[kpaintner]

I am fairly new to reloading. I have a question when it comes to case trimming. I notice a lot of people recommend that you trim cases before decapping and resizing. This does not make sense to me. Doesn't resizing stretch the case? So if you trim all the cases to the same length and then resize, don't you stand a pretty good chance that 1. cases may be slightly different in length and 2. the case could stretch past the max length. I think it makes more sense to decap/resize and then trim. What is the correct way and why?

Thanks,
Kevin

 

[JeepsAndGuns]

I always trim after I size and de-cap. I use the Lee case trimmer and a cordless drill. With the lee trimmer, the primer has to be removed. I really like my lee trimmers. Much easyer to use.

 

[Safeshot]

I also trim after resizing and de-caping. I also use Lee case trimmers, but in a drill press. It is easy, accurate, and very fast. I hold the case in a pair of pliers with leather padded jaws. Reformed cases for 7.7mm Japanese or 8mm Mauser from 30/06 cases can be "trimmed" to length in just a few seconds. If you experience "chatter" try a higher spindle speed on the drill press. Good luck in what ever method you decide to use.

 

[Calgacus]

In thepory yes, after resizing is the best time to trim the cases. It is just that there isn't a lot of difference, and not a lot wrong with doing it the other way.

Cases are much more likely to contract rather than expand in length, by firing alone. It is primarily forming them back to an easy fit in the chamber that lengthens them. But it generally takes a few firings to do this to a harmless extent, and doing it before the last of them does little harm.

Basically firing thins (and therefore increases the sheet area of) the cases even where they are thick. Sizing has to squash them back again, only partly by thickening the brass, and it does it where they are most sizeable, i.e where they are thinnest and most annealed. The part of that process which isn't thickening of the brass, turns into added neck length.

Not all cases are alike in what happens. An old-fashioned one, with a very tapered body and thin walls, has a powder chamber which tapers from head to shoulder. There is a pronounced tendency for the pressure on that slope to stretch the brass forward, producing thinning near the head. A modern case, nearly straight-bodied and with strongly tapered wall thickness, tapers internally from the shoulder rearward. The tendency is for brass to be squeezed rearward.

This has two useful effects. The modern case has less tendency to separate near the head. There is also less tendency for it to lengthen. Finally, precision reloaders such as benchresters load to quite high pressures, but have their chambers and reloading dies very nearly identical in size, and they resize the neck only enough to give a very light hold on the bullet. They often use very few cases for a long period with no trimming at all. Note, though, that someone who hunts with cartridges in his pocket couldn't risk either of these, for fear of shifting bullets (dangerous if it is inwards), or missing the shot of a lifetime because dirt prevents the cartridge from chambering.

There is one more advantage of trimming your cases with the primers removed. You can use very inexpensive trimming devices such as the Lee hand case length gauge and cutter, aligned by a pilot ending in a rod which protrudes through the flash-hole. Even by hand this devices is fast enough to do this occasional job for many rifle reloaders.

 

[JeepsAndGuns]

Well I can add a that I got some once fired 30-06 brass. I measured before I sized and they were under the max length. I then sent them through the full length sizer and they now measured above the max length. Thats why I always trim after I size.

 

[Ike27]

The process is to trim after you full length/neck size.

 

[jjk308 In Memoriam RIP]

After.
And don't forget annealing, especially if you reuse cases a few times.
And also remember that hot loads use up cases fast and that nobody is immune to the "brain farts" (my psychologist wife's term for momentary idiocy) that result in double stroking the powder measure and blowing up a gun. To compensate for the inevitable brain fart use a routine of inspection and also keep away from economical but dangerous small loads of fast burning powder.

 

[felonius]

I agree with jjk308 about the "light loads" and everyone on the trim after the size. When you start reloading, you should develope a rhythm after the cases have been initially processed.

1.Decap/size ALL brass for the given caliber.
2.Check OAL and check for any sign of case failure (neck cracks, unusual wear around head, damaged primer pocket ect.
3.Trim any oversized brass and debur/chamfer neck. I like to true up the primer pocket so they are all uniform. Prime brass. All like brass, all like results!
4. On powder dumping for rifles: I like to measure each one with a dig. scale ($25). visually inspect all and set a loose bullet on top as its checked. It takes a bit more time but it pays off. Increased accuracy and safety.
Pistols? Depends. On 45's and 9mm's I dump them all, visually inspect, dump out every tenth load onto your scale and check for serious jumps in weight (usually arent any) put loose bullet on top of tested rounds.

I get good results from this. Havent had a squib round or a double dump (didnt say "never had"-jinx!) with these precautions. Am I fast? Nope. Am I accurate? Yep. Is it relaxing? definately.
Do I know it all? No hell no. Just what I've learned from older loaders and my bibles (manuals). Alot of folks helped me with what I know- I owe it to them to help others when I can.

 

[Big commander]

I am fairly new to reloading. I have a question when it comes to case trimming. I notice a lot of people recommend that you trim cases before decapping and resizing.

If you notice that a lot of people recommend trimming before sizing ... you have a recommendation of a lot of people that don't have a clue what it's all about ... you always find them at the bar! Stay away from idiots! You ask "why?" ... well you need to have a "new" case ... you only have a "new" case when you trim at the end of the resizing, decapping and deburring procedure. Common sense is not given to everyone at birth, neither is some intelligence! You used your common sense in asking this question ... you are 100% right by expressing your doubt.

 

[panrobercik]

I don't see how I could trim with lee trimmer before decaping /resizing... Case length gauge goes through the primer hole.

 

[49204]

I've been reloading for a lot of years, and I generally use a depriming punch as the first step. Keeps primer grit off my press, and lets me handle the deprime and primer pocket cleaner before I use the case cleaner. After I deprime, and inspect brass, I trim to length. The little Lee trimmer works just fine, by hand or with a drill press.

Then I resize and use the trimmer again, to make sure the case mouth is square, and chamfer inside and out to break the edges....

 

[Big commander]

With all due respect Optimist, I don't understand why you trim twice, once before and once after resizing. I can understand that you "like" to do it but don't grasp the advantage it gives in doing so.
If you say that you're a "little bit too maniacal" in reloading ... that I can understand and this is certainly 100 times better than being a sloppy reloader (the kind I avoid when he is to close to me while shooting at the range).
If you would have an interesting reason ... please ... I learn everyday .

 

[49204]

Case can gain a thousandth or so when you full length size. I generally do that only on the first pass through after the brass is made up from .30-06 to 8x57 or 7x57, and after first firing. Should have made that a little plainer. Makes me sound like Mister Maniacal, the Obsessive Compulsive Reloader....

Have been told, though, that there is a strong resemblance...

 

[Lightning]

The Gentlemen are right

You cannot be to careful, in following safe practice, right powder, right charge, right primer, and good case prep. If you have no desire to put a potential grenade next to your face follow the long established procedures and heed these ole guys here and reloading will be a satisfying hobby.

 

[gunsgunsguns]

I've found that, for me, it depends on what I'm using to trim the cases. Using a Lee pilot shaft trimmer, I've had real sticky problems if I resize before trimming. I like the Lee, just screw it together and go, but have found the shaft tends to bind if you've sized the case. Haven't really found the cases to have stretched significantly after resizing.
Using RCBS or Lyman, haven't had much, if any binding, but they do require a little set up.