Case Trimming

[Davidm]

This may be a stupid question but how do you guys trim your brass for the big bore calibers?
For my smaller calibers I use a Lyman accutrimmer and yes for my 458 lott I do have a 458 pilot but I have yet to use it on the lott cases since I had about 100 new cases and I haven't reloaded all of them yet. So I don't know how much they will stretch when I put them true the dies.

 

[Ray B]

I have used RCBS & Forster trimmers, but for the last few years I've been using CH and LE Wilson. The theory is different since you stabilize the case in a sleeve, case base against a bolthead then the trimmer blade cuts evenly and exactly just the amount of metal desired.

 

[Dr Ray]

This may be a stupid question but how do you guys trim your brass for the big bore calibers?
For my smaller calibers I use a Lyman accutrimmer and yes for my 458 lott I do have a 458 pilot but I have yet to use it on the lott cases since I had about 100 new cases and I haven't reloaded all of them yet. So I don't know how much they will stretch when I put them true the dies.

Measure the base both vote and after firing to see what the expansion was. Measure the length of the cases before and after. Check with manufacturer what the maximum length should be and trim as necessary. Watch for bright "ring" near base as you are working up loads.
It's important you do trim as one day you'll have an issue with very high pressure and possibly a stuck Case when you least need it.
Only way to know how much cases expand or stretch is to measure the new cases.
The maximum length of the case should be 2.8 inches or a tad over 71mm.
Also suggest you measure the rims before and after firing too as these are inductive of high pressure.
The Lott operates at a fairly high 62500 lbs pressure so expect the cases to expand.

 

[GuttormG]

Big fan of the Lee case trimmer; fast,easy, no adjustments to fiddle with. Nothing fancy, it just does trim each case to the correct length.

http://leeprecision.com/case-conditioning-tools/case-trimming-tools/


Trimming after sizing

 

[Dr Ray]

Meant to write before and after
Not vote ..
Problem with fat thumb and predictive text.

 

[Shootist43]

I'm just getting ready to start reloading for larger caliber rifles. I have an old Lyman hand crank trimmer and was planning to use it when necessary. I also use Lee Case Gauges to insure the headspace is correct. I see that they have some gauges for 458 Caliber but that they will make a custom case gauge for any caliber. Check out this link if you are interested http://leeprecision.com/case-conditioning-tools/case-trimming-tools/case-length-gauge-holder

 

[GuttormG]

hmm, not sure why I ended with that picture; I am using the old type, a special shellholder and combined cutter and gauge; costs like nothing.

 

[Desert Dog]

An old-school Forster hand trimmer is what I use for big bores. The chuck on it gives the best consistency of any of the hand trimmers out there.

For doing big lots of smaller calibers, I use my Franklin Arsenal Case prep machine.

https://ads.midwayusa.com/product/6...nal-_-628405&gclid=CKXrq4mF3NQCFQiqaQod8o8IYg

 

[alby]

Hi all,
Fairly new to big bore reloading. I use a hand held Hornady de-burring tool to trim my .400 Jeffery and .375 H&H al little time consuming and cuddly to ensure case mouth is trimmed straight.
Does anybody see any issues doing it this way?
Cheers Alby

 

[lwaters]

I use an old pacific hand crank trimmer for my 375 ruger. I just use a new case to set the length.

 

[Desert Dog]

Hi all,
Fairly new to big bore reloading. I use a hand held Hornady de-burring tool to trim my .400 Jeffery and .375 H&H al little time consuming and cuddly to ensure case mouth is trimmed straight.
Does anybody see any issues doing it this way?
Cheers Alby

A deburring/chamfering tool is definitely not ideal or recommended for trimming brass. It will never be straight, will cause MUCH too sharp of an angle on the lip, and could take forever. Trimming to uniform length is such an important step in the reloading process (for accuracy and safety), that I would never consider doing it with a deburring tool. After a FL resize, my hunting ammo always goes through the trimmer.

Most of the big-bore small-batch loaders I know use the Forster Classic trimmer.

 

[lwaters]

I had a file trim die for a 270. You just screwed it in the press and filed of the excess. Then use the deburring tool to clean up inside the neck.

 

[Ray B]

Years ago I used the deburring tool to shorten case necks. A couple reasons why it worked were: I only had a couple boxes of cases; and I didn't shoot any of them enough that they became appreciably lengthened. For reasons stated above, I obtained an actual case trimmer to accomplish the job.

 

[alby]

Thanks Desert Dog,
I'll check out the Forster.
Alby.

 

[sandman0921]

Desert Dog,

I use the same (Forster) for my 404 Jeffery, 450 Rigby, and 450 NE 3 1/4 inch. I have contemplated getting Wilson Case Holders made for my Wilson case trimmer, but haven't seen the need to change.

alby,

If you go with the Forster, be sure to get the Forster Classic Trimmer. As far as I remember they have pilots for every caliber up to .500. Not sure about beyond that (.510, .577, .600).....

 

[BobT]

I have been using a Lyman trimmer for years, I just got a Wilson set up and I like it much better than the Lyman.

 

[8x68]

I use an old pacific hand crank trimmer for my 375 ruger. I just use a new case to set the length.

Same here. Mine is an old Horandy/Pacific hand crank case trimmer. I use a set of dial calipers to measure case length.

 

[ZG47]

I don't do big bore reloading but I can state that using a separate neck expansion die as opposed to the expander button on a full length sizing die reduces the need for trimming. You either remove the expander button completely or in the case of a headed decapping pin, such as on a Hornady Zip spindle, replace it with a smaller button.

 

[Bob Nelson 35Whelen]

Big fan of the Lee case trimmer; fast,easy, no adjustments to fiddle with. Nothing fancy, it just does trim each case to the correct length.

http://leeprecision.com/case-conditioning-tools/case-trimming-tools/


Trimming after sizing

View attachment 192076

@GuttormG
I use the even simpler Lee case length trimmer. Yes they are caliber specific but very quick and easy. Screw case length gauge into trimmer pilot insert into case and trim.
Bob

 

[Bob Nelson 35Whelen]

I'm just getting ready to start reloading for larger caliber rifles. I have an old Lyman hand crank trimmer and was planning to use it when necessary. I also use Lee Case Gauges to insure the headspace is correct. I see that they have some gauges for 458 Caliber but that they will make a custom case gauge for any caliber. Check out this link if you are interested http://leeprecision.com/case-conditioning-tools/case-trimming-tools/case-length-gauge-holder

@Shootist43
Art I had Lee make the FLS, seating and crimping dies for my 25. While the were at it they did the case trim pilot free of charge for me. Great service and great products at reasonable cost. 99% of my reloading gear is Lee.
Bob