I have been shooting non comp bench rest for a long time. I think 95% of my flyers were my fault , not the gun or cartridge. You never stated what kind of rifle you are shooting or if your talking about competitive shooting.
Headspace and accuracy
- Thread starter rain164845
- Start date
I have been shooting non comp bench rest for a long time. I think 95% of my flyers were my fault , not the gun or cartridge. You never stated what kind of rifle you are shooting or if your talking about competitive shooting.
Do you test things and publish your results?
Perhaps someone will learn from my experiment.
I know I did.
Well for me a case gauge that measures to SAAMI specs is useless
No one i know sizes their cases to SAAMI specs
You size your brass to match your chamber. All new brass is created to fit the tightest of.chambers. i don't even bother to start load development until that brass is fully fireformed.
I am a full length resizer not a neck sizer. I have tried neck sizing and just prefer full length resizing. Now that said i have dies that are made from my fired brass.
Sure the old rat turd in a violin case works but it sure will reduce the life.of your brass.
All these different methods can create accurate ammo. Whatever works for you.
No one i know sizes their cases to SAAMI specs
You size your brass to match your chamber. All new brass is created to fit the tightest of.chambers. i don't even bother to start load development until that brass is fully fireformed.
I am a full length resizer not a neck sizer. I have tried neck sizing and just prefer full length resizing. Now that said i have dies that are made from my fired brass.
Sure the old rat turd in a violin case works but it sure will reduce the life.of your brass.
All these different methods can create accurate ammo. Whatever works for you.
I think the takeaway for me is that there was no change in accuracy from .007 headspace to .0015 headspace.
It goes without saying that more headspace will reduce case life, but that was not the question.
Also, I notice flyers when I have a hard to chamber case.
So, I think when setting the sizing die, it is probably best to get on the side of an extra thou of shoulder setback rather than too little.
It goes without saying that more headspace will reduce case life, but that was not the question.
Also, I notice flyers when I have a hard to chamber case.
So, I think when setting the sizing die, it is probably best to get on the side of an extra thou of shoulder setback rather than too little.
If the targets were overlaid, there would be a group at about 9p clock. I consider the rest flyers. Frequent flyers.
Ned Ludd
Silver $$ Contributor
Not being one that likes to fireform brass and get nothing in return (except fired brass), I routinely do load development in prepped virgin brass. I often shoot local matches using the same. Typically, loads developed this way require only very minor tweaking once the brass is fireformed, so I view it as getting a little better return for my efforts. The key here is that in both .223 and .308, I often see the shoulders on virgin brass move from .005" to .008" on the first firing with virgin brass. I have never noticed the excessive headspace to be any impediment whatsoever to precision using virgin brass. What I have noticed is that it possible to blow primers with the excessive headspace of virgin brass, even with loads that are not overpressure. Typically, I have seen this occur on rare occasions and only at the upper end of a charge weight test series, but at pressures well under MAX as predicted by Quickload. Presumably, case movement during the firing process combined with the extra headspace is largely responsible, allowing the primer to pop out at pressures under which it would never exhibit such behavior in fireformed (longer) brass.
Looks like your load has gone out of tune to me. Powder charge, seating depth or a combination of both. Have you changed any lots of components lately?
What about the temperature?
Brians356
Gold $$ Contributor
To flog a dead horse, .008" headspace with virgin brass is not "excessive", it's perfectly within spec and therefore "normal".
If you can find a single virgin case that exhibits only .002" or less headspace inside a production chamber, trot it out so we can all marvel at it. If you can find two, I'll buy one from you.
"Excessive headspace" has a specific connotation in the jargon of firearms and reloading, specifically "dangerous headspace". In the context of this forum, it's fair to say it has a more focused meaning (valid or otherwise) tailored to perceived best practices for precision shooting. But there are undoubtedly neophytes reading this forum who merit not being unduly alarmed or led astray by ill-chosen terminology or misleading characterizations.
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Sorry I thought that went without saying, as in the powder charge may be out of tune for the temperature.
A short oal chamber, like .001 to .0005 over go-gauge; or even cut to fit the virgin or small-base sized unfired brass, will deliver longer brass life and enhance performance.
