Inconsistencies with virgin brass and new bullets

[mwilkins]

As I am waiting on the rest of the reloading equipment to come in and being the impatient person that I am, I have been working with the gear that is here learning how to use it. So today I decided to take weight and measurements of both Lapua Brass and Berger bullets.

All weights are in grams and were taken on a Mettler Pc 8000 digital scale.

From a new box of 100 count Lapua .338 brass, my sample was taken from 20 pcs. Weights throughout the sample were all very close being 21.2 g to 21.3 g. Case length was not that bad either. With it being new brass, I figured it might be a little closer but not knowing what the manufacturing tolerances are, who knows. They will all get trimmed in the end to be equal. Lengths were from 2.717 to 2.722.

Berger .338 Hybrid OTM 300's. Same process as above, weights were 19.4 g to 19.5 g. Only 3 of the 20 were at the lighter weight. Ogive lengths were .973 to .976. All looked pretty good until I measured overall length. These were anywhere from 1.798 to 1.818. I automatically assume some of this is due to inconsistencies with the Meplat and would account for several thousands of the overall length but should a .020 variance be something to be concerned about? Only place I can think of that would be affected would be max length to fit the magazine. Obviously I will go through all 100 bullets before loading and group them by weight and length. Just need know if this is getting a little anal and overly picky...... Take into consideration I am trying to learn and absorb all the information I can before actually starting to load.

 

[Creature]

The only thing I would mention about using new brass would be to neck size to assure consistent neck tension. It probably doesn't need it with lapua brass but I've seen some with slightly deformed mouths from shipping. I use the larger bushing with redding type s dies.

 

[former naval person]

There are all sorts of inconsistencies with virgins of any caliber. JMHO (Having used the words anal and virgin together is a bad thing.) Load it, shoot it and trim it. Then worry about it. A caliber that size is tolerant of a few grains of brass weight difference, and OAL of the bullet tells you nothing. Got to use the OGIVE. That measuring device (or devices) will give you a few more anal moments...How much force did you use to get the last measurement? Were the calipers square? OMG. Do the best you can and shoot.

 

[ksthomas]

Creature,

Actually, we DO recommend a quick N/S or (better, in my opinion) a pass over an expander mandrel for the reasons you cited. Hey, we try to make 'em as close as we can at the factory, but what happens in shipping is out of our control. Never hurts to touch them up a bit before that first seating, just to make sure everything is round and uniform.

 

[Cproflow]

I had asked Kevin a similar question awhile back, and his suggestion is a sound one. I don't have a N/S or an expanding mandrel in .308, so I just used my Lee Collet Die to attempt the same outcome. It does seem to expand them just a touch, and absolutely took care of any out of round cases (there were a few).

 

[mwilkins]

Guys, as stated in the first post, I am trying to learn as much as possible before I actually start doing my own loads so if a comment is made that is out of place and seems to be of shear ignorance, my apologies. I am a techy so I look at everything from a technical view. Hence the reason for weighing and measuring all brass and bullets. I just like to know what I am dealing with.

So from the replies that I am reading, and thanks by the way for those replies, before attempting to load anything, make a pass through my dies with the brass to ensure of a round case but not to worry about the length of the cases until once fired. At that time I can trim all cases back to the shortest case length (given it is above the minimum case length) so that all subsequent loads will be more consistent.

 

[ksthomas]

mwilkins,

Since you mention it, yeah, there is something you should bear in mind here. As Einstein once said, "Not everything that can be measured is important, and not everything that's important can be measured." As far as I know, Albert wasn't a handloader, but it's still very good advice for us. We tend to get bogged down in minutia, measuring every little aspect of case dimensions. Not necessarily a bad thing, unless we start wasting time measuring and fretting over things that really don't make a difference. Case length can be one of those items, and I've seen a lot of guys really get wrapped around the axel over this. Just make sure that the brass is short enough to keep it from encroaching on the chamber throat, but don't get too carried away beyond that. OAL can be another, and I've seen guys waste tons of time over the variations they find when seating bullets. Doesn't make a bit of difference, so long as the ogive measurement remains constant. And with a good seating die and halfway reasonable technique, they will, regardless of how much variation you see in the actual OAL.

Just take your time, and evaluate whether or not whatever you're doing is actually time well spent, or time chasing your tail. Most of all, don't hesitate to ask questions if something's not clear to you. Plenty of knowledgeable folks around here, and questions are always welcome.

 

[Dan Newberry]

mwilkins,

Since you mention it, yeah, there is something you should bear in mind here. As Einstein once said, "Not everything that can be measured is important, and not everything that's important can be measured." As far as I know, Albert wasn't a handloader, but it's still very good advice for us. We tend to get bogged down in minutia, measuring every little aspect of case dimensions. Not necessarily a bad thing, unless we start wasting time measuring and fretting over things that really don't make a difference. Case length can be one of those items, and I've seen a lot of guys really get wrapped around the axel over this. Just make sure that the brass is short enough to keep it from encroaching on the chamber throat, but don't get too carried away beyond that. OAL can be another, and I've seen guys waste tons of time over the variations they find when seating bullets. Doesn't make a bit of difference, so long as the ogive measurement remains constant. And with a good seating die and halfway reasonable technique, they will, regardless of how much variation you see in the actual OAL.

Just take your time, and evaluate whether or not whatever you're doing is actually time well spent, or time chasing your tail. Most of all, don't hesitate to ask questions if something's not clear to you. Plenty of knowledgeable folks around here, and questions are always welcome.

Excellent advice. If more handloaders understood these basic truths, there might be a lot less money spent on measuring gadgets, and a lot more spent on bullets, brass, and powder.

Develop the load right, and any difference any of this ancillary minutiae might make will get lost inside the noise of a 1/4 minute group.

Dan

 

[Aimsmall55]

From a new box of 100 count Lapua .338 brass, my sample was taken from 20 pcs. Weights throughout the sample were all very close being 21.2 g to 21.3 g. Case length was not that bad either. With it being new brass, I figured it might be a little closer but not knowing what the manufacturing tolerances are, who knows. They will all get trimmed in the end to be equal. Lengths were from 2.717 to 2.722.

Your weighing Lapua??? Hell, gonna trim them too?? Virgin ?? You have much to learn Grass Hopper!! Get a caliper , comparator, and measure your head space before you fire and your set. Start out at sammi COAL and shoot 3. go 10/1000's longer and shoot 3 ect..... Just don't jam them. Oh and Berger metplates are always ridiculous, hence load to the ogive.