I have 400 brass that vary in weight from 150-170 grains after resizing, annealing, trimming, and polishing. They are unprimed. Many fall in the 155-160 grain range. What are acceptable variations before a person worries about high pressure in the heavier cases?

Should I work a load up in the heavy cases and use that load in the lighter weight cases as well? Will pressure, velocity, and accuracy vary between them if I do?

I plan to use old 150 grain cup and core semi round nose bullets. Any load suggestions?

Thank you.

I weighed my brass and put them in separate bunches that were not more than 5 grains apart,, and worked up loads for each group and never had any problems. I feel that 5 grains in the cases will not affect pressure enough to worry about. Or you can just select a load a load 10 grains below max and use that for all the hunting ammo.. if it is accurate in your rifle...

Back in the day I never heard of weighing brass, so it was never even a concern. That being said, fill them both right to the top with the powder you intend to use and weigh the charges. If the variation in capacity isn't huge, I don't think you have anything to worry about.

I've never weighed cases but I do sort and load them by brand. I doubt you'll see much if any difference from a hunting rifle. Now benchrest shooters, that's another story...

Or toss the obvious offenders into a bag and send them to me

5 grains +/- of brass in a 160g case = potentially 3% case volume difference = +/- 1.25 gr of powder in your normal 40g charge = don't load them to max pressure (why risk this in a 99 anyway!!) and you'll be fine.

If You cull out the heaviest and lightest brass and measure every powder charge within .1g you will probably improve your ES/SD across all of your reloads, and win yourself a dead possum!

I always try to keep my hunting loads to shoot under 1 inch. where I hunt most of my shots are under 100 yds. but I like to make head shots if possible and a 1 incher is all that is needed.. my 300 savage can easily do that even with a 10% lower powder charge and there is no tracking involved.. befor you all jump on me for taking head shots and the possibilities of a wounded deer getting away , I shoot enough to have the nessary skills to make a head shot easy.. I use the same gun to kill wood chucks and never miss them. I spent time on the army rifle team. and was an expert rifleman for the 20 years I was in the army... I also survived my time in Vietnam. and other combat missions.

Unless you tinkebell the trigger, get a proper crown. Put on a good modern scope. I doubt you will notice.

I would match head stamp, then weigh .

Use 2.5 grains at first.......keep them in groups. You should be able to find lots of fifty that are pretty dang close.

Nifty nifty a matched box of fifty!

One box at a time.

Good shooting Hubert!

But I like pseudo kosher venison,.............as in exanguation. Just no messy salt bath!

Or Rabbi!

I've got a current production batch of Federal brass that averages 169 grains, and some older (who knows when?) Federal brass that averages 155.

That's a good logical step I can take. Thanks!

Thanks Jeff. The lure of the dead possum is strong.

Anything south of full patch loads in any case is probably okay for hunting ammo. Weighing everything thing out for consistency is a thing from the world of bench rest shooting. Which isn’t a bad practice but those guys are usually very anal about how they put their ammo together, and for good reason considering the nature of their sport. The big thing with me is avoiding the urge to make the 300 into a 308, not that that is what you are attempting to do.

Benchresters I know use Harrell powder measures and don't weigh charges. SOP in that world.

I would sort the brass by make and then into +- 5gr. batches if I were to get anal about it. I would also take closer notice to water capacity over case weight- alloy makeup will have an effect on case weight also. eg: different makes of brass could weigh the same but have different capacity.

Then there's differences in web thickness and wall thickness between brands/lots that have a bearing on safety but not on case capacity or weight. Not to mention case neck uniformity effecting performance.

Lots of variables that can suck you down the rabbit hole if you start getting too anal, IMO. Just sort by brand and weight within the brand, keep trimmed to uniform length and worry more about bullet selection/seating, and breathing/trigger control/wind doping/and all the stuff that should really matter to a rifleman.

if they were primed/fired you could test capacity with water. fill to top of neck then weigh the water. gives the most accurate measure,
with the 300 i wouldn't worry about the variation you have. want to hotrod it use your 308.

