Help a newbie with Lapua case Prep

[mihkmihk]

I've only been reloading about a year, but I finally decided to buy some good brass (Lapua in .223 for my Kimber 84 bolt action). I've got it in my head that this stuff is like the fine china and I don't want to ruin it. I had a few questions:

1) The decapping rod on my RCBS full length resizing die fits easily through the flash hole (I tested it by hand, backwards so to speak). Some online info said to remove the decapping rod to not widen the small hole of Lapua brass, but is this necessary?

2) Most of this is measuring 2.250-2.252 in length. Should I trim them to the same size? If so, what length? (all the way to 2.240 like the "trim to length" says?)

3) Does this brass need the inside of the mouth chamfered or leave it alone?

Thanks!

 

[TheBlueEyedBear]

There are more opinions on case prep than I have number of posts. But, I feel for your .223 if your shortest length is 2.250, trim them all to 2.249 for uniformity. My opinion for champfering is to lightly do the outside and none on the inside. Just use a piece of 0000 steel wool to take off any rough 'stuff' on the inside.
And then there is the question as to whether or not to turn necks. I turn every piece of brass. The one simple rule is: The more uniform your brass is the better chance you have to build a more accurate piece of ammunition. It's all about consistency. Can you imagine having every piece of brass EXACTLY the same??!! Don't know if that is really possible,, but, that is something to strive for.
Just my humble opinion.

Barry

 

[BoydAllen]

1. With the flash hole size that you have described, use your dies like you would for any other brass. You don't need to remove the decapping pin.
2. The need to trim before first loading depends on the condition of the case mouths, if they are smooth and square, you don't need to, but one thing that I have learned recently is that running too close to maximum length (closer than .010) is undesirable when it comes to the highest levels of accuracy, and that any gap that results, will not hurt accuracy, so for that reason, you may want to trim.
3. Any damage to bullets' heels will show up on the target, so I would recommend that you pay close attention to the chamfer, any time that you are loading, including the first time. Ordinary chamfer tools can leave a burr. It is better to remove it.

All of the above is answered as if you were trying for the best accuracy. If that is not the plan, feel free to ignore any or all of it.

 

[SpencerC]

If you have .223 brass that is 2.250" in length, you may have a problem......

 

[mihkmihk]

Spencer I misspoke; the brass is closer to but 1-2 thousandsth above 1.750.

 

[SpencerC]

All of the new-in-box Lapua brass I have used has all been 1.752". No need to worry about the length at this time. I trimmed my latest batch just for something to do, I also neck turned afterwards. Recommended trim length is 1.750" and only needed if your brass is 1.760"+

I believe the bit you read about your decapping rod not fitting the flash hole would have to do with the .308 Palma brass that uses a small primer as opposed to it's "regular" .308 Win brother and it's large primer. There is no issue using a standard .223 decapping/sizing die with Lapua .223 brass.

Depending on the bullet you use you may or may not need to chamfer and debur. If you use flat base bullets, you may find it easier to use a little bit more chamfer, but if you are using boat tails then really none is needed. I always put a little on mine just to clean the lip up a little bit, nothing excessive.

 

[artbosco]

There's no point in trimming it until it's been fired. When you do it's best to pick up a Sinclair chamber length gauge (only a few bucks) and find out how long your chamber is then trim to 10 thousandths or so short of that.

It's best to trim to 20 thousandths leaving the first 10 thousands as a safety zone.

Chamber Length Safety Zone

Q: How many thousandths shy of actual chamber length does one establish as a safety zone, before assigning a trim "from" length, once measurements have established a rifle's true chamber length?

Mike Bryant

A: I use .010" for each increment. For instance, if the chamber length is 1.570" from the base to the end of the neck on the chamber, then the maximum case length would be 1.560" with a trim length of 1.550". Don't let the cases get over 1.560" and you'll be in good shape.

Jackie Schmidt

A; I use a .010" window. 6mmPPC chambers have been shortened to 1.510". Since shooters fire cases to expand them, the cases come out close to 1.500". I trim them back to 1.490."