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bearchaser
09-11-2014, 06:01 PM
so tell me. What is the best mythod you all use to trim your brass?
hand trimmer or power? I have the lee trimmer,but sometimes it
isn't very good..The cases get different measurements? Thanks John)chill(

tzander
09-11-2014, 06:10 PM
I use a Wilson hand trimmer and it works very well. Tony

David Halblom
09-11-2014, 06:11 PM
so tell me. What is the best mythod you all use to trim your brass?
hand trimmer or power? I have the lee trimmer,but sometimes it
isn't very good..The cases get different measurements? Thanks John)chill(

case holder and a Wilson case trimmer, the gold standard of BR shooters. Never more than .0005 variance, normally, unmeasurable variance with the tools at hand at a match. Get the base, bolt it down and go to it.

Lee Martin
09-11-2014, 06:14 PM
A South Bend lathe. My hand trimmer is a Wilson and it too is tops.

-Lee
www.singleactions.com

Dusty Stevens
09-11-2014, 06:56 PM
PMA trimmer is the berries

abintx
09-11-2014, 11:43 PM
This is my powered trimmer. Easy to use. Great results, especially with the 3-way cutter, when properly adjusted. :)

http://www.youtube.com/watch?v=3lXo96H-h7k

r44astro
09-12-2014, 04:04 PM
PMA trimmer is the berries

I second that!

Carson
02-07-2015, 01:39 PM
PMA trimmer is the berries


Interesting concept of locating off of the cartridge shoulder.


Video link;

https://www.youtube.com/watch?v=L6JNeL8MDCc


Website link;

http://www.pmatool.com/case-trimmers-and-accessories/

Boyd Allen
02-07-2015, 01:49 PM
Just remember, when indexing off of case shoulders, for your overall lengths to be consistent, your shoulder to head measurements have to be consistent as well. Recently I have played with one of these, and find that is really slick to work with, and extremely well made. Just remember that It only takes a little pressure to complete the cut. https://www.youtube.com/watch?v=L6JNeL8MDCc
This is not to say that other tools do not do the job, just that this one is a real pleasure to adjust and use.

Carson
02-07-2015, 02:05 PM
Just remember, when indexing off of case shoulders, for your overall lengths to be consistent, your shoulder to head measurements have to be consistent as well. Recently I have played with one of these, and find that is really slick to work with, and extremely well made. Just remember that It only takes a little pressure to complete the cut. https://www.youtube.com/watch?v=L6JNeL8MDCc
This is not to say that other tools do not do the job, just that this one is a real pleasure to adjust and use.


It sort of shifts the importance of a proper length neck up to the distance between the neck face and shoulder where it should be. No?

If you trim a case with this method even if you show some variation in overall case length after, when the cases are fired they are going to be stretched out uniform when the pressure fills the case in the chamber.

I'm really liking this idea.

and sure your going to have to keep your mean overall case length in mind as that is where the specification is called out.

I think my only reservation at this point is I don't understand the design enough to know where the brass chips are ending up. Brass has a way of working its way into places and jamming up the works on other machine tools.


P.S. Oops. Now I see they should fall out the big cut-a-ways.

abintx
02-07-2015, 07:59 PM
It sort of shifts the importance of a proper length neck up to the distance between the neck face and shoulder where it should be. No?

If you trim a case with this method even if you show some variation in overall case length after, when the cases are fired they are going to be stretched out uniform when the pressure fills the case in the chamber.

I'm really liking this idea.

and sure your going to have to keep your mean overall case length in mind as that is where the specification is called out.

I think my only reservation at this point is I don't understand the design enough to know where the brass chips are ending up. Brass has a way of working its way into places and jamming up the works on other machine tools.


P.S. Oops. Now I see they should fall out the big cut-a-ways.

So why not just trim that way from the Start?

I see tools that index off of and trim from the shoulder as tools designed for Convenience and Less Expense and nothing more. They assume that the bottom 2/3rds or 3/4ths of the case remains identical [in its length dimension] to all the other cases for eternity. :)

Carson
02-07-2015, 10:09 PM
So why not just trim that way from the Start?

I see tools that index off of and trim from the shoulder as tools designed for Convenience and Less Expense and nothing more. They assume that the bottom 2/3rds or 3/4ths of the case remains identical [in its length dimension] to all the other cases for eternity. :)

Because I just ordered my new spiffy case neck trimmer? :)


Actually I thought I would give it a try.

I've seen a lot of variations in case length in my batch's over the years. If this cutter works like it looks like it will it should leave a more uniform neck length. Say I've trimmed and got a uniform neck length. Then I shoot one set of cases and they get stretched a little more on the overall case length. It seems like I might have a more accurate round if the short case expands to fill the chamber as it will stick the neck out just as far as the longer case.

It may just seem better in theory than actual practice but I thought I would give it a try.

Actually I've been wrestling with learning to manipulate my brass to keep it uniform. Not just with overall length. It's has been a struggle. That's one of the reasons I searched up this old thread.

The first time I fire-formed brass for a 6PPC I was worried about overall case neck length. I trimmed my cases before they had reached a good chamber fit, now I've got some that I have to trim short to match each other. Recently I measured the neck depth on a chamber gauge I got from my Gunsmith. It looks like I have plenty of room out front to hold off some till they settle.

