Whats the typical weight deviation of good bullets?


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OC_
December 8, 2010, 03:25 AM
Hi guys,

I'm just getting into handloading and I plan on pulling the bullets of this cheap surplus 7.62x54r that gives me poor groups. I plan on weighing everything and reassembling them into so-called 'mexican match' rounds. I still don't have all the equipment yet, but i was messing around and was able to pull and weigh the bullets from 2 separate rounds. One of the rounds was about 1.2gr heavier than the other.

So my question is, whats the standard deviation of good bullets? This ammo is supposed to be 147gr light ball; i would think that the 148+gr one would be a flyer out at the range?

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MovedWest
December 8, 2010, 03:34 AM
You use different terminology, so we'll need clarification. Are you wanting the standard deviation weights of bullets or rounds? The bullet is the projectile that ends up being the business end of the round. 1.2gr difference between rounds is not bad.

-MW

OC_
December 8, 2010, 03:47 AM
Oh, sorry about that. I meant just the bullet (projectile).

But, i will be weighing everything else individually as well, so i should have asked about powder and cases, too.

SlamFire1
December 8, 2010, 09:26 AM
In an older Shooting Times article about the Marine Rifle team, they show a picture of a Marine Tech sorting Sierra match kings by tenth of a grain. The bullet was either 168.0 or it went into a reject bin. Sierra match bullets are supposed to be held to a tenth, or two tenths, I forget.

The older 174 FMJBT's were held plus or minus 2 grains. That is a 4 grain maximum spread.

You will just have to shoot your military ball.

I conducted load tests in my Ruger M77 tactical in 308, and I was shooting IMI 148 grain FMJBT's, ball ammo, and Hornady 150 FMJBT's. I hit a sweet spot with the Hornadys', but the military bullets were just awful.

You can try weight sorting the things but you cannot measure the out of balance. Groups are not going to be good from a bullet in which the center of gravity is outside the axis of rotation. It will wobble.

So, don't expect much from military surplus bullets, they are not target bullets.

150 grain 1968 WRA Ball

http://img.photobucket.com/albums/v479/SlamFire/Targets/150gr1968WRABall.jpg

148 IMI with IMR 3031

http://img.photobucket.com/albums/v479/SlamFire/Targets/148IMIFMJIMR3031.jpg

Hornday 150 FMJBT
http://img.photobucket.com/albums/v479/SlamFire/Targets/150Hornday410grsIMR3031-1.jpg

kaferhaus
December 8, 2010, 12:52 PM
A good rifle bullet (match) should have no more than +- .1 grain deviation from the published weight.

Most premium hunting bullets are usually +- .2

I weight sort any hunting bullet that's going to be used for long range hunting, ie: 250-350yds.

although with my target rifles from a bench, I can shoot .5MOA at 600yds, I nor anyone else can approach that with a hunting rifle shooting from a field position so I self limit myself to what I can shoot offhand into 2MOA.

cougar1717
December 8, 2010, 01:58 PM
OP, it's been my experience that in a box of 100 Sierra hunting bullets, the range should be .4 grains (+- .2gr). I would expect more for match bullets. Please take this with a grain of salt because making a rifle more accurate through handloading is a great experience, but what you are proposing (disassembling surplus ammo, making more consistent powder charges, reseating the same bullet in more consistent groups) is really not worth your time over just shooting the surplus ammo. Things might be different if you would replace the surplus bullet with a match bullet or a hunting bullet. Something to also consider is that the rifling (if surplus) may also be worn. Even the best match ammo will give bad groups if the rifle is not accurate.

Walkalong
December 8, 2010, 02:14 PM
I have never weighed bullets to be shot offhand, because like kaferhaus posted, I could not shoot to their potential anyway. As long as they group decently from a bench they are plenty good enough for hunting at any reasonable range. +/- .2 should be more than adequate for what you want. Any name brand bullet except for FMJ's (Although that Hornady FMJ looks like it shoots pretty well for Slamfire1.) should shoot well enough, and definitely a great deal better than cheap milsurp surplus.

rcmodel
December 8, 2010, 02:21 PM
The whole accuracy problem with pulled FMJ military bullets is not the weight variation.
Slight weight variation has little if any effect on accuracy.

The problem with them is, the open base of the jacket is not 100% perfectly square with the bullet shank on every one.
Any one that is off even a frog-hair will get tipped by escaping gas more on one side and start a wobble as it comes out of the muzzle crown. (assuming the crown is perfectly 100% square with the bore too.)

That is why the most accurate match bullets made in the world have the jacket opening in the nose, not the base.
They can make perfectly square bullet jacket bases in the bullet swaging die, if they don't have excess jacket squirting out more on one side then the other.

rc

Walkalong
December 8, 2010, 02:35 PM
The problem with them is, the open base of the jacket is not 100% perfectly square with the bullet shank on every one.

Correct. http://www.thehighroad.org/showpost.php?p=6912168&postcount=11

zfk55
December 9, 2010, 02:59 PM
For us its all sorts of sorts.

We only have one projectile for the AR 10s. The Sierra Matchking 175s.
We trim meplats, point and sort. Typically I seem to find only three weights with a semi-rare odd one. 174.9, 175 and 175.1. The odd one always seems to be 175.2. Spread allowance is 1/10th gr. Meplat trimming comes close to equalizing projectile weights, and pointing makes a real difference at 400 yards and out to 1,000.

The trimmer indexes on the projectile's ogive, not the base. Once the brass is sized and trimmed we sort it by weight as well allowing no more that a one tenth spread. Out of 100 we'll typically have 6 different weight categories. Surprisingly, both Lapua and LR are neck and neck for consistency for us.

Sizing and seating are done with Redding Precision Match dies only. No other.

After reloading we also sort loaded cartridges by overall weight allowing no more than a two tenths spread. All sorts of sorts, but results are consistent and I make the time to do it.
Our private range is a 500 yard maximum.
------------------------------------------------------

Meplat Trimmer.

http://img.photobucket.com/albums/v87/zfk3155/MeplatTrimmer.jpg

The bullet Pointer.

http://img.photobucket.com/albums/v87/zfk3155/Armoury2003.jpg

Wilson Case Trimmer, the only one we use.

http://img.photobucket.com/albums/v87/zfk3155/wilson002.jpg

OC_
December 10, 2010, 12:49 AM
Thanks for the info guys. This ammo will be run though my PSL which has had a lot of work done to bring the accuracy up. I think some of you guys would be floored at what i can do with surplus ammo. My gun slugs out to .3105 which really limits the bullets that are available. I have a gas regulator, so i can fire heavy ammo and may try the match kings later on. They come in 174gr in .311 caliber. Its just a pain in the arse to adjust the regulator. I saw that sierra also has the Pro-Hunter in .311 at 150gr. Even though I only shoot paper, i think i may give this a try since they have to be more consistent than soviet bullets. Anyone have any stories with these?

rcmodel
December 10, 2010, 11:20 AM
I'd like to see somebody try a jacket base trimmer rather then a meplate trimmer on FMJ bullets.

I'd bet money the results would be much greater then whittling on the pointy end.

rc

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