Do you fire factory rounds in your rifle? Probably not the approach for you. If you handload all your ammunition this is the ticket. Can have your chamber set back, usually by removing a thousandth or two from barrel shoulder, or have your new barrel reamed to the spec you deriive by using a Wilson Case Gauge, or RCBS Precision Mic using your unfired but uniformed brass dimension.
To evaluate your chamber, compare virgin brass to a piece of once-fired. There's probably a lot of variation; at least with a factory chamber. If you're shooting a belted magnum, you want to headspace on shoulder not belt. Magnums show great improvement, again, unless done by competent smith who did more than run the reamer in one pass. Cutting the belt relief first, and then reaming to depth of your brass or specification will gain a lot. Improving a magnum chamber is very simple. RCBS Precision Mic uses a case-holder and a threaded micrometer like thimble with .0500" per revolution marked on the thimble. Thread onto your brass and record the before/after mic position. Wilson Case Gauge works similarly but need dial caliper to read the variation. The RCBS tool is not calibrated to any standard. Readings are unique to each mic. For $50 its a pretty versatile tool and fast & easy to use. It will accurately measure the change in your case.
If you buy a lot of brass, like 500 from the same production batch or lot # to cull from, find your most uniform brass before your chamber job, or setback. Tailor your chamber to that selected set of cases. Probably want to evaluate your sizing die as well. Basically want the minimum of case stretch from the first firing onward, and the least "work" put on the brass when reloading it. I have seen very large virgin:1x-fired sizes. If you don't have an initial stretch of significant length on your case, your brass will remain with all its original tensile strength and elasticity. If the energy your powder charge produces is not absorbed in stretching brass to a greater length than necessary, it delivers more pressure to your bullet.
edited to add: Of Course, this information is NOT Pertinent to Semi-Auto chambering rifles. Very critical to allow .0035 to .004 to allow proper seating for the semi-auto action. Also, no single loading unless stripped from magazine to give correct resistance effort to bolt seating inertia, otherwise could enable a SlamFire. Not a good thing...
Also, if handloading for several semi-auto rifles, must consider each chamber and set sizer .0035 - .004 from shallowest chamber depth.
Do you fire factory rounds in your rifle? Probably not the approach for you. If you handload all your ammunition this is the ticket. Can have your chamber set back, usually by removing a thousandth or two from barrel shoulder, or have your new barrel reamed to the spec you deriive by using a Wilson Case Gauge, or RCBS Precision Mic using your unfired but uniformed brass dimension.
To evaluate your chamber, compare virgin brass to a piece of once-fired. There's probably a lot of variation; at least with a factory chamber. If you're shooting a belted magnum, you want to headspace on shoulder not belt. Magnums show great improvement, again, unless done by competent smith who did more than run the reamer in one pass. Cutting the belt relief first, and then reaming to depth of your brass or specification will gain a lot. Improving a magnum chamber is very simple. RCBS Precision Mic uses a case-holder and a threaded micrometer like thimble with .0500" per revolution marked on the thimble. Thread onto your brass and record the before/after mic position. Wilson Case Gauge works similarly but need dial caliper to read the variation. The RCBS tool is not calibrated to any standard. Readings are unique to each mic. For $50 its a pretty versatile tool and fast & easy to use. It will accurately measure the change in your case.
If you buy a lot of brass, like 500 from the same production batch or lot # to cull from, find your most uniform brass before your chamber job, or setback. Tailor your chamber to that selected set of cases. Probably want to evaluate your sizing die as well. Basically want the minimum of case stretch from the first firing onward, and the least "work" put on the brass when reloading it. I have seen very large virgin:1x-fired sizes. If you don't have an initial stretch of significant length on your case, your brass will remain with all its original tensile strength and elasticity. If the energy your powder charge produces is not absorbed in stretching brass to a greater length than necessary, it delivers more pressure to your bullet.
edited to add: Of Course, this information is NOT Pertinent to Semi-Auto chambering rifles. Very critical to allow .0035 to .004 to allow proper seating for the semi-auto action. Also, no single loading unless stripped from magazine to give correct resistance effort to bolt seating inertia, otherwise could enable a SlamFire. Not a good thing...
