamber shoulder,...this means correct headspace right?

Now, if I am using the RCBS primer pocket uniformer, and a lee autoprime, how can I control the seating depth, or tell that is is incorrect? What else may cause the incorrect depth? Is there something to the uniformer other than running it in the pocket and twisting until the pocket is clean and shiny?

Thanks

[ 04-07-2003, 07:34: Message edited by: JustC ]

The best way to check uniformity of the capacity of your cases is to check the water capacity. Take your fired cases with the spent primers still in them and make sure they are all the same length. Weigh each one, fill it with water to the mouth of the case and weigh again. Then subtract the dry weight from that weight. If they are within �1g, that is probably not the cause of your flyers. You are likely to find some that exceed that and they should be culled, or used for foulers.

The other possibility is variation in bullet "grip". You can best uniform this by annealing case mouths about every four or five firings.

The body thickness of your case won't matter a great deal for flyers. The powder chamber capacity definitely will, and this can vary due to different thickness of the head or variance in extractor grooves when you cull only based on dry case weight. Same applies to the grip on the bullet. If one bullet seats hard and another seats easily, the grip will be different and will affect groups, particularly if there is quite a bit of clearance between chamber and brass on a seated bullet, or if the neck is worked excessively upon resizing.

[ 04-07-2003, 07:36: Message edited by: Bob338 ]

Bob338, is a varaiance in case capacity a situation which will cause uneven pressures and resulting velocity spreads? The battery on the chrono was fading yesterday, and the errors were more numerous than the readings, but a few rounds did register, and the spread was more than should be expected. Am I seeing variations due to what you suggested?

thanks

Hey JustC, One other thing Bob338 does is "mark" a case that threw a flier. If it throws another flier on the next firing, he removes it from the cases that get to go hunting.

A good tip I got from him a long time ago.

Of course it is. You asked for reasons for fliers and that's probably the most significant. Has more to do with it than the variant thickness of a case body, though if a case is very thin on one side and very thick on another, that will cause uneven combustion. Whether it will cause a flyer I wouldn't guess. It likely will be more of a factor than even very concentric ammo. Seating depth of bullets if they vary greatly also changes the volume of the powder chamber and will affect POI.

A significant variance in velocity also means variance in pressure. Pressure=velocity any way you look at it. If the bullet leaves the muzzle a greatly varying velocity it's not near as likely they can go to the same spot on the target.

Don't overlook the possibility of a problem in your barrel, particularly at the crown.

Bob338, thanks. I will do the water tests and see what developes.

onefunzr2, not the holy grail,...but being able to see it would be nice

I have a 27 1/2" pacnor finished at .875" on a trued 700action, skim bedded in an HS Precison, with the trigger done by the smith as well. I wouldn't say she is benchrest material, but better than the average hunting rig. With a 32x nightforce, centering on the bull and controling movement is also not the problem,.....I am perplexed by this accuracy issue however. It will do sub.5moa, it's just that damn flyer or two that are driving me insane

I take your advice to heart, with respect to the time factor involved. I have learned lots, by sitting and doing,.....it's the finer points that take the most effort, but will yield the most satisfaction in the end, I'm sure of it.

did you know that one of every thousand powder grains is actually a gremlin egg? these hatch in cool confined cylindrical spaces and only get their freedom when able to destroy a perfect bughole. Fortunately they are destroyed by sunlight, so no one ever sees them, just the damage they have done to the group.

My lot got more eggs than most, as far as I can tell

JusC,
Two in one hole and a flyer??? out 1/2", that gives you a 1/2 to 2/3 inch group and thats as good as a 280 Sporter is going to get regardless of what you do.....you do not have a problem, your creating one in your mind.

What kind of barrel are you using? Is it stress-relieved? It could have a miniscule warping problem as it heats up. Or perhaps there's a tiny flaw in one side of your bedding that is getting uneven pressure as the barrel and action heat up. If the flyers are always after shots 2 and 3, heating may be your problem, especially if the flyers are always in the same direction.

Atkinson and P-17, my barrel is a 27 1/2" pacnor select finished at .875" with an 11 degree, protected crown. This rifle has maybe 350rnds through it. I will have the smith pull her out, and look at the bedding.

It is usually after a few shots, you have a point there.

I will also be checking internal powder capacities, VIA the water test this weekend to determine if there are any "outliers" in the brass.

OK gentlemen. Here are some preliminary test results from this weekend;

I have completed the water test on the 15 fired cases which I had from the last range session. The extreme spread in internal powder capacity is .9gr!!!! Therefore, I can't foresee that being the problem.

I did take the time to use my primer pocket uniformer in each case, until no shavings came out of each individual one. I assume that by doing so, I have uniformed the over-all depth od each pocket, which should allow me to seat them more correctly/consistently.

