Rifle case weight vs volume

[cdoc42]

When we weigh our powder, what's an acceptable range +/- the goal? If you are weighing 56.0 gr of H4831, are you comfortable with a powder measure drop of 56.2 on occasion vs 55.9gr? Or are you dead-set on 56.0gr each time?

If so, stick the RP, Win and Fed cases because the average internal volume from the chart above between the 3 is 55.2gr and the deviation is RP -0.1gr, Win +0.2gr and Fed is -0.2gr.

Will that difference in air space above the charge make any difference?

[RC20]

Bart B pretty well lays it out. And its not a direct relatioship betwen weight and volume (I did some power to powder testing and came up with about a 4/6 to 1.

As a case lays down, the space above it is not relevant. 80% fill or better is generally better but lots of exceptions.

Compressed may work better, but that is gun (or barrel by barrel/chamber ) you have to test.

My 7mm did not shoot any better with hand loads than it did factory. Go figure. Still shot more than good enough to hunt with (if I hit it it dropped down and I only had one miss, too long a shot and I still did a graze).

[Shadow9mm]

For general practice/training mixed brass by caliber. For hunting loads or my precision type loads I separate by head stamp, and try to keep to to the same batch of brass if I can. Never sorted by weight or case capacity, that goes way beyond my my needs or abilities to shoot.

[Double K]

I assume your not a benchrest shooter or have a benchrest rifle or are using custom made bullets, in that case don't waste your time weighing cases.
Here's what you can do that can improve group sizes, this is assuming your a decent bench shooter with a good bench and rest, and your not shooting off your car hood over a rolled up jacket.
Do your absolute best at reloading how many ever cases you want to sort for quality of group, number every case one to whatever, say 100 cases, find a box that will hold how many ever that is, mark the spaces to correspond with the cases. Those cases live in those spaces from now until they're thrown away, they may leave to be shot or reloaded but that's where they belong.
You'll need a chronograph for the next part, shoot them in order in lots of 5 or 10 depending on cartridge, record the velocity from each case and where it landed on the target.
It'll be obvious when you come across a case that for whatever reason makes bullets land out of the normal grouping usually due to out of normal velocity, that's assuming your bullets have good run-out or your not shooting an innacurate bullet or one not appropriate for twist or a million other little things that can go wrong.
People will argue this all day but case manufacturer matters, I get the best groups from Lapua and Norma. Remington and Winchester are fine for hunting accuracy but if you want to see how good your gun really shoots use Lapua.

[Bart B.]

Interesting opinions on case volume and weight. There's another variable in loaded cartridges that when measured the traditional way the cartridge is positioned differently to the measuring device than it is in the chamber.

No commercial bullet runout gauge orients the bullet to the dial indicator like bottleneck cartridges align their bullet to the bore center when fired.

[BJung]

I am handloading for accuracy to find the best load for the best batch of bullets, cases, and powder combination I can find.

I don't have a benchrest rifle but use the same technique in almost all my firearms. In fact, I weigh pistol brass too sometimes if I want to make load that I shoot clay pigeons at 100 yards. I should shoot at a target someday to see what kind of group I get. Getting back to rifle cartridges. I resize all the rifle range brass on an electronic scale and come up with a bell curve. I might use the outliers or toss them. The majority of the brass that is on the center of the bell curve, I save for target use. I plan to use the others for hunting and practice. Discovering case volume grouping, I was thinking of breaking down brass into a more refined group. After fire-forming, I neck size with a custom Lee Collet die, expand the neck with a mandrel and turn the necks. Since I started casting, I have an okay set of mandrels now. And so, for the very best brass, I was planning to expand the necks to just under the bullet diameter by .001". I know this isn't a benchrest rifle but I'm trying to make the best cartridge possible. Afer I seat bullets, I turn the cartridge to find the high spot and mark the case. Traditional archers believe that the arrow is more important than the bow. My goal is not to shoot benchrest groups. Only the best the rifle can shoot. I want to try shooting at a target at 500-600 yards. After I find my petload and practice I like the idea of going out the field and shoot at clumps of dirt or whatever from different angles and distances. I think this will make me a better with the rifle.

[Bart B.]

Full length sizing bottleneck cases setting the case shoulder back a couple thousandths has been the norm for best accuracy since the late 1950's. Case necks are best centered on the case shoulder and straight on the case.

Dies don't have the expander ball but their necks are honed out to a couple thousandths less than a loaded round neck diameter. Or full length bushing dies are used.

[BJung]

I forgot about that, thanks. A problem I have is that the RCBS dies I have sizes the case with a sharp shoulder. After an initial fireform shot, the case looks more like a Weatherby shoulder that's round. I'll open a new thread to ask for a solution.

[Metal god]

I weigh pistol brass too

lol , and that's all I got to say about that ( gump )

I resize all the rifle-- range brass --on an electronic scale and come up with a bell curve.

Can you elaborate on what you mean by "range brass" ?

Is this random mixed range brass you pick up ?

Are you at least separating by headstamp ?

Also is this the same brass you are weighing and reloading to get consistent reloads ?

[Bart B.]

Originally Posted by burbank_jung

I forgot about that, thanks. A problem I have is that the RCBS dies I have sizes the case with a sharp shoulder. After an initial fireform shot, the case looks more like a Weatherby shoulder that's round. I'll open a new thread to ask for a solution.

Pictures of the cases at each stage would help because something ain't right.