Also, if handloading for several semi-auto rifles, must consider each chamber and set sizer .0035 - .004 from shallowest chamber depth.
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Ned Ludd
Silver $$ Contributor
Headspace can have more than one connotation, and just because that is the one you favor doesn't mean all others are incorrect. You might find that people on this forum would pay more attention to your expertise if it wasn't delivered in your typical arrogant and condescending manner. The facts are that virgin brass DOES exhibit excessive headspace, and yes, that IS normal. Further, if you think that can't become a safety issue, try bumping the shoulders of your brass back to the same measurement as virgin brass every time you resize and see how long it is before you get case head separation, which IS a safety issue. I guarantee you it will be much sooner than it needs to be. The specific reason most precision reloaders only bump the shoulders back .001" to .002", rather than the .005" to .008" the brass grows during the first firing, is to minimize the excessive headspace found with virgin brass.
He never described the rifle. Does a factory deer hunting rifle get out of tune. Just a bad setup of the sandbag could account for flyers?
Brians356
Gold $$ Contributor
I don't see any flyers. Do you?
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Brians356
Gold $$ Contributor
Not really. A simple noun like "headspace" has a definition which is not open to connotation. In this context (firearms) we refer to the SAAMI definition:
headspace: n The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats.
Only an adjective phrase such as "acceptable headspace" or "excessive headspace" may have different connotations. I previously allowed that "acceptible headspace" has a different connotation in this forum than in other contexts. So might "excessive headspace" if you only mean "detrimental to accuracy", or even (fair enough) "detrimental to brass case longevity".
But when you suggest that the headspace of a virgin case, which is well within SAAMI spec, is not only "excessive" but patently "dangerous", you've gone a bridge too far.
Any brass case, even a minimally-resized one, if reloaded enough times may eventually become dangerous, and requires monitoring. The fact that a repeatedly fully-resized case wears out faster than a minimally-resized one does not mean that any particular virgin or fully-resized case (within SAAMI spec) is somehow ipso facto "dangerous". It's disingenuous of someone who knows better to say that.
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We don't know anything about the quality of the rifle. The shooters experience and bench setup are very important. Were there flags, do you know how to use them? At 200 yards a 10 MPH cross wind can move the bullet 2". What he calls flyers always have verticle. It's important to understand how good your shooting skills are and be ware of what you need to improve on. Without shooting skills you will never shoots small groups. Every time I go to the range I work on something to improve my technique. The OP never gave us any info to indicate his skill level. A good test is to shoot someone elses rifle that shoots small groups and see how well you do.
Brians356
Gold $$ Contributor
Webster,
Fair enough, I get that. But I'm just applying the eyeball test here. To me, a "flyer" is an obvious outlier, like 4 holes all touching, and one hole 3/4" out of the group. Or, more like 3 or 4 nice groups with all nearly touching, and a fifth group with 4 in a small cluster and one flier. There needs to be a suggestion of precision, with obvious random spoilers. These groups, without any commentary at all to suggest otherwise, just look like every 1.5-in group I ever shot.
Also, almost by definition, I don't think one can justify claiming 2 flyers in only a 5-shot group. A statistical analysis won't support two of the five as being "outliers".
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Fair enough, I get that. But I'm just applying the eyeball test here. To me, a "flyer" is an obvious outlier, like 4 holes all touching, and one hole 3/4" out of the group. Or, more like 3 or 4 nice groups with all nearly touching, and a fifth group with 4 in a small cluster and one flier. There needs to be a suggestion of precision, with obvious random spoilers. These groups, without any commentary at all to suggest otherwise, just look like every 1.5-in group I ever shot.
Also, almost by definition, I don't think one can justify claiming 2 flyers in only a 5-shot group. A statistical analysis won't support two of the five as being "outliers".
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Agreed it could be any number of things. I'm not going back to the OP to remember the whole situation but if you were reloading for a factory deer rifle and settled on a powder charge right on the edge of a node then later got a dramatic temp swing I would bet it could get out of tune. I honestly don't remember if we're talking about a custom rifle shooting hand loads or a off the shelf rifle shooting off the shelf ammo now.
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