I am left with a neck tension issue or primer seating issue, which I have hopefully rectified. As far as neck tension,....does anyone have an opinion as to whether .003" sizing is too much bushing to use on unturned necks? should I order .002" and .001" bushings? This is not a benchrest chamber, and is not a tight neck, it is however a far cry from SAAMI. The gunsmith who cut it, has been very consistent in his work in the past, and I am considering too much neck tension as a possibilty with a standard (quality reamer) 280AI chamber being used.

Any ideas or comments on my testing/results, changes so far?

Thanks much for your help thus far, I am learning a lot from the more experienced members here.

In the tests I ran on neck tension, or bullet grip, I found that the lighter the tension the better the accuracy. I used tensions from .005" down to .001" and the lighter tension gave the best accuracy. Tension above .003" didn't seem to matter. Accuracy didn't change nor get worse after the .003" grip. These tests were probably not statistically significant. As best I recall they were done in a proven load through a 338/300WSM and a 338 Win Mag. I doubt I fired more than a couple or three of 3 shot groups at the various grips.

I settled on .002" grip as the compromise. I was concerned with both accuracy and bullets in the magazine not altering seating depth upon recoil. As to the latter, the .002" grip held, the .001" did not. Those bullets set back. Both rifles weigh under 8 pounds.

Thank you Bob338, I will possibly place an order for the bushing this week, as it can't hurt to give it a try. I'm running out of things to test, which makes me hopeful that I am closer to the culprit.

Three other things to look at for your flyers, and they may have been mentioned by others. First, don't overlook the possibility of a loose reticle in your scope. Had that problem once and it drove me insane. A change of scopes cured the problem. It's far more common that imagined. Second, annealing the necks after about 4 or 5 reloads is vital to uniforming neck tension. Necks tend to harden, become brittle and give very disparate tension as they do so. Annealing the necks makes significant difference in accuracy. I've noted accuracy deteriorating some time after the third firing and I anneal as a matter of course on the fourth or fifth resizing. Third, make sure your lugs and lug recesses are free of foreign matter.

Again, I'd reiterate that you should look carefully at your action and barrel. If you're getting consistent flyers after a few shots, that virtually screams mechanical problem, as opposed to handload problem. You'd be surprised by how many barrels throw flyers once they heat up a bit.

Also agree with P-17. Once had a 22-250 with same problem. Cryogenic treatment of the barrel cured the flyer.

I will be reloading these newly pocket uniformed, freshly trimmed, and chamfered cases this week, and will fire them this weekend. I will shoot groups of 5 taking notice of when the flyers occue (i.e. after a few shots to heat the barrel up) as well as marking them for a second firing to determine if they are it.

I may give annealing a try too. I beleive I printed a thread on that from this board.

Can a laser etched reticle in a nightforce become loose, or would that be the whole optical lens? If so, does the lens usually allow a few good shots, or would it be sporadic from the start.

thanks Bob338 and P-17 for your continued assistance.

Gentlemen, I have found an area near the foreward end of the stock, whcih drags a dollar bill ever so slightly. The bill will still pass through, but it feels as though it is close to touching when cool/removed from safe. I am starting to lean toward your suggestions of the heat-up and touch scenario. You can't look at the rifle and see anything out of the ordinary, but evidently, she has shifted in her barrel channel. the contact seems to be on the lower right hand area of the diameter, so the side clearance appears ok. I am assuming that if there is still the slightest resistance, even though the bill still passes through, would be exagerated when the barrel has heated up. I will be having the gunsmith take a look at it when I go to pick up the new rig, or maybe before. the weather is breaking here, and I got the itch

That clearance is your problem. Depending on the stock you have, when the rifle is on a front rest, or on your hold, the forend of the stock will spring enough for contact with the oscillating barrel. Hog the channel out enough to give you about .050" clearance and that should be your answer.

I'll advise as things become avaialable. Won't be wasting any more barrel life or case life until that channel is releived.

I agree with Bob338 exactly, depending on your hold and pressure on the forend in the rest it could be touching before you even PULL the trigger too. Inconsistancy is the result. Good luck.

When you finish cleaning that barrel channel, put the paper in there again. Using a one-handed grip around the barrel and stock, try to "squash" the barrel against the paper. At the same time, try to remove the paper with the other hand. If you can pinch the paper between the barrel and the stock at any time, you haven't opened the channel enough.

Brent and P-17, gunsmith has been notified and situation will be rectified. I look foreward to posting a group from this rig when it shows it's true colors once again. I know it's not a benchrest rifle, but a 150gr bullet in low.3's and high .2's was a real joy when it was available.

I will BTT this as soon as I get things ironed out. He is busy, so time is the mitigating factor now.