[BJung]

The cartridge on the left is a resized USGI 30-06 using an RCBS 7.7x58 resizing die. The case on the right is a fire formed USGI case that was initially resized, cut to length, and after fire forming, neck turned ( the brass wall is thick ). The shoulders of the resized case is not as sharp as I thought but look how much the fireformed case would be narrowed if I use the sizing die to try and bump the shoulder back.

[Bart B.]

Originally Posted by burbank_jung

I am handloading for accuracy to find the best load for the best batch of bullets, cases, and powder combination I can find.

I don't have a benchrest rifle but use the same technique in almost all my firearms.

Benchrest techniques used in competition have the 13 pound rifle resting on bags untouched by human's except for a finger on the 1 to 2 ounce trigger. The rifle recoils freely and very repeatable from shot to shot. 22 and 24 caliber bullets in small cases don't move the rifle very much during barrel time.

When we hold and aim the rifle, groups show how precise we shoot them. If you ever watch a dozen people shooting a 5 shot group shouldering a 12 pound 308 Win scoped match rifle with a 2 pound trigger resting on bags atop a bench then see groups at 100 yards ranging from 1/2 to well over 2 inches, you'll understand.

[old roper]

burgbank_jung

Lot of shooters use BR technique including F-Class Open which Bart hasn't comment on.

http://bulletin.accurateshooter.com/...-f-open-rifle/

This good article from Bryan Litz on how he prep his brass and shooting almost free recoil.

http://bulletin.accurateshooter.com/...e-built-rifle/

[hounddawg]

Follow the advice of Litz and Erik Cortina and you can't go wrong. I am a disciple of both. I started shooting F class 3 years ago and while I do not claim to be in their league I practice their "simple works" reloading practices.

Here is one of my 800 yard scorecards just to show that simple case and reloading is effective for me. The Peterson brass used in this match is on it's 11th reloading. It was cleaned, sized with a Redding bushing die, primed with a RCBS bench primer, chamfered. Powder was measured on a RCBS Chargemaster and checked to make sure it was within .1 grains. Berger 105 Hybrids were seated using a Lee 4 hole turret with a Redding seating die. No annealing, measuring or sorting of bullets or cases was performed

[BJung]

Handloaders use benchrest techniques for their non-benchrest rifles to improve the accuracy of their handloads. The Shooting Community is indebted to benchrest shooters for the techniques they developed. It's not that most shooters want to be like a benchrest shooter without the expensive rifle but have the best or better than needed handload for their rifle and acquire better than expected results. For example, my first rifle was an Enfield with a non-gunsmithing scope mount that shot 1" groups at 100yards. I was only separating brass by headstamps. The Arisaka shoots better. No disrespect to benchrest shooters, if a non-benchrest shooters is asking for information, he's picking your mind for your knowledge.

[Bart B.]

Here's a 20 shot group at 800 yards made before F class became a competition. Used a 13 pound scoped 308 Winchester palma rifle on bags from prone. First two marked shots were from the clean barrel, they typically leave several fps slower.

https://thefiringline.com/forums/att...9&d=1570130518

[hounddawg]

Here's a 20 shot group at 800 yards made before F class became a competition. Used a 13 pound scoped 308 Winchester palma rifle on bags from prone. First two marked shots were from the clean barrel, they typically leave several fps slower.

Darn Bart, that would beat todays International record

Ontopic were those cases annealed using a induction annealer, everything weight and volume sorted, bullets checked base to ogive etc and powder weighed to .01 gns or were they just loaded on a beam scale and shot

[Bart B.]

Originally Posted by hounddawg

Darn Bart, that would beat todays International record

Ontopic were those cases annealed using a induction annealer, everything weight and volume sorted, bullets checked base to ogive etc and powder weighed to .01 gns or were they just loaded on a beam scale and shot

45.3 +/- .1 grains of IMR4895 on a 1966 Redding beam scale under Sierra 155 grain HPMKs right out of the box. RWS primer in unprepped Winchester cases that were never annealed. Bullet runout about .002 inch seated long to set back about .003" when chambered.

Sloppy ammo does well if everything else is good enough.

[BJung]

I've seen target photos at long ranges but nothing like this. This is awesome. Really nice Bart B. I will dare and say that good shots are subject to variables. The more consistent, the better.. I noticed that you used "Winchester" cases and not Lapua. If you were to rank variables in the cartridge. How would you list them by importance? We're getting a bit off topic here so maybe a new thread is called for.

[BJung]

Thanks old roper for the links

[hounddawg]

Sloppy ammo does well if everything else is good enough.

for me everything is a decent barrel and the shooter talent/ability, all this obsession over reloading perfect ammo is mostly marketing bull aimed at people who think they can buy groups with a credit card instead of time at the range

[Reloadron]

With a focus on case volume and only case volume and powder loads for the average shooter I conclude that with any case and a load of +/- 0.1 grain is good enough. Short of shooting bench rest.

Ron

[Bart B.]

What's a decent barrel? What's the best way to install it?

Does the action matter? Smallest series of several 10-shot groups at 600 yards I know of were shot with a Winchester 70 control feed action based rifle with a 26 inch 1:11 twist Hart barrel, .7 to 1.5 inch groups.

[hounddawg]

Bart why is it you seem to have seen or shot all these jaw dropping groups but not a one of them can be found in any official record. Just curious

[Bart B.]

Originally Posted by hounddawg

Bart why is it you seem to have seen or shot all these jaw dropping groups but not a one of them can be found in any official record. Just curious

Same reason why all the other groups shot outside sanctioned events aren't recorded and saved for posterity.

High cost and low interest.