Carson
02-08-2015, 03:44 PM
After turning the necks to desired thickness I check some for length and as long as they aren't too long for the chamber, I leave them alone. After you fire form in almost all cases they will have shortened over their total length. That is when I trim to length and I trim to OAL and not off the shoulder. And I trim to the length of the shortest one after checking the length of a number of the fire formed cases. They will over a few firings lengthen again and now trim to print OAL of chamber. I do all this trimming in a Forster hand cranked trimmer. I'm an old crank. So after all of that then trimming off the shoulder index should work. That's my opinion, which I value highly.


Forster is what I've used the most, and had the best luck with, so that makes at least two of us that value your opinion.

Uthink Uknow
02-08-2015, 05:27 PM
Well, that's a start, Carson. That's two of us. They still make them so we know we're right.

Dick Grosbier
02-08-2015, 10:53 PM
I'm an old crank. .................................... That's my opinion, which I value highly.

Two true statements
Dick
(another old crank)

JerrySharrett
02-09-2015, 05:33 AM
After turning the necks to desired thickness I check some for length and as long as they aren't too long for the chamber, I leave them alone. After you fire form in almost all cases they will have shortened over their total length. That is when I trim to length and I trim to OAL and not off the shoulder. And I trim to the length of the shortest one after checking the length of a number of the fire formed cases. They will over a few firings lengthen again and now trim to print OAL of chamber. I do all this trimming in a Forster hand cranked trimmer. I'm an old crank. So after all of that then trimming off the shoulder index should work. That's my opinion, which I value highly.

Speaking of cranks, I agree completely with Francis up to two points.

1) Cranks came before wheels and Francis came BEFORE cranks.

2) I use a cordless variable speed drill where he uses the crank on the Forester. Why waste good energy?

Yes Dick, this thing is getting cranky isn't it?

JerrySharrett
02-09-2015, 05:41 AM
From a safety and accuracy standpoint ;

1) If cases are too long they MIGHT cause a safety issue but if you look at bullet jam and extreme neck tension I don't believe you can close the bolt on a case that is overly long and could cause excessive pressure.

2) As to the accuracy thing, some top shooters trim after EVERY target, some trim in the evening, and some don't trim at all since some of those only use cases a few times....why? They are shooting extreme pressure loads.


Edit- as to case/chamber relationship, I'll wager most shooters who buy built guns, have someone else chamber their barrels, or in many instances shooters who do their own have no idea what their chamber OAL is nor do they know what their chamber neck diameter actually is!!

.

lesloan
02-10-2015, 11:05 AM
PMA trimmer is the berries

This looks very much like the WFT (stands for World's Finest Trimmer), which works in exactly the same way. I've used a WFT for the past year or so and have been very happy with it. Fast, accurate and easy on the hands, which is a real blessing if you have a big stack of cases to trim.

fx77
02-12-2015, 05:19 PM
Giraud Trimmer indexes off the shoulder, shortens the neck, and champfers inside and outside in one pass...efficient

http://www.giraudtool.com/prod02.htm

BFoster
02-15-2015, 08:24 AM
Carsan

Me too. I've been using the same Forester "Original" case trimmer since 1968 and still like better than others I've tried. I just have several different cutter/handle assy's for different calipers. I just remove the the ring so in can slide the cutter assy out.

Ben

Carson
02-16-2015, 05:18 PM
I gave my new shiny PMA Case Trimmer a work out today.

The video and instructions show two ways to use it. If you have a Hardinge Turret Lathe laying around or know someone who does here is one more way.

First I bored a collet and then center a floating tool holder with a .375 piece of stock. I got my depth adjusted using the trimmer by hand, then I remove the adjustment knob and held it in the floating holder.

http://photos.imageevent.com/stokeybob/evenmorestuff/DSC06517sw.jpg

It ran pretty fast (slow RPM's), not that, that was really the point of the exercise. I completed 185 cases starting with the longest and moving in the cutter till each case set row glistened showing they had been trimmed.

Later I chamfered inside and out and lightly spun the case face on some steel wool.

It's been a long time since I trimmed any cases. Pretty satisfying seeing them looking all uniform the way they do.


Kind of trippy the way the little viewing port can be out of line where you can't see anything through it at first, then as soon as the cutter touches the case and starts to spin you can see through that whole area...

like magic.

feffer
02-17-2015, 01:38 AM
Concerning the length to trim to... At least for factory barrels, I've heard .01" shorter than SAAMI spec. So for a case with a spec of 1.750" one would trim to 1.740" and not re-trim until they began to exceed 1.745" Is that reasonable?

I've also followed this for my custom chambers, but in that case, I know the reamer spec or measure from a chamber cast.
Again, is .01" shorter reasonable?

It was mentioned that cases generally shrink after fire-forming. So if a PPC chamber is reamed to accept a maximum case length of 1.515" then they can be fire-formed first and then trimmed...correct? Maybe to something like, 1.500"?

Dusty Stevens
02-18-2015, 12:47 PM
Like wilbur said shorter is better than too long. Doesnt really matter as long as its shorter just dont let it get too long!