I'm concerned with accuracy. If they're inconsistent they won't be as accurate. I just don't know what the general consensus among shooters is as to what amount of weight variation is noticeable. If I can have a 3/4" load or an 1 1/2" load it's worth understanding.

See Gary's posts above.

I'd say taking the time to sort for headstamp, weight, and H2O capacity, (in that order) is worth it, given your large selection of brass, and depending on your obsession attention span. If you end up with 50 cases that are within 1% of each other, save those for your final loads. Do your load development with the others, set them aside for the next load development project, load up the 50 good ones with your best recipe and expect them to be very consistent, (..in that gun..).

After a point it's a rabbit hole Roy, only safe if guided by an ancient Houston-warehouse-rail-gun shaman (..like Gary, now that I think about it), and then we mortals are still dealing with the variables of temperature and wind and coffee intake every time we go out.

Thanks Jeff. Have you ever been shooting with someone that shows up with 5 different types of ammo and can't figure out why he can't get his rifle sighted in?

I'm not that guy.

...yip..., usually two days before deer season opens, when I'm just checking zero after bumping the scope getting my rifle back in the truck..., I just want the first shot to go where I point it.

If we stretch this out for another 10 posts..., could I sell you a free-floated forearm mod??

I use the same brand brass, never have worried about that. I have a large number of Lake City 308’s. Before I load them I need to see how it compares with all the Hornady match I use. It’s probably thicker inside.

I weighed all of them. Quite an eye opener.

Old Winchester was by far the most consistent with 90% falling within 4 grains of each other. Remington marked R-P had two distinct batches one heavy, one light, with brass tapering off on either side for several grains. REM-UMC was terrible, all over the map, over 20 grains variation in weight, seemingly no quality control. Peters nothing special there. Federal two distinct batches, one heavy one light, 10 grains apart. The new Federal is 10-15 grains heavier than anything else, also very consistent, but way heavier. Old Savage marked brass was featherweight, nearly 30 grains lighter than the new Federal brass.

If I was just starting out I'd buy new Federal brass. It weighs almost 170 grains on average vs 155 avg for the others, so work up loads from below very important. .

The Lake City will be about ten grains heavier if your batches are anything like mine.

mathman,

YEP. IF the 7.62x51NATO brass is as good quality as the LC M2 brass (that I get FREE from a NICE local Garand match shooter, who doesn't reload) & that I use exclusively for loading ammo for my .30-06 rifles & to reform/load into 9.3x62mm Mauser ammo, too.

So far, I've found NO "commercial brass" that is any better than Lake City M2 "once fired" cases..

yours, tex

Wow.. that's a lot of difference. Makes it clear why reloading manuals always stress to retest your loads when changing ANY component. Even if they have the same internal capacities, a thicker wall will make a difference on pressures when firing.

Have you compared it to Lapua?

mathman,

YES, and while I find Lapua to be FINE, I see it as NO BETTER quality than Lake City & COSTLY besides.

yours, tex

Impressive. I wish that were the case for the 308 stuff.

I'm not running down LC by the way. It's tough, and a lot of it has been really fine for most of my shooting.

I find all the accolades for LC interesting given that back in the day most of the jams we had with our coax M73 machine guns were caused by LC 7.62 ammo. The cases would rupture at the shoulder and when the rest of the case was extracted the shoulder and neck would remain stuck in the chamber causing a malfunction. We never had that happen with 7.62 from any other manufacturer.

Skidrow,

INTERESTING. - When I was an AD Mike Papa, we NEVER had a problem with our cases separating in the old M60 MG.
(Fyi, I used to TEACH the M60 & fired numerous THOUSANDS of rounds, when I was a Black Hat at USAMPS.)

I wonder why the M73 coaxial gun has that (potentially DEADLY) problem??

yours, tex

I've got no idea why. It was a pretty strange deal because we didn't have that problem with any other 7.62. Even stranger is that when we got M240s that problem went away. Can't explain it but it happened.

its all about what the shooter CAN do consistently, ABOVE, with that confidence.

Skidrow,

"PASSING STRANGE", imo.

yours, tex

Very different operating systems I believe. M73 being recoil operated, M240 being gas.

True.