In all my reloading books they give the case length as .850 for the .40 S&W. I assume that is the MAXimum length, because I have lots of cases that are a bit shorter than that?

Once I do finally need to trim some cases, what is the best method for doing so? I see lots of trimmer, but I don't have a clue which are the better ones to use. Also how do the trimmers know how much to trim, or do you take some off and then measure again and keep doing it till it is right? Seems like that would be very time consuming.

Wes

For all rotary or 'lathe' type trimmers, it is just guess and check until you get the right length.
Time consuming but foolproof once it is set up.

If you don't have 1000's of cases and multiple calibers to do, they are sort of an unnecessary investment.

I would recommend the Lee system which is already calibrated to trim to the maximum length.

http://www.cliffsgunsmithing.com/Catalog_Lee_CT.htm

Cheap to get set up and from what I have heard from my customers accurate and consistent.

If you want to speed things up, you can buy the Lee Zip-Trim.
It is like the cord you pull to start your lawnmower and it spins the case for lightning quick trimming.
I don't think it is on the website, but I also stock it.

-Spencer

I don`t load .40s but, if they are like 45acp and other straight walled pistol rounds I`ve loaded for they will wear out or be lost in the grass before they need trimming. I`d wait until I needed the trimer before purchasing one unless you need it for other cartridges.
When your ready for one, I use the RCBS lathe type trimmer and am happy with it. The Lee trimmer that fits in a cordless drill is a easy fast low cost alternitive that a lot of people use and swear by.

Straight-walled pistol cases tend to grow in length very slowly. And if you don't over crimp the case mouth they won't develop cracks either.

Have you seen just how dirt cheap 40 S&W once-fired brass is on ebay? I wouldn't waste my time trimming. Throw it into the recycle bin and buy some more.

Thanks for the answers guys. I am only reloading for my pistol currently, but will be doing more rifle and pistol rounds in the future. So am I right in thinkining that the .850 length is the MAXIMUM length, so shorter is fine?

Wes

If you are going for accuracy, the cases need to be trimmed to the same length, and mouths square. Set your trimmer up for whatever length you feel is right, trash any that are too short, and trim/square the rest. For just plinking, however, as said above, it's hardly worth the effort.

quote:

so shorter is fine?

NO. Rimless semi-auto pistol cases headspace off the case mouth. Keep them between the minimum "trim to" length and the max cartridge length.

quote:

Originally posted by WesN:
Once I do finally need to trim some cases, what is the best method for doing so? I see lots of trimmer, but I don't have a clue which are the better ones to use. Also how do the trimmers know how much to trim, or do you take some off and then measure again and keep doing it till it is right? Seems like that would be very time consuming. ...Wes

Hey Wes, All valid questions.

There are more expensive methods(aka Lathe Style Trimmers), but the Lee Case Length Gauge / Trimmer is simply an excellent tool. You can not trim them too short, and unlike the Lathe Trimmers, when you use the Lee they all end up the same length.

Go to a Gun Shop and look at one in your hands. Once you see it up close, it is obvious how it works and there is no adjustment.

I also like the fact I can carry the Lee into where the TV is located, place a trash can between my feet and trim cases without brass shavings going all over the place. Then a quick chamfer, a deburr, clean the primer pocket and I'm done on a pistol/revolver case.

If you have a lot to trim, you can put the Lee tool in a drill and go quicker, but don't go too fast or you can remove the Tempe rfrom the Hardened Cutter.

I guess I am confused then. I don't have any of my reloading manuals handy at work, but I thought there was a listing in it for CASE length which was .850 and then there was a range given for the overall cartridge length which is like 1.085-1.150. There is no range given that I recall for the trim-to length which would just be the case length I would think.

Wes

Trim to length is .840"

quote:

Originally posted by WesN:
listing in it for CASE length which was .850 and then there was a range given for the overall cartridge length which is like 1.085-1.150.

Wes

The case length listed in the manuals is a "not to exceed" length and the trim length is up to you. Normally, the trim length is .005" to .010" less than the case length in the manuals.

The overall length is also a decision that you make and I don't know where the manuals actually come up with that other than factory standards which have to fit in all guns. Normally, you need to find out at what length your seated bullet will first contact the lands in your gun and back off whatever amount you deem appropriate. If you seat the bullet into the lands there will be a spike in pressure because the bullet can't get a running start upon ignition. Too far back and accuracy might suffer. Some bullets in some guns like to be seated as close as .01" from the lands and other bullets like Barnes X bullets are recommended by the manufacturer to be seated .05" back.

Magazine length and type of action on your gun also needs to be considered. The loaded bullets need to fit in the magazine and the gun needs to cycle smoothly.


Without guns we are subjects, with guns we are citizens

Thanks woods. Now if I only knew what the lands was. I will have to do some more reading I reckon.

Wes

Just noticed that you are loading for a rimless pistol cartridge. My experience is with rifle calibers and may not be applicable to your situation. Please use the info in my previous post as pertaining to bolt action rifle reloading.

The lands of the rifle are also called the "rifling" in the barrel. They are what grabs the bullet and makes it spin as it travels through the barrel. Another term that is going to come up is "ogive". That is the place on the bullet (closest to the point) where it first reaches full diameter. The ogive-to-lands gap is called bullet jump and is what we are talking about when we say seat it back .01" - .05". Best measured by a gauge

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=570611

with comparators to match your caliber

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=231904

All of this may be useless for your auto pistol though


Without guns we are subjects, with guns we are citizens

I will be loading for rifle as well, I just only have the stuff for my pistols currently.

Wes